zcatgui/src/widgets/textarea/textarea.zig

//! TextArea Widget - Multi-line text editor
//!
//! A multi-line text input with cursor navigation, selection, and scrolling.
//! Supports line wrapping and handles large documents efficiently.
//!
//! This module re-exports types from the textarea/ subdirectory.

const std = @import("std");
const Context = @import("../../core/context.zig").Context;
const Command = @import("../../core/command.zig");
const Layout = @import("../../core/layout.zig");
const Style = @import("../../core/style.zig");

// Re-export types
pub const types = @import("types.zig");
pub const TextAreaConfig = types.TextAreaConfig;
pub const TextAreaColors = types.TextAreaColors;
pub const TextAreaResult = types.TextAreaResult;

// Re-export state
pub const state = @import("state.zig");
pub const TextAreaState = state.TextAreaState;

// Import render helpers
const render = @import("render.zig");

// =============================================================================
// Public API
// =============================================================================

/// Draw a text area and return interaction result
pub fn textArea(ctx: *Context, textarea_state: *TextAreaState) TextAreaResult {
    return textAreaEx(ctx, textarea_state, .{}, .{});
}

/// Draw a text area with custom configuration
pub fn textAreaEx(
    ctx: *Context,
    textarea_state: *TextAreaState,
    config: TextAreaConfig,
    colors: TextAreaColors,
) TextAreaResult {
    const bounds = ctx.layout.nextRect();
    return textAreaRect(ctx, bounds, textarea_state, config, colors);
}

/// Draw a text area in a specific rectangle
pub fn textAreaRect(
    ctx: *Context,
    bounds: Layout.Rect,
    textarea_state: *TextAreaState,
    config: TextAreaConfig,
    colors: TextAreaColors,
) TextAreaResult {
    var result = TextAreaResult{
        .changed = false,
        .clicked = false,
        .cursor_line = 0,
        .cursor_col = 0,
    };

    if (bounds.isEmpty()) return result;

    // Generate unique ID for this widget based on buffer memory address
    const widget_id: u64 = @intFromPtr(textarea_state.buffer.ptr);

    // Register as focusable in the active focus group
    ctx.registerFocusable(widget_id);

    // Check mouse interaction
    const mouse = ctx.input.mousePos();
    const hovered = bounds.contains(mouse.x, mouse.y);
    const clicked = hovered and ctx.input.mousePressed(.left);

    if (clicked) {
        // Request focus through the focus system
        ctx.requestFocus(widget_id);
        result.clicked = true;
    }

    // Check if this widget has focus
    const has_focus = ctx.hasFocus(widget_id);
    textarea_state.focused = has_focus;

    // Get colors
    const bg_color = if (has_focus) colors.background.lighten(5) else colors.background;
    const border_color = if (has_focus) colors.border_focused else colors.border;

    // Draw background and border (with rounded corners in fancy mode)
    const corner_radius: u8 = 3;
    if (Style.isFancy() and corner_radius > 0) {
        ctx.pushCommand(Command.roundedRect(bounds.x, bounds.y, bounds.w, bounds.h, bg_color, corner_radius));
        ctx.pushCommand(Command.roundedRectOutline(bounds.x, bounds.y, bounds.w, bounds.h, border_color, corner_radius));
        // Focus ring
        if (has_focus) {
            ctx.pushCommand(Command.focusRing(bounds.x, bounds.y, bounds.w, bounds.h, corner_radius));
        }
    } else {
        ctx.pushCommand(Command.rect(bounds.x, bounds.y, bounds.w, bounds.h, bg_color));
        ctx.pushCommand(Command.rectOutline(bounds.x, bounds.y, bounds.w, bounds.h, border_color));
    }

    // Calculate dimensions
    const char_width: u32 = 8;
    const char_height: u32 = 8;
    const line_height: u32 = char_height + 2;

    // Line numbers width
    const line_num_width: u32 = if (config.line_numbers)
        @as(u32, @intCast(render.countDigits(textarea_state.lineCount()))) * char_width + 8
    else
        0;

    // Inner area for text
    var text_area = bounds.shrink(config.padding);
    if (text_area.isEmpty()) return result;

    // Draw line numbers gutter
    if (config.line_numbers and line_num_width > 0) {
        ctx.pushCommand(Command.rect(
            text_area.x,
            text_area.y,
            line_num_width,
            text_area.h,
            colors.line_numbers_bg,
        ));
        // Adjust text area to exclude gutter
        text_area = Layout.Rect.init(
            text_area.x + @as(i32, @intCast(line_num_width)),
            text_area.y,
            text_area.w -| line_num_width,
            text_area.h,
        );
    }

    if (text_area.isEmpty()) return result;

    // Calculate visible area
    const visible_lines = text_area.h / line_height;
    const visible_cols = text_area.w / char_width;

    // Handle keyboard input if focused
    if (textarea_state.focused and !config.readonly) {
        const text_in = ctx.input.getTextInput();
        if (text_in.len > 0) {
            // Check for tab
            for (text_in) |c| {
                if (c == '\t') {
                    // Insert spaces for tab
                    var spaces: [8]u8 = undefined;
                    const count = @min(config.tab_size, 8);
                    @memset(spaces[0..count], ' ');
                    textarea_state.insert(spaces[0..count]);
                } else {
                    textarea_state.insert(&[_]u8{c});
                }
            }
            result.changed = true;
        }
    }

    // Ensure cursor is visible
    textarea_state.ensureCursorVisible(visible_lines, visible_cols);

    // Get cursor position
    const cursor_pos = textarea_state.getCursorPosition();
    result.cursor_line = cursor_pos.line;
    result.cursor_col = cursor_pos.col;

    // Draw text line by line
    const txt = textarea_state.text();
    var line_num: usize = 0;
    var line_start: usize = 0;

    for (txt, 0..) |c, i| {
        if (c == '\n') {
            if (line_num >= textarea_state.scroll_y and line_num < textarea_state.scroll_y + visible_lines) {
                const draw_line = line_num - textarea_state.scroll_y;
                const y = text_area.y + @as(i32, @intCast(draw_line * line_height));

                // Draw line number
                if (config.line_numbers) {
                    render.drawLineNumber(
                        ctx,
                        bounds.x + @as(i32, @intCast(config.padding)),
                        y,
                        line_num + 1,
                        colors.line_numbers_fg,
                    );
                }

                // Draw line text
                const line_text = txt[line_start..i];
                render.drawLineText(ctx, text_area.x, y, line_text, textarea_state.scroll_x, visible_cols, colors.text);

                // Draw selection on this line
                if (textarea_state.selection_start != null) {
                    render.drawLineSelection(
                        ctx,
                        text_area.x,
                        y,
                        line_start,
                        i,
                        textarea_state.cursor,
                        textarea_state.selection_start.?,
                        textarea_state.scroll_x,
                        visible_cols,
                        char_width,
                        line_height,
                        colors.selection,
                    );
                }

                // Draw cursor if on this line
                if (textarea_state.focused and cursor_pos.line == line_num) {
                    const cursor_x_pos = cursor_pos.col -| textarea_state.scroll_x;
                    if (cursor_x_pos < visible_cols) {
                        const cursor_x = text_area.x + @as(i32, @intCast(cursor_x_pos * char_width));
                        ctx.pushCommand(Command.rect(cursor_x, y, 2, line_height, colors.cursor));
                    }
                }
            }

            line_num += 1;
            line_start = i + 1;
        }
    }

    // Handle last line (no trailing newline)
    if (line_start <= txt.len and line_num >= textarea_state.scroll_y and line_num < textarea_state.scroll_y + visible_lines) {
        const draw_line = line_num - textarea_state.scroll_y;
        const y = text_area.y + @as(i32, @intCast(draw_line * line_height));

        // Draw line number
        if (config.line_numbers) {
            render.drawLineNumber(
                ctx,
                bounds.x + @as(i32, @intCast(config.padding)),
                y,
                line_num + 1,
                colors.line_numbers_fg,
            );
        }

        // Draw line text
        const line_text = if (line_start < txt.len) txt[line_start..] else "";
        render.drawLineText(ctx, text_area.x, y, line_text, textarea_state.scroll_x, visible_cols, colors.text);

        // Draw selection on this line
        if (textarea_state.selection_start != null) {
            render.drawLineSelection(
                ctx,
                text_area.x,
                y,
                line_start,
                txt.len,
                textarea_state.cursor,
                textarea_state.selection_start.?,
                textarea_state.scroll_x,
                visible_cols,
                char_width,
                line_height,
                colors.selection,
            );
        }

        // Draw cursor if on this line
        if (textarea_state.focused and cursor_pos.line == line_num) {
            const cursor_x_pos = cursor_pos.col -| textarea_state.scroll_x;
            if (cursor_x_pos < visible_cols) {
                const cursor_x = text_area.x + @as(i32, @intCast(cursor_x_pos * char_width));
                ctx.pushCommand(Command.rect(cursor_x, y, 2, line_height, colors.cursor));
            }
        }
    }

    // Draw placeholder if empty
    if (textarea_state.len == 0 and config.placeholder.len > 0) {
        const y = text_area.y;
        ctx.pushCommand(Command.text(text_area.x, y, config.placeholder, colors.placeholder));
    }

    return result;
}

// =============================================================================
// Tests
// =============================================================================

test "TextAreaState insert" {
    var buf: [256]u8 = undefined;
    var textarea_state = TextAreaState.init(&buf);

    textarea_state.insert("Hello");
    try std.testing.expectEqualStrings("Hello", textarea_state.text());
    try std.testing.expectEqual(@as(usize, 5), textarea_state.cursor);

    textarea_state.insertNewline();
    textarea_state.insert("World");
    try std.testing.expectEqualStrings("Hello\nWorld", textarea_state.text());
}

test "TextAreaState line count" {
    var buf: [256]u8 = undefined;
    var textarea_state = TextAreaState.init(&buf);

    textarea_state.insert("Line 1");
    try std.testing.expectEqual(@as(usize, 1), textarea_state.lineCount());

    textarea_state.insertNewline();
    textarea_state.insert("Line 2");
    try std.testing.expectEqual(@as(usize, 2), textarea_state.lineCount());

    textarea_state.insertNewline();
    textarea_state.insertNewline();
    textarea_state.insert("Line 4");
    try std.testing.expectEqual(@as(usize, 4), textarea_state.lineCount());
}

test "TextAreaState cursor position" {
    var buf: [256]u8 = undefined;
    var textarea_state = TextAreaState.init(&buf);

    textarea_state.insert("Hello\nWorld\nTest");

    // Cursor at end
    const pos = textarea_state.getCursorPosition();
    try std.testing.expectEqual(@as(usize, 2), pos.line);
    try std.testing.expectEqual(@as(usize, 4), pos.col);
}

test "TextAreaState cursor up/down" {
    var buf: [256]u8 = undefined;
    var textarea_state = TextAreaState.init(&buf);

    textarea_state.insert("Line 1\nLine 2\nLine 3");

    // Move up
    textarea_state.cursorUp(false);
    var pos = textarea_state.getCursorPosition();
    try std.testing.expectEqual(@as(usize, 1), pos.line);

    textarea_state.cursorUp(false);
    pos = textarea_state.getCursorPosition();
    try std.testing.expectEqual(@as(usize, 0), pos.line);

    // Move down
    textarea_state.cursorDown(false);
    pos = textarea_state.getCursorPosition();
    try std.testing.expectEqual(@as(usize, 1), pos.line);
}

test "TextAreaState home/end" {
    var buf: [256]u8 = undefined;
    var textarea_state = TextAreaState.init(&buf);

    textarea_state.insert("Hello World");
    textarea_state.cursorHome(false);

    try std.testing.expectEqual(@as(usize, 0), textarea_state.cursor);

    textarea_state.cursorEnd(false);
    try std.testing.expectEqual(@as(usize, 11), textarea_state.cursor);
}

test "TextAreaState selection" {
    var buf: [256]u8 = undefined;
    var textarea_state = TextAreaState.init(&buf);

    textarea_state.insert("Hello World");
    textarea_state.selectAll();

    try std.testing.expectEqual(@as(?usize, 0), textarea_state.selection_start);
    try std.testing.expectEqual(@as(usize, 11), textarea_state.cursor);

    textarea_state.insert("X");
    try std.testing.expectEqualStrings("X", textarea_state.text());
}

test "textArea generates commands" {
    var ctx = try Context.init(std.testing.allocator, 800, 600);
    defer ctx.deinit();

    var buf: [256]u8 = undefined;
    var textarea_state = TextAreaState.init(&buf);

    ctx.beginFrame();
    ctx.layout.row_height = 100;

    _ = textArea(&ctx, &textarea_state);

    // Should generate: rect (bg) + rect_outline (border)
    try std.testing.expect(ctx.commands.items.len >= 2);

    ctx.endFrame();
}

test "countDigits" {
    try std.testing.expectEqual(@as(usize, 1), render.countDigits(0));
    try std.testing.expectEqual(@as(usize, 1), render.countDigits(5));
    try std.testing.expectEqual(@as(usize, 2), render.countDigits(10));
    try std.testing.expectEqual(@as(usize, 3), render.countDigits(100));
    try std.testing.expectEqual(@as(usize, 4), render.countDigits(1234));
}