//! Style - Colors and visual styling
//!
//! Based on zcatui's style system, adapted for GUI with RGBA colors.

const std = @import("std");

// =============================================================================
// Render Mode - Simple vs Fancy
// =============================================================================

/// Render mode controls visual quality vs performance tradeoff
pub const RenderMode = enum {
    /// Fast rendering: rectangles, no AA on shapes, no shadows
    /// Best for: low-end hardware, SSH, WASM with limited resources
    simple,

    /// Pretty rendering: rounded corners, edge-fade AA, shadows
    /// Best for: desktop with good CPU, visual polish needed
    fancy,
};

/// Global render mode - widgets check this to decide how to render
var global_render_mode: RenderMode = .fancy;

/// Get current render mode
pub fn getRenderMode() RenderMode {
    return global_render_mode;
}

/// Set render mode
pub fn setRenderMode(mode: RenderMode) void {
    global_render_mode = mode;
}

/// Check if fancy rendering is enabled
pub fn isFancy() bool {
    return global_render_mode == .fancy;
}

/// RGBA Color
pub const Color = struct {
    r: u8,
    g: u8,
    b: u8,
    a: u8 = 255,

    const Self = @This();

    /// Create a color from RGB values
    pub fn rgb(r: u8, g: u8, b: u8) Self {
        return .{ .r = r, .g = g, .b = b, .a = 255 };
    }

    /// Create a color from RGBA values
    pub fn rgba(r: u8, g: u8, b: u8, a: u8) Self {
        return .{ .r = r, .g = g, .b = b, .a = a };
    }

    /// Convert to u32 (RGBA format)
    pub fn toU32(self: Self) u32 {
        return (@as(u32, self.r) << 24) |
            (@as(u32, self.g) << 16) |
            (@as(u32, self.b) << 8) |
            @as(u32, self.a);
    }

    /// Convert to u32 (ABGR format for SDL)
    pub fn toABGR(self: Self) u32 {
        return (@as(u32, self.a) << 24) |
            (@as(u32, self.b) << 16) |
            (@as(u32, self.g) << 8) |
            @as(u32, self.r);
    }

    /// Blend this color over another
    pub fn blend(self: Self, bg_color: Self) Self {
        if (self.a == 255) return self;
        if (self.a == 0) return bg_color;

        const alpha = @as(u16, self.a);
        const inv_alpha = 255 - alpha;

        return .{
            .r = @intCast((@as(u16, self.r) * alpha + @as(u16, bg_color.r) * inv_alpha) / 255),
            .g = @intCast((@as(u16, self.g) * alpha + @as(u16, bg_color.g) * inv_alpha) / 255),
            .b = @intCast((@as(u16, self.b) * alpha + @as(u16, bg_color.b) * inv_alpha) / 255),
            .a = 255,
        };
    }

    /// Darken color by percentage (0-100)
    pub fn darken(self: Self, percent: u8) Self {
        const factor = @as(u16, 100 - @min(percent, 100));
        return .{
            .r = @intCast((@as(u16, self.r) * factor) / 100),
            .g = @intCast((@as(u16, self.g) * factor) / 100),
            .b = @intCast((@as(u16, self.b) * factor) / 100),
            .a = self.a,
        };
    }

    /// Lighten color by percentage (0-100)
    pub fn lighten(self: Self, percent: u8) Self {
        const factor = @as(u16, @min(percent, 100));
        return .{
            .r = @intCast(@as(u16, self.r) + ((@as(u16, 255) - self.r) * factor) / 100),
            .g = @intCast(@as(u16, self.g) + ((@as(u16, 255) - self.g) * factor) / 100),
            .b = @intCast(@as(u16, self.b) + ((@as(u16, 255) - self.b) * factor) / 100),
            .a = self.a,
        };
    }

    /// Return same color with different alpha
    pub fn withAlpha(self: Self, alpha: u8) Self {
        return .{
            .r = self.r,
            .g = self.g,
            .b = self.b,
            .a = alpha,
        };
    }

    // =========================================================================
    // Predefined colors
    // =========================================================================

    pub const transparent = Color.rgba(0, 0, 0, 0);
    pub const black = Color.rgb(0, 0, 0);
    pub const white = Color.rgb(255, 255, 255);
    pub const red = Color.rgb(255, 0, 0);
    pub const green = Color.rgb(0, 255, 0);
    pub const blue = Color.rgb(0, 0, 255);
    pub const yellow = Color.rgb(255, 255, 0);
    pub const cyan = Color.rgb(0, 255, 255);
    pub const magenta = Color.rgb(255, 0, 255);
    pub const gray = Color.rgb(128, 128, 128);
    pub const dark_gray = Color.rgb(64, 64, 64);
    pub const light_gray = Color.rgb(192, 192, 192);

    // UI colors
    pub const background = Color.rgb(30, 30, 30);
    pub const foreground = Color.rgb(220, 220, 220);
    pub const primary = Color.rgb(66, 135, 245);
    pub const secondary = Color.rgb(100, 100, 100);
    pub const success = Color.rgb(76, 175, 80);
    pub const warning = Color.rgb(255, 152, 0);
    pub const danger = Color.rgb(244, 67, 54);
    pub const border = Color.rgb(80, 80, 80);
};

/// Visual style for widgets
pub const Style = struct {
    foreground: Color = Color.foreground,
    background: Color = Color.background,
    border: ?Color = null,
    border_radius: u8 = 0,

    const Self = @This();

    /// Set foreground color
    pub fn fg(self: Self, color: Color) Self {
        var s = self;
        s.foreground = color;
        return s;
    }

    /// Set background color
    pub fn bg(self: Self, color: Color) Self {
        var s = self;
        s.background = color;
        return s;
    }

    /// Set border color
    pub fn withBorder(self: Self, color: Color) Self {
        var s = self;
        s.border = color;
        return s;
    }
};

// =============================================================================
// Theme
// =============================================================================

/// A theme defines colors for all UI elements
pub const Theme = struct {
    /// Theme name
    name: []const u8 = "custom",

    // Base colors
    background: Color,
    foreground: Color,
    primary: Color,
    secondary: Color,
    success: Color,
    warning: Color,
    danger: Color,
    border: Color,

    // Surface colors (panels, cards)
    surface: Color,
    surface_variant: Color,

    // Text variants
    text_primary: Color,
    text_secondary: Color,
    text_disabled: Color,

    // Button colors
    button_bg: Color,
    button_fg: Color,
    button_hover: Color,
    button_active: Color,
    button_disabled_bg: Color,
    button_disabled_fg: Color,

    // Input colors
    input_bg: Color,
    input_fg: Color,
    input_border: Color,
    input_focus_border: Color,
    input_placeholder: Color,

    // Selection colors
    selection_bg: Color,
    selection_fg: Color,

    // Header/menu bar
    header_bg: Color,
    header_fg: Color,

    // Table colors
    table_header_bg: Color,
    table_row_even: Color,
    table_row_odd: Color,
    table_row_hover: Color,
    table_row_selected: Color,

    // Scrollbar
    scrollbar_track: Color,
    scrollbar_thumb: Color,
    scrollbar_thumb_hover: Color,

    // Modal/dialog
    modal_overlay: Color,
    modal_bg: Color,

    const Self = @This();

    /// Dark theme (default)
    pub const dark = Self{
        .name = "dark",
        .background = Color.rgb(30, 30, 30),
        .foreground = Color.rgb(220, 220, 220),
        .primary = Color.rgb(66, 135, 245),
        .secondary = Color.rgb(100, 100, 100),
        .success = Color.rgb(76, 175, 80),
        .warning = Color.rgb(255, 152, 0),
        .danger = Color.rgb(244, 67, 54),
        .border = Color.rgb(80, 80, 80),

        .surface = Color.rgb(40, 40, 40),
        .surface_variant = Color.rgb(50, 50, 50),

        .text_primary = Color.rgb(220, 220, 220),
        .text_secondary = Color.rgb(160, 160, 160),
        .text_disabled = Color.rgb(100, 100, 100),

        .button_bg = Color.rgb(60, 60, 60),
        .button_fg = Color.rgb(220, 220, 220),
        .button_hover = Color.rgb(80, 80, 80),
        .button_active = Color.rgb(50, 50, 50),
        .button_disabled_bg = Color.rgb(45, 45, 45),
        .button_disabled_fg = Color.rgb(100, 100, 100),

        .input_bg = Color.rgb(45, 45, 45),
        .input_fg = Color.rgb(220, 220, 220),
        .input_border = Color.rgb(80, 80, 80),
        .input_focus_border = Color.rgb(66, 135, 245),
        .input_placeholder = Color.rgb(120, 120, 120),

        .selection_bg = Color.rgb(66, 135, 245),
        .selection_fg = Color.rgb(255, 255, 255),

        .header_bg = Color.rgb(35, 35, 40),
        .header_fg = Color.rgb(200, 200, 200),

        .table_header_bg = Color.rgb(50, 50, 50),
        .table_row_even = Color.rgb(35, 35, 35),
        .table_row_odd = Color.rgb(40, 40, 40),
        .table_row_hover = Color.rgb(50, 50, 60),
        .table_row_selected = Color.rgb(66, 135, 245),

        .scrollbar_track = Color.rgb(40, 40, 40),
        .scrollbar_thumb = Color.rgb(80, 80, 80),
        .scrollbar_thumb_hover = Color.rgb(100, 100, 100),

        .modal_overlay = Color.rgba(0, 0, 0, 180),
        .modal_bg = Color.rgb(45, 45, 50),
    };

    /// Light theme
    pub const light = Self{
        .name = "light",
        .background = Color.rgb(245, 245, 245),
        .foreground = Color.rgb(30, 30, 30),
        .primary = Color.rgb(33, 150, 243),
        .secondary = Color.rgb(158, 158, 158),
        .success = Color.rgb(76, 175, 80),
        .warning = Color.rgb(255, 152, 0),
        .danger = Color.rgb(244, 67, 54),
        .border = Color.rgb(200, 200, 200),

        .surface = Color.rgb(255, 255, 255),
        .surface_variant = Color.rgb(240, 240, 240),

        .text_primary = Color.rgb(30, 30, 30),
        .text_secondary = Color.rgb(100, 100, 100),
        .text_disabled = Color.rgb(180, 180, 180),

        .button_bg = Color.rgb(230, 230, 230),
        .button_fg = Color.rgb(30, 30, 30),
        .button_hover = Color.rgb(210, 210, 210),
        .button_active = Color.rgb(190, 190, 190),
        .button_disabled_bg = Color.rgb(240, 240, 240),
        .button_disabled_fg = Color.rgb(180, 180, 180),

        .input_bg = Color.rgb(255, 255, 255),
        .input_fg = Color.rgb(30, 30, 30),
        .input_border = Color.rgb(180, 180, 180),
        .input_focus_border = Color.rgb(33, 150, 243),
        .input_placeholder = Color.rgb(160, 160, 160),

        .selection_bg = Color.rgb(33, 150, 243),
        .selection_fg = Color.rgb(255, 255, 255),

        .header_bg = Color.rgb(255, 255, 255),
        .header_fg = Color.rgb(50, 50, 50),

        .table_header_bg = Color.rgb(240, 240, 240),
        .table_row_even = Color.rgb(255, 255, 255),
        .table_row_odd = Color.rgb(248, 248, 248),
        .table_row_hover = Color.rgb(235, 245, 255),
        .table_row_selected = Color.rgb(33, 150, 243),

        .scrollbar_track = Color.rgb(240, 240, 240),
        .scrollbar_thumb = Color.rgb(200, 200, 200),
        .scrollbar_thumb_hover = Color.rgb(180, 180, 180),

        .modal_overlay = Color.rgba(0, 0, 0, 120),
        .modal_bg = Color.rgb(255, 255, 255),
    };

    /// High contrast dark theme
    pub const high_contrast_dark = Self{
        .name = "high_contrast_dark",
        .background = Color.rgb(0, 0, 0),
        .foreground = Color.rgb(255, 255, 255),
        .primary = Color.rgb(0, 200, 255),
        .secondary = Color.rgb(180, 180, 180),
        .success = Color.rgb(0, 255, 0),
        .warning = Color.rgb(255, 255, 0),
        .danger = Color.rgb(255, 0, 0),
        .border = Color.rgb(255, 255, 255),

        .surface = Color.rgb(20, 20, 20),
        .surface_variant = Color.rgb(40, 40, 40),

        .text_primary = Color.rgb(255, 255, 255),
        .text_secondary = Color.rgb(200, 200, 200),
        .text_disabled = Color.rgb(128, 128, 128),

        .button_bg = Color.rgb(40, 40, 40),
        .button_fg = Color.rgb(255, 255, 255),
        .button_hover = Color.rgb(60, 60, 60),
        .button_active = Color.rgb(20, 20, 20),
        .button_disabled_bg = Color.rgb(30, 30, 30),
        .button_disabled_fg = Color.rgb(100, 100, 100),

        .input_bg = Color.rgb(0, 0, 0),
        .input_fg = Color.rgb(255, 255, 255),
        .input_border = Color.rgb(255, 255, 255),
        .input_focus_border = Color.rgb(0, 200, 255),
        .input_placeholder = Color.rgb(150, 150, 150),

        .selection_bg = Color.rgb(0, 200, 255),
        .selection_fg = Color.rgb(0, 0, 0),

        .header_bg = Color.rgb(0, 0, 0),
        .header_fg = Color.rgb(255, 255, 255),

        .table_header_bg = Color.rgb(30, 30, 30),
        .table_row_even = Color.rgb(0, 0, 0),
        .table_row_odd = Color.rgb(20, 20, 20),
        .table_row_hover = Color.rgb(40, 40, 60),
        .table_row_selected = Color.rgb(0, 200, 255),

        .scrollbar_track = Color.rgb(20, 20, 20),
        .scrollbar_thumb = Color.rgb(150, 150, 150),
        .scrollbar_thumb_hover = Color.rgb(200, 200, 200),

        .modal_overlay = Color.rgba(0, 0, 0, 200),
        .modal_bg = Color.rgb(20, 20, 20),
    };

    /// Solarized Dark theme
    pub const solarized_dark = Self{
        .name = "solarized_dark",
        .background = Color.rgb(0, 43, 54), // base03
        .foreground = Color.rgb(131, 148, 150), // base0
        .primary = Color.rgb(38, 139, 210), // blue
        .secondary = Color.rgb(88, 110, 117), // base01
        .success = Color.rgb(133, 153, 0), // green
        .warning = Color.rgb(181, 137, 0), // yellow
        .danger = Color.rgb(220, 50, 47), // red
        .border = Color.rgb(88, 110, 117), // base01

        .surface = Color.rgb(7, 54, 66), // base02
        .surface_variant = Color.rgb(0, 43, 54), // base03

        .text_primary = Color.rgb(147, 161, 161), // base1
        .text_secondary = Color.rgb(131, 148, 150), // base0
        .text_disabled = Color.rgb(88, 110, 117), // base01

        .button_bg = Color.rgb(7, 54, 66),
        .button_fg = Color.rgb(147, 161, 161),
        .button_hover = Color.rgb(88, 110, 117),
        .button_active = Color.rgb(0, 43, 54),
        .button_disabled_bg = Color.rgb(0, 43, 54),
        .button_disabled_fg = Color.rgb(88, 110, 117),

        .input_bg = Color.rgb(0, 43, 54),
        .input_fg = Color.rgb(147, 161, 161),
        .input_border = Color.rgb(88, 110, 117),
        .input_focus_border = Color.rgb(38, 139, 210),
        .input_placeholder = Color.rgb(88, 110, 117),

        .selection_bg = Color.rgb(38, 139, 210),
        .selection_fg = Color.rgb(253, 246, 227),

        .header_bg = Color.rgb(7, 54, 66),
        .header_fg = Color.rgb(147, 161, 161),

        .table_header_bg = Color.rgb(7, 54, 66),
        .table_row_even = Color.rgb(0, 43, 54),
        .table_row_odd = Color.rgb(7, 54, 66),
        .table_row_hover = Color.rgb(88, 110, 117),
        .table_row_selected = Color.rgb(38, 139, 210),

        .scrollbar_track = Color.rgb(0, 43, 54),
        .scrollbar_thumb = Color.rgb(88, 110, 117),
        .scrollbar_thumb_hover = Color.rgb(101, 123, 131),

        .modal_overlay = Color.rgba(0, 0, 0, 180),
        .modal_bg = Color.rgb(7, 54, 66),
    };

    /// Solarized Light theme
    pub const solarized_light = Self{
        .name = "solarized_light",
        .background = Color.rgb(253, 246, 227), // base3
        .foreground = Color.rgb(101, 123, 131), // base00
        .primary = Color.rgb(38, 139, 210), // blue
        .secondary = Color.rgb(147, 161, 161), // base1
        .success = Color.rgb(133, 153, 0), // green
        .warning = Color.rgb(181, 137, 0), // yellow
        .danger = Color.rgb(220, 50, 47), // red
        .border = Color.rgb(147, 161, 161), // base1

        .surface = Color.rgb(238, 232, 213), // base2
        .surface_variant = Color.rgb(253, 246, 227), // base3

        .text_primary = Color.rgb(88, 110, 117), // base01
        .text_secondary = Color.rgb(101, 123, 131), // base00
        .text_disabled = Color.rgb(147, 161, 161), // base1

        .button_bg = Color.rgb(238, 232, 213),
        .button_fg = Color.rgb(88, 110, 117),
        .button_hover = Color.rgb(147, 161, 161),
        .button_active = Color.rgb(253, 246, 227),
        .button_disabled_bg = Color.rgb(253, 246, 227),
        .button_disabled_fg = Color.rgb(147, 161, 161),

        .input_bg = Color.rgb(253, 246, 227),
        .input_fg = Color.rgb(88, 110, 117),
        .input_border = Color.rgb(147, 161, 161),
        .input_focus_border = Color.rgb(38, 139, 210),
        .input_placeholder = Color.rgb(147, 161, 161),

        .selection_bg = Color.rgb(38, 139, 210),
        .selection_fg = Color.rgb(253, 246, 227),

        .header_bg = Color.rgb(238, 232, 213),
        .header_fg = Color.rgb(88, 110, 117),

        .table_header_bg = Color.rgb(238, 232, 213),
        .table_row_even = Color.rgb(253, 246, 227),
        .table_row_odd = Color.rgb(238, 232, 213),
        .table_row_hover = Color.rgb(147, 161, 161),
        .table_row_selected = Color.rgb(38, 139, 210),

        .scrollbar_track = Color.rgb(253, 246, 227),
        .scrollbar_thumb = Color.rgb(147, 161, 161),
        .scrollbar_thumb_hover = Color.rgb(131, 148, 150),

        .modal_overlay = Color.rgba(0, 0, 0, 120),
        .modal_bg = Color.rgb(238, 232, 213),
    };
};

// =============================================================================
// Theme Manager
// =============================================================================

/// Global theme manager
pub const ThemeManager = struct {
    /// Current theme
    current: *const Theme,

    const Self = @This();

    /// Initialize with default dark theme
    pub fn init() Self {
        return Self{
            .current = &Theme.dark,
        };
    }

    /// Set current theme
    pub fn setTheme(self: *Self, theme: *const Theme) void {
        self.current = theme;
    }

    /// Get current theme
    pub fn getTheme(self: Self) *const Theme {
        return self.current;
    }

    /// Switch to dark theme
    pub fn setDark(self: *Self) void {
        self.current = &Theme.dark;
    }

    /// Switch to light theme
    pub fn setLight(self: *Self) void {
        self.current = &Theme.light;
    }

    /// Toggle between dark and light
    pub fn toggle(self: *Self) void {
        if (std.mem.eql(u8, self.current.name, "dark")) {
            self.current = &Theme.light;
        } else {
            self.current = &Theme.dark;
        }
    }
};

/// Global theme manager instance
var global_theme_manager: ?ThemeManager = null;

/// Get global theme manager
pub fn getThemeManager() *ThemeManager {
    if (global_theme_manager == null) {
        global_theme_manager = ThemeManager.init();
    }
    return &global_theme_manager.?;
}

/// Get current theme (convenience function)
pub fn currentTheme() *const Theme {
    return getThemeManager().current;
}

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

test "Color creation" {
    const c = Color.rgb(100, 150, 200);
    try std.testing.expectEqual(@as(u8, 100), c.r);
    try std.testing.expectEqual(@as(u8, 150), c.g);
    try std.testing.expectEqual(@as(u8, 200), c.b);
    try std.testing.expectEqual(@as(u8, 255), c.a);
}

test "Color darken" {
    const white = Color.white;
    const darkened = white.darken(50);
    try std.testing.expectEqual(@as(u8, 127), darkened.r);
}

test "Color blend" {
    const fg = Color.rgba(255, 0, 0, 128);
    const bg = Color.rgb(0, 0, 255);
    const blended = fg.blend(bg);

    // Should be purple-ish
    try std.testing.expect(blended.r > 100);
    try std.testing.expect(blended.b > 100);
}

test "Theme dark" {
    const theme = Theme.dark;
    try std.testing.expect(std.mem.eql(u8, theme.name, "dark"));
    try std.testing.expectEqual(@as(u8, 30), theme.background.r);
}

test "Theme light" {
    const theme = Theme.light;
    try std.testing.expect(std.mem.eql(u8, theme.name, "light"));
    try std.testing.expectEqual(@as(u8, 245), theme.background.r);
}

test "ThemeManager toggle" {
    var tm = ThemeManager.init();
    try std.testing.expect(std.mem.eql(u8, tm.current.name, "dark"));

    tm.toggle();
    try std.testing.expect(std.mem.eql(u8, tm.current.name, "light"));

    tm.toggle();
    try std.testing.expect(std.mem.eql(u8, tm.current.name, "dark"));
}

test "ThemeManager setTheme" {
    var tm = ThemeManager.init();
    tm.setTheme(&Theme.solarized_dark);
    try std.testing.expect(std.mem.eql(u8, tm.current.name, "solarized_dark"));

    tm.setTheme(&Theme.high_contrast_dark);
    try std.testing.expect(std.mem.eql(u8, tm.current.name, "high_contrast_dark"));
}