//! Modal Widget - Overlay dialogs
//!
//! Provides modal dialogs that render on top of other content:
//! - Modal: Dialog with title, message, and buttons
//! - Confirm: Yes/No dialog
//! - Alert: OK dialog
//! - Input: Text input dialog
//!
//! Modals block interaction with the underlying UI until dismissed.

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");
const Input = @import("../core/input.zig");
const button = @import("button.zig");
const text_input = @import("text_input.zig");

// =============================================================================
// Modal State
// =============================================================================

/// Modal state (caller-managed)
pub const ModalState = struct {
    /// Whether the modal is visible
    visible: bool = false,
    /// Currently focused button index
    focused_button: usize = 0,
    /// For input dialogs: text state
    input_state: ?*text_input.TextInputState = null,

    const Self = @This();

    /// Show the modal
    pub fn show(self: *Self) void {
        self.visible = true;
        self.focused_button = 0;
    }

    /// Hide the modal
    pub fn hide(self: *Self) void {
        self.visible = false;
    }

    /// Focus next button
    pub fn focusNext(self: *Self, button_count: usize) void {
        if (button_count > 0) {
            self.focused_button = (self.focused_button + 1) % button_count;
        }
    }

    /// Focus previous button
    pub fn focusPrev(self: *Self, button_count: usize) void {
        if (button_count > 0) {
            if (self.focused_button == 0) {
                self.focused_button = button_count - 1;
            } else {
                self.focused_button -= 1;
            }
        }
    }
};

// =============================================================================
// Modal Configuration
// =============================================================================

/// Modal button definition
pub const ModalButton = struct {
    label: []const u8,
    importance: button.Importance = .normal,
};

/// Predefined button sets
pub const ButtonSet = struct {
    pub const ok = [_]ModalButton{
        .{ .label = "OK", .importance = .primary },
    };

    pub const ok_cancel = [_]ModalButton{
        .{ .label = "OK", .importance = .primary },
        .{ .label = "Cancel", .importance = .normal },
    };

    pub const yes_no = [_]ModalButton{
        .{ .label = "Yes", .importance = .primary },
        .{ .label = "No", .importance = .normal },
    };

    pub const yes_no_cancel = [_]ModalButton{
        .{ .label = "Yes", .importance = .primary },
        .{ .label = "No", .importance = .normal },
        .{ .label = "Cancel", .importance = .normal },
    };
};

/// Modal configuration
pub const ModalConfig = struct {
    /// Dialog title
    title: []const u8 = "Dialog",
    /// Message lines
    message: []const u8 = "",
    /// Dialog width
    width: u32 = 300,
    /// Dialog height (0 = auto)
    height: u32 = 0,
    /// Buttons
    buttons: []const ModalButton = &ButtonSet.ok,
    /// Show input field
    show_input: bool = false,
    /// Input placeholder
    input_placeholder: []const u8 = "",
    /// Corner radius (default 8 for fancy mode)
    corner_radius: u8 = 8,
    /// Show shadow (fancy mode only)
    show_shadow: bool = true,
};

/// Modal colors
pub const ModalColors = struct {
    /// Backdrop color (semi-transparent overlay)
    backdrop: Style.Color = Style.Color.rgba(0, 0, 0, 180),
    /// Dialog background
    background: Style.Color = Style.Color.rgb(45, 45, 50),
    /// Border color
    border: Style.Color = Style.Color.rgb(80, 80, 85),
    /// Title bar background
    title_bg: Style.Color = Style.Color.rgb(55, 55, 60),
    /// Title text color
    title_fg: Style.Color = Style.Color.rgb(220, 220, 220),
    /// Message text color
    message_fg: Style.Color = Style.Color.rgb(200, 200, 200),
    /// Shadow color (fancy mode only)
    shadow: Style.Color = Style.Color.rgba(0, 0, 0, 80),
};

/// Modal result
pub const ModalResult = struct {
    /// Button index that was clicked (-1 if none)
    button_clicked: i32 = -1,
    /// Whether the modal was dismissed (Escape)
    dismissed: bool = false,
    /// For input modals: the input text when submitted
    input_text: ?[]const u8 = null,
};

// =============================================================================
// Modal Functions
// =============================================================================

/// Draw a modal dialog
pub fn modal(
    ctx: *Context,
    state: *ModalState,
    config: ModalConfig,
) ModalResult {
    return modalEx(ctx, state, config, .{});
}

/// Draw a modal dialog with custom colors
pub fn modalEx(
    ctx: *Context,
    state: *ModalState,
    config: ModalConfig,
    colors: ModalColors,
) ModalResult {
    var result = ModalResult{};

    if (!state.visible) return result;

    const screen_w = ctx.layout.area.w;
    const screen_h = ctx.layout.area.h;

    // Calculate dialog dimensions
    const dialog_w = @min(config.width, screen_w -| 40);
    const title_h: u32 = 28;
    const padding: u32 = 16;
    const button_h: u32 = 32;
    const input_h: u32 = if (config.show_input) 28 else 0;

    // Estimate message height (rough: 16px per line, wrap at dialog width)
    const msg_lines = countLines(config.message);
    const msg_h: u32 = @max(1, msg_lines) * 18;

    const content_h = msg_h + input_h + button_h + padding * 3;
    const dialog_h = if (config.height > 0) config.height else title_h + content_h + padding;

    // Center dialog
    const dialog_x = @as(i32, @intCast((screen_w -| dialog_w) / 2));
    const dialog_y = @as(i32, @intCast((screen_h -| dialog_h) / 2));

    // Draw backdrop (semi-transparent overlay)
    ctx.pushCommand(Command.rect(0, 0, screen_w, screen_h, colors.backdrop));

    // Check render mode for fancy features
    const fancy = Style.isFancy() and config.corner_radius > 0;

    // Draw shadow first (behind dialog) in fancy mode
    if (fancy and config.show_shadow) {
        ctx.pushCommand(Command.shadowFloat(dialog_x, dialog_y, dialog_w, dialog_h, config.corner_radius));
    }

    // Draw dialog border and background based on render mode
    if (fancy) {
        // Fancy mode: rounded corners
        ctx.pushCommand(Command.roundedRect(dialog_x, dialog_y, dialog_w, dialog_h, colors.background, config.corner_radius));
        ctx.pushCommand(Command.roundedRectOutline(dialog_x, dialog_y, dialog_w, dialog_h, colors.border, config.corner_radius));
    } else {
        // Simple mode: square corners
        ctx.pushCommand(Command.rectOutline(
            dialog_x - 1,
            dialog_y - 1,
            dialog_w + 2,
            dialog_h + 2,
            colors.border,
        ));
        ctx.pushCommand(Command.rect(dialog_x, dialog_y, dialog_w, dialog_h, colors.background));
    }

    // Draw title bar (inside dialog, so no rounded corners needed)
    ctx.pushCommand(Command.rect(dialog_x, dialog_y, dialog_w, title_h, colors.title_bg));

    // Draw title text
    const title_text_x = dialog_x + @as(i32, @intCast(padding));
    const title_text_y = dialog_y + @as(i32, @intCast((title_h - 8) / 2));
    ctx.pushCommand(Command.text(title_text_x, title_text_y, config.title, colors.title_fg));

    // Draw message
    const msg_x = dialog_x + @as(i32, @intCast(padding));
    var msg_y = dialog_y + @as(i32, @intCast(title_h + padding));
    ctx.pushCommand(Command.text(msg_x, msg_y, config.message, colors.message_fg));
    msg_y += @as(i32, @intCast(msg_h + padding));

    // Draw input field if enabled
    if (config.show_input) {
        if (state.input_state) |input_st| {
            const input_rect = Layout.Rect.init(
                dialog_x + @as(i32, @intCast(padding)),
                msg_y,
                dialog_w -| (padding * 2),
                24,
            );

            // Input rendering
            const input_bg = Style.Color.rgb(35, 35, 40);
            const input_radius: u8 = 3;
            if (fancy) {
                ctx.pushCommand(Command.roundedRect(input_rect.x, input_rect.y, input_rect.w, input_rect.h, input_bg, input_radius));
                ctx.pushCommand(Command.roundedRectOutline(input_rect.x, input_rect.y, input_rect.w, input_rect.h, colors.border, input_radius));
            } else {
                ctx.pushCommand(Command.rect(input_rect.x, input_rect.y, input_rect.w, input_rect.h, input_bg));
                ctx.pushCommand(Command.rectOutline(input_rect.x, input_rect.y, input_rect.w, input_rect.h, colors.border));
            }

            const txt = input_st.text();
            if (txt.len > 0) {
                ctx.pushCommand(Command.text(input_rect.x + 4, input_rect.y + 4, txt, colors.message_fg));
            } else if (config.input_placeholder.len > 0) {
                ctx.pushCommand(Command.text(
                    input_rect.x + 4,
                    input_rect.y + 4,
                    config.input_placeholder,
                    Style.Color.rgb(120, 120, 120),
                ));
            }
        }
        msg_y += @as(i32, @intCast(input_h + padding));
    }

    // Draw buttons
    const button_count = config.buttons.len;
    if (button_count > 0) {
        const btn_width: u32 = 80;
        const btn_spacing: u32 = 12;
        const total_btn_width = button_count * btn_width + (button_count - 1) * btn_spacing;
        var btn_x = dialog_x + @as(i32, @intCast((dialog_w -| total_btn_width) / 2));
        const btn_y = dialog_y + @as(i32, @intCast(dialog_h - button_h - padding));

        for (config.buttons, 0..) |btn, i| {
            const is_focused = state.focused_button == i;

            // Button background
            const btn_bg = if (is_focused)
                Style.Color.primary
            else switch (btn.importance) {
                .primary => Style.Color.primary.darken(30),
                .normal => Style.Color.rgb(60, 60, 65),
                .danger => Style.Color.danger.darken(30),
            };

            const btn_radius: u8 = 4;
            if (fancy) {
                ctx.pushCommand(Command.roundedRect(btn_x, btn_y, btn_width, button_h - 4, btn_bg, btn_radius));
                if (is_focused) {
                    ctx.pushCommand(Command.roundedRectOutline(btn_x, btn_y, btn_width, button_h - 4, Style.Color.rgb(200, 200, 200), btn_radius));
                }
            } else {
                ctx.pushCommand(Command.rect(btn_x, btn_y, btn_width, button_h - 4, btn_bg));
                if (is_focused) {
                    ctx.pushCommand(Command.rectOutline(btn_x, btn_y, btn_width, button_h - 4, Style.Color.rgb(200, 200, 200)));
                }
            }

            // Button text
            const text_w = btn.label.len * 8;
            const text_x = btn_x + @as(i32, @intCast((btn_width -| @as(u32, @intCast(text_w))) / 2));
            const text_y = btn_y + @as(i32, @intCast((button_h - 4 - 8) / 2));
            ctx.pushCommand(Command.text(text_x, text_y, btn.label, Style.Color.rgb(240, 240, 240)));

            // Check click
            const btn_rect = Layout.Rect.init(btn_x, btn_y, btn_width, button_h - 4);
            const mouse = ctx.input.mousePos();
            if (btn_rect.contains(mouse.x, mouse.y) and ctx.input.mousePressed(.left)) {
                result.button_clicked = @intCast(i);
                state.hide();
                if (config.show_input) {
                    if (state.input_state) |input_st| {
                        result.input_text = input_st.text();
                    }
                }
            }

            btn_x += @as(i32, @intCast(btn_width + btn_spacing));
        }
    }

    // Handle keyboard navigation
    if (ctx.input.keyPressed(.tab)) {
        if (ctx.input.modifiers.shift) {
            state.focusPrev(button_count);
        } else {
            state.focusNext(button_count);
        }
    }

    if (ctx.input.keyPressed(.left)) {
        state.focusPrev(button_count);
    }

    if (ctx.input.keyPressed(.right)) {
        state.focusNext(button_count);
    }

    // Enter confirms focused button
    if (ctx.input.keyPressed(.enter)) {
        result.button_clicked = @intCast(state.focused_button);
        state.hide();
        if (config.show_input) {
            if (state.input_state) |input_st| {
                result.input_text = input_st.text();
            }
        }
    }

    // Escape dismisses
    if (ctx.input.keyPressed(.escape)) {
        result.dismissed = true;
        state.hide();
    }

    return result;
}

// =============================================================================
// Convenience Functions
// =============================================================================

/// Show an alert dialog (OK button only)
pub fn alert(
    ctx: *Context,
    state: *ModalState,
    title: []const u8,
    message: []const u8,
) ModalResult {
    return modal(ctx, state, .{
        .title = title,
        .message = message,
        .buttons = &ButtonSet.ok,
    });
}

/// Show a confirm dialog (Yes/No buttons)
pub fn confirm(
    ctx: *Context,
    state: *ModalState,
    title: []const u8,
    message: []const u8,
) ModalResult {
    return modal(ctx, state, .{
        .title = title,
        .message = message,
        .buttons = &ButtonSet.yes_no,
    });
}

/// Show an input dialog (text field + OK/Cancel)
pub fn inputDialog(
    ctx: *Context,
    state: *ModalState,
    title: []const u8,
    message: []const u8,
    placeholder: []const u8,
) ModalResult {
    return modal(ctx, state, .{
        .title = title,
        .message = message,
        .buttons = &ButtonSet.ok_cancel,
        .show_input = true,
        .input_placeholder = placeholder,
    });
}

// =============================================================================
// Helpers
// =============================================================================

fn countLines(text: []const u8) u32 {
    if (text.len == 0) return 0;
    var lines: u32 = 1;
    for (text) |c| {
        if (c == '\n') lines += 1;
    }
    return lines;
}

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

test "ModalState show/hide" {
    var state = ModalState{};

    try std.testing.expect(!state.visible);

    state.show();
    try std.testing.expect(state.visible);
    try std.testing.expectEqual(@as(usize, 0), state.focused_button);

    state.hide();
    try std.testing.expect(!state.visible);
}

test "ModalState focus navigation" {
    var state = ModalState{};
    state.show();

    // 3 buttons
    state.focusNext(3);
    try std.testing.expectEqual(@as(usize, 1), state.focused_button);

    state.focusNext(3);
    try std.testing.expectEqual(@as(usize, 2), state.focused_button);

    state.focusNext(3); // Wrap around
    try std.testing.expectEqual(@as(usize, 0), state.focused_button);

    state.focusPrev(3); // Wrap to end
    try std.testing.expectEqual(@as(usize, 2), state.focused_button);
}

test "countLines" {
    try std.testing.expectEqual(@as(u32, 0), countLines(""));
    try std.testing.expectEqual(@as(u32, 1), countLines("hello"));
    try std.testing.expectEqual(@as(u32, 2), countLines("hello\nworld"));
    try std.testing.expectEqual(@as(u32, 3), countLines("a\nb\nc"));
}