#include <lvgl/lvgl.h>
#include <android/native_window.h>
#include <android/log.h>
#include <android_native_app_glue.h>
#include <time.h>
#include <stdlib.h>
#include <unistd.h>

#define LOG_TAG "lvgl_particles"
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__)

static lv_display_t * display = NULL;
static lv_indev_t * indev = NULL;
static void * disp_buf = NULL;
static ANativeWindow * native_window = NULL;
static int32_t window_width = 0;
static int32_t window_height = 0;
static lv_obj_t * label_fps = NULL;

static bool touch_down = false;
static int32_t touch_x = 0;
static int32_t touch_y = 0;

static void my_flush_cb(lv_display_t * disp, const lv_area_t * area, uint8_t * px_map) {
    if (!native_window) {
        lv_display_flush_ready(disp);
        return;
    }

    ANativeWindow_Buffer buffer;
    if (ANativeWindow_lock(native_window, &buffer, NULL) < 0) {
        lv_display_flush_ready(disp);
        return;
    }

    int32_t width = lv_area_get_width(area);
    int32_t height = lv_area_get_height(area);

    // Assume 32-bit RGBA
    uint32_t * dst_base = (uint32_t *)buffer.bits;
    uint32_t * src = (uint32_t *)px_map;
    int stride = buffer.stride;

    for (int y = 0; y < height; y++) {
        uint32_t * dst_line = dst_base + (area->y1 + y) * stride + area->x1;
        memcpy(dst_line, src + y * width, width * sizeof(uint32_t));
    }

    ANativeWindow_unlockAndPost(native_window);
    lv_display_flush_ready(disp);
}

static void my_input_read(lv_indev_t * indev, lv_indev_data_t * data) {
    data->point.x = touch_x;
    data->point.y = touch_y;
    data->state = touch_down ? LV_INDEV_STATE_PRESSED : LV_INDEV_STATE_RELEASED;
}

#include <math.h>

typedef struct {
    int32_t x;
    int32_t y;
    int32_t vx;
    int32_t vy;
    lv_color_t color;
    int32_t size;
    int32_t life;
} Particle;

#define MAX_PARTICLES 100
static Particle particles[MAX_PARTICLES];
static int particle_count = 0;

static void create_particle(int32_t x, int32_t y) {
    if (particle_count < MAX_PARTICLES) {
        Particle *p = &particles[particle_count++];
        p->x = x;
        p->y = y;
        p->vx = (rand() % 10) - 5;
        p->vy = (rand() % 10) - 5;
        p->color = lv_color_make(rand() % 255, rand() % 255, rand() % 255);
        p->size = (rand() % 15) + 5;
        p->life = 100;
    }
}

static void update_particles(void) {
    for (int i = 0; i < particle_count; i++) {
        Particle *p = &particles[i];
        p->x += p->vx;
        p->y += p->vy;
        p->life--;

        if (p->life <= 0 || p->x < 0 || p->x > window_width || p->y < 0 || p->y > window_height) {
            *p = particles[--particle_count];
            i--;
        }
    }
}

static void draw_particles(lv_layer_t * layer) {
    lv_draw_rect_dsc_t draw_dsc;
    lv_draw_rect_dsc_init(&draw_dsc);
    draw_dsc.radius = LV_RADIUS_CIRCLE;

    for (int i = 0; i < particle_count; i++) {
        Particle *p = &particles[i];
        draw_dsc.bg_color = p->color;
        draw_dsc.bg_opa = (p->life * 255) / 100;

        lv_area_t area;
        area.x1 = p->x - p->size / 2;
        area.y1 = p->y - p->size / 2;
        area.x2 = area.x1 + p->size;
        area.y2 = area.y1 + p->size;

        lv_draw_rect(layer, &draw_dsc, &area);
    }
}

static void particle_timer_cb(lv_timer_t * timer) {
    if (touch_down) {
        for (int i = 0; i < 5; i++) {
             create_particle(touch_x, touch_y);
        }
    } else {
         // Auto emit
         static float t = 0;
         t += 0.1f;
         int cx = window_width / 2 + cos(t) * (window_width / 4);
         int cy = window_height / 2 + sin(t) * (window_height / 4);
         create_particle(cx, cy);
    }

    update_particles();
    lv_obj_invalidate(lv_scr_act()); // Force redraw
}

static void canvas_draw_event_cb(lv_event_t * e) {
    lv_layer_t * layer = lv_event_get_layer(e);
    draw_particles(layer);
}

static void create_ui(void) {
    lv_obj_t * label = lv_label_create(lv_screen_active());
    lv_label_set_text(label, "Touch to create particles!");
    lv_obj_set_style_text_font(label, &lv_font_montserrat_14, 0);
    lv_obj_align(label, LV_ALIGN_TOP_MID, 0, 50);

    // FPS label
    label_fps = lv_label_create(lv_screen_active());
    lv_label_set_text(label_fps, "FPS: 0");
    lv_obj_set_style_text_font(label_fps, &lv_font_montserrat_14, 0);
    lv_obj_align(label_fps, LV_ALIGN_TOP_MID, 0, 100);

    // Add draw event to screen for particles
    lv_obj_add_event_cb(lv_screen_active(), canvas_draw_event_cb, LV_EVENT_DRAW_POST, NULL);

    lv_timer_create(particle_timer_cb, 16, NULL);
}

static void handle_cmd(struct android_app* app, int32_t cmd) {
    switch (cmd) {
        case APP_CMD_INIT_WINDOW:
            LOGI("Init Window");
            native_window = app->window;
            window_width = ANativeWindow_getWidth(native_window);
            window_height = ANativeWindow_getHeight(native_window);
            ANativeWindow_setBuffersGeometry(native_window, window_width, window_height, WINDOW_FORMAT_RGBA_8888);

            if (!display) {
                display = lv_display_create(window_width, window_height);
                lv_display_set_color_format(display, LV_COLOR_FORMAT_ARGB8888);
                lv_display_set_flush_cb(display, my_flush_cb);

                size_t buf_size = window_width * window_height * 4;
                disp_buf = malloc(buf_size);
                lv_display_set_buffers(display, disp_buf, NULL, buf_size, LV_DISPLAY_RENDER_MODE_FULL);

                indev = lv_indev_create();
                lv_indev_set_type(indev, LV_INDEV_TYPE_POINTER);
                lv_indev_set_read_cb(indev, my_input_read);

                create_ui();
            } else {
                 lv_display_set_resolution(display, window_width, window_height);
                 lv_obj_invalidate(lv_scr_act());
            }
            break;
        case APP_CMD_TERM_WINDOW:
            native_window = NULL;
            break;
        case APP_CMD_DESTROY:
            if (display) {
                lv_display_delete(display);
                display = NULL;
            }
            if (indev) {
                lv_indev_delete(indev);
                indev = NULL;
            }
            if (disp_buf) {
                free(disp_buf);
                disp_buf = NULL;
            }
            break;
    }
}

static int32_t handle_input(struct android_app* app, AInputEvent* event) {
    if (AInputEvent_getType(event) == AINPUT_EVENT_TYPE_MOTION) {
        int action = AMotionEvent_getAction(event) & AMOTION_EVENT_ACTION_MASK;
        touch_x = AMotionEvent_getX(event, 0);
        touch_y = AMotionEvent_getY(event, 0);
        if (action == AMOTION_EVENT_ACTION_DOWN || action == AMOTION_EVENT_ACTION_MOVE) {
            touch_down = true;
        } else {
            touch_down = false;
        }
        return 1;
    }
    return 0;
}

void android_main(struct android_app* app) {
    srand(time(NULL));
    lv_init();

    app->onAppCmd = handle_cmd;
    app->onInputEvent = handle_input;

    int frame_count = 0;
    time_t last_time = time(NULL);

    while (1) {
        int ident;
        int events;
        struct android_poll_source* source;

        uint32_t timeout = lv_timer_handler();
        if (timeout > 50) timeout = 50;

        while ((ident = ALooper_pollAll(timeout, NULL, &events, (void**)&source)) >= 0) {
            if (source != NULL) source->process(app, source);
            if (app->destroyRequested != 0) return;
        }

        lv_tick_inc(timeout);

        frame_count++;
        time_t current_time = time(NULL);
        if (current_time - last_time >= 1) {
            if (label_fps) {
                lv_label_set_text_fmt(label_fps, "FPS: %d", frame_count);
            }
            frame_count = 0;
            last_time = current_time;
        }
    }
}