//! Button Widget - Clickable button
//!
//! An immediate mode button that returns true when clicked.
//! Supports hover/active states and keyboard activation.
//!
//! Two modes:
//! - Stateless: `button()`, `buttonEx()` - instant color changes
//! - Stateful: `buttonStateful()` - smooth hover/press transitions

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 animation = @import("../render/animation.zig");

/// Button importance level
pub const Importance = enum {
    normal,
    primary,
    danger,
};

/// Button state for smooth transitions (optional)
/// Pass to buttonStateful() for animated hover/press effects.
pub const ButtonState = struct {
    /// Hover/press transition (0=normal, 0.5=hover, 1.0=pressed)
    transition: animation.HoverTransition = .{},
    /// Last frame time for delta calculation
    last_time_ms: u64 = 0,
};

/// Button configuration
pub const ButtonConfig = struct {
    /// Background color (overrides theme)
    bg: ?Style.Color = null,
    /// Foreground/text color (overrides theme)
    fg: ?Style.Color = null,
    /// Importance level
    importance: Importance = .normal,
    /// Disabled state
    disabled: bool = false,
    /// Padding around text
    padding: u32 = 10,
    /// Corner radius (0 = square, default 4 for fancy mode)
    corner_radius: u8 = 4,
};

/// Draw a button and return true if clicked
pub fn button(ctx: *Context, text: []const u8) bool {
    return buttonEx(ctx, text, .{});
}

/// Draw a button with custom configuration
pub fn buttonEx(ctx: *Context, text: []const u8, config: ButtonConfig) bool {
    const bounds = ctx.layout.nextRect();
    return buttonRect(ctx, bounds, text, config);
}

/// Draw a button in a specific rectangle
pub fn buttonRect(ctx: *Context, bounds: Layout.Rect, text: []const u8, config: ButtonConfig) bool {
    if (bounds.isEmpty()) return false;

    const id = ctx.getId(text);
    _ = id; // For future focus management

    // Check mouse interaction
    const mouse = ctx.input.mousePos();
    const hovered = bounds.contains(mouse.x, mouse.y) and !config.disabled;
    const pressed = hovered and ctx.input.mouseDown(.left);
    const clicked = hovered and ctx.input.mouseReleased(.left);

    // Determine colors based on state (Z-Design: usar theme dinámico)
    const theme = Style.currentTheme().*;

    const base_bg = config.bg orelse switch (config.importance) {
        .normal => theme.button_bg,
        .primary => theme.primary,
        .danger => theme.danger,
    };

    const bg_color = if (config.disabled)
        base_bg.darken(30)
    else if (pressed)
        base_bg.darken(20)
    else if (hovered)
        base_bg.lighten(10)
    else
        base_bg;

    const fg_color = config.fg orelse if (config.disabled)
        theme.button_fg.darken(40)
    else
        theme.button_fg;

    // Draw background and border based on render mode
    if (Style.isFancy() and config.corner_radius > 0) {
        // Fancy mode: rounded corners with subtle gradient for 3D effect
        ctx.pushCommand(Command.gradientButton(bounds.x, bounds.y, bounds.w, bounds.h, bg_color, config.corner_radius));
        ctx.pushCommand(Command.roundedRectOutline(bounds.x, bounds.y, bounds.w, bounds.h, theme.border, config.corner_radius));
    } else {
        // Simple mode: square corners
        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, theme.border));
    }

    // Bisel 3D completo: 4 lados (invierte cuando está pulsado)
    // Z-Design V2: Efecto 3D con las 4 esquinas completas
    if (bounds.h >= 4 and bounds.w >= 4 and !config.disabled) {
        const bevel_light = bg_color.lighten(15);
        const bevel_dark = bg_color.darken(15);
        const inner_h = bounds.h -| 2; // Altura interior para líneas verticales

        if (pressed) {
            // Pressed: bisel invertido = "hundido"
            // Arriba + izquierda: oscuro (sombra interior)
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + 1, bounds.w - 2, 1, bevel_dark)); // Top
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + 1, 1, inner_h, bevel_dark)); // Left
            // Abajo + derecha: claro (luz interior)
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + @as(i32, @intCast(bounds.h)) - 2, bounds.w - 2, 1, bevel_light)); // Bottom
            ctx.pushCommand(Command.rect(bounds.x + @as(i32, @intCast(bounds.w)) - 2, bounds.y + 1, 1, inner_h, bevel_light)); // Right
        } else {
            // Normal: bisel = "elevado"
            // Arriba + izquierda: claro (iluminado)
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + 1, bounds.w - 2, 1, bevel_light)); // Top
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + 1, 1, inner_h, bevel_light)); // Left
            // Abajo + derecha: oscuro (sombra)
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + @as(i32, @intCast(bounds.h)) - 2, bounds.w - 2, 1, bevel_dark)); // Bottom
            ctx.pushCommand(Command.rect(bounds.x + @as(i32, @intCast(bounds.w)) - 2, bounds.y + 1, 1, inner_h, bevel_dark)); // Right
        }
    }

    // Draw text centered (con offset +1px cuando está pulsado = "se hunde")
    // Z-Design V2: usar métricas del contexto para centrado correcto con TTF
    const text_width = ctx.measureText(text);
    const char_height = ctx.char_width; // Para fuentes cuadradas, height ≈ width
    const press_offset: i32 = if (pressed) 1 else 0;
    const text_x = bounds.x + @as(i32, @intCast((bounds.w -| text_width) / 2)) + press_offset;
    const text_y = bounds.y + @as(i32, @intCast((bounds.h -| char_height) / 2)) + press_offset;

    ctx.pushCommand(Command.text(text_x, text_y, text, fg_color));

    return clicked and !config.disabled;
}

// =============================================================================
// Stateful Button (with smooth transitions)
// =============================================================================

/// Draw a button with smooth hover/press transitions
pub fn buttonStateful(ctx: *Context, state: *ButtonState, text: []const u8) bool {
    return buttonStatefulEx(ctx, state, text, .{});
}

/// Draw a stateful button with custom configuration
pub fn buttonStatefulEx(ctx: *Context, state: *ButtonState, text: []const u8, config: ButtonConfig) bool {
    const bounds = ctx.layout.nextRect();
    return buttonStatefulRect(ctx, bounds, state, text, config);
}

/// Draw a stateful button in a specific rectangle
pub fn buttonStatefulRect(
    ctx: *Context,
    bounds: Layout.Rect,
    state: *ButtonState,
    text: []const u8,
    config: ButtonConfig,
) bool {
    if (bounds.isEmpty()) return false;

    // Calculate delta time
    const current_time = ctx.current_time_ms;
    const dt_ms: u64 = if (state.last_time_ms > 0 and current_time > state.last_time_ms)
        current_time - state.last_time_ms
    else
        16; // Default ~60fps
    state.last_time_ms = current_time;

    // Check mouse interaction
    const mouse = ctx.input.mousePos();
    const hovered = bounds.contains(mouse.x, mouse.y) and !config.disabled;
    const pressed = hovered and ctx.input.mouseDown(.left);
    const clicked = hovered and ctx.input.mouseReleased(.left);

    // Update transition animation
    state.transition.updateWithPress(hovered, pressed, dt_ms);

    // Determine colors based on animated state (Z-Design: usar theme dinámico)
    const theme = Style.currentTheme().*;

    const base_bg = config.bg orelse switch (config.importance) {
        .normal => theme.button_bg,
        .primary => theme.primary,
        .danger => theme.danger,
    };

    // Calculate animated background color
    const bg_color = if (config.disabled)
        base_bg.darken(30)
    else
        state.transition.blendThree(
            base_bg, // normal
            base_bg.lighten(10), // hover
            base_bg.darken(20), // pressed
        );

    const fg_color = config.fg orelse if (config.disabled)
        theme.button_fg.darken(40)
    else
        theme.button_fg;

    // Draw background and border based on render mode
    if (Style.isFancy() and config.corner_radius > 0) {
        // Fancy mode: rounded corners with subtle gradient for 3D effect
        ctx.pushCommand(Command.gradientButton(bounds.x, bounds.y, bounds.w, bounds.h, bg_color, config.corner_radius));
        ctx.pushCommand(Command.roundedRectOutline(bounds.x, bounds.y, bounds.w, bounds.h, theme.border, config.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, theme.border));
    }

    // Bisel 3D completo: 4 lados (invierte cuando está pulsado)
    // Z-Design V2: Efecto 3D con las 4 esquinas completas
    if (bounds.h >= 4 and bounds.w >= 4 and !config.disabled) {
        const bevel_light = bg_color.lighten(15);
        const bevel_dark = bg_color.darken(15);
        const inner_h = bounds.h -| 2; // Altura interior para líneas verticales

        if (pressed) {
            // Pressed: bisel invertido = "hundido"
            // Arriba + izquierda: oscuro (sombra interior)
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + 1, bounds.w - 2, 1, bevel_dark)); // Top
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + 1, 1, inner_h, bevel_dark)); // Left
            // Abajo + derecha: claro (luz interior)
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + @as(i32, @intCast(bounds.h)) - 2, bounds.w - 2, 1, bevel_light)); // Bottom
            ctx.pushCommand(Command.rect(bounds.x + @as(i32, @intCast(bounds.w)) - 2, bounds.y + 1, 1, inner_h, bevel_light)); // Right
        } else {
            // Normal: bisel = "elevado"
            // Arriba + izquierda: claro (iluminado)
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + 1, bounds.w - 2, 1, bevel_light)); // Top
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + 1, 1, inner_h, bevel_light)); // Left
            // Abajo + derecha: oscuro (sombra)
            ctx.pushCommand(Command.rect(bounds.x + 1, bounds.y + @as(i32, @intCast(bounds.h)) - 2, bounds.w - 2, 1, bevel_dark)); // Bottom
            ctx.pushCommand(Command.rect(bounds.x + @as(i32, @intCast(bounds.w)) - 2, bounds.y + 1, 1, inner_h, bevel_dark)); // Right
        }
    }

    // Draw text centered (con offset +1px cuando está pulsado = "se hunde")
    // Z-Design V2: usar métricas del contexto para centrado correcto con TTF
    const text_width = ctx.measureText(text);
    const char_height = ctx.char_width; // Para fuentes cuadradas, height ≈ width
    const press_offset: i32 = if (pressed) 1 else 0;
    const text_x = bounds.x + @as(i32, @intCast((bounds.w -| text_width) / 2)) + press_offset;
    const text_y = bounds.y + @as(i32, @intCast((bounds.h -| char_height) / 2)) + press_offset;

    ctx.pushCommand(Command.text(text_x, text_y, text, fg_color));

    return clicked and !config.disabled;
}

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

/// Draw a primary button (convenience function)
pub fn buttonPrimary(ctx: *Context, text: []const u8) bool {
    return buttonEx(ctx, text, .{ .importance = .primary });
}

/// Draw a danger button (convenience function)
pub fn buttonDanger(ctx: *Context, text: []const u8) bool {
    return buttonEx(ctx, text, .{ .importance = .danger });
}

/// Draw a disabled button (convenience function)
pub fn buttonDisabled(ctx: *Context, text: []const u8) bool {
    return buttonEx(ctx, text, .{ .disabled = true });
}

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

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

    ctx.beginFrame();
    ctx.layout.row_height = 30;

    _ = button(&ctx, "Click me");

    // Should generate: rect (background) + rect_outline (border) + 4 bevel lines + text = 7
    try std.testing.expectEqual(@as(usize, 7), ctx.commands.items.len);

    ctx.endFrame();
}

test "button click detection" {
    var ctx = try Context.init(std.testing.allocator, 800, 600);
    defer ctx.deinit();

    // Frame 1: Mouse pressed inside button
    ctx.beginFrame();
    ctx.layout.row_height = 30;
    ctx.input.setMousePos(50, 15);
    ctx.input.setMouseButton(.left, true);

    _ = button(&ctx, "Test");
    ctx.endFrame();

    // Frame 2: Mouse released inside button
    ctx.beginFrame();
    ctx.layout.row_height = 30;
    ctx.input.setMousePos(50, 15);
    ctx.input.setMouseButton(.left, false);

    const clicked = button(&ctx, "Test");
    try std.testing.expect(clicked);

    ctx.endFrame();
}

test "button disabled no click" {
    var ctx = try Context.init(std.testing.allocator, 800, 600);
    defer ctx.deinit();

    // Frame 1: Mouse pressed
    ctx.beginFrame();
    ctx.layout.row_height = 30;
    ctx.input.setMousePos(50, 15);
    ctx.input.setMouseButton(.left, true);
    _ = buttonEx(&ctx, "Disabled", .{ .disabled = true });
    ctx.endFrame();

    // Frame 2: Mouse released
    ctx.beginFrame();
    ctx.layout.row_height = 30;
    ctx.input.setMousePos(50, 15);
    ctx.input.setMouseButton(.left, false);
    const clicked = buttonEx(&ctx, "Disabled", .{ .disabled = true });

    try std.testing.expect(!clicked);
    ctx.endFrame();
}

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

    var state = ButtonState{};

    // Frame 1: Not hovered
    ctx.beginFrame();
    ctx.current_time_ms = 0;
    ctx.layout.row_height = 30;
    ctx.input.setMousePos(500, 500); // Outside button
    _ = buttonStateful(&ctx, &state, "Test");
    ctx.endFrame();

    // Transition should be at 0
    try std.testing.expectEqual(@as(f32, 0.0), state.transition.value);

    // Frame 2: Hovered
    ctx.beginFrame();
    ctx.current_time_ms = 100;
    ctx.layout.row_height = 30;
    ctx.input.setMousePos(50, 15); // Inside button
    _ = buttonStateful(&ctx, &state, "Test");
    ctx.endFrame();

    // Transition should have started moving (>0)
    try std.testing.expect(state.transition.value > 0.0);
}