UPDATE: Webapp

base/src/user_model/common.rs

@@ -205,6 +205,16 @@ impl UserModel {
         self.model.to_bytes()
     }
 
+    /// Returns the workbook name
+    pub fn get_name(&self) -> String {
+        self.model.workbook.name.clone()
+    }
+
+    /// Sets the name of a workbook
+    pub fn set_name(&mut self, name: &str) {
+        self.model.workbook.name = name.to_string();
+    }
+
     /// Undoes last change if any, places the change in the redo list and evaluates the model if needed
     ///
     /// See also:

bindings/wasm/src/lib.rs

@@ -37,8 +37,8 @@ pub struct Model {
 #[wasm_bindgen]
 impl Model {
     #[wasm_bindgen(constructor)]
-    pub fn new(locale: &str, timezone: &str) -> Result<Model, JsError> {
+    pub fn new(name: &str, locale: &str, timezone: &str) -> Result<Model, JsError> {
-        let model = BaseModel::new_empty("workbook", locale, timezone).map_err(to_js_error)?;
+        let model = BaseModel::new_empty(name, locale, timezone).map_err(to_js_error)?;
         Ok(Model { model })
     }
 
@@ -482,4 +482,19 @@ impl Model {
             .map_err(|e| to_js_error(e.to_string()))?;
         Ok(())
     }
+
+    #[wasm_bindgen(js_name = "toBytes")]
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.model.to_bytes()
+    }
+
+    #[wasm_bindgen(js_name = "getName")]
+    pub fn get_name(&self) -> String {
+        self.model.get_name()
+    }
+
+    #[wasm_bindgen(js_name = "setName")]
+    pub fn set_name(&mut self, name: &str) {
+        self.model.set_name(name);
+    }
 }

webapp/src/App.css

@@ -1,6 +1,6 @@
 #root {
   position: absolute;
-  inset: 10px;
+  inset: 0px;
-  border: 1px solid #aaa;
+  margin: 0px;
-  border-radius: 4px;
+  border: none;
 }

webapp/src/App.tsx

@@ -4,6 +4,14 @@ import "./i18n";
 import styled from "@emotion/styled";
 import init, { Model } from "@ironcalc/wasm";
 import { useEffect, useState } from "react";
+import { FileBar } from "./AppComponents/FileBar";
+import {
+  createNewModel,
+  loadModelFromStorageOrCreate,
+  saveModelToStorage,
+  saveSelectedModelInStorage,
+  selectModelFromStorage,
+} from "./AppComponents/storage";
 import { WorkbookState } from "./components/workbookState";
 
 function App() {
@@ -11,25 +19,31 @@ function App() {
   const [workbookState, setWorkbookState] = useState<WorkbookState | null>(
     null,
   );
+
   useEffect(() => {
     async function start() {
       await init();
       const queryString = window.location.search;
       const urlParams = new URLSearchParams(queryString);
-      const modelName = urlParams.get("model");
+      const modelHash = urlParams.get("model");
-      // If there is a model name ?model=example.ic we try to load it
+      // If there is a model name ?model=modelHash we try to load it
       // if there is not, or the loading failed we load an empty model
-      if (modelName) {
+      if (modelHash) {
+        // Get a remote model
         try {
           const model_bytes = new Uint8Array(
-            await (await fetch(`./${modelName}`)).arrayBuffer(),
+            await (await fetch(`/api/model/${modelHash}`)).arrayBuffer(),
           );
-          setModel(Model.from_bytes(model_bytes));
+          const importedModel = Model.from_bytes(model_bytes);
+          localStorage.removeItem("selected");
+          setModel(importedModel);
         } catch (e) {
-          setModel(new Model("en", "UTC"));
+          alert("Model not found, or failed to load");
         }
       } else {
-        setModel(new Model("en", "UTC"));
+        // try to load from local storage
+        const newModel = loadModelFromStorageOrCreate();
+        setModel(newModel);
       }
       setWorkbookState(new WorkbookState());
     }
@@ -40,10 +54,52 @@ function App() {
     return <Loading>Loading</Loading>;
   }
 
+  // We try to save the model every second
+  setInterval(() => {
+    const queue = model.flushSendQueue();
+    if (queue.length !== 1) {
+      saveSelectedModelInStorage(model);
+    }
+  }, 1000);
+
   // We could use context for model, but the problem is that it should initialized to null.
   // Passing the property down makes sure it is always defined.
-  return <Workbook model={model} workbookState={workbookState} />;
+
+  return (
+    <Wrapper>
+      <FileBar
+        model={model}
+        onModelUpload={async (blob) => {
+          const bytes = new Uint8Array(await blob.arrayBuffer());
+          const newModel = Model.from_bytes(bytes);
+          saveModelToStorage(newModel);
+
+          setModel(newModel);
+        }}
+        newModel={() => {
+          setModel(createNewModel());
+        }}
+        setModel={(uuid: string) => {
+          const newModel = selectModelFromStorage(uuid);
+          if (newModel) {
+            setModel(newModel);
           }
+        }}
+      />
+      <Workbook model={model} workbookState={workbookState} />
+    </Wrapper>
+  );
+}
+
+const Wrapper = styled("div")`
+  margin: 0px;
+  padding: 0px;
+  width: 100%;
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  position: absolute;
+`;
 
 const Loading = styled("div")`
   height: 100%;

webapp/src/AppComponents/FileBar.tsx

@@ -0,0 +1,108 @@
+import styled from "@emotion/styled";
+import type { Model } from "@ironcalc/wasm";
+import { IronCalcLogo } from "./../icons";
+import { FileMenu } from "./FileMenu";
+import { ShareButton } from "./ShareButton";
+import { WorkbookTitle } from "./WorkbookTitle";
+import { updateNameSelectedWorkbook } from "./storage";
+
+export function FileBar(properties: {
+  model: Model;
+  newModel: () => void;
+  setModel: (key: string) => void;
+  onModelUpload: (blob: Blob) => void;
+}) {
+  return (
+    <FileBarWrapper>
+      <IronCalcLogo style={{ width: "120px", marginLeft: "10px" }} />
+      <Divider />
+      <FileMenu
+        newModel={properties.newModel}
+        setModel={properties.setModel}
+        onModelUpload={properties.onModelUpload}
+        onDownload={() => {
+          const model = properties.model;
+          const arrayBuffer = model.toBytes();
+          const fileName = model.getName();
+          fetch("/api/download", {
+            method: "POST",
+            headers: {
+              "Content-Type": "application/octet-stream",
+              "Content-Disposition": `attachment; filename="${fileName}"`,
+            },
+            body: arrayBuffer,
+          })
+            .then((response) => {
+              if (!response.ok) throw new Error("Network response was not ok");
+              return response.blob();
+            })
+            .then((blob) => {
+              // Create a link element and trigger a download
+              const url = window.URL.createObjectURL(blob);
+              const a = document.createElement("a");
+              a.style.display = "none";
+              a.href = url;
+
+              // Use the same filename or change as needed
+              a.download = `${fileName}.xlsx`;
+              document.body.appendChild(a);
+              a.click();
+
+              // Clean up
+              window.URL.revokeObjectURL(url);
+              a.remove();
+            })
+            .catch((error) => {
+              console.error("Error:", error);
+            });
+        }}
+      />
+      <WorkbookTitle
+        name={properties.model.getName()}
+        onNameChange={(name) => {
+          properties.model.setName(name);
+          updateNameSelectedWorkbook(properties.model, name);
+        }}
+      />
+      <ShareButton
+        onClick={() => {
+          const model = properties.model;
+          const arrayBuffer = model.toBytes();
+          const fileName = model.getName();
+          fetch("/api/share", {
+            method: "POST",
+            headers: {
+              "Content-Type": "application/octet-stream",
+              "Content-Disposition": `attachment; filename="${fileName}"`,
+            },
+            body: arrayBuffer,
+          })
+            .then((response) => {
+              if (!response.ok) throw new Error("Network response was not ok");
+              return response.text();
+            })
+            .then((hash) => {
+              console.log(hash);
+            });
+        }}
+      />
+    </FileBarWrapper>
+  );
+}
+
+const Divider = styled("div")`
+  margin: 10px;
+  height: 12px;
+  border-left: 1px solid #e0e0e0;
+`;
+
+const FileBarWrapper = styled("div")`
+  height: 60px;
+  width: 100%;
+  background: "#FFF";
+  display: flex;
+  line-height: 60px;
+  align-items: center;
+  border-bottom: 1px solid grey;
+  position: relative;
+`;

webapp/src/AppComponents/FileMenu.tsx

@@ -0,0 +1,120 @@
+import styled from "@emotion/styled";
+import { Menu, MenuItem, Modal } from "@mui/material";
+import { useRef, useState } from "react";
+import { UploadFileDialog } from "./UploadFileDialog";
+import { getModelsMetadata, getSelectedUuuid } from "./storage";
+
+export function FileMenu(props: {
+  newModel: () => void;
+  setModel: (key: string) => void;
+  onDownload: () => void;
+  onModelUpload: (blob: Blob) => void;
+}) {
+  const [isMenuOpen, setMenuOpen] = useState(false);
+  const [isImportMenuOpen, setImportMenuOpen] = useState(false);
+  const anchorElement = useRef<HTMLDivElement>(null);
+  const models = getModelsMetadata();
+  const uuids = Object.keys(models);
+  const selectedUuid = getSelectedUuuid();
+
+  const elements = [];
+  for (const uuid of uuids) {
+    elements.push(
+      <MenuItemWrapper
+        key={uuid}
+        onClick={() => {
+          props.setModel(uuid);
+          setMenuOpen(false);
+        }}
+        style={{ justifyContent: "flex-start" }}
+      >
+        <span style={{ width: "20px" }}>
+          {uuid === selectedUuid ? "•" : ""}
+        </span>
+        <MenuItemText>{models[uuid]}</MenuItemText>
+      </MenuItemWrapper>,
+    );
+  }
+
+  return (
+    <>
+      <FileMenuWrapper
+        onClick={(): void => setMenuOpen(true)}
+        ref={anchorElement}
+      >
+        File
+      </FileMenuWrapper>
+      <Menu
+        open={isMenuOpen}
+        onClose={(): void => setMenuOpen(false)}
+        anchorEl={anchorElement.current}
+        // anchorOrigin={properties.anchorOrigin}
+      >
+        <MenuItemWrapper onClick={props.newModel}>
+          <MenuItemText>New</MenuItemText>
+        </MenuItemWrapper>
+        <MenuItemWrapper
+          onClick={() => {
+            setImportMenuOpen(true);
+            setMenuOpen(false);
+          }}
+        >
+          <MenuItemText>Import</MenuItemText>
+        </MenuItemWrapper>
+        <MenuItemWrapper>
+          <MenuItemText onClick={props.onDownload}>
+            Download (.xlsx)
+          </MenuItemText>
+        </MenuItemWrapper>
+        <MenuDivider />
+        {elements}
+      </Menu>
+      <Modal
+        open={isImportMenuOpen}
+        onClose={() => {
+          setImportMenuOpen(false);
+        }}
+        aria-labelledby="modal-modal-title"
+        aria-describedby="modal-modal-description"
+      >
+        <>
+          <UploadFileDialog
+            onClose={() => setImportMenuOpen(false)}
+            onModelUpload={props.onModelUpload}
+          />
+        </>
+      </Modal>
+    </>
+  );
+}
+
+const MenuDivider = styled("div")`
+  width: 80%;
+  margin: auto;
+  border-top: 1px solid #e0e0e0;
+`;
+
+const MenuItemText = styled("div")`
+  color: #000;
+`;
+
+const MenuItemWrapper = styled(MenuItem)`
+  display: flex;
+  justify-content: space-between;
+  font-size: 14px;
+  width: 100%;
+`;
+
+const FileMenuWrapper = styled("div")`
+  display: flex;
+  align-items: center;
+  font-size: 12px;
+  font-family: Inter;
+  padding: 10px;
+  height: 20px;
+  border-radius: 4px;
+  margin: 10px;
+  &:hover {
+    background-color: #f2f2f2;
+  }
+`;

webapp/src/AppComponents/ShareButton.tsx

@@ -0,0 +1,28 @@
+import { Share2 } from "lucide-react";
+
+export function ShareButton(properties: { onClick: () => void }) {
+  const { onClick } = properties;
+  return (
+    <div
+      onClick={onClick}
+      onKeyDown={() => {}}
+      style={{
+        position: "absolute",
+        right: "0px",
+        cursor: "pointer",
+        color: "#FFFFFF",
+        background: "#F2994A",
+        padding: "0px 10px",
+        height: "36px",
+        lineHeight: "36px",
+        borderRadius: "4px",
+        marginRight: "10px",
+        display: "flex",
+        alignItems: "center",
+      }}
+    >
+      <Share2 style={{ width: "16px", height: "16px", marginRight: "10px" }} />
+      <span>Share</span>
+    </div>
+  );
+}

webapp/src/AppComponents/UploadFileDialog.tsx

@@ -0,0 +1,263 @@
+import styled from "@emotion/styled";
+import { BookOpen, FileUp } from "lucide-react";
+import { type DragEvent, useRef, useState } from "react";
+
+export function UploadFileDialog(properties: {
+  onClose: () => void;
+  onModelUpload: (blob: Blob) => void;
+}) {
+  const [hover, setHover] = useState(false);
+  const [message, setMessage] = useState("Drop file here");
+  const fileInputRef = useRef<HTMLInputElement>(null);
+
+  const { onClose, onModelUpload } = properties;
+  const handleDragEnter = (event: DragEvent<HTMLDivElement>) => {
+    event.preventDefault();
+    event.stopPropagation();
+    console.log("Enter");
+    setHover(true);
+  };
+
+  const handleDragOver = (event: DragEvent<HTMLDivElement>) => {
+    event.preventDefault();
+    event.stopPropagation();
+    event.dataTransfer.dropEffect = "copy";
+    // setHover(true);
+  };
+
+  const handleDragLeave = (event: DragEvent<HTMLDivElement>) => {
+    event.preventDefault();
+    event.stopPropagation();
+    console.log("Leave");
+    setHover(false);
+  };
+
+  const handleDrop = (event: DragEvent<HTMLDivElement>) => {
+    event.preventDefault();
+    event.stopPropagation();
+    console.log("Dropping");
+
+    const dt = event.dataTransfer;
+    const items = dt.items;
+
+    if (items) {
+      // Use DataTransferItemList to access the file(s)
+      for (let i = 0; i < items.length; i++) {
+        // If dropped items aren't files, skip them
+        if (items[i].kind === "file") {
+          const file = items[i].getAsFile();
+          if (file) {
+            handleFileUpload(file);
+          }
+        }
+      }
+    } else {
+      const files = dt.files;
+      for (let i = 0; i < files.length; i++) {
+        handleFileUpload(files[i]);
+      }
+    }
+  };
+
+  const handleFileUpload = (file: File) => {
+    setMessage(`Uploading ${file.name}...`);
+
+    // Read the file as ArrayBuffer
+    const reader = new FileReader();
+    reader.onload = () => {
+      const arrayBuffer = reader.result;
+
+      // Fetch request to upload the file
+      fetch("/api/upload", {
+        method: "POST",
+        headers: {
+          "Content-Type": "application/octet-stream",
+          "Content-Disposition": `attachment; filename="${file.name}"`,
+        },
+        body: arrayBuffer,
+      })
+        .then((response) => {
+          if (!response.ok) throw new Error("Network response was not ok");
+          return response.blob();
+        })
+        .then((blob) => {
+          setMessage(`File ${file.name} uploaded successfully!`);
+          onModelUpload(blob);
+        })
+        .catch((error) => {
+          setMessage(`Error uploading file: ${error.message}`);
+        });
+    };
+    reader.readAsArrayBuffer(file);
+  };
+  return (
+    <UploadDialog>
+      <UploadTitle>
+        <span style={{ flexGrow: 2, marginLeft: 12 }}>Import a .xlsx File</span>
+        <Cross
+          style={{ marginRight: 12 }}
+          onClick={onClose}
+          onKeyDown={() => {}}
+        >
+          <svg
+            width="16"
+            height="16"
+            viewBox="0 0 16 16"
+            fill="none"
+            xmlns="http://www.w3.org/2000/svg"
+          >
+            <title>Close</title>
+            <path
+              d="M12 4.5L4 12.5"
+              stroke="#333333"
+              strokeLinecap="round"
+              strokeLinejoin="round"
+            />
+            <path
+              d="M4 4.5L12 12.5"
+              stroke="#333333"
+              strokeLinecap="round"
+              strokeLinejoin="round"
+            />
+          </svg>
+        </Cross>
+      </UploadTitle>
+      <DropZone
+        onDragEnter={handleDragEnter}
+        onDragOver={handleDragOver}
+        // onDragLeave={handleDragLeave}
+        onDragExit={handleDragLeave}
+        onDrop={handleDrop}
+      >
+        {!hover ? (
+          <>
+            <div style={{ flexGrow: 2 }} />
+            <div>
+              <FileUp
+                style={{
+                  width: 16,
+                  color: "#EFAA6D",
+                  backgroundColor: "#F2994A1A",
+                  padding: "2px 4px",
+                  borderRadius: 4,
+                }}
+              />
+            </div>
+            <div style={{ fontSize: 12 }}>
+              <span style={{ color: "#333333" }}>
+                Drag and drop a file here or{" "}
+              </span>
+              <input
+                ref={fileInputRef}
+                type="file"
+                multiple
+                accept="*"
+                style={{ display: "none" }}
+                onChange={(event) => {
+                  const files = event.target.files;
+                  if (files) {
+                    for (const file of files) {
+                      handleFileUpload(file);
+                    }
+                  }
+                }}
+              />
+              <DocLink
+                onClick={() => {
+                  if (fileInputRef.current) {
+                    fileInputRef.current.click();
+                  }
+                }}
+              >
+                click to browse
+              </DocLink>
+            </div>
+            <div style={{ flexGrow: 2 }} />
+          </>
+        ) : (
+          <>
+            <div style={{ flexGrow: 2 }} />
+            <div>Drop file here</div>
+            <div style={{ flexGrow: 2 }} />
+          </>
+        )}
+      </DropZone>
+
+      <UploadFooter>
+        <BookOpen
+          style={{ width: 16, height: 16, marginLeft: 12, marginRight: 8 }}
+        />
+        <span>Learn more about importing files into IronCalc</span>
+      </UploadFooter>
+    </UploadDialog>
+  );
+}
+
+const Cross = styled("div")`
+  &:hover {
+    background-color: #f5f5f5;
+  }
+  border-radius: 4px;
+  height: 16px;
+  width: 16px;
+`;
+
+const DocLink = styled("span")`
+  color: #f2994a;
+  text-decoration: underline;
+`;
+
+const UploadFooter = styled("div")`
+  height: 40px;
+  border-top: 1px solid #e0e0e0;
+  font-size: 12px;
+  font-weight: 400;
+  color: #757575;
+  display: flex;
+  align-items: center;
+`;
+
+const UploadTitle = styled("div")`
+  display: flex;
+  align-items: center;
+  border-bottom: 1px solid #e0e0e0;
+  height: 40px;
+  font-size: 14px;
+  font-weight: 500;
+`;
+
+const UploadDialog = styled("div")`
+  display: flex;
+  flex-direction: column;
+  position: absolute;
+  left: 50%;
+  top: 50%;
+  transform: translate(-50%, -50%);
+  width: 455px;
+  height: 285px;
+  background: #fff;
+  border: 1px solid #e0e0e0;
+  border-radius: 8px;
+  box-shadow: 0px 1px 3px 0px #0000001a;
+  font-family: Inter;
+`;
+
+const DropZone = styled("div")`
+  flex-grow: 2;
+  border-radius: 10px;
+  text-align: center;
+  margin: 12px;
+  color: #aaa;
+  font-family: Arial, sans-serif;
+  cursor: pointer;
+  background-color: #faebd7;
+  border: 1px dashed #f2994a;
+  background: linear-gradient(
+    180deg,
+    rgba(242, 153, 74, 0.08) 0%,
+    rgba(242, 153, 74, 0) 100%
+  );
+  display: flex;
+  flex-direction: column;
+  vertical-align: center;
+`;

webapp/src/AppComponents/WorkbookTitle.tsx

@@ -0,0 +1,100 @@
+import styled from "@emotion/styled";
+import { type ChangeEvent, useEffect, useRef, useState } from "react";
+
+export function WorkbookTitle(props: {
+  name: string;
+  onNameChange: (name: string) => void;
+}) {
+  const [width, setWidth] = useState(0);
+  const [value, setValue] = useState(props.name);
+  const mirrorDivRef = useRef<HTMLDivElement>(null);
+
+  const handleChange = (event: ChangeEvent<HTMLTextAreaElement>) => {
+    setValue(event.target.value);
+    if (mirrorDivRef.current) {
+      setWidth(mirrorDivRef.current.scrollWidth);
+    }
+  };
+
+  useEffect(() => {
+    if (mirrorDivRef.current) {
+      setWidth(mirrorDivRef.current.scrollWidth);
+    }
+  }, []);
+
+  useEffect(() => {
+    setValue(props.name);
+  }, [props.name]);
+
+  return (
+    <div
+      style={{
+        position: "absolute",
+        left: "50%",
+        textAlign: "center",
+        transform: "translateX(-50%)",
+        // height: "60px",
+        // lineHeight: "60px",
+        padding: "8px",
+        fontSize: "14px",
+        fontWeight: "700",
+        fontFamily: "Inter",
+        width,
+      }}
+    >
+      <TitleWrapper
+        value={value}
+        rows={1}
+        onChange={handleChange}
+        onBlur={(event) => {
+          props.onNameChange(event.target.value);
+        }}
+        style={{ width: width }}
+        spellCheck="false"
+      >
+        {value}
+      </TitleWrapper>
+      <div
+        ref={mirrorDivRef}
+        style={{
+          position: "absolute",
+          top: "-9999px",
+          left: "-9999px",
+          whiteSpace: "pre-wrap",
+          textWrap: "nowrap",
+          visibility: "hidden",
+          fontFamily: "inherit",
+          fontSize: "inherit",
+          lineHeight: "inherit",
+          padding: "inherit",
+          border: "inherit",
+        }}
+      >
+        {value}
+      </div>
+    </div>
+  );
+}
+
+const TitleWrapper = styled("textarea")`
+    vertical-align: middle;
+    text-align: center;
+    height: 20px;
+    line-height: 20px;
+    border-radius: 4px;
+    padding: inherit;
+    overflow: hidden;
+    outline: none;
+    resize: none;
+    text-wrap: nowrap;
+    border: none;
+    &:hover {
+      background-color: #f2f2f2;
+    }
+    &:focus {
+      border: 1px solid grey;
+    }
+    font-weight: inherit;
+    font-family: inherit;
+    font-size: inherit;
+  `;

webapp/src/AppComponents/storage.ts

@@ -0,0 +1,112 @@
+import { Model } from "@ironcalc/wasm";
+import { base64ToBytes, bytesToBase64 } from "./util";
+
+const MAX_WORKBOOKS = 50;
+
+type ModelsMetadata = Record<string, string>;
+
+export function updateNameSelectedWorkbook(model: Model, newName: string) {
+  const uuid = localStorage.getItem("selected");
+  if (uuid) {
+    const modelsJson = localStorage.getItem("models");
+    if (modelsJson) {
+      try {
+        const models = JSON.parse(modelsJson);
+        models[uuid] = newName;
+        localStorage.setItem("models", JSON.stringify(models));
+      } catch (e) {
+        console.warn("Failed saving new name");
+      }
+    }
+    const modeBytes = model.toBytes();
+    localStorage.setItem(uuid, bytesToBase64(modeBytes));
+  }
+}
+
+export function getModelsMetadata(): ModelsMetadata {
+  let modelsJson = localStorage.getItem("models");
+  if (!modelsJson) {
+    modelsJson = "{}";
+  }
+  return JSON.parse(modelsJson);
+}
+
+// Pick a different name Workbook{N} where N = 1, 2, 3
+function getNewName(existingNames: string[]): string {
+  const baseName = "Workbook";
+  let index = 1;
+  while (index < MAX_WORKBOOKS) {
+    const name = `${baseName}${index}`;
+    index += 1;
+    if (!existingNames.includes(name)) {
+      return name;
+    }
+  }
+  // FIXME: Too many workbooks?
+  return "Workbook-Infinity";
+}
+
+export function createNewModel(): Model {
+  const models = getModelsMetadata();
+  const name = getNewName(Object.values(models));
+
+  const model = new Model(name, "en", "UTC");
+  const uuid = crypto.randomUUID();
+  localStorage.setItem("selected", uuid);
+  localStorage.setItem(uuid, bytesToBase64(model.toBytes()));
+
+  models[uuid] = name;
+  localStorage.setItem("models", JSON.stringify(models));
+  return model;
+}
+
+export function loadModelFromStorageOrCreate(): Model {
+  const uuid = localStorage.getItem("selected");
+  if (uuid) {
+    // We try to load the selected model
+    const modelBytesString = localStorage.getItem(uuid);
+    if (modelBytesString) {
+      return Model.from_bytes(base64ToBytes(modelBytesString));
+    }
+    // If it doesn't exist we create one at that uuid
+    const newModel = new Model("Workbook1", "en", "UTC");
+    localStorage.setItem("selected", uuid);
+    localStorage.setItem(uuid, bytesToBase64(newModel.toBytes()));
+    return newModel;
+  }
+  // If there was no selected model we create a new one
+  return createNewModel();
+}
+
+export function saveSelectedModelInStorage(model: Model) {
+  const uuid = localStorage.getItem("selected");
+  if (uuid) {
+    const modeBytes = model.toBytes();
+    localStorage.setItem(uuid, bytesToBase64(modeBytes));
+  }
+}
+
+export function saveModelToStorage(model: Model) {
+  const uuid = crypto.randomUUID();
+  localStorage.setItem("selected", uuid);
+  localStorage.setItem(uuid, bytesToBase64(model.toBytes()));
+  let modelsJson = localStorage.getItem("models");
+  if (!modelsJson) {
+    modelsJson = "{}";
+  }
+  const models = JSON.parse(modelsJson);
+  models[uuid] = model.getName();
+  localStorage.setItem("models", JSON.stringify(models));
+}
+
+export function selectModelFromStorage(uuid: string): Model | undefined {
+  localStorage.setItem("selected", uuid);
+  const modelBytesString = localStorage.getItem(uuid);
+  if (modelBytesString) {
+    return Model.from_bytes(base64ToBytes(modelBytesString));
+  }
+}
+
+export function getSelectedUuuid(): string | null {
+  return localStorage.getItem("selected");
+}

webapp/src/AppComponents/util.ts

@@ -0,0 +1,18 @@
+export function base64ToBytes(base64: string): Uint8Array {
+  //   const binString = atob(base64);
+  //   return Uint8Array.from(binString, (m) => m.codePointAt(0));
+
+  return new Uint8Array(
+    atob(base64)
+      .split("")
+      .map((c) => c.charCodeAt(0)),
+  );
+}
+
+export function bytesToBase64(bytes: Uint8Array): string {
+  const binString = Array.from(bytes, (byte) =>
+    String.fromCodePoint(byte),
+  ).join("");
+  // btoa(String.fromCharCode(...bytes));
+  return btoa(binString);
+}

webapp/src/components/WorksheetCanvas/worksheetCanvas.ts

@@ -30,6 +30,7 @@ export interface CanvasSettings {
     columnGuide: HTMLDivElement;
     rowGuide: HTMLDivElement;
     columnHeaders: HTMLDivElement;
+    editor: HTMLDivElement;
   };
   onColumnWidthChanges: (sheet: number, column: number, width: number) => void;
   onRowHeightChanges: (sheet: number, row: number, height: number) => void;
@@ -48,6 +49,23 @@ export const defaultCellFontFamily = fonts.regular;
 export const headerFontFamily = fonts.regular;
 export const frozenSeparatorWidth = 3;
 
+// Get a 10% transparency of an hex color
+function hexToRGBA10Percent(colorHex: string): string {
+  // Remove the leading hash (#) if present
+  const hex = colorHex.replace(/^#/, "");
+
+  // Parse the hex color
+  const red = Number.parseInt(hex.substring(0, 2), 16);
+  const green = Number.parseInt(hex.substring(2, 4), 16);
+  const blue = Number.parseInt(hex.substring(4, 6), 16);
+
+  // Set the alpha (opacity) to 0.1 (10%)
+  const alpha = 0.1;
+
+  // Return the RGBA color string
+  return `rgba(${red}, ${green}, ${blue}, ${alpha})`;
+}
+
 export default class WorksheetCanvas {
   sheetWidth: number;
 
@@ -61,6 +79,8 @@ export default class WorksheetCanvas {
 
   canvas: HTMLCanvasElement;
 
+  editor: HTMLDivElement;
+
   areaOutline: HTMLDivElement;
 
   cellOutline: HTMLDivElement;
@@ -92,6 +112,7 @@ export default class WorksheetCanvas {
     this.height = options.height;
     this.ctx = this.setContext();
     this.workbookState = options.workbookState;
+    this.editor = options.elements.editor;
 
     this.cellOutline = options.elements.cellOutline;
     this.cellOutlineHandle = options.elements.cellOutlineHandle;
@@ -1092,7 +1113,7 @@ export default class WorksheetCanvas {
       this.getColumnWidth(selectedSheet, selectedColumn) + 2 * padding;
     const height = this.getRowHeight(selectedSheet, selectedRow) + 2 * padding;
 
-    const { cellOutline, areaOutline, cellOutlineHandle } = this;
+    const { cellOutline, editor, areaOutline, cellOutlineHandle } = this;
     const cellEditing = null;
 
     cellOutline.style.visibility = "visible";
@@ -1105,6 +1126,19 @@ export default class WorksheetCanvas {
       cellOutlineHandle.style.visibility = "hidden";
     }
 
+    if (this.workbookState.getEditingCell()?.sheet === selectedSheet) {
+      editor.style.left = `${x + 3}px`;
+      editor.style.top = `${y + 3}px`;
+    } else {
+      // If the editing cell is not in the same sheet as the selected sheet
+      // we take the editor out of view
+      editor.style.left = "-9999px";
+      editor.style.top = "-9999px";
+    }
+
+    editor.style.width = `${width - 1}px`;
+    editor.style.height = `${height - 1}px`;
+
     // Position the cell outline and clip it
     cellOutline.style.left = `${x - padding}px`;
     cellOutline.style.top = `${y - padding}px`;
@@ -1214,6 +1248,63 @@ export default class WorksheetCanvas {
     cellOutlineHandle.style.top = `${handleY - handleHeight / 2}px`;
   }
 
+  private drawActiveRanges(topLeftCell: Cell, bottomRightCell: Cell): void {
+    let activeRanges = this.workbookState.getActiveRanges();
+    const ctx = this.ctx;
+    ctx.setLineDash([2, 2]);
+    const referencedRange =
+      this.workbookState.getEditingCell()?.referencedRange || null;
+    if (referencedRange) {
+      activeRanges = activeRanges.concat([
+        {
+          ...referencedRange.range,
+          color: "#343423",
+        },
+      ]);
+    }
+    const activeRangesCount = activeRanges.length;
+    for (let rangeIndex = 0; rangeIndex < activeRangesCount; rangeIndex += 1) {
+      const range = activeRanges[rangeIndex];
+
+      const allowedOffset = 1; // to make borders look nicer
+      const minRow = topLeftCell.row - allowedOffset;
+      const maxRow = bottomRightCell.row + allowedOffset;
+      const minColumn = topLeftCell.column - allowedOffset;
+      const maxColumn = bottomRightCell.column + allowedOffset;
+
+      if (
+        minRow <= range.rowEnd &&
+        range.rowStart <= maxRow &&
+        minColumn <= range.columnEnd &&
+        range.columnStart < maxColumn
+      ) {
+        // Range in the viewport.
+        const displayRange: typeof range = {
+          ...range,
+          rowStart: Math.max(minRow, range.rowStart),
+          rowEnd: Math.min(maxRow, range.rowEnd),
+          columnStart: Math.max(minColumn, range.columnStart),
+          columnEnd: Math.min(maxColumn, range.columnEnd),
+        };
+        const [xStart, yStart] = this.getCoordinatesByCell(
+          displayRange.rowStart,
+          displayRange.columnStart,
+        );
+        const [xEnd, yEnd] = this.getCoordinatesByCell(
+          displayRange.rowEnd + 1,
+          displayRange.columnEnd + 1,
+        );
+        ctx.strokeStyle = range.color;
+        ctx.lineWidth = 1;
+        ctx.strokeRect(xStart, yStart, xEnd - xStart, yEnd - yStart);
+        ctx.fillStyle = hexToRGBA10Percent(range.color);
+        ctx.fillRect(xStart, yStart, xEnd - xStart, yEnd - yStart);
+      }
+    }
+
+    ctx.setLineDash([]);
+  }
+
   renderSheet(): void {
     console.time("renderSheet");
     this._renderSheet();
@@ -1352,5 +1443,6 @@ export default class WorksheetCanvas {
 
     this.drawCellOutline();
     this.drawExtendToArea();
+    this.drawActiveRanges(topLeftCell, bottomRightCell);
   }
 }

webapp/src/components/editor/editor.tsx

@@ -0,0 +1,286 @@
+// This is the cell editor for IronCalc
+// It is also the most difficult part of the UX. It is based on an idea of Mateusz Kopec.
+// There is a hidden texarea and we only show the caret. What we see is a div with the same text content
+// but in HTML so we can have different colors.
+// Some keystrokes have different behaviour than a raw HTML text area.
+// For those cases we capture the keydown event and stop its propagation.
+// As the editor changes content we need to propagate those changes so the spreadsheet can
+// mark with colors the active ranges or update the formula in the formula bar
+//
+// Events outside the editor might influence the editor
+// 1. Clicking on a different cell:
+//    * might either terminate the editing
+//    * or add the external cell to the formula
+// 2. Clicking on a sheet tab would open the new sheet or terminate editing
+// 3. Clicking somewhere else will finish editing
+//
+// Keyboard navigation is also fairly complex. For instance RightArrow might:
+// 1. End editing and navigate to the cell on the right
+// 2. Move the cursor to the right
+// 3. Insert in the formula the cell name on the right
+
+import type { Model } from "@ironcalc/wasm";
+import {
+  type CSSProperties,
+  type KeyboardEvent,
+  useCallback,
+  useEffect,
+  useRef,
+  useState,
+} from "react";
+import type { WorkbookState } from "../workbookState";
+import getFormulaHTML from "./util";
+
+const commonCSS: CSSProperties = {
+  fontWeight: "inherit",
+  fontFamily: "inherit",
+  fontSize: "inherit",
+  position: "absolute",
+  left: 0,
+  top: 0,
+  whiteSpace: "pre",
+  width: "100%",
+  padding: 0,
+  lineHeight: "22px",
+};
+
+const caretColor = "#FF8899";
+
+interface EditorOptions {
+  minimalWidth: number | string;
+  minimalHeight: number | string;
+  display: boolean;
+  expand: boolean;
+  originalText: string;
+  onEditEnd: () => void;
+  onTextUpdated: () => void;
+  model: Model;
+  workbookState: WorkbookState;
+  type: "cell" | "formula-bar";
+}
+
+const Editor = (options: EditorOptions) => {
+  const {
+    display,
+    expand,
+    minimalHeight,
+    minimalWidth,
+    model,
+    onEditEnd,
+    onTextUpdated,
+    originalText,
+    workbookState,
+    type,
+  } = options;
+
+  const [width, setWidth] = useState(minimalWidth);
+  const [height, setHeight] = useState(minimalHeight);
+  const [text, setText] = useState(originalText);
+  const [styledFormula, setStyledFormula] = useState(
+    getFormulaHTML(model, text, "").html,
+  );
+
+  const formulaRef = useRef<HTMLDivElement>(null);
+  const maskRef = useRef<HTMLDivElement>(null);
+  const textareaRef = useRef<HTMLTextAreaElement>(null);
+
+  useEffect(() => {
+    setText(originalText);
+    setStyledFormula(getFormulaHTML(model, originalText, "").html);
+    if (textareaRef.current) {
+      textareaRef.current.value = originalText;
+    }
+  }, [originalText, model]);
+
+  const onKeyDown = useCallback(
+    (event: KeyboardEvent) => {
+      const { key, shiftKey, altKey } = event;
+      const textarea = textareaRef.current;
+      if (!textarea) {
+        return;
+      }
+      switch (key) {
+        case "Enter": {
+          if (altKey) {
+            // new line
+            const start = textarea.selectionStart;
+            const end = textarea.selectionEnd;
+            const newText = `${text.slice(0, start)}\n${text.slice(end)}`;
+            setText(newText);
+            setTimeout(() => {
+              textarea.setSelectionRange(start + 1, start + 1);
+            }, 0);
+            event.stopPropagation();
+            event.preventDefault();
+            return;
+          }
+          // end edit and select cell bellow
+          setTimeout(() => {
+            const cell = workbookState.getEditingCell();
+            if (cell) {
+              model.setUserInput(
+                cell.sheet,
+                cell.row,
+                cell.column,
+                cell.text + (cell.referencedRange?.str || ""),
+              );
+              const sign = shiftKey ? -1 : 1;
+              model.setSelectedSheet(cell.sheet);
+              model.setSelectedCell(cell.row + sign, cell.column);
+              workbookState.clearEditingCell();
+            }
+            onEditEnd();
+          }, 0);
+          // event bubbles up
+          return;
+        }
+        case "Tab": {
+          // end edit and select cell to the right
+          const cell = workbookState.getEditingCell();
+          if (cell) {
+            workbookState.clearEditingCell();
+            model.setUserInput(
+              cell.sheet,
+              cell.row,
+              cell.column,
+              cell.text + (cell.referencedRange?.str || ""),
+            );
+            const sign = shiftKey ? -1 : 1;
+            model.setSelectedSheet(cell.sheet);
+            model.setSelectedCell(cell.row, cell.column + sign);
+            if (textareaRef.current) {
+              textareaRef.current.value = "";
+              setStyledFormula(getFormulaHTML(model, "", "").html);
+            }
+            event.stopPropagation();
+            event.preventDefault();
+          }
+          onEditEnd();
+          return;
+        }
+        case "Escape": {
+          // quit editing without modifying the cell
+          const cell = workbookState.getEditingCell();
+          if (cell) {
+            model.setSelectedSheet(cell.sheet);
+          }
+          workbookState.clearEditingCell();
+          onEditEnd();
+          return;
+        }
+        // TODO: Arrow keys navigate in Excel
+        case "ArrowRight": {
+          return;
+        }
+        default: {
+          // We run this in a timeout because the value is not yet in the textarea
+          // since we are capturing the keydown event
+          setTimeout(() => {
+            const cell = workbookState.getEditingCell();
+            if (cell) {
+              // accept whatever is in the referenced range
+              const value = textarea.value;
+              const styledFormula = getFormulaHTML(model, value, "");
+
+              cell.text = value;
+              cell.referencedRange = null;
+              cell.cursorStart = textarea.selectionStart;
+              cell.cursorEnd = textarea.selectionEnd;
+              workbookState.setEditingCell(cell);
+
+              workbookState.setActiveRanges(styledFormula.activeRanges);
+              setStyledFormula(styledFormula.html);
+
+              onTextUpdated();
+            }
+          }, 0);
+        }
+      }
+    },
+    [model, text, onEditEnd, onTextUpdated, workbookState],
+  );
+
+  useEffect(() => {
+    if (display) {
+      textareaRef.current?.focus();
+    }
+  }, [display]);
+
+  const onChange = useCallback(() => {
+    if (textareaRef.current) {
+      textareaRef.current.value = "";
+      setStyledFormula(getFormulaHTML(model, "", "").html);
+    }
+
+    // This happens if the blur hasn't been taken care before by
+    // onclick or onpointerdown events
+    // If we are editing a cell finish that
+    const cell = workbookState.getEditingCell();
+    if (cell) {
+      model.setUserInput(
+        cell.sheet,
+        cell.row,
+        cell.column,
+        workbookState.getEditingText(),
+      );
+      workbookState.clearEditingCell();
+    }
+    onEditEnd();
+  }, [model, workbookState, onEditEnd]);
+
+  const isCellEditing = workbookState.getEditingCell() !== null;
+
+  const showEditor =
+    (isCellEditing && display) || type === "formula-bar" ? "block" : "none";
+
+  return (
+    <div
+      style={{
+        position: "relative",
+        width,
+        height,
+        overflow: "hidden",
+        display: showEditor,
+        background: "#FFF",
+      }}
+    >
+      <div
+        ref={maskRef}
+        style={{
+          ...commonCSS,
+          textAlign: "left",
+          pointerEvents: "none",
+          height,
+        }}
+      >
+        <div ref={formulaRef}>{styledFormula}</div>
+      </div>
+      <textarea
+        ref={textareaRef}
+        rows={1}
+        style={{
+          ...commonCSS,
+          color: "transparent",
+          backgroundColor: "transparent",
+          caretColor,
+          outline: "none",
+          resize: "none",
+          border: "none",
+          height,
+          overflow: "hidden",
+        }}
+        defaultValue={text}
+        spellCheck="false"
+        onKeyDown={onKeyDown}
+        onBlur={onChange}
+        onClick={(event) => {
+          // Prevents this from bubbling up and focusing on the spreadsheet
+          if (isCellEditing && type === "cell") {
+            event.stopPropagation();
+          }
+        }}
+      />
+    </div>
+  );
+};
+export default Editor;

webapp/src/components/editor/util.tsx

@@ -0,0 +1,194 @@
+import {
+  type Model,
+  type Range,
+  type Reference,
+  type TokenType,
+  getTokens,
+} from "@ironcalc/wasm";
+import type { ActiveRange } from "../workbookState";
+
+export function tokenIsReferenceType(token: TokenType): token is Reference {
+  return typeof token === "object" && "Reference" in token;
+}
+
+export function tokenIsRangeType(token: TokenType): token is Range {
+  return typeof token === "object" && "Range" in token;
+}
+
+export function isInReferenceMode(text: string, cursor: number): boolean {
+  // FIXME
+  // This is a gross oversimplification
+  // Returns true if both are true:
+  // 1. Cursor is at the end
+  // 2. Last char is one of [',', '(', '+', '*', '-', '/', '<', '>', '=', '&']
+  // This has many false positives like '="1+' and also likely some false negatives
+  // The right way of doing this is to have a partial parse of the formula tree
+  // and check if the next token could be a reference
+  if (!text.startsWith("=")) {
+    return false;
+  }
+  if (text === "=") {
+    return true;
+  }
+  const l = text.length;
+  const chars = [",", "(", "+", "*", "-", "/", "<", ">", "=", "&"];
+  if (cursor === l && chars.includes(text[l - 1])) {
+    return true;
+  }
+  return false;
+}
+
+// IronCalc Color Palette
+export function getColor(index: number, alpha = 1): string {
+  const colors = [
+    {
+      name: "Cyan",
+      rgba: [89, 185, 188, 1],
+      hex: "#59B9BC",
+    },
+    {
+      name: "Flamingo",
+      rgba: [236, 87, 83, 1],
+      hex: "#EC5753",
+    },
+    {
+      hex: "#3358B7",
+      rgba: [51, 88, 183, 1],
+      name: "Blue",
+    },
+    {
+      hex: "#F8CD3C",
+      rgba: [248, 205, 60, 1],
+      name: "Yellow",
+    },
+    {
+      hex: "#3BB68A",
+      rgba: [59, 182, 138, 1],
+      name: "Emerald",
+    },
+    {
+      hex: "#523E93",
+      rgba: [82, 62, 147, 1],
+      name: "Violet",
+    },
+    {
+      hex: "#A23C52",
+      rgba: [162, 60, 82, 1],
+      name: "Burgundy",
+    },
+    {
+      hex: "#8CB354",
+      rgba: [162, 60, 82, 1],
+      name: "Wasabi",
+    },
+    {
+      hex: "#D03627",
+      rgba: [208, 54, 39, 1],
+      name: "Red",
+    },
+    {
+      hex: "#1B717E",
+      rgba: [27, 113, 126, 1],
+      name: "Teal",
+    },
+  ];
+  if (alpha === 1) {
+    return colors[index % 10].hex;
+  }
+  const { rgba } = colors[index % 10];
+  return `rgba(${rgba[0]}, ${rgba[1]}, ${rgba[2]}, ${alpha})`;
+}
+
+function getFormulaHTML(
+  model: Model,
+  text: string,
+  referenceRange: string,
+): { html: JSX.Element[]; activeRanges: ActiveRange[] } {
+  let html: JSX.Element[] = [];
+  const activeRanges: ActiveRange[] = [];
+  let colorCount = 0;
+  if (text.startsWith("=")) {
+    const formula = text.slice(1);
+    const tokens = getTokens(formula);
+    const tokenCount = tokens.length;
+    const usedColors: Record<string, string> = {};
+    const sheet = model.getSelectedSheet();
+    const sheetList = model.getWorksheetsProperties().map((s) => s.name);
+    for (let index = 0; index < tokenCount; index += 1) {
+      const { token, start, end } = tokens[index];
+      if (tokenIsReferenceType(token)) {
+        const { sheet: refSheet, row, column } = token.Reference;
+        const sheetIndex = refSheet ? sheetList.indexOf(refSheet) : sheet;
+        const key = `${sheetIndex}-${row}-${column}`;
+        let color = usedColors[key];
+        if (!color) {
+          color = getColor(colorCount);
+          usedColors[key] = color;
+          colorCount += 1;
+        }
+        html.push(
+          <span key={index} style={{ color }}>
+            {formula.slice(start, end)}
+          </span>,
+        );
+        activeRanges.push({
+          sheet: sheetIndex,
+          rowStart: row,
+          columnStart: column,
+          rowEnd: row,
+          columnEnd: column,
+          color,
+        });
+      } else if (tokenIsRangeType(token)) {
+        let {
+          sheet: refSheet,
+          left: { row: rowStart, column: columnStart },
+          right: { row: rowEnd, column: columnEnd },
+        } = token.Range;
+        const sheetIndex = refSheet ? sheetList.indexOf(refSheet) : sheet;
+
+        const key = `${sheetIndex}-${rowStart}-${columnStart}:${rowEnd}-${columnEnd}`;
+        let color = usedColors[key];
+        if (!color) {
+          color = getColor(colorCount);
+          usedColors[key] = color;
+          colorCount += 1;
+        }
+
+        if (rowStart > rowEnd) {
+          [rowStart, rowEnd] = [rowEnd, rowStart];
+        }
+        if (columnStart > columnEnd) {
+          [columnStart, columnEnd] = [columnEnd, columnStart];
+        }
+        html.push(
+          <span key={index} style={{ color }}>
+            {formula.slice(start, end)}
+          </span>,
+        );
+        colorCount += 1;
+
+        activeRanges.push({
+          sheet: sheetIndex,
+          rowStart,
+          columnStart,
+          rowEnd,
+          columnEnd,
+          color,
+        });
+      } else {
+        html.push(<span key={index}>{formula.slice(start, end)}</span>);
+      }
+    }
+    // If there is a reference range add it at the end
+    if (referenceRange !== "") {
+      html.push(<span key="reference">{referenceRange}</span>);
+    }
+    html = [<span key="equals">=</span>].concat(html);
+  } else {
+    html = [<span key="single">{text}</span>];
+  }
+  return { html, activeRanges };
+}
+
+export default getFormulaHTML;

webapp/src/components/formulaDialog.tsx

@@ -1,50 +0,0 @@
-import {
-  Button,
-  Dialog,
-  DialogActions,
-  DialogContent,
-  DialogTitle,
-  TextField,
-} from "@mui/material";
-import { useState } from "react";
-import { useTranslation } from "react-i18next";
-
-interface FormulaDialogProps {
-  isOpen: boolean;
-  close: () => void;
-  onFormulaChanged: (name: string) => void;
-  defaultFormula: string;
-}
-
-export const FormulaDialog = (properties: FormulaDialogProps) => {
-  const { t } = useTranslation();
-  const [formula, setFormula] = useState(properties.defaultFormula);
-  return (
-    <Dialog open={properties.isOpen} onClose={properties.close}>
-      <DialogTitle>{t("formula_input.title")}</DialogTitle>
-      <DialogContent dividers>
-        <TextField
-          defaultValue={formula}
-          label={t("formula_input.label")}
-          onClick={(event) => event.stopPropagation()}
-          onKeyDown={(event) => {
-            event.stopPropagation();
-          }}
-          onChange={(event) => {
-            setFormula(event.target.value);
-          }}
-          spellCheck="false"
-        />
-      </DialogContent>
-      <DialogActions>
-        <Button
-          onClick={() => {
-            properties.onFormulaChanged(formula);
-          }}
-        >
-          {t("formula_input.update")}
-        </Button>
-      </DialogActions>
-    </Dialog>
-  );
-};

webapp/src/components/formulabar.tsx

@@ -1,28 +1,35 @@
+import type { Model } from "@ironcalc/wasm";
 import { Button, styled } from "@mui/material";
 import { ChevronDown } from "lucide-react";
-import { useState } from "react";
 import { Fx } from "../icons";
-import { FormulaDialog } from "./formulaDialog";
+import Editor from "./editor/editor";
+import type { WorkbookState } from "./workbookState";
 
 type FormulaBarProps = {
   cellAddress: string;
   formulaValue: string;
-  onChange: (value: string) => void;
+  model: Model;
+  workbookState: WorkbookState;
+  onChange: () => void;
+  onTextUpdated: () => void;
 };
 
 const formulaBarHeight = 30;
-const headerColumnWidth = 30;
+const headerColumnWidth = 35;
 
 function FormulaBar(properties: FormulaBarProps) {
-  const [formulaDialogOpen, setFormulaDialogOpen] = useState(false);
+  const {
-  const handleCloseFormulaDialog = () => {
+    cellAddress,
-    setFormulaDialogOpen(false);
+    formulaValue,
-  };
+    model,
-
+    onChange,
+    onTextUpdated,
+    workbookState,
+  } = properties;
   return (
     <Container>
       <AddressContainer>
-        <CellBarAddress>{properties.cellAddress}</CellBarAddress>
+        <CellBarAddress>{cellAddress}</CellBarAddress>
         <StyledButton>
           <ChevronDown />
         </StyledButton>
@@ -32,23 +39,40 @@ function FormulaBar(properties: FormulaBarProps) {
         <FormulaSymbolButton>
           <Fx />
         </FormulaSymbolButton>
-        <Editor
+        <EditorWrapper
-          onClick={() => {
+          onClick={(event) => {
-            setFormulaDialogOpen(true);
+            const [sheet, row, column] = model.getSelectedCell();
+            workbookState.setEditingCell({
+              sheet,
+              row,
+              column,
+              text: formulaValue,
+              referencedRange: null,
+              cursorStart: formulaValue.length,
+              cursorEnd: formulaValue.length,
+              focus: "formula-bar",
+              activeRanges: [],
+            });
+            event.stopPropagation();
+            event.preventDefault();
           }}
         >
-          {properties.formulaValue}
+          <Editor
-        </Editor>
+            minimalWidth={"100%"}
-      </FormulaContainer>
+            minimalHeight={"100%"}
-      <FormulaDialog
+            display={true}
-        isOpen={formulaDialogOpen}
+            expand={false}
-        close={handleCloseFormulaDialog}
+            originalText={formulaValue}
-        defaultFormula={properties.formulaValue}
+            model={model}
-        onFormulaChanged={(newName) => {
+            workbookState={workbookState}
-          properties.onChange(newName);
+            onEditEnd={() => {
-          setFormulaDialogOpen(false);
+              onChange();
             }}
+            onTextUpdated={onTextUpdated}
+            type="formula-bar"
           />
+        </EditorWrapper>
+      </FormulaContainer>
     </Container>
   );
 }
@@ -113,7 +137,7 @@ const CellBarAddress = styled("div")`
   text-align: "center";
 `;
 
-const Editor = styled("div")`
+const EditorWrapper = styled("div")`
   position: relative;
   width: 100%;
   padding: 0px;
@@ -127,6 +151,7 @@ const Editor = styled("div")`
   span {
     min-width: 1px;
   }
+  font-family: monospace;
 `;
 
 export default FormulaBar;

webapp/src/components/navigation/navigation.tsx

@@ -3,6 +3,7 @@ import { ChevronLeft, ChevronRight, Menu, Plus } from "lucide-react";
 import { useState } from "react";
 import { useTranslation } from "react-i18next";
 import { StyledButton } from "../toolbar";
+import type { WorkbookState } from "../workbookState";
 import SheetListMenu from "./menus";
 import Sheet from "./sheet";
 import type { SheetOptions } from "./types";
@@ -10,6 +11,7 @@ import type { SheetOptions } from "./types";
 export interface NavigationProps {
   sheets: SheetOptions[];
   selectedIndex: number;
+  workbookState: WorkbookState;
   onSheetSelected: (index: number) => void;
   onAddBlankSheet: () => void;
   onSheetColorChanged: (hex: string) => void;
@@ -19,7 +21,7 @@ export interface NavigationProps {
 
 function Navigation(props: NavigationProps) {
   const { t } = useTranslation();
-  const { onSheetSelected, sheets, selectedIndex } = props;
+  const { workbookState, onSheetSelected, sheets, selectedIndex } = props;
   const [anchorEl, setAnchorEl] = useState<null | HTMLButtonElement>(null);
   const open = Boolean(anchorEl);
   const handleClick = (event: React.MouseEvent<HTMLButtonElement>) => {
@@ -63,6 +65,7 @@ function Navigation(props: NavigationProps) {
               onDeleted={(): void => {
                 props.onSheetDeleted();
               }}
+              workbookState={workbookState}
             />
           ))}
         </SheetInner>

webapp/src/components/navigation/sheet.tsx

@@ -2,7 +2,10 @@ import { Button, Menu, MenuItem, styled } from "@mui/material";
 import { ChevronDown } from "lucide-react";
 import { useRef, useState } from "react";
 import ColorPicker from "../colorPicker";
+import { isInReferenceMode } from "../editor/util";
+import type { WorkbookState } from "../workbookState";
 import { SheetRenameDialog } from "./menus";
+
 interface SheetProps {
   name: string;
   color: string;
@@ -11,9 +14,11 @@ interface SheetProps {
   onColorChanged: (hex: string) => void;
   onRenamed: (name: string) => void;
   onDeleted: () => void;
+  workbookState: WorkbookState;
 }
+
 function Sheet(props: SheetProps) {
-  const { name, color, selected, onSelected } = props;
+  const { name, color, selected, workbookState, onSelected } = props;
   const [anchorEl, setAnchorEl] = useState<null | HTMLButtonElement>(null);
   const [colorPickerOpen, setColorPickerOpen] = useState(false);
   const colorButton = useRef(null);
@@ -35,8 +40,18 @@ function Sheet(props: SheetProps) {
     <>
       <Wrapper
         style={{ borderBottomColor: color, fontWeight: selected ? 600 : 400 }}
-        onClick={() => {
+        onClick={(event) => {
           onSelected();
+          event.stopPropagation();
+          event.preventDefault();
+        }}
+        onPointerDown={(event) => {
+          // If it is in browse mode stop he event
+          const cell = workbookState.getEditingCell();
+          if (cell && isInReferenceMode(cell.text, cell.cursorStart)) {
+            event.stopPropagation();
+            event.preventDefault();
+          }
         }}
         ref={colorButton}
       >

webapp/src/components/tests/model.test.ts

@@ -7,7 +7,7 @@ import { expect, test } from "vitest";
 test("simple calculation", async () => {
   const buffer = await readFile("node_modules/@ironcalc/wasm/wasm_bg.wasm");
   initSync(buffer);
-  const model = new Model("en", "UTC");
+  const model = new Model("workbook", "en", "UTC");
   model.setUserInput(0, 1, 1, "=21*2");
   expect(model.getFormattedCellValue(0, 1, 1)).toBe("42");
 });

webapp/src/components/usePointer.ts

@@ -1,10 +1,14 @@
+import type { Model } from "@ironcalc/wasm";
 import { type PointerEvent, type RefObject, useCallback, useRef } from "react";
 import type WorksheetCanvas from "./WorksheetCanvas/worksheetCanvas";
 import {
   headerColumnWidth,
   headerRowHeight,
 } from "./WorksheetCanvas/worksheetCanvas";
+import { isInReferenceMode } from "./editor/util";
 import type { Cell } from "./types";
+import { rangeToStr } from "./util";
+import type { WorkbookState } from "./workbookState";
 
 interface PointerSettings {
   canvasElement: RefObject<HTMLCanvasElement>;
@@ -15,6 +19,9 @@ interface PointerSettings {
   onAreaSelected: () => void;
   onExtendToCell: (cell: Cell) => void;
   onExtendToEnd: () => void;
+  model: Model;
+  workbookState: WorkbookState;
+  refresh: () => void;
 }
 
 interface PointerEvents {
@@ -27,6 +34,7 @@ interface PointerEvents {
 const usePointer = (options: PointerSettings): PointerEvents => {
   const isSelecting = useRef(false);
   const isExtending = useRef(false);
+  const isInsertingRef = useRef(false);
 
   const onPointerMove = useCallback(
     (event: PointerEvent): void => {
@@ -36,43 +44,50 @@ const usePointer = (options: PointerSettings): PointerEvents => {
         return;
       }
 
-      if (isSelecting.current) {
+      if (
-        const { canvasElement, worksheetCanvas } = options;
+        !(isSelecting.current || isExtending.current || isInsertingRef.current)
+      ) {
+        return;
+      }
+      const { canvasElement, model, worksheetCanvas } = options;
       const canvas = canvasElement.current;
       const worksheet = worksheetCanvas.current;
       // Silence the linter
       if (!worksheet || !canvas) {
         return;
       }
-        let x = event.clientX;
-        let y = event.clientY;
       const canvasRect = canvas.getBoundingClientRect();
-        x -= canvasRect.x;
+      const x = event.clientX - canvasRect.x;
-        y -= canvasRect.y;
+      const y = event.clientY - canvasRect.y;
-        const cell = worksheet.getCellByCoordinates(x, y);
+
-        if (cell) {
-          options.onAreaSelecting(cell);
-        } else {
-          console.log("Failed");
-        }
-      } else if (isExtending.current) {
-        const { canvasElement, worksheetCanvas } = options;
-        const canvas = canvasElement.current;
-        const worksheet = worksheetCanvas.current;
-        // Silence the linter
-        if (!worksheet || !canvas) {
-          return;
-        }
-        let x = event.clientX;
-        let y = event.clientY;
-        const canvasRect = canvas.getBoundingClientRect();
-        x -= canvasRect.x;
-        y -= canvasRect.y;
       const cell = worksheet.getCellByCoordinates(x, y);
       if (!cell) {
         return;
       }
+
+      if (isSelecting.current) {
+        options.onAreaSelecting(cell);
+      } else if (isExtending.current) {
         options.onExtendToCell(cell);
+      } else if (isInsertingRef.current) {
+        const { refresh, workbookState } = options;
+        const editingCell = workbookState.getEditingCell();
+        if (!editingCell || !editingCell.referencedRange) {
+          return;
+        }
+        const range = editingCell.referencedRange.range;
+        range.rowEnd = cell.row;
+        range.columnEnd = cell.column;
+
+        const sheetNames = model.getWorksheetsProperties().map((s) => s.name);
+
+        editingCell.referencedRange.str = rangeToStr(
+          range,
+          editingCell.sheet,
+          sheetNames[range.sheet],
+        );
+        workbookState.setEditingCell(editingCell);
+        refresh();
       }
     },
     [options],
@@ -90,6 +105,10 @@ const usePointer = (options: PointerSettings): PointerEvents => {
         isExtending.current = false;
         worksheetElement.current?.releasePointerCapture(event.pointerId);
         options.onExtendToEnd();
+      } else if (isInsertingRef.current) {
+        const { worksheetElement } = options;
+        isInsertingRef.current = false;
+        worksheetElement.current?.releasePointerCapture(event.pointerId);
       }
     },
     [options],
@@ -99,7 +118,14 @@ const usePointer = (options: PointerSettings): PointerEvents => {
     (event: PointerEvent) => {
       let x = event.clientX;
       let y = event.clientY;
-      const { canvasElement, worksheetElement, worksheetCanvas } = options;
+      const {
+        canvasElement,
+        model,
+        refresh,
+        worksheetElement,
+        worksheetCanvas,
+        workbookState,
+      } = options;
       const worksheet = worksheetCanvas.current;
       const canvas = canvasElement.current;
       const worksheetWrapper = worksheetElement.current;
@@ -132,8 +158,60 @@ const usePointer = (options: PointerSettings): PointerEvents => {
         }
         return;
       }
+
+      const editingCell = workbookState.getEditingCell();
       const cell = worksheet.getCellByCoordinates(x, y);
       if (cell) {
+        if (editingCell) {
+          if (
+            cell.row === editingCell.row &&
+            cell.column === editingCell.column
+          ) {
+            // We are clicking on the cell we are editing
+            // we do nothing
+            return;
+          }
+          // now we are editing one cell and we click in another one
+          // If we can insert a range we do that
+          const text = editingCell.text;
+          if (isInReferenceMode(text, editingCell.cursorEnd)) {
+            const range = {
+              sheet: model.getSelectedSheet(),
+              rowStart: cell.row,
+              rowEnd: cell.row,
+              columnStart: cell.column,
+              columnEnd: cell.column,
+            };
+            const sheetNames = model
+              .getWorksheetsProperties()
+              .map((s) => s.name);
+            editingCell.referencedRange = {
+              range,
+              str: rangeToStr(
+                range,
+                editingCell.sheet,
+                sheetNames[range.sheet],
+              ),
+            };
+            workbookState.setEditingCell(editingCell);
+            event.stopPropagation();
+            event.preventDefault();
+            isInsertingRef.current = true;
+            worksheetWrapper.setPointerCapture(event.pointerId);
+            refresh();
+            return;
+          }
+          // We are clicking away but we are not in reference mode
+          // We finish the editing
+          workbookState.clearEditingCell();
+          model.setUserInput(
+            editingCell.sheet,
+            editingCell.row,
+            editingCell.column,
+            editingCell.text,
+          );
+          // we continue to select the new cell
+        }
         options.onCellSelected(cell, event);
         isSelecting.current = true;
         worksheetWrapper.setPointerCapture(event.pointerId);

webapp/src/components/util.ts

@@ -40,3 +40,22 @@ export const getCellAddress = (selectedArea: Area, selectedCell?: Cell) => {
         selectedArea.rowStart
       }:${columnNameFromNumber(selectedArea.columnEnd)}${selectedArea.rowEnd}`;
 };
+
+export function rangeToStr(
+  range: {
+    sheet: number;
+    rowStart: number;
+    rowEnd: number;
+    columnStart: number;
+    columnEnd: number;
+  },
+  referenceSheet: number,
+  referenceName: string,
+): string {
+  const { sheet, rowStart, rowEnd, columnStart, columnEnd } = range;
+  const sheetName = sheet === referenceSheet ? "" : `'${referenceName}'!`;
+  if (rowStart === rowEnd && columnStart === columnEnd) {
+    return `${sheetName}${columnNameFromNumber(columnStart)}${rowStart}`;
+  }
+  return `${sheetName}${columnNameFromNumber(columnStart)}${rowStart}:${columnNameFromNumber(columnEnd)}${rowEnd}`;
+}

webapp/src/components/workbook.tsx

@@ -1,6 +1,6 @@
 import type { BorderOptions, Model, WorksheetProperties } from "@ironcalc/wasm";
 import { styled } from "@mui/material/styles";
-import { useEffect, useRef, useState } from "react";
+import { useCallback, useEffect, useRef, useState } from "react";
 import { LAST_COLUMN } from "./WorksheetCanvas/constants";
 import FormulaBar from "./formulabar";
 import Navigation from "./navigation/navigation";
@@ -143,11 +143,35 @@ const Workbook = (props: { model: Model; workbookState: WorkbookState }) => {
       setRedrawId((id) => id + 1);
     },
     onEditKeyPressStart: (initText: string): void => {
-      console.log(initText);
+      const { sheet, row, column } = model.getSelectedView();
-      throw new Error("Function not implemented.");
+      workbookState.setEditingCell({
+        sheet,
+        row,
+        column,
+        text: initText,
+        cursorStart: initText.length,
+        cursorEnd: initText.length,
+        focus: "cell",
+        referencedRange: null,
+        activeRanges: [],
+      });
+      setRedrawId((id) => id + 1);
     },
     onCellEditStart: (): void => {
-      throw new Error("Function not implemented.");
+      const { sheet, row, column } = model.getSelectedView();
+      const text = model.getCellContent(sheet, row, column);
+      workbookState.setEditingCell({
+        sheet,
+        row,
+        column,
+        text,
+        cursorStart: text.length,
+        cursorEnd: text.length,
+        referencedRange: null,
+        focus: "cell",
+        activeRanges: [],
+      });
+      setRedrawId((id) => id + 1);
     },
     onBold: () => {
       const { sheet, row, column } = model.getSelectedView();
@@ -237,26 +261,52 @@ const Workbook = (props: { model: Model; workbookState: WorkbookState }) => {
     if (!rootRef.current) {
       return;
     }
+    if (!workbookState.getEditingCell()) {
       rootRef.current.focus();
+    }
   });
 
+  const cellAddress = useCallback(() => {
     const {
-    sheet,
       row,
       column,
       range: [rowStart, columnStart, rowEnd, columnEnd],
     } = model.getSelectedView();
-
+    return getCellAddress(
-  const cellAddress = getCellAddress(
       { rowStart, rowEnd, columnStart, columnEnd },
       { row, column },
     );
-  const formulaValue = model.getCellContent(sheet, row, column);
+  }, [model]);
 
-  const style = model.getCellStyle(sheet, row, column);
+  const formulaValue = () => {
+    const cell = workbookState.getEditingCell();
+    if (cell) {
+      return workbookState.getEditingText();
+    }
+    const { sheet, row, column } = model.getSelectedView();
+    return model.getCellContent(sheet, row, column);
+  };
+
+  const getCellStyle = useCallback(() => {
+    const { sheet, row, column } = model.getSelectedView();
+    return model.getCellStyle(sheet, row, column);
+  }, [model]);
+
+  const style = getCellStyle();
 
   return (
-    <Container ref={rootRef} onKeyDown={onKeyDown} tabIndex={0}>
+    <Container
+      ref={rootRef}
+      onKeyDown={onKeyDown}
+      tabIndex={0}
+      onClick={(event) => {
+        if (!workbookState.getEditingCell()) {
+          rootRef.current?.focus();
+        } else {
+          event.stopPropagation();
+        }
+      }}
+    >
       <Toolbar
         canUndo={model.canUndo()}
         canRedo={model.canRedo()}
@@ -304,19 +354,25 @@ const Workbook = (props: { model: Model; workbookState: WorkbookState }) => {
         verticalAlign={style.alignment ? style.alignment.vertical : "center"}
         canEdit={true}
         numFmt={style.num_fmt}
-        showGridLines={model.getShowGridLines(sheet)}
+        showGridLines={model.getShowGridLines(model.getSelectedSheet())}
         onToggleShowGridLines={(show) => {
+          const sheet = model.getSelectedSheet();
           model.setShowGridLines(sheet, show);
           setRedrawId((id) => id + 1);
         }}
       />
       <FormulaBar
-        cellAddress={cellAddress}
+        cellAddress={cellAddress()}
-        formulaValue={formulaValue}
+        formulaValue={formulaValue()}
-        onChange={(value) => {
+        onChange={() => {
-          model.setUserInput(sheet, row, column, value);
+          setRedrawId((id) => id + 1);
+          rootRef.current?.focus();
+        }}
+        onTextUpdated={() => {
           setRedrawId((id) => id + 1);
         }}
+        model={model}
+        workbookState={workbookState}
       />
       <Worksheet
         model={model}
@@ -325,9 +381,11 @@ const Workbook = (props: { model: Model; workbookState: WorkbookState }) => {
           setRedrawId((id) => id + 1);
         }}
       />
+
       <Navigation
         sheets={info}
         selectedIndex={model.getSelectedSheet()}
+        workbookState={workbookState}
         onSheetSelected={(sheet: number): void => {
           model.setSelectedSheet(sheet);
           setRedrawId((value) => value + 1);
@@ -368,6 +426,7 @@ const Container = styled("div")`
   display: flex;
   flex-direction: column;
   height: 100%;
+  position: relative;
   font-family: ${({ theme }) => theme.typography.fontFamily};
 
   &:focus {

webapp/src/components/workbookState.ts

@@ -1,3 +1,18 @@
+// This are properties of the workbook that are not permanently stored
+// They only happen at 'runtime' while the workbook is being used:
+//
+// * What are we editing
+// * Are we copying styles?
+// * Are we extending a cell? (by pulling the cell outline handle down, for instance)
+//
+// Editing the cell is the most complex operation.
+//
+// * What cell are we editing?
+// * Are we doing that from the cell editor or the formula editor?
+// * What is the text content of the cell right now
+// * The active ranges can technically be computed from the text.
+//   Those are the ranges or cells that appear in the formula
+
 import type { CellStyle } from "@ironcalc/wasm";
 
 export enum AreaType {
@@ -15,15 +30,58 @@ export interface Area {
   columnEnd: number;
 }
 
+// Active ranges are ranges in the sheet that are highlighted when editing a formula
+export interface ActiveRange {
+  sheet: number;
+  rowStart: number;
+  rowEnd: number;
+  columnStart: number;
+  columnEnd: number;
+  color: string;
+}
+
+export interface ReferencedRange {
+  range: {
+    sheet: number;
+    rowStart: number;
+    rowEnd: number;
+    columnStart: number;
+    columnEnd: number;
+  };
+  str: string;
+}
+
+type Focus = "cell" | "formula-bar";
+
+// The cell that we are editing
+export interface EditingCell {
+  sheet: number;
+  row: number;
+  column: number;
+  // raw text in the editor
+  text: string;
+  // position of the cursor
+  cursorStart: number;
+  cursorEnd: number;
+  // referenced range
+  referencedRange: ReferencedRange | null;
+  focus: Focus;
+  activeRanges: ActiveRange[];
+}
+
+// Those are styles that are copied
 type AreaStyles = CellStyle[][];
 
 export class WorkbookState {
   private extendToArea: Area | null;
   private copyStyles: AreaStyles | null;
+  private cell: EditingCell | null;
 
   constructor() {
+    // the extendTo area is the area we are covering
     this.extendToArea = null;
     this.copyStyles = null;
+    this.cell = null;
   }
 
   getExtendToArea(): Area | null {
@@ -45,4 +103,49 @@ export class WorkbookState {
   getCopyStyles(): AreaStyles | null {
     return this.copyStyles;
   }
+
+  setActiveRanges(activeRanges: ActiveRange[]) {
+    if (!this.cell) {
+      return;
+    }
+    this.cell.activeRanges = activeRanges;
+  }
+
+  getActiveRanges(): ActiveRange[] {
+    return this.cell?.activeRanges || [];
+  }
+
+  getEditingCell(): EditingCell | null {
+    return this.cell;
+  }
+
+  setEditingCell(cell: EditingCell) {
+    this.cell = cell;
+  }
+
+  clearEditingCell() {
+    this.cell = null;
+  }
+
+  isCellEditorActive(): boolean {
+    if (this.cell) {
+      return this.cell.focus === "cell";
+    }
+    return false;
+  }
+
+  isFormulaEditorActive(): boolean {
+    if (this.cell) {
+      return this.cell.focus === "formula-bar";
+    }
+    return false;
+  }
+
+  getEditingText(): string {
+    const cell = this.cell;
+    if (cell) {
+      return cell.text + (cell.referencedRange?.str || "");
+    }
+    return "";
+  }
 }

webapp/src/components/worksheet.tsx

@@ -6,6 +6,7 @@ import {
   outlineColor,
 } from "./WorksheetCanvas/constants";
 import WorksheetCanvas from "./WorksheetCanvas/worksheetCanvas";
+import Editor from "./editor/editor";
 import type { Cell } from "./types";
 import usePointer from "./usePointer";
 import { AreaType, type WorkbookState } from "./workbookState";
@@ -32,7 +33,8 @@ function Worksheet(props: {
 
   const worksheetElement = useRef<HTMLDivElement>(null);
   const scrollElement = useRef<HTMLDivElement>(null);
-  // const rootElement = useRef<HTMLDivElement>(null);
+
+  const editorElement = useRef<HTMLDivElement>(null);
   const spacerElement = useRef<HTMLDivElement>(null);
   const cellOutline = useRef<HTMLDivElement>(null);
   const areaOutline = useRef<HTMLDivElement>(null);
@@ -45,8 +47,11 @@ function Worksheet(props: {
 
   const ignoreScrollEventRef = useRef(false);
 
+  const [originalText, setOriginalText] = useState("");
+
   const { model, workbookState, refresh } = props;
   const [clientWidth, clientHeight] = useWindowSize();
+
   useEffect(() => {
     const canvasRef = canvasElement.current;
     const columnGuideRef = columnResizeGuide.current;
@@ -58,6 +63,7 @@ function Worksheet(props: {
     const handle = cellOutlineHandle.current;
     const area = areaOutline.current;
     const extendTo = extendToOutline.current;
+    const editor = editorElement.current;
 
     if (
       !canvasRef ||
@@ -69,7 +75,8 @@ function Worksheet(props: {
       !handle ||
       !area ||
       !extendTo ||
-      !scrollElement.current
+      !scrollElement.current ||
+      !editor
     )
       return;
     model.setWindowWidth(clientWidth - 37);
@@ -88,6 +95,7 @@ function Worksheet(props: {
         cellOutlineHandle: handle,
         areaOutline: area,
         extendToOutline: extendTo,
+        editor: editor,
       },
       onColumnWidthChanges(sheet, column, width) {
         model.setColumnWidth(sheet, column, width);
@@ -100,7 +108,7 @@ function Worksheet(props: {
     });
     const scrollX = model.getScrollX();
     const scrollY = model.getScrollY();
-    const [sheetWidth, sheetHeight] = [scrollX + 100_000, scrollY + 500_000]; //canvas.getSheetDimensions();
+    const [sheetWidth, sheetHeight] = [scrollX + 100_000, scrollY + 500_000];
     if (spacerElement.current) {
       spacerElement.current.style.height = `${sheetHeight}px`;
       spacerElement.current.style.width = `${sheetWidth}px`;
@@ -127,10 +135,6 @@ function Worksheet(props: {
     worksheetCanvas.current = canvas;
   });
 
-  const sheetNames = model
-    .getWorksheetsProperties()
-    .map((s: { name: string }) => s.name);
-
   const {
     onPointerMove,
     onPointerDown,
@@ -138,6 +142,9 @@ function Worksheet(props: {
     onPointerUp,
     // onContextMenu,
   } = usePointer({
+    model,
+    workbookState,
+    refresh,
     onCellSelected: (cell: Cell, event: React.MouseEvent) => {
       event.preventDefault();
       event.stopPropagation();
@@ -310,21 +317,49 @@ function Worksheet(props: {
       <SheetContainer
         className="sheet-container"
         ref={worksheetElement}
-        onPointerDown={(event) => {
+        onPointerDown={onPointerDown}
-          onPointerDown(event);
-        }}
         onPointerMove={onPointerMove}
         onPointerUp={onPointerUp}
         onDoubleClick={(event) => {
+          // Starts editing cell
           const { sheet, row, column } = model.getSelectedView();
-          const _text = model.getCellContent(sheet, row, column) || "";
+          const text = model.getCellContent(sheet, row, column) || "";
-          // TODO
+          workbookState.setEditingCell({
+            sheet,
+            row,
+            column,
+            text,
+            cursorStart: text.length,
+            cursorEnd: text.length,
+            focus: "cell",
+            referencedRange: null,
+            activeRanges: [],
+          });
+          setOriginalText(text);
           event.stopPropagation();
           event.preventDefault();
         }}
       >
         <SheetCanvas ref={canvasElement} />
         <CellOutline ref={cellOutline} />
+        <EditorWrapper ref={editorElement}>
+          <Editor
+            minimalWidth={"100%"}
+            minimalHeight={"100%"}
+            display={workbookState.getEditingCell()?.focus === "cell"}
+            expand={true}
+            originalText={workbookState.getEditingText() || originalText}
+            onEditEnd={(): void => {
+              props.refresh();
+            }}
+            onTextUpdated={(): void => {
+              props.refresh();
+            }}
+            model={model}
+            workbookState={workbookState}
+            type={"cell"}
+          />
+        </EditorWrapper>
         <AreaOutline ref={areaOutline} />
         <ExtendToOutline ref={extendToOutline} />
         <CellOutlineHandle
@@ -461,4 +496,21 @@ const ExtendToOutline = styled("div")`
   border-radius: 3px;
 `;
 
+const EditorWrapper = styled("div")`
+  position: absolute;
+  width: 100%;
+  padding: 0px;
+  border-width: 0px;
+  outline: none;
+  resize: none;
+  white-space: pre-wrap;
+  vertical-align: bottom;
+  overflow: hidden;
+  text-align: left;
+  span {
+    min-width: 1px;
+  }
+  font-family: monospace;
+`;
+
 export default Worksheet;

webapp/src/icons/index.ts

@@ -20,6 +20,8 @@ import InsertColumnRightIcon from "./insert-column-right.svg?react";
 import InsertRowAboveIcon from "./insert-row-above.svg?react";
 import InsertRowBelow from "./insert-row-below.svg?react";
 
+import IronCalcLogo from "./orange+black.svg?react";
+
 import Fx from "./fx.svg?react";
 
 export {
@@ -42,5 +44,6 @@ export {
   InsertColumnRightIcon,
   InsertRowAboveIcon,
   InsertRowBelow,
+  IronCalcLogo,
   Fx,
 };

webapp/src/index.css

@@ -1,4 +1,5 @@
 body {
+  inset: 0px;
   margin: 0;
   padding: 0;
 }

webapp/src/main.tsx

@@ -1,8 +1,8 @@
-import React from "react";
 import ReactDOM from "react-dom/client";
 import App from "./App.tsx";
 import "./index.css";
 import ThemeProvider from "@mui/material/styles/ThemeProvider";
+import React from "react";
 import { theme } from "./theme.ts";
 
 // biome-ignore lint: we know the 'root' element exists.