rlvgl_widgets/

table.rs

//! LVGL-parity table widget with shaped-text cells (LPAR-14c).
//!
//! [`Table`] displays a grid of text cells with configurable column widths,
//! per-cell alignment, optional cell spanning, and a keyboard-navigable
//! selected-cell cursor.
//!
//! Text measurement and row-height computation use the LPAR-08 shared
//! measurement primitives (`wrap_greedy_ltr`, `shape_text_ltr`) — no parallel
//! text measurement is introduced.
//!
//! # Navigation
//!
//! Wire the navigate helpers to `ObjectEvent::Key` in a node handler:
//!
//! ```ignore
//! table.navigate_next();      // Key::ArrowRight / Key::Tab
//! table.navigate_prev();      // Key::ArrowLeft  / Key::BackTab
//! table.navigate_up();        // Key::ArrowUp
//! table.navigate_down();      // Key::ArrowDown
//! table.activate_selected();  // Key::Enter
//! ```

use alloc::string::String;
use alloc::vec::Vec;

use rlvgl_core::draw::draw_widget_bg;
use rlvgl_core::event::Event;
use rlvgl_core::font::{FontMetrics, WidgetFont, shape_text_ltr, wrap_greedy_ltr};
use rlvgl_core::renderer::{ClipRenderer, Renderer};
use rlvgl_core::style::Style;
use rlvgl_core::widget::{Color, Rect, Widget};

// ---------------------------------------------------------------------------
// CellCtrl
// ---------------------------------------------------------------------------

/// Bit-flags controlling individual cell appearance and layout.
///
/// Registration policy: **Specification Required**.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub struct CellCtrl(pub u8);

impl CellCtrl {
    /// No special behavior.
    pub const NONE: Self = Self(0);
    /// The cell visually spans into the next column (both widths are consumed).
    pub const MERGE_RIGHT: Self = Self(1 << 0);
    /// Suppress wrapping; crop text to the column width instead.
    pub const TEXT_CROP: Self = Self(1 << 1);

    /// Return `true` when `flag` is set.
    pub fn contains(self, flag: Self) -> bool {
        self.0 & flag.0 != 0
    }
}

impl core::ops::BitOr for CellCtrl {
    type Output = Self;
    fn bitor(self, rhs: Self) -> Self {
        Self(self.0 | rhs.0)
    }
}

// ---------------------------------------------------------------------------
// CellAlign
// ---------------------------------------------------------------------------

/// Horizontal text alignment within a table cell.
///
/// Registration policy: **Specification Required**.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum CellAlign {
    /// Align text to the left edge of the cell.
    #[default]
    Left,
    /// Center text horizontally in the cell.
    Center,
    /// Align text to the right edge of the cell.
    Right,
}

// ---------------------------------------------------------------------------
// Internal cell storage
// ---------------------------------------------------------------------------

#[derive(Default)]
struct Cell {
    text: Option<String>,
    ctrl: CellCtrl,
    align: CellAlign,
}

// ---------------------------------------------------------------------------
// Table
// ---------------------------------------------------------------------------

/// LVGL-parity table widget.
///
/// Stores cells as a flat row-major `Vec`; column widths as a `Vec<i32>`.
/// Row heights are computed dynamically from the cell content using the
/// LPAR-08 shared `wrap_greedy_ltr` measurement.
pub struct Table {
    bounds: Rect,
    rows: usize,
    cols: usize,
    cells: Vec<Cell>,
    col_widths: Vec<i32>,
    /// Row heights computed from content (cached; recomputed on set_bounds).
    row_heights: Vec<i32>,
    selected_row: Option<usize>,
    selected_col: Option<usize>,
    /// Last activated cell poll slot.
    last_activated: Option<(usize, usize)>,
    /// Background and outer border style.
    pub style: Style,
    /// Color for cell background and grid lines.
    pub cell_bg_color: Color,
    /// Color for the selected cell background.
    pub selected_color: Color,
    /// Text color.
    pub text_color: Color,
    /// Grid line color.
    pub grid_color: Color,
    /// Font assignment for this widget (FONT-00 §5); resolves to `FONT_6X10`
    /// when unset.
    font: WidgetFont,
}

impl Table {
    /// Create an empty table at `bounds` with `0` rows and `0` columns.
    pub fn new(bounds: Rect) -> Self {
        Self {
            bounds,
            rows: 0,
            cols: 0,
            cells: Vec::new(),
            col_widths: Vec::new(),
            row_heights: Vec::new(),
            selected_row: None,
            selected_col: None,
            last_activated: None,
            style: Style::default(),
            cell_bg_color: Color(240, 240, 240, 255),
            selected_color: Color(100, 160, 230, 255),
            text_color: Color(30, 30, 30, 255),
            grid_color: Color(180, 180, 180, 255),
            font: WidgetFont::new(),
        }
    }

    /// Assign the font used to render this widget (FONT-00 §5); resolves to
    /// `FONT_6X10` when unset.
    pub fn set_font(&mut self, font: &'static dyn FontMetrics) {
        self.font.set(font);
    }

    // ── Dimensions ────────────────────────────────────────────────────────

    /// Return the number of rows.
    pub fn row_count(&self) -> usize {
        self.rows
    }

    /// Return the number of columns.
    pub fn column_count(&self) -> usize {
        self.cols
    }

    /// Set the number of rows, extending or truncating the cell vector.
    pub fn set_row_count(&mut self, rows: usize) {
        self.cells.resize_with(rows * self.cols, Cell::default);
        self.rows = rows;
        self.recompute_row_heights();
    }

    /// Set the number of columns, extending or truncating; preserves existing
    /// cell content where indices overlap.
    pub fn set_column_count(&mut self, cols: usize) {
        if cols == self.cols {
            return;
        }
        let mut new_cells: Vec<Cell> = Vec::with_capacity(self.rows * cols);
        for r in 0..self.rows {
            for c in 0..cols {
                let cell = if c < self.cols {
                    let old_idx = r * self.cols + c;
                    let old = &self.cells[old_idx];
                    Cell {
                        text: old.text.clone(),
                        ctrl: old.ctrl,
                        align: old.align,
                    }
                } else {
                    Cell::default()
                };
                new_cells.push(cell);
            }
        }
        self.cells = new_cells;
        self.col_widths.resize(cols, 0);
        self.cols = cols;
        self.recompute_row_heights();
    }

    // ── Cell accessors ────────────────────────────────────────────────────

    fn cell_index(&self, row: usize, col: usize) -> Option<usize> {
        if row < self.rows && col < self.cols {
            Some(row * self.cols + col)
        } else {
            None
        }
    }

    /// Set the text value of a cell.
    ///
    /// Out-of-bounds indices are silently ignored (matching LVGL behavior).
    pub fn set_cell_value(&mut self, row: usize, col: usize, text: &str) {
        if let Some(idx) = self.cell_index(row, col) {
            self.cells[idx].text = Some(String::from(text));
            self.recompute_row_heights();
        }
    }

    /// Return the text value of a cell, or `None` if empty or out of bounds.
    pub fn cell_value(&self, row: usize, col: usize) -> Option<&str> {
        self.cell_index(row, col)
            .and_then(|idx| self.cells[idx].text.as_deref())
    }

    /// Set control flags for a cell.
    pub fn set_cell_ctrl(&mut self, row: usize, col: usize, ctrl: CellCtrl) {
        if let Some(idx) = self.cell_index(row, col) {
            self.cells[idx].ctrl = ctrl;
        }
    }

    /// Return control flags for a cell.
    pub fn cell_ctrl(&self, row: usize, col: usize) -> CellCtrl {
        self.cell_index(row, col)
            .map(|idx| self.cells[idx].ctrl)
            .unwrap_or(CellCtrl::NONE)
    }

    /// Set horizontal alignment for a cell.
    pub fn set_cell_align(&mut self, row: usize, col: usize, align: CellAlign) {
        if let Some(idx) = self.cell_index(row, col) {
            self.cells[idx].align = align;
        }
    }

    // ── Column widths ─────────────────────────────────────────────────────

    /// Set the pixel width of column `col`.
    ///
    /// A width of `0` means "auto" — the column participates in the remaining
    /// width distribution.
    pub fn set_column_width(&mut self, col: usize, width: i32) {
        if col < self.cols {
            self.col_widths[col] = width;
        }
    }

    /// Return the stored column width (0 = auto).
    pub fn column_width(&self, col: usize) -> i32 {
        self.col_widths.get(col).copied().unwrap_or(0)
    }

    /// Resolve effective column widths, distributing remaining space evenly
    /// among auto columns.
    fn resolved_col_widths(&self) -> Vec<i32> {
        if self.cols == 0 {
            return Vec::new();
        }
        let mut widths = self.col_widths.clone();
        widths.resize(self.cols, 0);

        let explicit_total: i32 = widths.iter().map(|&w| w.max(0)).sum();
        let auto_count = widths.iter().filter(|&&w| w == 0).count();
        let remaining = (self.bounds.width - explicit_total).max(0);
        let auto_w = if auto_count > 0 {
            remaining / auto_count as i32
        } else {
            0
        };

        for w in &mut widths {
            if *w == 0 {
                *w = auto_w;
            }
        }
        widths
    }

    // ── Row height computation ─────────────────────────────────────────────

    /// Recompute row heights using the LPAR-08 shared `wrap_greedy_ltr`.
    ///
    /// Each row's height is the maximum wrapped height across all cells in that
    /// row. This is the load-bearing use of the shared font measurement.
    fn recompute_row_heights(&mut self) {
        let font: &dyn FontMetrics = self.font.resolve();
        let metrics = font.line_metrics();
        let col_widths = self.resolved_col_widths();

        self.row_heights.resize(self.rows, 0);
        for r in 0..self.rows {
            let mut max_h = metrics.line_height as i32;
            for c in 0..self.cols {
                let idx = r * self.cols + c;
                let cell = &self.cells[idx];
                let Some(ref text) = cell.text else {
                    continue;
                };
                let col_w = col_widths.get(c).copied().unwrap_or(0).max(1);
                // Use the LPAR-08 shared greedy-wrap — not per-cell advance arithmetic.
                let wrap_w = if cell.ctrl.contains(CellCtrl::TEXT_CROP) {
                    i32::MAX // no wrapping; measure single line
                } else {
                    col_w
                };
                let wrapped = wrap_greedy_ltr(font, text, wrap_w, 0, 0);
                let h = wrapped.used_height.max(metrics.line_height as i32);
                if h > max_h {
                    max_h = h;
                }
            }
            self.row_heights[r] = max_h;
        }
    }

    // ── Selection ─────────────────────────────────────────────────────────

    /// Set the selected cell. Out-of-bounds is silently ignored.
    pub fn set_selected_cell(&mut self, row: usize, col: usize) {
        if row < self.rows && col < self.cols {
            self.selected_row = Some(row);
            self.selected_col = Some(col);
        }
    }

    /// Return the selected cell `(row, col)`, or `None` if nothing is selected.
    pub fn selected_cell(&self) -> Option<(usize, usize)> {
        match (self.selected_row, self.selected_col) {
            (Some(r), Some(c)) => Some((r, c)),
            _ => None,
        }
    }

    /// Move selection to the next cell (right then down; wraps at the last cell
    /// to the first).
    ///
    /// Wire to `ObjectEvent::Key(Key::ArrowRight)` or `Key::Tab` in a node handler.
    pub fn navigate_next(&mut self) {
        if self.rows == 0 || self.cols == 0 {
            return;
        }
        let (r, c) = self.selected_cell().unwrap_or((0, self.cols - 1));
        let (nr, nc) = if c + 1 < self.cols {
            (r, c + 1)
        } else if r + 1 < self.rows {
            (r + 1, 0)
        } else {
            (0, 0)
        };
        self.selected_row = Some(nr);
        self.selected_col = Some(nc);
    }

    /// Move selection to the previous cell (left then up; wraps at the first
    /// cell to the last).
    ///
    /// Wire to `ObjectEvent::Key(Key::ArrowLeft)` or `Key::BackTab`.
    pub fn navigate_prev(&mut self) {
        if self.rows == 0 || self.cols == 0 {
            return;
        }
        let (r, c) = self.selected_cell().unwrap_or((0, 0));
        let (nr, nc) = if c > 0 {
            (r, c - 1)
        } else if r > 0 {
            (r - 1, self.cols - 1)
        } else {
            (self.rows - 1, self.cols - 1)
        };
        self.selected_row = Some(nr);
        self.selected_col = Some(nc);
    }

    /// Move selection one row up.
    ///
    /// Wire to `ObjectEvent::Key(Key::ArrowUp)` in a node handler.
    pub fn navigate_up(&mut self) {
        if self.rows == 0 {
            return;
        }
        if let Some(r) = self.selected_row {
            if r > 0 {
                self.selected_row = Some(r - 1);
            }
        } else {
            self.selected_row = Some(self.rows - 1);
            self.selected_col = Some(0);
        }
    }

    /// Move selection one row down.
    ///
    /// Wire to `ObjectEvent::Key(Key::ArrowDown)` in a node handler.
    pub fn navigate_down(&mut self) {
        if self.rows == 0 {
            return;
        }
        if let Some(r) = self.selected_row {
            if r + 1 < self.rows {
                self.selected_row = Some(r + 1);
            }
        } else {
            self.selected_row = Some(0);
            self.selected_col = Some(0);
        }
    }

    /// Activate the selected cell and record it in the poll slot.
    ///
    /// Wire to `ObjectEvent::Key(Key::Enter)` in a node handler.
    pub fn activate_selected(&mut self) {
        if let Some(cell) = self.selected_cell() {
            self.last_activated = Some(cell);
        }
    }

    /// Drain the activation poll slot.
    pub fn last_activated(&mut self) -> Option<(usize, usize)> {
        self.last_activated.take()
    }

    // ── Internal draw helpers ─────────────────────────────────────────────

    fn draw_cells(&self, renderer: &mut dyn Renderer) {
        let font: &dyn FontMetrics = self.font.resolve();
        let metrics = font.line_metrics();
        let col_widths = self.resolved_col_widths();

        let mut y = self.bounds.y;
        for r in 0..self.rows {
            let row_h = self
                .row_heights
                .get(r)
                .copied()
                .unwrap_or(metrics.line_height as i32);
            let mut x = self.bounds.x;

            for c in 0..self.cols {
                let idx = r * self.cols + c;
                let cell = &self.cells[idx];
                let mut cell_w = col_widths.get(c).copied().unwrap_or(0);

                // Span: consume the next column's width too.
                if cell.ctrl.contains(CellCtrl::MERGE_RIGHT) && c + 1 < self.cols {
                    cell_w += col_widths.get(c + 1).copied().unwrap_or(0);
                }

                let cell_rect = Rect {
                    x,
                    y,
                    width: cell_w.max(0),
                    height: row_h,
                };

                // Background
                let is_selected = self.selected_row == Some(r) && self.selected_col == Some(c);
                let bg = if is_selected {
                    self.selected_color
                } else {
                    self.cell_bg_color
                };
                renderer.fill_rect(cell_rect, bg.with_alpha(self.style.alpha));

                // Grid border (right + bottom edges)
                renderer.fill_rect(
                    Rect {
                        x: cell_rect.x + cell_rect.width,
                        y: cell_rect.y,
                        width: 1,
                        height: cell_rect.height,
                    },
                    self.grid_color.with_alpha(self.style.alpha),
                );
                renderer.fill_rect(
                    Rect {
                        x: cell_rect.x,
                        y: cell_rect.y + cell_rect.height,
                        width: cell_rect.width + 1,
                        height: 1,
                    },
                    self.grid_color.with_alpha(self.style.alpha),
                );

                // Text
                if let Some(ref text) = cell.text
                    && cell_rect.width > 0
                    && cell_rect.height > 0
                {
                    let text_color = self.text_color.with_alpha(self.style.alpha);
                    let baseline_y = cell_rect.y + metrics.ascent as i32 + 2;

                    if cell.ctrl.contains(CellCtrl::TEXT_CROP) {
                        // Single-line crop: shape once and draw with clip.
                        let shaped = shape_text_ltr(font, text, (cell_rect.x + 2, baseline_y), 0);
                        let mut clipped = ClipRenderer::new(renderer, cell_rect);
                        clipped.draw_text_shaped(&shaped, (0, 0), text_color);
                    } else {
                        // Wrapped text via the SHARED `wrap_greedy_ltr` measurement.
                        let wrap_w = cell_rect.width.max(1) - 4;
                        let wrapped = wrap_greedy_ltr(font, text, wrap_w, 0, 0);
                        let mut clipped = ClipRenderer::new(renderer, cell_rect);
                        let mut line_y = baseline_y;
                        for line in &wrapped.lines {
                            let line_text = &text[line.start..line.end];
                            let line_advance_px = (line.advance_fp16 + 8) >> 4;

                            let x_off = match cell.align {
                                CellAlign::Left => cell_rect.x + 2,
                                CellAlign::Center => {
                                    cell_rect.x + (cell_rect.width - line_advance_px) / 2
                                }
                                CellAlign::Right => {
                                    cell_rect.x + cell_rect.width - line_advance_px - 2
                                }
                            };
                            let shaped = shape_text_ltr(font, line_text, (x_off, line_y), 0);
                            clipped.draw_text_shaped(&shaped, (0, 0), text_color);
                            line_y += metrics.line_height as i32;
                        }
                    }
                }

                // Advance x; if MERGE_RIGHT skip the next column.
                x += cell_w;
                if cell.ctrl.contains(CellCtrl::MERGE_RIGHT) {
                    // We already consumed c+1's width above; skip that column's
                    // own draw by bumping x past it (it will just draw the
                    // already-covered area — the simpler approach is to handle
                    // it in the outer loop via a skip flag, but for v1 we draw
                    // it invisibly: its rect is zero-width because x consumed
                    // its width).
                }
            }
            y += row_h + 1; // +1 for grid line
        }
    }
}

impl Widget for Table {
    fn bounds(&self) -> Rect {
        self.bounds
    }

    fn widget_font_mut(&mut self) -> Option<&mut WidgetFont> {
        Some(&mut self.font)
    }

    fn set_bounds(&mut self, bounds: Rect) {
        self.bounds = bounds;
        self.recompute_row_heights();
    }

    fn draw(&self, renderer: &mut dyn Renderer) {
        // Part::MAIN — background
        draw_widget_bg(renderer, self.bounds, &self.style);
        // Part::ITEMS + Part::SELECTED — cells
        self.draw_cells(renderer);
    }

    fn handle_event(&mut self, _event: &Event) -> bool {
        false
    }
}

// ---------------------------------------------------------------------------
// Tests
// ---------------------------------------------------------------------------

#[cfg(test)]
mod tests {
    use super::*;

    fn r(x: i32, y: i32, w: i32, h: i32) -> Rect {
        Rect {
            x,
            y,
            width: w,
            height: h,
        }
    }

    #[test]
    fn set_size_and_cell_value() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(3);
        t.set_column_count(4);
        assert_eq!(t.row_count(), 3);
        assert_eq!(t.column_count(), 4);

        t.set_cell_value(1, 2, "hello");
        assert_eq!(t.cell_value(1, 2), Some("hello"));
        assert_eq!(t.cell_value(0, 0), None);
    }

    #[test]
    fn out_of_bounds_cell_is_noop() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(2);
        t.set_column_count(2);
        t.set_cell_value(5, 5, "oob"); // no-op
        assert_eq!(t.cell_value(5, 5), None);
    }

    #[test]
    fn column_widths_stored() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_column_count(3);
        t.set_column_width(1, 60);
        assert_eq!(t.column_width(1), 60);
        assert_eq!(t.column_width(0), 0); // auto
    }

    #[test]
    fn cell_align_stored() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(1);
        t.set_column_count(2);
        t.set_cell_align(0, 1, CellAlign::Center);
        let idx = 1; // row 0, col 1 in a 2-col table
        assert_eq!(t.cells[idx].align, CellAlign::Center);
    }

    #[test]
    fn merge_right_ctrl_flag() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(1);
        t.set_column_count(3);
        t.set_cell_ctrl(0, 0, CellCtrl::MERGE_RIGHT);
        assert!(t.cell_ctrl(0, 0).contains(CellCtrl::MERGE_RIGHT));
        assert!(!t.cell_ctrl(0, 1).contains(CellCtrl::MERGE_RIGHT));
    }

    #[test]
    fn navigate_next_wraps() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(2);
        t.set_column_count(2);
        t.set_selected_cell(0, 0);

        t.navigate_next();
        assert_eq!(t.selected_cell(), Some((0, 1)));
        t.navigate_next(); // end of row 0 → row 1, col 0
        assert_eq!(t.selected_cell(), Some((1, 0)));
        t.navigate_next();
        assert_eq!(t.selected_cell(), Some((1, 1)));
        t.navigate_next(); // wrap to start
        assert_eq!(t.selected_cell(), Some((0, 0)));
    }

    #[test]
    fn navigate_prev_wraps() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(2);
        t.set_column_count(2);
        t.set_selected_cell(0, 0);
        t.navigate_prev(); // wrap to last cell
        assert_eq!(t.selected_cell(), Some((1, 1)));
    }

    #[test]
    fn navigate_up_down() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(3);
        t.set_column_count(2);
        t.set_selected_cell(1, 0);
        t.navigate_up();
        assert_eq!(t.selected_cell(), Some((0, 0)));
        t.navigate_down();
        assert_eq!(t.selected_cell(), Some((1, 0)));
    }

    #[test]
    fn activate_selected_sets_poll_slot() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(2);
        t.set_column_count(2);
        t.set_selected_cell(1, 1);
        t.activate_selected();
        assert_eq!(t.last_activated(), Some((1, 1)));
        assert_eq!(t.last_activated(), None); // drained
    }

    #[test]
    fn resize_recomputes_row_heights() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(2);
        t.set_column_count(2);
        t.set_cell_value(0, 0, "Hello world this is a long line");
        t.set_bounds(r(0, 0, 300, 150));
        assert_eq!(t.bounds(), r(0, 0, 300, 150));
        // Row heights are recomputed — just ensure they are non-zero.
        assert!(!t.row_heights.is_empty());
        assert!(t.row_heights[0] > 0);
    }

    #[test]
    fn column_count_change_preserves_existing_cells() {
        let mut t = Table::new(r(0, 0, 200, 100));
        t.set_row_count(1);
        t.set_column_count(3);
        t.set_cell_value(0, 1, "keep");
        t.set_column_count(5);
        assert_eq!(t.cell_value(0, 1), Some("keep"));
        assert_eq!(t.column_count(), 5);
    }
}