oxidize_pdf/advanced_tables/

table_renderer.rs

//! Table renderer for converting advanced tables to PDF content

use super::cell_style::{BorderConfiguration, BorderStyle, CellAlignment, CellStyle};
use super::header_builder::HeaderBuilder;
use super::table_builder::{AdvancedTable, CellData, RowData};
use crate::error::PdfError;
use crate::graphics::Color;
use crate::page::Page;
use crate::text::{measure_text, Font};

/// Renderer for advanced tables
pub struct TableRenderer {
    /// Default row height when not specified
    pub default_row_height: f64,
    /// Default header height
    pub default_header_height: f64,
    /// Whether to auto-calculate cell heights based on content
    pub auto_height: bool,
}

impl TableRenderer {
    /// Create a new table renderer
    pub fn new() -> Self {
        Self {
            default_row_height: 25.0,
            default_header_height: 30.0,
            auto_height: true,
        }
    }

    /// Calculate the total height needed to render a table
    ///
    /// This is essential for intelligent positioning and layout management.
    /// Returns the height in points from bottom to top of the rendered table.
    pub fn calculate_table_height(&self, table: &AdvancedTable) -> f64 {
        let mut total_height = 0.0;

        // Calculate header height
        if table.show_header {
            if let Some(header) = &table.header {
                // For complex headers, calculate based on levels and row spans
                total_height += header.calculate_height();
            } else if !table.columns.is_empty() {
                // Simple header from column definitions
                total_height += self.default_header_height;
            }
        }

        // Calculate rows height, tracking rows absorbed by rowspan.
        // When auto_height is enabled, expand rows to fit multiline content
        // (mirrors the same logic used in render_rows).
        let mut rows_to_skip: usize = 0;
        for (row_idx, row) in table.rows.iter().enumerate() {
            if rows_to_skip > 0 {
                rows_to_skip -= 1;
                continue;
            }

            let base_height = row.min_height.unwrap_or(self.default_row_height);
            let row_height = if self.auto_height {
                let content_height = self.calculate_content_row_height(table, row, row_idx);
                base_height.max(content_height)
            } else {
                base_height
            };

            let max_rowspan = row.cells.iter().map(|cell| cell.rowspan).max().unwrap_or(1);
            if max_rowspan > 1 {
                total_height += row_height * max_rowspan as f64;
                rows_to_skip = max_rowspan - 1;
            } else {
                total_height += row_height;
            }
        }

        // Add small buffer for table borders
        if table.table_border {
            total_height += 2.0; // Top and bottom borders
        }

        total_height
    }

    /// Render a table to a PDF page
    pub fn render_table(
        &self,
        page: &mut Page,
        table: &AdvancedTable,
        x: f64,
        y: f64,
    ) -> Result<f64, PdfError> {
        // Validate table structure
        table
            .validate()
            .map_err(|e| PdfError::InvalidOperation(e.to_string()))?;

        let mut current_y = y;

        // Render header if present
        if table.show_header {
            if let Some(header) = &table.header {
                current_y = self.render_header(page, table, header, x, current_y)?;
            } else if !table.columns.is_empty() {
                // Render simple header from column definitions
                current_y = self.render_simple_header(page, table, x, current_y)?;
            }
        }

        // Render table rows
        current_y = self.render_rows(page, table, x, current_y)?;

        // Render table border if enabled
        if table.table_border {
            self.render_table_border(page, table, x, y, current_y)?;
        }

        Ok(current_y)
    }

    /// Render table headers
    fn render_header(
        &self,
        page: &mut Page,
        table: &AdvancedTable,
        header: &HeaderBuilder,
        x: f64,
        start_y: f64,
    ) -> Result<f64, PdfError> {
        let mut current_y = start_y;
        let column_positions = self.calculate_column_positions(table, x);

        for level in header.levels.iter() {
            let row_height = self.default_header_height;

            for cell in level {
                let cell_x = column_positions[cell.start_col];
                let cell_width = self.calculate_span_width(table, cell.start_col, cell.colspan);
                let cell_height = row_height * cell.rowspan as f64;

                let style = cell.style.as_ref().unwrap_or(&table.header_style);

                self.render_cell(
                    page,
                    &cell.text,
                    cell_x,
                    current_y - cell_height,
                    cell_width,
                    cell_height,
                    style,
                )?;
            }

            current_y -= row_height;
        }

        Ok(current_y)
    }

    /// Render simple header from column definitions
    fn render_simple_header(
        &self,
        page: &mut Page,
        table: &AdvancedTable,
        x: f64,
        start_y: f64,
    ) -> Result<f64, PdfError> {
        let column_positions = self.calculate_column_positions(table, x);
        let header_height = self.default_header_height;

        for (col_idx, column) in table.columns.iter().enumerate() {
            let cell_x = column_positions[col_idx];
            let cell_width = column.width;

            self.render_cell(
                page,
                &column.header,
                cell_x,
                start_y - header_height,
                cell_width,
                header_height,
                &table.header_style,
            )?;
        }

        Ok(start_y - header_height)
    }

    /// Calculate the minimum height needed for a row's content
    fn calculate_content_row_height(
        &self,
        table: &AdvancedTable,
        row: &RowData,
        row_idx: usize,
    ) -> f64 {
        let mut max_height = self.default_row_height;

        let mut actual_col = 0usize;
        for cell in row.cells.iter() {
            let style = self.resolve_cell_style(table, cell, row_idx, actual_col);
            let font = style.font.clone().unwrap_or(Font::Helvetica);
            let font_size = style.font_size.unwrap_or(12.0);
            // Sum column widths for colspan
            let col_width: f64 = (actual_col..actual_col + cell.colspan)
                .filter_map(|c| table.columns.get(c).map(|col| col.width))
                .sum();
            let available_width = col_width - style.padding.left - style.padding.right;

            if available_width > 0.0 && style.text_wrap {
                let lines =
                    self.wrap_text_to_lines(&cell.content, available_width, &font, font_size);
                let line_height = font_size * 1.2;
                let needed =
                    (lines.len() as f64 * line_height) + style.padding.top + style.padding.bottom;
                if needed > max_height {
                    max_height = needed;
                }
            }

            actual_col += cell.colspan;
        }

        max_height
    }

    /// Render table data rows
    fn render_rows(
        &self,
        page: &mut Page,
        table: &AdvancedTable,
        x: f64,
        start_y: f64,
    ) -> Result<f64, PdfError> {
        let mut current_y = start_y;
        let column_positions = self.calculate_column_positions(table, x);
        let num_cols = table.columns.len();
        // Track the last row index each column is occupied through (exclusive upper bound).
        // rowspan_end[c] > row_idx means column c is occupied by a rowspan from a previous row.
        let mut rowspan_end: Vec<usize> = vec![0; num_cols];

        for (row_idx, row) in table.rows.iter().enumerate() {
            // Calculate row height: explicit min_height, or auto-fit content
            let base_height = row.min_height.unwrap_or(self.default_row_height);
            let row_height = if self.auto_height {
                let content_height = self.calculate_content_row_height(table, row, row_idx);
                base_height.max(content_height)
            } else {
                base_height
            };

            // Track actual column position (accounts for colspan and rowspan)
            let mut actual_col = 0usize;
            for cell in row.cells.iter() {
                // Skip columns occupied by rowspan from previous rows
                while actual_col < num_cols && rowspan_end[actual_col] > row_idx {
                    actual_col += 1;
                }

                if actual_col >= column_positions.len() {
                    break;
                }

                let cell_x = column_positions[actual_col];
                let cell_width = self.calculate_span_width(table, actual_col, cell.colspan);
                let cell_height = row_height * cell.rowspan as f64;

                let style = self.resolve_cell_style(table, cell, row_idx, actual_col);

                self.render_cell(
                    page,
                    &cell.content,
                    cell_x,
                    current_y - cell_height,
                    cell_width,
                    cell_height,
                    &style,
                )?;

                // Record rowspan: this cell occupies columns through row_idx + rowspan - 1
                if cell.rowspan > 1 {
                    for c in actual_col..(actual_col + cell.colspan).min(num_cols) {
                        rowspan_end[c] = row_idx + cell.rowspan;
                    }
                }

                actual_col += cell.colspan;
            }

            current_y -= row_height;
        }

        Ok(current_y)
    }

    /// Render an individual cell
    #[allow(clippy::too_many_arguments)]
    fn render_cell(
        &self,
        page: &mut Page,
        content: &str,
        x: f64,
        y: f64,
        width: f64,
        height: f64,
        style: &CellStyle,
    ) -> Result<(), PdfError> {
        // Draw background if specified
        if let Some(bg_color) = style.background_color {
            page.graphics()
                .save_state()
                .set_fill_color(bg_color)
                .rectangle(x, y, width, height)
                .fill()
                .restore_state();
        }

        // Draw borders
        self.render_cell_borders(page, x, y, width, height, &style.border)?;

        // Draw text content
        if !content.is_empty() {
            self.render_cell_text(page, content, x, y, width, height, style)?;
        }

        Ok(())
    }

    /// Render cell borders
    fn render_cell_borders(
        &self,
        page: &mut Page,
        x: f64,
        y: f64,
        width: f64,
        height: f64,
        border_config: &BorderConfiguration,
    ) -> Result<(), PdfError> {
        let graphics = page.graphics();

        // Top border
        if border_config.top.style != BorderStyle::None {
            graphics
                .save_state()
                .set_stroke_color(border_config.top.color)
                .set_line_width(border_config.top.width);

            self.apply_line_style(graphics, border_config.top.style);

            graphics
                .move_to(x, y + height)
                .line_to(x + width, y + height)
                .stroke()
                .restore_state();
        }

        // Bottom border
        if border_config.bottom.style != BorderStyle::None {
            graphics
                .save_state()
                .set_stroke_color(border_config.bottom.color)
                .set_line_width(border_config.bottom.width);

            self.apply_line_style(graphics, border_config.bottom.style);

            graphics
                .move_to(x, y)
                .line_to(x + width, y)
                .stroke()
                .restore_state();
        }

        // Left border
        if border_config.left.style != BorderStyle::None {
            graphics
                .save_state()
                .set_stroke_color(border_config.left.color)
                .set_line_width(border_config.left.width);

            self.apply_line_style(graphics, border_config.left.style);

            graphics
                .move_to(x, y)
                .line_to(x, y + height)
                .stroke()
                .restore_state();
        }

        // Right border
        if border_config.right.style != BorderStyle::None {
            graphics
                .save_state()
                .set_stroke_color(border_config.right.color)
                .set_line_width(border_config.right.width);

            self.apply_line_style(graphics, border_config.right.style);

            graphics
                .move_to(x + width, y)
                .line_to(x + width, y + height)
                .stroke()
                .restore_state();
        }

        Ok(())
    }

    /// Apply line style for borders
    fn apply_line_style(
        &self,
        _graphics: &mut crate::graphics::GraphicsContext,
        _style: BorderStyle,
    ) {
        // TODO: Implement line styles when GraphicsContext supports dash patterns
        // For now, all borders will be solid
    }

    /// Truncate text to fit within a specified width, adding ellipsis if needed
    fn truncate_text_to_width(
        &self,
        text: &str,
        max_width: f64,
        font: &Font,
        font_size: f64,
    ) -> String {
        // If text already fits, return as-is
        let full_width = measure_text(text, font, font_size);
        if full_width <= max_width {
            return text.to_string();
        }

        // If even ellipsis doesn't fit, return empty string
        let ellipsis = "...";
        let ellipsis_width = measure_text(ellipsis, font, font_size);
        if ellipsis_width > max_width {
            return String::new();
        }

        // If exactly ellipsis width, return ellipsis
        if ellipsis_width == max_width {
            return ellipsis.to_string();
        }

        // Linear scan: iterate character by character until width is exceeded.
        // For typical cell text (<100 chars) this is simpler and avoids allocating a Vec<char>.
        let available_width = max_width - ellipsis_width;
        let mut last_fit_end = 0usize;
        let mut width_so_far = 0.0f64;

        for (byte_pos, ch) in text.char_indices() {
            let ch_len = ch.len_utf8();
            let ch_str = &text[byte_pos..byte_pos + ch_len];
            let ch_width = measure_text(ch_str, font, font_size);
            if width_so_far + ch_width > available_width {
                break;
            }
            width_so_far += ch_width;
            last_fit_end = byte_pos + ch_len;
        }

        if last_fit_end == 0 {
            ellipsis.to_string()
        } else {
            format!("{}{}", &text[..last_fit_end], ellipsis)
        }
    }

    /// Wrap text into multiple lines that fit within the given width.
    ///
    /// Uses incremental width tracking to avoid remeasuring the full current line on
    /// every word — a significant saving in the hot path for tables with many cells.
    fn wrap_text_to_lines(
        &self,
        text: &str,
        max_width: f64,
        font: &Font,
        font_size: f64,
    ) -> Vec<String> {
        let mut lines = Vec::new();

        // Split by existing newlines first
        for paragraph in text.split('\n') {
            if paragraph.is_empty() {
                lines.push(String::new());
                continue;
            }

            // If paragraph fits, add it directly (single measure check)
            let paragraph_width = measure_text(paragraph, font, font_size);
            if paragraph_width <= max_width {
                lines.push(paragraph.to_string());
                continue;
            }

            // Word-wrap the paragraph
            let words: Vec<&str> = paragraph.split_whitespace().collect();
            if words.is_empty() {
                continue;
            }

            let mut current_line = String::new();
            let mut current_line_width = 0.0f64;
            let space_width = measure_text(" ", font, font_size);

            for word in words {
                let word_width = measure_text(word, font, font_size);

                if current_line.is_empty() {
                    // First word on the line
                    if word_width <= max_width {
                        current_line = word.to_string();
                        current_line_width = word_width;
                    } else {
                        // Word is too long — break it character by character
                        let chars: Vec<char> = word.chars().collect();
                        let mut char_line = String::new();
                        let mut char_line_width = 0.0f64;
                        for c in chars {
                            let char_width = measure_text(&c.to_string(), font, font_size);
                            if char_line_width + char_width <= max_width {
                                char_line.push(c);
                                char_line_width += char_width;
                            } else {
                                if !char_line.is_empty() {
                                    lines.push(char_line);
                                }
                                char_line = c.to_string();
                                char_line_width = char_width;
                            }
                        }
                        current_line = char_line;
                        current_line_width = char_line_width;
                    }
                } else {
                    // Test adding word to current line using incremental width
                    let test_width = current_line_width + space_width + word_width;

                    if test_width <= max_width {
                        current_line.push(' ');
                        current_line.push_str(word);
                        current_line_width = test_width;
                    } else {
                        // Start new line
                        lines.push(current_line);
                        if word_width <= max_width {
                            current_line = word.to_string();
                            current_line_width = word_width;
                        } else {
                            // Word is too long — break it character by character
                            let chars: Vec<char> = word.chars().collect();
                            let mut char_line = String::new();
                            let mut char_line_width = 0.0f64;
                            for c in chars {
                                let char_width = measure_text(&c.to_string(), font, font_size);
                                if char_line_width + char_width <= max_width {
                                    char_line.push(c);
                                    char_line_width += char_width;
                                } else {
                                    if !char_line.is_empty() {
                                        lines.push(char_line);
                                    }
                                    char_line = c.to_string();
                                    char_line_width = char_width;
                                }
                            }
                            current_line = char_line;
                            current_line_width = char_line_width;
                        }
                    }
                }
            }

            // Add remaining text
            if !current_line.is_empty() {
                lines.push(current_line);
            }
        }

        if lines.is_empty() {
            lines.push(String::new());
        }

        lines
    }

    /// Render text within a cell
    #[allow(clippy::too_many_arguments)]
    fn render_cell_text(
        &self,
        page: &mut Page,
        content: &str,
        x: f64,
        y: f64,
        width: f64,
        height: f64,
        style: &CellStyle,
    ) -> Result<(), PdfError> {
        let font = style.font.clone().unwrap_or(Font::Helvetica);
        let font_size = style.font_size.unwrap_or(12.0);
        let text_color = style.text_color.unwrap_or(Color::black());

        // Calculate available width for text (considering padding)
        let available_width = width - style.padding.left - style.padding.right;

        if available_width <= 0.0 {
            return Ok(());
        }

        // Check if text wrapping is enabled
        if style.text_wrap {
            // Wrap text into multiple lines
            let lines = self.wrap_text_to_lines(content, available_width, &font, font_size);

            if lines.is_empty() || (lines.len() == 1 && lines[0].is_empty()) {
                return Ok(());
            }

            // Calculate line height (typically 1.2x font size)
            let line_height = font_size * 1.2;
            let total_text_height = lines.len() as f64 * line_height;

            // Calculate available height (considering padding)
            let available_height = height - style.padding.top - style.padding.bottom;

            // Calculate starting Y position (top of text block, vertically centered)
            // In PDF coordinate system, Y increases upward
            let text_block_top =
                y + height - style.padding.top - (available_height - total_text_height) / 2.0;

            // Render each line
            for (line_idx, line) in lines.iter().enumerate() {
                if line.is_empty() {
                    continue;
                }

                // Calculate X position based on alignment
                let text_x = match style.alignment {
                    CellAlignment::Left => x + style.padding.left,
                    CellAlignment::Center => {
                        let line_width = measure_text(line, &font, font_size);
                        x + style.padding.left + (available_width - line_width) / 2.0
                    }
                    CellAlignment::Right => {
                        let line_width = measure_text(line, &font, font_size);
                        x + width - style.padding.right - line_width
                    }
                    CellAlignment::Justify => x + style.padding.left,
                };

                // Y position for this line (descending from top)
                let text_y = text_block_top - (line_idx as f64 + 0.8) * line_height;

                // Only render if within cell bounds
                if text_y >= y + style.padding.bottom {
                    page.text()
                        .set_font(font.clone(), font_size)
                        .set_fill_color(text_color)
                        .at(text_x, text_y)
                        .write(line)?;
                }
            }
        } else {
            // Original truncation behavior
            let display_text =
                self.truncate_text_to_width(content, available_width, &font, font_size);

            // Calculate text position based on alignment and padding
            let text_x = match style.alignment {
                CellAlignment::Left => x + style.padding.left,
                CellAlignment::Center => {
                    // For center alignment, we need to calculate based on actual text width
                    let text_width = measure_text(&display_text, &font, font_size);
                    x + style.padding.left + (available_width - text_width) / 2.0
                }
                CellAlignment::Right => {
                    let text_width = measure_text(&display_text, &font, font_size);
                    x + width - style.padding.right - text_width
                }
                CellAlignment::Justify => x + style.padding.left,
            };

            // Vertically center with padding applied
            let text_y = style
                .padding
                .pad_vertically(&page.coordinate_system(), y + height / 2.0);

            // Only render text if we have something to display
            if !display_text.is_empty() {
                let text_obj = page
                    .text()
                    .set_font(font, font_size)
                    .set_fill_color(text_color);

                text_obj.at(text_x, text_y).write(&display_text)?;
            }
        }

        Ok(())
    }

    /// Calculate column positions based on widths
    fn calculate_column_positions(&self, table: &AdvancedTable, start_x: f64) -> Vec<f64> {
        let mut positions = Vec::new();
        let mut current_x = start_x;

        for column in &table.columns {
            positions.push(current_x);
            current_x += column.width + table.cell_spacing;
        }

        positions
    }

    /// Calculate width for a cell that spans multiple columns
    fn calculate_span_width(&self, table: &AdvancedTable, start_col: usize, colspan: usize) -> f64 {
        let mut total_width = 0.0;

        for i in 0..colspan {
            if let Some(column) = table.columns.get(start_col + i) {
                total_width += column.width;
                if i > 0 {
                    total_width += table.cell_spacing;
                }
            }
        }

        total_width
    }

    /// Resolve the effective style for a cell
    fn resolve_cell_style(
        &self,
        table: &AdvancedTable,
        cell: &CellData,
        row_idx: usize,
        col_idx: usize,
    ) -> CellStyle {
        // Priority: cell style > specific cell style > row style > column style > table default

        if let Some(cell_style) = &cell.style {
            return cell_style.clone();
        }

        table.get_cell_style(row_idx, col_idx)
    }

    /// Render table border
    fn render_table_border(
        &self,
        page: &mut Page,
        table: &AdvancedTable,
        x: f64,
        start_y: f64,
        end_y: f64,
    ) -> Result<(), PdfError> {
        let total_width = table.calculate_width();
        let height = start_y - end_y;

        page.graphics()
            .save_state()
            .set_stroke_color(Color::black())
            .set_line_width(1.0)
            .rectangle(x, end_y, total_width, height)
            .stroke()
            .restore_state();

        Ok(())
    }
}

impl Default for TableRenderer {
    fn default() -> Self {
        Self::new()
    }
}

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

    #[test]
    fn test_truncate_text_to_width_no_truncation_needed() {
        let renderer = TableRenderer::new();
        let text = "Short";
        let max_width = 100.0;
        let font = Font::Helvetica;
        let font_size = 12.0;

        let result = renderer.truncate_text_to_width(text, max_width, &font, font_size);
        assert_eq!(result, "Short");
    }

    #[test]
    fn test_truncate_text_to_width_with_truncation() {
        let renderer = TableRenderer::new();
        let text = "This is a very long text that should be truncated";
        let max_width = 50.0; // Very narrow width
        let font = Font::Helvetica;
        let font_size = 12.0;

        let result = renderer.truncate_text_to_width(text, max_width, &font, font_size);
        assert!(result.ends_with("..."));
        assert!(result.len() < text.len());

        // Verify the truncated text fits within the width
        let truncated_width = measure_text(&result, &font, font_size);
        assert!(truncated_width <= max_width);
    }

    #[test]
    fn test_truncate_text_to_width_empty_when_too_narrow() {
        let renderer = TableRenderer::new();
        let text = "Any text";
        let max_width = 5.0; // Too narrow even for ellipsis
        let font = Font::Helvetica;
        let font_size = 12.0;

        let result = renderer.truncate_text_to_width(text, max_width, &font, font_size);
        assert_eq!(result, "");
    }

    #[test]
    fn test_truncate_text_to_width_exactly_ellipsis_width() {
        let renderer = TableRenderer::new();
        let text = "Some text";
        let font = Font::Helvetica;
        let font_size = 12.0;

        // Calculate width that exactly fits ellipsis
        let ellipsis_width = measure_text("...", &font, font_size);

        let result = renderer.truncate_text_to_width(text, ellipsis_width, &font, font_size);
        assert_eq!(result, "...");
    }

    #[test]
    fn test_truncate_text_to_width_single_character() {
        let renderer = TableRenderer::new();
        let text = "A";
        let max_width = 50.0;
        let font = Font::Helvetica;
        let font_size = 12.0;

        let result = renderer.truncate_text_to_width(text, max_width, &font, font_size);
        assert_eq!(result, "A");
    }

    #[test]
    fn test_truncate_text_to_width_different_fonts() {
        let renderer = TableRenderer::new();
        let text = "This text will be truncated";
        let max_width = 60.0;
        let font_size = 12.0;

        // Test with different fonts
        let helvetica_result =
            renderer.truncate_text_to_width(text, max_width, &Font::Helvetica, font_size);
        let courier_result =
            renderer.truncate_text_to_width(text, max_width, &Font::Courier, font_size);
        let times_result =
            renderer.truncate_text_to_width(text, max_width, &Font::TimesRoman, font_size);

        // All should be truncated and fit within width
        for result in [&helvetica_result, &courier_result, &times_result] {
            assert!(result.ends_with("..."));
            assert!(result.len() < text.len());
        }

        // Courier (monospace) might have different truncation point
        // All results should be valid and within width limits
        assert!(!helvetica_result.is_empty());
        assert!(!courier_result.is_empty());
        assert!(!times_result.is_empty());
    }

    #[test]
    fn test_truncate_text_to_width_empty_input() {
        let renderer = TableRenderer::new();
        let text = "";
        let max_width = 100.0;
        let font = Font::Helvetica;
        let font_size = 12.0;

        let result = renderer.truncate_text_to_width(text, max_width, &font, font_size);
        assert_eq!(result, "");
    }

    #[test]
    fn test_truncate_text_to_width_unicode_characters() {
        let renderer = TableRenderer::new();
        let text = "Héllö Wørld with ümlauts and émojis 🚀🎉";
        let max_width = 80.0;
        let font = Font::Helvetica;
        let font_size = 12.0;

        let result = renderer.truncate_text_to_width(text, max_width, &font, font_size);

        // Should handle unicode properly
        if result != text {
            assert!(result.ends_with("..."));
        }

        // Verify width constraint
        let result_width = measure_text(&result, &font, font_size);
        assert!(result_width <= max_width);
    }

    // ================== truncate_text_to_width linear scan tests ==================

    #[test]
    fn test_truncate_linear_short_text_fits() {
        let renderer = TableRenderer::new();
        let text = "Hi";
        let font = Font::Helvetica;
        let font_size = 12.0;
        // A wide width means text fits unchanged
        let result = renderer.truncate_text_to_width(text, 500.0, &font, font_size);
        assert_eq!(result, "Hi");
    }

    #[test]
    fn test_truncate_linear_overflow_adds_ellipsis() {
        let renderer = TableRenderer::new();
        let text = "This is a long sentence that will not fit";
        let font = Font::Helvetica;
        let font_size = 12.0;
        let result = renderer.truncate_text_to_width(text, 40.0, &font, font_size);
        assert!(
            result.ends_with("..."),
            "Expected ellipsis suffix, got: {result}"
        );
        assert!(result.len() < text.len());
        let result_width = measure_text(&result, &font, font_size);
        assert!(result_width <= 40.0, "Truncated text exceeds max_width");
    }

    #[test]
    fn test_truncate_linear_unicode() {
        let renderer = TableRenderer::new();
        // Multi-byte UTF-8 characters: each Japanese kanji is 3 bytes
        let text = "日本語テスト文字列";
        let font = Font::Helvetica;
        let font_size = 12.0;
        let result = renderer.truncate_text_to_width(text, 50.0, &font, font_size);
        // Result must be valid UTF-8 (no partial char splits)
        assert!(std::str::from_utf8(result.as_bytes()).is_ok());
        if result != text {
            assert!(
                result.ends_with("..."),
                "Truncated unicode should end with ellipsis"
            );
        }
        let result_width = measure_text(&result, &font, font_size);
        assert!(result_width <= 50.0);
    }

    // ================== wrap_text_to_lines tests (Issue #131) ==================

    #[test]
    fn test_wrap_text_to_lines_no_wrap_needed() {
        let renderer = TableRenderer::new();
        let text = "Short text";
        let max_width = 200.0;
        let font = Font::Helvetica;
        let font_size = 12.0;

        let lines = renderer.wrap_text_to_lines(text, max_width, &font, font_size);
        assert_eq!(lines.len(), 1);
        assert_eq!(lines[0], "Short text");
    }

    #[test]
    fn test_wrap_text_to_lines_simple_wrap() {
        let renderer = TableRenderer::new();
        let text = "This is a longer text that should wrap to multiple lines";
        let max_width = 80.0; // Narrow width to force wrapping
        let font = Font::Helvetica;
        let font_size = 12.0;

        let lines = renderer.wrap_text_to_lines(text, max_width, &font, font_size);
        assert!(lines.len() > 1, "Text should wrap to multiple lines");

        // Verify all lines fit within max_width
        for line in &lines {
            let line_width = measure_text(line, &font, font_size);
            assert!(
                line_width <= max_width + 1.0, // Small tolerance for floating point
                "Line '{}' exceeds max_width (width: {}, max: {})",
                line,
                line_width,
                max_width
            );
        }
    }

    #[test]
    fn test_wrap_text_to_lines_preserves_newlines() {
        let renderer = TableRenderer::new();
        let text = "Line one\nLine two\nLine three";
        let max_width = 200.0; // Wide enough for any single line
        let font = Font::Helvetica;
        let font_size = 12.0;

        let lines = renderer.wrap_text_to_lines(text, max_width, &font, font_size);
        assert_eq!(lines.len(), 3);
        assert_eq!(lines[0], "Line one");
        assert_eq!(lines[1], "Line two");
        assert_eq!(lines[2], "Line three");
    }

    #[test]
    fn test_wrap_text_to_lines_empty_input() {
        let renderer = TableRenderer::new();
        let text = "";
        let max_width = 100.0;
        let font = Font::Helvetica;
        let font_size = 12.0;

        let lines = renderer.wrap_text_to_lines(text, max_width, &font, font_size);
        assert_eq!(lines.len(), 1);
        assert_eq!(lines[0], "");
    }

    #[test]
    fn test_wrap_text_to_lines_single_word_too_long() {
        let renderer = TableRenderer::new();
        let text = "Supercalifragilisticexpialidocious";
        let max_width = 50.0; // Too narrow for the word
        let font = Font::Helvetica;
        let font_size = 12.0;

        let lines = renderer.wrap_text_to_lines(text, max_width, &font, font_size);
        // Word should be broken across lines
        assert!(lines.len() >= 1, "Should produce at least one line");

        // When we join all lines, we should get the original word
        let joined: String = lines.join("");
        assert_eq!(joined, text);
    }

    #[test]
    fn test_wrap_text_to_lines_multiple_spaces() {
        let renderer = TableRenderer::new();
        let text = "Word   with   spaces";
        let max_width = 200.0;
        let font = Font::Helvetica;
        let font_size = 12.0;

        let lines = renderer.wrap_text_to_lines(text, max_width, &font, font_size);
        assert_eq!(lines.len(), 1);
        // The implementation treats each space-separated segment as a word
        assert!(!lines[0].is_empty());
    }

    #[test]
    fn test_wrap_text_to_lines_unicode() {
        let renderer = TableRenderer::new();
        let text = "日本語テキスト with English words";
        let max_width = 100.0;
        let font = Font::Helvetica;
        let font_size = 12.0;

        let lines = renderer.wrap_text_to_lines(text, max_width, &font, font_size);
        // Should handle unicode without panic
        assert!(!lines.is_empty());
    }
}