"""Custom widget for rendering envelope list items with configurable display."""

from datetime import datetime
from typing import Any, Dict, Optional

from textual.app import ComposeResult
from textual.containers import Horizontal, Vertical
from textual.widgets import Label, Static

from src.maildir_gtd.config import EnvelopeDisplayConfig, get_config


class EnvelopeListItem(Static):
    """A widget for rendering a single envelope in the list.

    Supports configurable layout:
    - 2-line mode: sender/date on line 1, subject on line 2
    - 3-line mode: adds a preview line

    Displays read/unread status with NerdFont icons.
    """

    DEFAULT_CSS = """
    EnvelopeListItem {
        height: auto;
        width: 1fr;
        padding: 0;
    }

    EnvelopeListItem .envelope-row-1 {
        height: 1;
        width: 1fr;
    }

    EnvelopeListItem .envelope-row-2 {
        height: 1;
        width: 1fr;
    }

    EnvelopeListItem .envelope-row-3 {
        height: 1;
        width: 1fr;
    }

    EnvelopeListItem .status-icon {
        width: 2;
        padding: 0 1 0 0;
    }

    EnvelopeListItem .checkbox {
        width: 2;
        padding: 0 1 0 0;
    }

    EnvelopeListItem .sender-name {
        width: 1fr;
        color: $text-muted;
    }

    EnvelopeListItem .message-datetime {
        width: auto;
        padding: 0 1;
        color: $text-disabled;
    }

    EnvelopeListItem .email-subject {
        width: 1fr;
        padding: 0 3;
        color: $text-muted;
    }

    EnvelopeListItem .email-preview {
        width: 1fr;
        padding: 0 3;
        color: $text-muted;
    }

    EnvelopeListItem.unread .sender-name {
        text-style: bold;
        color: $text;
    }

    EnvelopeListItem.unread .message-datetime {
        color: $text-muted;
    }

    EnvelopeListItem.unread .email-subject {
        text-style: bold;
        color: $text;
    }
    """

    def __init__(
        self,
        envelope: Dict[str, Any],
        config: Optional[EnvelopeDisplayConfig] = None,
        is_selected: bool = False,
        **kwargs,
    ):
        """Initialize the envelope list item.

        Args:
            envelope: The envelope data dictionary from himalaya
            config: Display configuration (uses global config if not provided)
            is_selected: Whether this item is currently selected
        """
        super().__init__(**kwargs)
        self.envelope = envelope
        self.config = config or get_config().envelope_display
        self._is_selected = is_selected

        # Parse envelope data
        self._parse_envelope()

    def _parse_envelope(self) -> None:
        """Parse envelope data into display-ready values."""
        # Get sender info
        from_data = self.envelope.get("from", {})
        self.sender_name = from_data.get("name") or from_data.get("addr", "Unknown")
        if not self.sender_name:
            self.sender_name = from_data.get("addr", "Unknown")

        # Truncate sender name if needed
        max_len = self.config.max_sender_length
        if len(self.sender_name) > max_len:
            self.sender_name = self.sender_name[: max_len - 1] + "\u2026"  # ellipsis

        # Get subject
        self.subject = str(self.envelope.get("subject", "")).strip() or "(No subject)"

        # Parse date
        self.formatted_datetime = self._format_datetime()

        # Get read/unread status (himalaya uses "flags" field)
        flags = self.envelope.get("flags", [])
        self.is_read = "Seen" in flags if isinstance(flags, list) else False
        self.is_flagged = "Flagged" in flags if isinstance(flags, list) else False
        self.has_attachment = (
            "Attachments" in flags if isinstance(flags, list) else False
        )

        # Message ID for selection tracking
        self.message_id = int(self.envelope.get("id", 0))

    def _format_datetime(self) -> str:
        """Format the message date/time according to config."""
        date_str = self.envelope.get("date", "")
        if not date_str:
            return ""

        try:
            # Parse ISO format date
            if "Z" in date_str:
                date_str = date_str.replace("Z", "+00:00")
            dt = datetime.fromisoformat(date_str)

            # Convert to local timezone
            dt = dt.astimezone()

            parts = []
            if self.config.show_date:
                parts.append(dt.strftime(self.config.date_format))
            if self.config.show_time:
                parts.append(dt.strftime(self.config.time_format))

            return " ".join(parts)
        except (ValueError, TypeError):
            return "Invalid Date"

    def compose(self) -> ComposeResult:
        """Compose the widget layout."""
        # Determine status icon
        if self.is_read:
            status_icon = self.config.icon_read
            status_class = "status-icon read"
        else:
            status_icon = self.config.icon_unread
            status_class = "status-icon unread"

        # Add flagged/attachment indicators
        extra_icons = ""
        if self.is_flagged:
            extra_icons += f" {self.config.icon_flagged}"
        if self.has_attachment:
            extra_icons += f" {self.config.icon_attachment}"

        # Build the layout based on config.lines
        with Vertical(classes="envelope-content"):
            # Row 1: Status icon, checkbox, sender, datetime
            with Horizontal(classes="envelope-row-1"):
                yield Label(status_icon + extra_icons, classes=status_class)
                if self.config.show_checkbox:
                    checkbox_char = "\uf4a7" if self._is_selected else "\ue640"
                    yield Label(checkbox_char, classes="checkbox")
                yield Label(self.sender_name, classes="sender-name", markup=False)
                yield Label(self.formatted_datetime, classes="message-datetime")

            # Row 2: Subject
            with Horizontal(classes="envelope-row-2"):
                yield Label(self.subject, classes="email-subject", markup=False)

            # Row 3: Preview (only in 3-line mode with preview enabled)
            if self.config.lines == 3 and self.config.show_preview:
                preview = self.envelope.get("preview", "")[:60]
                if preview:
                    with Horizontal(classes="envelope-row-3"):
                        yield Label(preview, classes="email-preview", markup=False)

    def on_mount(self) -> None:
        """Set up classes on mount."""
        if not self.is_read:
            self.add_class("unread")
        if self._is_selected:
            self.add_class("selected")

    def set_selected(self, selected: bool) -> None:
        """Update the selection state."""
        self._is_selected = selected
        if selected:
            self.add_class("selected")
        else:
            self.remove_class("selected")

        # Update checkbox display
        if self.config.show_checkbox:
            try:
                checkbox = self.query_one(".checkbox", Label)
                checkbox.update("\uf4a7" if selected else "\ue640")
            except Exception:
                pass  # Widget may not be mounted yet


class GroupHeader(Static):
    """A header widget for grouping envelopes by date."""

    DEFAULT_CSS = """
    GroupHeader {
        height: 1;
        width: 1fr;
        background: $surface;
        color: $text-muted;
        text-style: bold;
        padding: 0 1;
    }
    """

    def __init__(self, label: str, **kwargs):
        """Initialize the group header.

        Args:
            label: The header label (e.g., "Today", "December 2025")
        """
        super().__init__(**kwargs)
        self.label = label

    def compose(self) -> ComposeResult:
        """Compose just returns itself as a Static."""
        yield Label(self.label, classes="group-header-label")