/*!
# GRAMAR

<pre class="rust">
opComp   => '=' | '<' | '>' | '<=' } '>=' | '<>'
opFactor => '*' | '/'
unaryOp  => '-' | '+'

expr    => concat (opComp concat)*
concat  => term ('&' term)*
term    => factor (opFactor factor)*
factor  => prod (opProd prod)*
prod    => power ('^' power)*
power   => (unaryOp)* range '%'*
range   => primary (':' primary)?
primary => '(' expr ')'
        => number
        => function '(' f_args ')'
        => name
        => string
        => '{' a_args '}'
        => bool
        => bool()
        => error

f_args  => e (',' e)*
</pre>
*/

use std::collections::HashMap;

use crate::functions::Function;
use crate::language::get_language;
use crate::locale::get_locale;
use crate::types::Table;

use super::lexer;
use super::token;
use super::token::OpUnary;
use super::token::TableReference;
use super::token::TokenType;
use super::types::*;
use super::utils::number_to_column;

use token::OpCompare;

pub mod move_formula;
pub mod stringify;
pub mod walk;

#[cfg(test)]
mod tests;

pub(crate) fn parse_range(formula: &str) -> Result<(i32, i32, i32, i32), String> {
    let mut lexer = lexer::Lexer::new(
        formula,
        lexer::LexerMode::A1,
        #[allow(clippy::expect_used)]
        get_locale("en").expect(""),
        #[allow(clippy::expect_used)]
        get_language("en").expect(""),
    );
    if let TokenType::Range {
        left,
        right,
        sheet: _,
    } = lexer.next_token()
    {
        Ok((left.column, left.row, right.column, right.row))
    } else {
        Err("Not a range".to_string())
    }
}

fn get_table_column_by_name(table_column_name: &str, table: &Table) -> Option<i32> {
    for (index, table_column) in table.columns.iter().enumerate() {
        if table_column.name == table_column_name {
            return Some(index as i32);
        }
    }
    None
}

pub(crate) struct Reference<'a> {
    sheet_name: &'a Option<String>,
    sheet_index: u32,
    absolute_row: bool,
    absolute_column: bool,
    row: i32,
    column: i32,
}

#[derive(PartialEq, Clone, Debug)]
pub enum Node {
    BooleanKind(bool),
    NumberKind(f64),
    StringKind(String),
    ReferenceKind {
        sheet_name: Option<String>,
        sheet_index: u32,
        absolute_row: bool,
        absolute_column: bool,
        row: i32,
        column: i32,
    },
    RangeKind {
        sheet_name: Option<String>,
        sheet_index: u32,
        absolute_row1: bool,
        absolute_column1: bool,
        row1: i32,
        column1: i32,
        absolute_row2: bool,
        absolute_column2: bool,
        row2: i32,
        column2: i32,
    },
    WrongReferenceKind {
        sheet_name: Option<String>,
        absolute_row: bool,
        absolute_column: bool,
        row: i32,
        column: i32,
    },
    WrongRangeKind {
        sheet_name: Option<String>,
        absolute_row1: bool,
        absolute_column1: bool,
        row1: i32,
        column1: i32,
        absolute_row2: bool,
        absolute_column2: bool,
        row2: i32,
        column2: i32,
    },
    OpRangeKind {
        left: Box<Node>,
        right: Box<Node>,
    },
    OpConcatenateKind {
        left: Box<Node>,
        right: Box<Node>,
    },
    OpSumKind {
        kind: token::OpSum,
        left: Box<Node>,
        right: Box<Node>,
    },
    OpProductKind {
        kind: token::OpProduct,
        left: Box<Node>,
        right: Box<Node>,
    },
    OpPowerKind {
        left: Box<Node>,
        right: Box<Node>,
    },
    FunctionKind {
        kind: Function,
        args: Vec<Node>,
    },
    InvalidFunctionKind {
        name: String,
        args: Vec<Node>,
    },
    ArrayKind(Vec<Node>),
    VariableKind(String),
    CompareKind {
        kind: OpCompare,
        left: Box<Node>,
        right: Box<Node>,
    },
    UnaryKind {
        kind: OpUnary,
        right: Box<Node>,
    },
    ErrorKind(token::Error),
    ParseErrorKind {
        formula: String,
        message: String,
        position: usize,
    },
    EmptyArgKind,
}

#[derive(Clone)]
pub struct Parser {
    lexer: lexer::Lexer,
    worksheets: Vec<String>,
    context: Option<CellReferenceRC>,
    tables: HashMap<String, Table>,
}

impl Parser {
    pub fn new(worksheets: Vec<String>, tables: HashMap<String, Table>) -> Parser {
        let lexer = lexer::Lexer::new(
            "",
            lexer::LexerMode::A1,
            #[allow(clippy::expect_used)]
            get_locale("en").expect(""),
            #[allow(clippy::expect_used)]
            get_language("en").expect(""),
        );
        Parser {
            lexer,
            worksheets,
            context: None,
            tables,
        }
    }
    pub fn set_lexer_mode(&mut self, mode: lexer::LexerMode) {
        self.lexer.set_lexer_mode(mode)
    }

    pub fn set_worksheets(&mut self, worksheets: Vec<String>) {
        self.worksheets = worksheets;
    }

    pub fn parse(&mut self, formula: &str, context: &Option<CellReferenceRC>) -> Node {
        self.lexer.set_formula(formula);
        self.context.clone_from(context);
        self.parse_expr()
    }

    fn get_sheet_index_by_name(&self, name: &str) -> Option<u32> {
        let worksheets = &self.worksheets;
        for (i, sheet) in worksheets.iter().enumerate() {
            if sheet == name {
                return Some(i as u32);
            }
        }
        None
    }

    fn parse_expr(&mut self) -> Node {
        let mut t = self.parse_concat();
        if let Node::ParseErrorKind { .. } = t {
            return t;
        }
        let mut next_token = self.lexer.peek_token();
        while let TokenType::Compare(op) = next_token {
            self.lexer.advance_token();
            let p = self.parse_concat();
            if let Node::ParseErrorKind { .. } = p {
                return p;
            }
            t = Node::CompareKind {
                kind: op,
                left: Box::new(t),
                right: Box::new(p),
            };
            next_token = self.lexer.peek_token();
        }
        t
    }

    fn parse_concat(&mut self) -> Node {
        let mut t = self.parse_term();
        if let Node::ParseErrorKind { .. } = t {
            return t;
        }
        let mut next_token = self.lexer.peek_token();
        while next_token == TokenType::And {
            self.lexer.advance_token();
            let p = self.parse_term();
            if let Node::ParseErrorKind { .. } = p {
                return p;
            }
            t = Node::OpConcatenateKind {
                left: Box::new(t),
                right: Box::new(p),
            };
            next_token = self.lexer.peek_token();
        }
        t
    }

    fn parse_term(&mut self) -> Node {
        let mut t = self.parse_factor();
        if let Node::ParseErrorKind { .. } = t {
            return t;
        }
        let mut next_token = self.lexer.peek_token();
        while let TokenType::Addition(op) = next_token {
            self.lexer.advance_token();
            let p = self.parse_factor();
            if let Node::ParseErrorKind { .. } = p {
                return p;
            }
            t = Node::OpSumKind {
                kind: op,
                left: Box::new(t),
                right: Box::new(p),
            };

            next_token = self.lexer.peek_token();
        }
        t
    }

    fn parse_factor(&mut self) -> Node {
        let mut t = self.parse_prod();
        if let Node::ParseErrorKind { .. } = t {
            return t;
        }
        let mut next_token = self.lexer.peek_token();
        while let TokenType::Product(op) = next_token {
            self.lexer.advance_token();
            let p = self.parse_prod();
            if let Node::ParseErrorKind { .. } = p {
                return p;
            }
            t = Node::OpProductKind {
                kind: op,
                left: Box::new(t),
                right: Box::new(p),
            };
            next_token = self.lexer.peek_token();
        }
        t
    }

    fn parse_prod(&mut self) -> Node {
        let mut t = self.parse_power();
        if let Node::ParseErrorKind { .. } = t {
            return t;
        }
        let mut next_token = self.lexer.peek_token();
        while next_token == TokenType::Power {
            self.lexer.advance_token();
            let p = self.parse_power();
            if let Node::ParseErrorKind { .. } = p {
                return p;
            }
            t = Node::OpPowerKind {
                left: Box::new(t),
                right: Box::new(p),
            };
            next_token = self.lexer.peek_token();
        }
        t
    }

    fn parse_power(&mut self) -> Node {
        let mut next_token = self.lexer.peek_token();
        let mut sign = 1;
        while let TokenType::Addition(op) = next_token {
            self.lexer.advance_token();
            if op == token::OpSum::Minus {
                sign = -sign;
            }
            next_token = self.lexer.peek_token();
        }

        let mut t = self.parse_range();
        if let Node::ParseErrorKind { .. } = t {
            return t;
        }
        if sign == -1 {
            t = Node::UnaryKind {
                kind: token::OpUnary::Minus,
                right: Box::new(t),
            }
        }
        next_token = self.lexer.peek_token();
        while next_token == TokenType::Percent {
            self.lexer.advance_token();
            t = Node::UnaryKind {
                kind: token::OpUnary::Percentage,
                right: Box::new(t),
            };
            next_token = self.lexer.peek_token();
        }
        t
    }

    fn parse_range(&mut self) -> Node {
        let t = self.parse_primary();
        if let Node::ParseErrorKind { .. } = t {
            return t;
        }
        let next_token = self.lexer.peek_token();
        if next_token == TokenType::Colon {
            self.lexer.advance_token();
            let p = self.parse_primary();
            if let Node::ParseErrorKind { .. } = p {
                return p;
            }
            return Node::OpRangeKind {
                left: Box::new(t),
                right: Box::new(p),
            };
        }
        t
    }

    fn parse_primary(&mut self) -> Node {
        let next_token = self.lexer.next_token();
        match next_token {
            TokenType::LeftParenthesis => {
                let t = self.parse_expr();
                if let Node::ParseErrorKind { .. } = t {
                    return t;
                }

                if let Err(err) = self.lexer.expect(TokenType::RightParenthesis) {
                    return Node::ParseErrorKind {
                        formula: self.lexer.get_formula(),
                        position: err.position,
                        message: err.message,
                    };
                }
                t
            }
            TokenType::Number(s) => Node::NumberKind(s),
            TokenType::String(s) => Node::StringKind(s),
            TokenType::LeftBrace => {
                let t = self.parse_expr();
                if let Node::ParseErrorKind { .. } = t {
                    return t;
                }
                let mut next_token = self.lexer.peek_token();
                let mut args: Vec<Node> = vec![t];
                while next_token == TokenType::Semicolon {
                    self.lexer.advance_token();
                    let p = self.parse_expr();
                    if let Node::ParseErrorKind { .. } = p {
                        return p;
                    }
                    next_token = self.lexer.peek_token();
                    args.push(p);
                }
                if let Err(err) = self.lexer.expect(TokenType::RightBrace) {
                    return Node::ParseErrorKind {
                        formula: self.lexer.get_formula(),
                        position: err.position,
                        message: err.message,
                    };
                }
                Node::ArrayKind(args)
            }
            TokenType::Reference {
                sheet,
                row,
                column,
                absolute_column,
                absolute_row,
            } => {
                let context = match &self.context {
                    Some(c) => c,
                    None => {
                        return Node::ParseErrorKind {
                            formula: self.lexer.get_formula(),
                            position: self.lexer.get_position() as usize,
                            message: "Expected context for the reference".to_string(),
                        }
                    }
                };
                let sheet_index = match &sheet {
                    Some(name) => self.get_sheet_index_by_name(name),
                    None => self.get_sheet_index_by_name(&context.sheet),
                };
                let a1_mode = self.lexer.is_a1_mode();
                let row = if absolute_row || !a1_mode {
                    row
                } else {
                    row - context.row
                };
                let column = if absolute_column || !a1_mode {
                    column
                } else {
                    column - context.column
                };
                match sheet_index {
                    Some(index) => Node::ReferenceKind {
                        sheet_name: sheet,
                        sheet_index: index,
                        row,
                        column,
                        absolute_row,
                        absolute_column,
                    },
                    None => Node::WrongReferenceKind {
                        sheet_name: sheet,
                        row,
                        column,
                        absolute_row,
                        absolute_column,
                    },
                }
            }
            TokenType::Range { sheet, left, right } => {
                let context = match &self.context {
                    Some(c) => c,
                    None => {
                        return Node::ParseErrorKind {
                            formula: self.lexer.get_formula(),
                            position: self.lexer.get_position() as usize,
                            message: "Expected context for the reference".to_string(),
                        }
                    }
                };
                let sheet_index = match &sheet {
                    Some(name) => self.get_sheet_index_by_name(name),
                    None => self.get_sheet_index_by_name(&context.sheet),
                };
                let mut row1 = left.row;
                let mut column1 = left.column;
                let mut row2 = right.row;
                let mut column2 = right.column;

                let mut absolute_column1 = left.absolute_column;
                let mut absolute_column2 = right.absolute_column;
                let mut absolute_row1 = left.absolute_row;
                let mut absolute_row2 = right.absolute_row;

                if row1 > row2 {
                    (row2, row1) = (row1, row2);
                    (absolute_row2, absolute_row1) = (absolute_row1, absolute_row2);
                }
                if column1 > column2 {
                    (column2, column1) = (column1, column2);
                    (absolute_column2, absolute_column1) = (absolute_column1, absolute_column2);
                }

                if self.lexer.is_a1_mode() {
                    if !absolute_row1 {
                        row1 -= context.row
                    };
                    if !absolute_column1 {
                        column1 -= context.column
                    };
                    if !absolute_row2 {
                        row2 -= context.row
                    };
                    if !absolute_column2 {
                        column2 -= context.column
                    };
                }

                match sheet_index {
                    Some(index) => Node::RangeKind {
                        sheet_name: sheet,
                        sheet_index: index,
                        row1,
                        column1,
                        row2,
                        column2,
                        absolute_column1,
                        absolute_column2,
                        absolute_row1,
                        absolute_row2,
                    },
                    None => Node::WrongRangeKind {
                        sheet_name: sheet,
                        row1,
                        column1,
                        row2,
                        column2,
                        absolute_column1,
                        absolute_column2,
                        absolute_row1,
                        absolute_row2,
                    },
                }
            }
            TokenType::Ident(name) => {
                let next_token = self.lexer.peek_token();
                if next_token == TokenType::LeftParenthesis {
                    // It's a function call "SUM(.."
                    self.lexer.advance_token();
                    let args = match self.parse_function_args() {
                        Ok(s) => s,
                        Err(e) => return e,
                    };
                    if let Err(err) = self.lexer.expect(TokenType::RightParenthesis) {
                        return Node::ParseErrorKind {
                            formula: self.lexer.get_formula(),
                            position: err.position,
                            message: err.message,
                        };
                    }
                    if let Some(function_kind) = Function::get_function(&name) {
                        return Node::FunctionKind {
                            kind: function_kind,
                            args,
                        };
                    } else {
                        return Node::InvalidFunctionKind { name, args };
                    }
                }
                Node::VariableKind(name)
            }
            TokenType::Error(kind) => Node::ErrorKind(kind),
            TokenType::Illegal(error) => Node::ParseErrorKind {
                formula: self.lexer.get_formula(),
                position: error.position,
                message: error.message,
            },
            TokenType::EOF => Node::ParseErrorKind {
                formula: self.lexer.get_formula(),
                position: 0,
                message: "Unexpected end of input.".to_string(),
            },
            TokenType::Boolean(value) => Node::BooleanKind(value),
            TokenType::Compare(_) => {
                // A primary Node cannot start with an operator
                Node::ParseErrorKind {
                    formula: self.lexer.get_formula(),
                    position: 0,
                    message: "Unexpected token: 'COMPARE'".to_string(),
                }
            }
            TokenType::Addition(_) => {
                // A primary Node cannot start with an operator
                Node::ParseErrorKind {
                    formula: self.lexer.get_formula(),
                    position: 0,
                    message: "Unexpected token: 'SUM'".to_string(),
                }
            }
            TokenType::Product(_) => {
                // A primary Node cannot start with an operator
                Node::ParseErrorKind {
                    formula: self.lexer.get_formula(),
                    position: 0,
                    message: "Unexpected token: 'PRODUCT'".to_string(),
                }
            }
            TokenType::Power => {
                // A primary Node cannot start with an operator
                Node::ParseErrorKind {
                    formula: self.lexer.get_formula(),
                    position: 0,
                    message: "Unexpected token: 'POWER'".to_string(),
                }
            }
            TokenType::RightParenthesis
            | TokenType::RightBracket
            | TokenType::Colon
            | TokenType::Semicolon
            | TokenType::RightBrace
            | TokenType::Comma
            | TokenType::Bang
            | TokenType::And
            | TokenType::Percent => Node::ParseErrorKind {
                formula: self.lexer.get_formula(),
                position: 0,
                message: format!("Unexpected token: '{:?}'", next_token),
            },
            TokenType::LeftBracket => Node::ParseErrorKind {
                formula: self.lexer.get_formula(),
                position: 0,
                message: "Unexpected token: '['".to_string(),
            },
            TokenType::StructuredReference {
                table_name,
                specifier,
                table_reference,
            } => {
                // We will try to convert to a normal reference
                // table_name[column_name] => cell1:cell2
                // table_name[[#This Row], [column_name]:[column_name]] => cell1:cell2
                if let Some(context) = &self.context {
                    let context_sheet_index = match self.get_sheet_index_by_name(&context.sheet) {
                        Some(i) => i,
                        None => {
                            return Node::ParseErrorKind {
                                formula: self.lexer.get_formula(),
                                position: 0,
                                message: "sheet not found".to_string(),
                            };
                        }
                    };
                    // table-name => table
                    let table = match self.tables.get(&table_name) {
                        Some(t) => t,
                        None => {
                            let message = format!(
                                "Table not found: '{table_name}' at '{}!{}{}'",
                                context.sheet,
                                number_to_column(context.column)
                                    .unwrap_or(format!("{}", context.column)),
                                context.row
                            );
                            return Node::ParseErrorKind {
                                formula: self.lexer.get_formula(),
                                position: 0,
                                message,
                            };
                        }
                    };
                    let table_sheet_index = match self.get_sheet_index_by_name(&table.sheet_name) {
                        Some(i) => i,
                        None => {
                            return Node::ParseErrorKind {
                                formula: self.lexer.get_formula(),
                                position: 0,
                                message: "sheet not found".to_string(),
                            };
                        }
                    };

                    let sheet_name = if table_sheet_index == context_sheet_index {
                        None
                    } else {
                        Some(table.sheet_name.clone())
                    };

                    // context must be with tables.reference
                    #[allow(clippy::expect_used)]
                    let (column_start, mut row_start, column_end, mut row_end) =
                        parse_range(&table.reference).expect("Failed parsing range");

                    let totals_row_count = table.totals_row_count as i32;
                    let header_row_count = table.header_row_count as i32;
                    row_end -= totals_row_count;

                    match specifier {
                        Some(token::TableSpecifier::ThisRow) => {
                            row_start = context.row;
                            row_end = context.row;
                        }
                        Some(token::TableSpecifier::Totals) => {
                            if totals_row_count != 0 {
                                row_start = row_end + 1;
                                row_end = row_start;
                            } else {
                                // Table1[#Totals] is #REF! if Table1 does not have totals
                                return Node::ErrorKind(token::Error::REF);
                            }
                        }
                        Some(token::TableSpecifier::Headers) => {
                            row_end = row_start;
                        }
                        Some(token::TableSpecifier::Data) => {
                            row_start += header_row_count;
                        }
                        Some(token::TableSpecifier::All) => {
                            if totals_row_count != 0 {
                                row_end += 1;
                            }
                        }
                        None => {
                            // skip the headers
                            row_start += header_row_count;
                        }
                    }
                    match table_reference {
                        None => {
                            return Node::RangeKind {
                                sheet_name,
                                sheet_index: table_sheet_index,
                                absolute_row1: true,
                                absolute_column1: true,
                                row1: row_start,
                                column1: column_start,
                                absolute_row2: true,
                                absolute_column2: true,
                                row2: row_end,
                                column2: column_end,
                            };
                        }
                        Some(TableReference::ColumnReference(s)) => {
                            let column_index = match get_table_column_by_name(&s, table) {
                                Some(s) => s + column_start,
                                None => {
                                    return Node::ParseErrorKind {
                                        formula: self.lexer.get_formula(),
                                        position: self.lexer.get_position() as usize,
                                        message: format!(
                                            "Expecting column: {s} in table {table_name}"
                                        ),
                                    };
                                }
                            };
                            if row_start == row_end {
                                return Node::ReferenceKind {
                                    sheet_name,
                                    sheet_index: table_sheet_index,
                                    absolute_row: true,
                                    absolute_column: true,
                                    row: row_start,
                                    column: column_index,
                                };
                            }
                            return Node::RangeKind {
                                sheet_name,
                                sheet_index: table_sheet_index,
                                absolute_row1: true,
                                absolute_column1: true,
                                row1: row_start,
                                column1: column_index,
                                absolute_row2: true,
                                absolute_column2: true,
                                row2: row_end,
                                column2: column_index,
                            };
                        }
                        Some(TableReference::RangeReference((left, right))) => {
                            let left_column_index = match get_table_column_by_name(&left, table) {
                                Some(f) => f + column_start,
                                None => {
                                    return Node::ParseErrorKind {
                                        formula: self.lexer.get_formula(),
                                        position: self.lexer.get_position() as usize,
                                        message: format!(
                                            "Expecting column: {left} in table {table_name}"
                                        ),
                                    };
                                }
                            };

                            let right_column_index = match get_table_column_by_name(&right, table) {
                                Some(f) => f + column_start,
                                None => {
                                    return Node::ParseErrorKind {
                                        formula: self.lexer.get_formula(),
                                        position: self.lexer.get_position() as usize,
                                        message: format!(
                                            "Expecting column: {right} in table {table_name}"
                                        ),
                                    };
                                }
                            };
                            return Node::RangeKind {
                                sheet_name,
                                sheet_index: table_sheet_index,
                                absolute_row1: true,
                                absolute_column1: true,
                                row1: row_start,
                                column1: left_column_index,
                                absolute_row2: true,
                                absolute_column2: true,
                                row2: row_end,
                                column2: right_column_index,
                            };
                        }
                    }
                }
                Node::ParseErrorKind {
                    formula: self.lexer.get_formula(),
                    position: 0,
                    message: "Structured references not supported in R1C1 mode".to_string(),
                }
            }
        }
    }

    fn parse_function_args(&mut self) -> Result<Vec<Node>, Node> {
        let mut args: Vec<Node> = Vec::new();
        let mut next_token = self.lexer.peek_token();
        if next_token == TokenType::RightParenthesis {
            return Ok(args);
        }
        if self.lexer.peek_token() == TokenType::Comma {
            args.push(Node::EmptyArgKind);
        } else {
            let t = self.parse_expr();
            if let Node::ParseErrorKind { .. } = t {
                return Err(t);
            }
            args.push(t);
        }
        next_token = self.lexer.peek_token();
        while next_token == TokenType::Comma {
            self.lexer.advance_token();
            if self.lexer.peek_token() == TokenType::Comma {
                args.push(Node::EmptyArgKind);
                next_token = TokenType::Comma;
            } else if self.lexer.peek_token() == TokenType::RightParenthesis {
                args.push(Node::EmptyArgKind);
                return Ok(args);
            } else {
                let p = self.parse_expr();
                if let Node::ParseErrorKind { .. } = p {
                    return Err(p);
                }
                next_token = self.lexer.peek_token();
                args.push(p);
            }
        }
        Ok(args)
    }
}