#import "modules/std.sx";
#import "modules/compiler.sx";
#import "modules/sdl3.sx";
#import "modules/opengl.sx";
#import "modules/math";
#import "modules/stb.sx";
#import "modules/stb_truetype.sx";
#import "ui";

configure_build :: () {
    opts := build_options();
    inline if OS == {
        case .wasm: {        
            opts.set_output_path(if POINTER_SIZE == 4 then "sx-out/wasm32/index.html" else "sx-out/wasm32/index.html");
            opts.add_link_flag("-sUSE_SDL=3");
            opts.add_link_flag("-sMAX_WEBGL_VERSION=2");
            opts.add_link_flag("-sFULL_ES3=1");
            opts.add_link_flag("--preload-file assets");
            opts.add_link_flag("-sALLOW_MEMORY_GROWTH=1");
        }
        case .macos: {
            opts.set_output_path("sx-out/macos/game");
        }
    }
}
#run configure_build();

libc :: #library "c";
emscripten_set_main_loop :: (func: *void, fps: s32, sim_infinite: s32) #foreign libc;

WIDTH  :f32: 800;
HEIGHT :f32: 600;

// --- Frame state (globals for emscripten callback) ---
g_window : *void = ---;
g_pipeline : *UIPipeline = ---;
g_running : bool = true;

load_texture :: (path: [:0]u8) -> u32 {
    w : s32 = 0;
    h : s32 = 0;
    ch : s32 = 0;
    pixels := stbi_load(path, @w, @h, @ch, 4);
    if xx pixels == 0 { return 0; }

    tex : u32 = 0;
    glGenTextures(1, @tex);
    glBindTexture(GL_TEXTURE_2D, tex);
    glTexImage2D(GL_TEXTURE_2D, 0, xx GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, xx GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, xx GL_LINEAR);

    stbi_image_free(pixels);
    tex;
}

save_snapshot :: (path: [:0]u8, w: s32, h: s32) {
    stride : s64 = w * 4;
    buf_size : s64 = stride * h;
    pixels : [*]u8 = xx context.allocator.alloc(buf_size);
    glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, pixels);

    // Flip vertically (GL reads bottom-up, PNG expects top-down)
    row_buf : [*]u8 = xx context.allocator.alloc(stride);
    i : s32 = 0;
    while i < h / 2 {
        top : s64 = xx i * stride;
        bot : s64 = xx (h - 1 - i) * stride;
        memcpy(row_buf, @pixels[top], stride);
        memcpy(@pixels[top], @pixels[bot], stride);
        memcpy(@pixels[bot], row_buf, stride);
        i += 1;
    }

    stbi_write_png(path, w, h, 4, pixels, xx stride);
    out("Saved ");
    out(path);
    out("\n");
}

run_ui_tests :: (pipeline: *UIPipeline) {
    // Do a layout pass first so frames are computed
    glClearColor(0.12, 0.12, 0.15, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);
    pipeline.tick();

    // Button "Click Me" is roughly at center x=400, y=165 based on golden
    btn_x : f32 = 400.0;
    btn_y : f32 = 165.0;
    btn_pos := Point.{ x = btn_x, y = btn_y };
    // Empty area below the rects
    empty_x : f32 = 400.0;
    empty_y : f32 = 500.0;

    // --- Test 1: Click button (no drag) ---
    out("=== Test 1: button click ===\n");
    out("expect: Button tapped!\n");
    e :Event = .mouse_down(MouseButtonData.{ position = btn_pos, button = .left });
    pipeline.dispatch_event(@e);
    e = .mouse_up(MouseButtonData.{ position = btn_pos, button = .left });
    pipeline.dispatch_event(@e);
    out("=== end test 1 ===\n\n");

    // --- Test 2: Drag from button area (should scroll, NOT tap) ---
    out("=== Test 2: drag from button ===\n");
    out("expect: NO Button tapped, scroll should move\n");
    e = .mouse_down(MouseButtonData.{ position = btn_pos, button = .left });
    pipeline.dispatch_event(@e);
    // Move down 50px in steps (exceeds 4px threshold)
    i : s32 = 1;
    while i <= 10 {
        e = .mouse_moved(MouseMotionData.{
            position = Point.{ x = btn_x, y = btn_y + xx i * 5.0 },
            delta = Point.{ x = 0.0, y = 5.0 }
        });
        pipeline.dispatch_event(@e);
        i += 1;
    }
    e = .mouse_up(MouseButtonData.{ position = Point.{ x = btn_x, y = btn_y + 50.0 }, button = .left });
    pipeline.dispatch_event(@e);
    out("=== end test 2 ===\n\n");

    // --- Test 3: Drag from empty area (should scroll) ---
    out("=== Test 3: drag from empty area ===\n");
    out("expect: scroll should move\n");
    e = .mouse_down(MouseButtonData.{ position = Point.{ x = empty_x, y = empty_y }, button = .left });
    pipeline.dispatch_event(@e);
    i = 1;
    while i <= 10 {
        e = .mouse_moved(MouseMotionData.{
            position = Point.{ x = empty_x, y = empty_y - xx i * 5.0 },
            delta = Point.{ x = 0.0, y = 0.0 - 5.0 }
        });
        pipeline.dispatch_event(@e);
        i += 1;
    }
    e = .mouse_up(MouseButtonData.{ position = Point.{ x = empty_x, y = empty_y - 50.0 }, button = .left });
    pipeline.dispatch_event(@e);
    out("=== end test 3 ===\n\n");

    // Render after tests and save snapshot to see scrolled state
    glClear(GL_COLOR_BUFFER_BIT);
    pipeline.tick();
    save_snapshot("goldens/test_after_drag.png", xx WIDTH, xx HEIGHT);
}

// One frame of the main loop — called repeatedly by emscripten or desktop while-loop
frame :: () {
    sdl_event : SDL_Event = .none;
    while SDL_PollEvent(sdl_event) {
        print("SDL event: {}\n", sdl_event.tag);

        if sdl_event == {
            case .quit: { g_running = false; }
            case .key_up: (e) {
                if e.key == { case .escape: { g_running = false; } }
            }
        }

        ui_event := translate_sdl_event(@sdl_event);
        if ui_event != .none {
            print("  ui event dispatched\n");
            g_pipeline.*.dispatch_event(@ui_event);
        } else {
            print("  -> .none\n");
        }
    }

    glClearColor(0.12, 0.12, 0.15, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    g_pipeline.*.tick();

    SDL_GL_SwapWindow(g_window);
}

main :: () -> void {
    SDL_Init(SDL_INIT_VIDEO);

    inline if OS == .wasm {
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
    } else {
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    }
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);

    window := SDL_CreateWindow("SX UI Demo", xx WIDTH, xx HEIGHT, SDL_WINDOW_OPENGL);
    gl_ctx := SDL_GL_CreateContext(window);
    SDL_GL_MakeCurrent(window, gl_ctx);
    SDL_GL_SetSwapInterval(1);

    load_gl(xx SDL_GL_GetProcAddress);

    // --- Build UI ---
    pipeline : UIPipeline = ---;
    pipeline.init(WIDTH, HEIGHT);
    pipeline.init_font("assets/fonts/default.ttf", 32.0);

    scroll_content := VStack.{ spacing = 10.0, alignment = .center } {
        self.add(
            Label.{ text = "Hello, SX!", font_size = 24.0, color = COLOR_WHITE }
                |> padding(EdgeInsets.all(8.0))
        );
        self.add(
            RectView.{ color = COLOR_YELLOW, preferred_height = 80.0, corner_radius = 8.0 }
                |> padding(EdgeInsets.all(8.0))
                |> on_tap(closure(() { out("Yellow tapped!\n"); }))
        );
        self.add(
            Button.{ label = "Click Me", font_size = 14.0, style = ButtonStyle.default(), on_tap = closure(() { out("Button tapped!\n"); }) }
        );
        self.add(HStack.{ spacing = 10.0, alignment = .center } {
            self.add(RectView.{ color = COLOR_RED, preferred_width = 200.0, preferred_height = 300.0, corner_radius = 4.0 });
            self.add(RectView.{ color = COLOR_GREEN, preferred_width = 200.0, preferred_height = 300.0, corner_radius = 4.0 });
        });
        self.add(
            RectView.{ color = COLOR_DARK_GRAY, preferred_height = 60.0 }
                |> padding(EdgeInsets.symmetric(16.0, 8.0))
                |> background(COLOR_BLUE, 8.0)
        );
        self.add(RectView.{ color = COLOR_ORANGE, preferred_height = 120.0, corner_radius = 12.0 });
        self.add(RectView.{ color = COLOR_GRAY, preferred_height = 200.0, corner_radius = 8.0 });
    };

    root := ScrollView.{ child = ViewChild.{ view = scroll_content }, axes = .vertical };
    pipeline.set_root(root);

    // Store state in globals for frame callback
    g_window = xx window;
    g_pipeline = @pipeline;

    // --- Main loop ---
    inline if OS == .wasm {
        emscripten_set_main_loop(xx frame, 0, 1);
    } else {
        while g_running {
            frame();
        }
    }

    SDL_GL_DestroyContext(gl_ctx);
    SDL_DestroyWindow(window);
    SDL_Quit();
}