//! Popup and Modal widgets for zcatui.
//!
//! Provides overlay widgets that render on top of other content:
//! - Popup: Simple overlay with content
//! - Modal: Popup with title, optional buttons, and backdrop
//!
//! ## Example
//!
//! ```zig
//! const popup = Popup.init()
//!     .setContent(myWidget)
//!     .setSize(40, 10)
//!     .center();
//!
//! popup.render(area, buf);
//! ```

const std = @import("std");
const buffer_mod = @import("../buffer.zig");
const Buffer = buffer_mod.Buffer;
const Rect = buffer_mod.Rect;
const Cell = buffer_mod.Cell;
const style_mod = @import("../style.zig");
const Style = style_mod.Style;
const Color = style_mod.Color;
const block_mod = @import("block.zig");
const Block = block_mod.Block;
const Borders = block_mod.Borders;
const text_mod = @import("../text.zig");
const Line = text_mod.Line;
const Span = text_mod.Span;
const Alignment = text_mod.Alignment;

// ============================================================================
// Popup
// ============================================================================

/// A simple popup overlay.
///
/// Renders content in a floating box that can be positioned anywhere
/// on screen. Supports optional backdrop dimming.
pub const Popup = struct {
    /// Content area dimensions.
    width: u16 = 40,
    height: u16 = 10,

    /// Position (if null, will be centered).
    x: ?u16 = null,
    y: ?u16 = null,

    /// Block wrapper for the popup.
    block: ?Block = null,

    /// Style for the popup content area.
    content_style: Style = Style.default,

    /// Whether to dim the background.
    dim_background: bool = true,

    /// Background dim character and style.
    dim_char: u21 = ' ',
    dim_style: Style = Style.default.bg(Color.black),

    /// Content render function.
    render_content: ?*const fn (Rect, *Buffer) void = null,

    /// Creates a new popup.
    pub fn init() Popup {
        return .{};
    }

    /// Sets the popup dimensions.
    pub fn setSize(self: Popup, width: u16, height: u16) Popup {
        var p = self;
        p.width = width;
        p.height = height;
        return p;
    }

    /// Sets the popup position.
    pub fn setPosition(self: Popup, x: u16, y: u16) Popup {
        var p = self;
        p.x = x;
        p.y = y;
        return p;
    }

    /// Centers the popup (clears explicit position).
    pub fn center(self: Popup) Popup {
        var p = self;
        p.x = null;
        p.y = null;
        return p;
    }

    /// Sets the block wrapper.
    pub fn setBlock(self: Popup, block: Block) Popup {
        var p = self;
        p.block = block;
        return p;
    }

    /// Sets the content style.
    pub fn setContentStyle(self: Popup, style: Style) Popup {
        var p = self;
        p.content_style = style;
        return p;
    }

    /// Enables/disables background dimming.
    pub fn setDimBackground(self: Popup, dim: bool) Popup {
        var p = self;
        p.dim_background = dim;
        return p;
    }

    /// Sets the dim style.
    pub fn setDimStyle(self: Popup, style: Style) Popup {
        var p = self;
        p.dim_style = style;
        return p;
    }

    /// Sets the content render function.
    pub fn setRenderContent(self: Popup, render_fn: *const fn (Rect, *Buffer) void) Popup {
        var p = self;
        p.render_content = render_fn;
        return p;
    }

    /// Calculates the popup area within the given container.
    pub fn getPopupArea(self: Popup, container: Rect) Rect {
        const w = @min(self.width, container.width);
        const h = @min(self.height, container.height);

        const px = if (self.x) |x|
            @min(x, container.width -| w)
        else
            container.x + (container.width -| w) / 2;

        const py = if (self.y) |y|
            @min(y, container.height -| h)
        else
            container.y + (container.height -| h) / 2;

        return Rect.init(px, py, w, h);
    }

    /// Renders the popup.
    pub fn render(self: Popup, area: Rect, buf: *Buffer) void {
        // Dim background if enabled
        if (self.dim_background) {
            self.renderDimBackground(area, buf);
        }

        // Calculate popup position
        const popup_area = self.getPopupArea(area);

        // Clear popup area with content style
        self.clearArea(popup_area, buf);

        // Render block if set
        var content_area = popup_area;
        if (self.block) |block| {
            block.render(popup_area, buf);
            content_area = block.inner(popup_area);
        }

        // Render content if function provided
        if (self.render_content) |render_fn| {
            render_fn(content_area, buf);
        }
    }

    fn renderDimBackground(self: Popup, area: Rect, buf: *Buffer) void {
        var y = area.top();
        while (y < area.bottom()) : (y += 1) {
            var x = area.left();
            while (x < area.right()) : (x += 1) {
                if (buf.getCell(x, y)) |cell| {
                    // Keep the character but apply dim style
                    cell.setStyle(self.dim_style);
                }
            }
        }
    }

    fn clearArea(self: Popup, area: Rect, buf: *Buffer) void {
        var y = area.top();
        while (y < area.bottom()) : (y += 1) {
            var x = area.left();
            while (x < area.right()) : (x += 1) {
                if (buf.getCell(x, y)) |cell| {
                    cell.setChar(' ');
                    cell.setStyle(self.content_style);
                }
            }
        }
    }
};

// ============================================================================
// Modal
// ============================================================================

/// Button definition for modal dialogs.
pub const ModalButton = struct {
    label: []const u8,
    style: Style = Style.default,
    focused_style: Style = Style.default.bg(Color.blue).fg(Color.white),
};

/// A modal dialog with title, message, and buttons.
///
/// Provides a complete dialog experience with:
/// - Title bar
/// - Message content
/// - Action buttons (OK, Cancel, etc.)
/// - Keyboard navigation support
pub const Modal = struct {
    /// Dialog title.
    title: []const u8 = "Dialog",

    /// Message lines.
    message: []const []const u8 = &.{},

    /// Buttons.
    buttons: []const ModalButton = &.{},

    /// Currently focused button index.
    focused_button: usize = 0,

    /// Popup dimensions.
    width: u16 = 50,
    height: u16 = 0, // Auto-calculated if 0

    /// Styles.
    title_style: Style = Style.default.fg(Color.cyan).bold(),
    message_style: Style = Style.default,
    border_style: Style = Style.default.fg(Color.white),
    background_style: Style = Style.default,

    /// Whether to dim background.
    dim_background: bool = true,

    /// Creates a new modal.
    pub fn init() Modal {
        return .{};
    }

    /// Sets the title.
    pub fn setTitle(self: Modal, title: []const u8) Modal {
        var m = self;
        m.title = title;
        return m;
    }

    /// Sets the message lines.
    pub fn setMessage(self: Modal, message: []const []const u8) Modal {
        var m = self;
        m.message = message;
        return m;
    }

    /// Sets the buttons.
    pub fn setButtons(self: Modal, buttons: []const ModalButton) Modal {
        var m = self;
        m.buttons = buttons;
        return m;
    }

    /// Sets the focused button index.
    pub fn setFocusedButton(self: Modal, index: usize) Modal {
        var m = self;
        m.focused_button = @min(index, if (self.buttons.len > 0) self.buttons.len - 1 else 0);
        return m;
    }

    /// Sets the width.
    pub fn setWidth(self: Modal, width: u16) Modal {
        var m = self;
        m.width = width;
        return m;
    }

    /// Sets explicit height (0 = auto).
    pub fn setHeight(self: Modal, height: u16) Modal {
        var m = self;
        m.height = height;
        return m;
    }

    /// Sets the title style.
    pub fn setTitleStyle(self: Modal, style: Style) Modal {
        var m = self;
        m.title_style = style;
        return m;
    }

    /// Sets the message style.
    pub fn setMessageStyle(self: Modal, style: Style) Modal {
        var m = self;
        m.message_style = style;
        return m;
    }

    /// Sets the border style.
    pub fn setBorderStyle(self: Modal, style: Style) Modal {
        var m = self;
        m.border_style = style;
        return m;
    }

    /// Enables/disables background dimming.
    pub fn setDimBackground(self: Modal, dim: bool) Modal {
        var m = self;
        m.dim_background = dim;
        return m;
    }

    /// Focuses the next button.
    pub fn focusNext(self: *Modal) void {
        if (self.buttons.len > 0) {
            self.focused_button = (self.focused_button + 1) % self.buttons.len;
        }
    }

    /// Focuses the previous button.
    pub fn focusPrev(self: *Modal) void {
        if (self.buttons.len > 0) {
            if (self.focused_button == 0) {
                self.focused_button = self.buttons.len - 1;
            } else {
                self.focused_button -= 1;
            }
        }
    }

    /// Returns the currently focused button index.
    pub fn getFocusedButton(self: Modal) usize {
        return self.focused_button;
    }

    /// Calculates the required height.
    fn calculateHeight(self: Modal) u16 {
        if (self.height > 0) return self.height;

        // Title (1) + border (2) + message lines + blank + buttons (1) + padding
        const message_lines: u16 = @intCast(self.message.len);
        const button_line: u16 = if (self.buttons.len > 0) 1 else 0;
        const padding: u16 = 2; // Top and bottom padding inside border

        return 2 + padding + message_lines + 1 + button_line;
    }

    /// Renders the modal.
    pub fn render(self: Modal, area: Rect, buf: *Buffer) void {
        const height = self.calculateHeight();
        const width = @min(self.width, area.width);

        // Create popup
        var popup = Popup.init()
            .setSize(width, height)
            .setDimBackground(self.dim_background)
            .center();

        // Create block with title
        const block = Block.init()
            .title(self.title)
            .titleStyle(self.title_style)
            .setBorders(Borders.all)
            .style(self.border_style);

        popup = popup.setBlock(block);
        popup = popup.setContentStyle(self.background_style);

        // Render popup frame
        if (self.dim_background) {
            popup.renderDimBackground(area, buf);
        }

        const popup_area = popup.getPopupArea(area);
        popup.clearArea(popup_area, buf);
        block.render(popup_area, buf);

        const content_area = block.inner(popup_area);

        // Render message
        self.renderMessage(content_area, buf);

        // Render buttons
        if (self.buttons.len > 0) {
            self.renderButtons(content_area, buf);
        }
    }

    fn renderMessage(self: Modal, area: Rect, buf: *Buffer) void {
        var y = area.top();
        for (self.message) |line| {
            if (y >= area.bottom() -| 2) break; // Leave room for buttons

            // Center the message
            const line_len: u16 = @intCast(@min(line.len, area.width));
            const x = area.left() + (area.width -| line_len) / 2;

            _ = buf.setString(x, y, line, self.message_style);
            y += 1;
        }
    }

    fn renderButtons(self: Modal, area: Rect, buf: *Buffer) void {
        // Calculate total button width
        var total_width: u16 = 0;
        for (self.buttons) |button| {
            total_width += @as(u16, @intCast(button.label.len)) + 4; // [ label ]
        }
        total_width += @as(u16, @intCast(self.buttons.len)) - 1; // Spaces between

        // Position at bottom, centered
        const y = area.bottom() -| 1;
        var x = area.left() + (area.width -| total_width) / 2;

        for (self.buttons, 0..) |button, i| {
            const is_focused = i == self.focused_button;
            const btn_style = if (is_focused) button.focused_style else button.style;

            // Render button: [ label ]
            _ = buf.setString(x, y, "[ ", btn_style);
            x += 2;
            _ = buf.setString(x, y, button.label, btn_style);
            x += @intCast(button.label.len);
            _ = buf.setString(x, y, " ]", btn_style);
            x += 2;

            if (i < self.buttons.len - 1) {
                x += 1; // Space between buttons
            }
        }
    }
};

// ============================================================================
// Confirm Dialog Helper
// ============================================================================

/// Creates a standard confirmation modal with OK/Cancel buttons.
pub fn confirmDialog(title: []const u8, message: []const []const u8) Modal {
    return Modal.init()
        .setTitle(title)
        .setMessage(message)
        .setButtons(&.{
            .{ .label = "OK", .focused_style = Style.default.bg(Color.green).fg(Color.white) },
            .{ .label = "Cancel", .focused_style = Style.default.bg(Color.red).fg(Color.white) },
        });
}

/// Creates a standard alert modal with just an OK button.
pub fn alertDialog(title: []const u8, message: []const []const u8) Modal {
    return Modal.init()
        .setTitle(title)
        .setMessage(message)
        .setButtons(&.{
            .{ .label = "OK", .focused_style = Style.default.bg(Color.blue).fg(Color.white) },
        });
}

/// Creates a yes/no/cancel modal.
pub fn yesNoCancelDialog(title: []const u8, message: []const []const u8) Modal {
    return Modal.init()
        .setTitle(title)
        .setMessage(message)
        .setButtons(&.{
            .{ .label = "Yes", .focused_style = Style.default.bg(Color.green).fg(Color.white) },
            .{ .label = "No", .focused_style = Style.default.bg(Color.yellow).fg(Color.black) },
            .{ .label = "Cancel", .focused_style = Style.default.bg(Color.red).fg(Color.white) },
        });
}

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

test "Popup basic" {
    const popup = Popup.init()
        .setSize(20, 10)
        .center();

    const container = Rect.init(0, 0, 80, 24);
    const popup_area = popup.getPopupArea(container);

    // Should be centered
    try std.testing.expectEqual(@as(u16, 30), popup_area.x); // (80-20)/2
    try std.testing.expectEqual(@as(u16, 7), popup_area.y); // (24-10)/2
    try std.testing.expectEqual(@as(u16, 20), popup_area.width);
    try std.testing.expectEqual(@as(u16, 10), popup_area.height);
}

test "Popup positioned" {
    const popup = Popup.init()
        .setSize(20, 10)
        .setPosition(5, 3);

    const container = Rect.init(0, 0, 80, 24);
    const popup_area = popup.getPopupArea(container);

    try std.testing.expectEqual(@as(u16, 5), popup_area.x);
    try std.testing.expectEqual(@as(u16, 3), popup_area.y);
}

test "Modal focus navigation" {
    var modal = Modal.init()
        .setButtons(&.{
            .{ .label = "A" },
            .{ .label = "B" },
            .{ .label = "C" },
        });

    try std.testing.expectEqual(@as(usize, 0), modal.getFocusedButton());

    modal.focusNext();
    try std.testing.expectEqual(@as(usize, 1), modal.getFocusedButton());

    modal.focusNext();
    try std.testing.expectEqual(@as(usize, 2), modal.getFocusedButton());

    modal.focusNext(); // Wraps around
    try std.testing.expectEqual(@as(usize, 0), modal.getFocusedButton());

    modal.focusPrev(); // Wraps back
    try std.testing.expectEqual(@as(usize, 2), modal.getFocusedButton());
}

test "confirmDialog creates correct buttons" {
    const dialog = confirmDialog("Test", &.{"Message"});

    try std.testing.expectEqual(@as(usize, 2), dialog.buttons.len);
    try std.testing.expectEqualStrings("OK", dialog.buttons[0].label);
    try std.testing.expectEqualStrings("Cancel", dialog.buttons[1].label);
}

test "alertDialog creates single button" {
    const dialog = alertDialog("Alert", &.{"Warning!"});

    try std.testing.expectEqual(@as(usize, 1), dialog.buttons.len);
    try std.testing.expectEqualStrings("OK", dialog.buttons[0].label);
}