#include "tft.h"
#include "state_tracking.h"

static const char* TAG = "tft";

static esp_lcd_panel_io_handle_t lcd_io_handle = NULL;
static esp_lcd_panel_handle_t lcd_handle = NULL;

static lv_disp_draw_buf_t lv_disp_buf;
static lv_disp_drv_t lv_disp_drv;
static lv_disp_t *lv_display = NULL;
static lv_color_t *lv_buf_1 = NULL;
static lv_color_t *lv_buf_2 = NULL;

lv_obj_t* screen;
static lv_style_t style_screen;

SemaphoreHandle_t xGuiSemaphore;

static bool replay_handler(const char* event, char* arg) {
    return false;
}

static bool notify_lvgl_flush_ready(
    esp_lcd_panel_io_handle_t panel_io,
    esp_lcd_panel_io_event_data_t *edata,
    void *user_ctx
) {
    lv_disp_drv_t *disp_driver = (lv_disp_drv_t *)user_ctx;
    lv_disp_flush_ready(disp_driver);
    return false;
}

const char base64_chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/// Base 64 encodes a u16... sort of. This doesn't do any of the fancy padding stuff.
static void encode_base64(char* buf, size_t start_idx, uint16_t value) {
    buf[start_idx+0] = base64_chars[(value >> 10) & 0x3F];
    buf[start_idx+1] = base64_chars[(value >> 4) & 0x3F];
    buf[start_idx+2] = base64_chars[(value << 2) & 0x3F];
}

static void lvgl_flush_cb(lv_disp_drv_t *drv, const lv_area_t *area, lv_color_t *color_map) {
    esp_lcd_panel_handle_t panel_handle = (esp_lcd_panel_handle_t) drv->user_data;

    int offsetx1 = area->x1;
    int offsetx2 = area->x2;
    int offsety1 = area->y1;
    int offsety2 = area->y2;

    esp_lcd_panel_draw_bitmap(panel_handle, offsetx1, offsety1, offsetx2 + 1, offsety2 + 1, color_map);

    // TODO: change this to be a kconfig value
    #if false

    if (is_state_tracking()) {
        size_t size = (offsetx2 + 1 - offsetx1) * (offsety2 + 1 - offsety1) + 1;
        // if (size > 1024) {
        //     ESP_LOGW("tft_track_state", "Write too big (%d)! truncating to 1024!", size);
        // }
        // size = MIN(1024, size);


        // 24 bytes for the offsets
        // 3 bytes per encoded color
        // 1 byte for null terminator
        size_t alloc_size = 24 + size * 3 + 1;
        char* buf = (char*)malloc(alloc_size);

        if (buf != nullptr) {
            size_t initial_offset = sprintf(buf, "%d,%d,%d,%d:", offsetx1, offsety1, offsetx2 + 1, offsety2 + 1);

            for (size_t i = 0; i < size; i++) {
                size_t index = initial_offset + i * 3;

                // we assume that the size of the color data is 16b
                static_assert(sizeof(lv_color_t) == sizeof(uint16_t), "lv_color_t must be 16b wide");
                encode_base64(buf, index, color_map[i].full);
            }
            buf[initial_offset + (size-1) * 3 + 1] = '\0';

            event_occured("TFT_W", buf);
            free(buf);
        } else {
            ESP_LOGE("tft_track_state", "buffer alloc failed!");
        }
    }

    #endif
}

static void IRAM_ATTR lv_tick_task(void *param) {
	lv_tick_inc(LVGL_UPDATE_PERIOD_MS);
}

static void initialize_spi() {
    ESP_LOGI(TAG, "Initializing SPI bus (MOSI:%d, MISO:%d, CLK:%d)",
             TFT_PIN_MOSI, TFT_PIN_MISO, TFT_PIN_CLK);

    spi_bus_config_t bus = {
        .mosi_io_num = TFT_PIN_MOSI,
        .miso_io_num = TFT_PIN_MISO,
        .sclk_io_num = TFT_PIN_CLK,
        .quadwp_io_num = GPIO_NUM_NC,
        .quadhd_io_num = GPIO_NUM_NC,
        .data4_io_num = GPIO_NUM_NC,
        .data5_io_num = GPIO_NUM_NC,
        .data6_io_num = GPIO_NUM_NC,
        .data7_io_num = GPIO_NUM_NC,
        .max_transfer_sz = SPI_MAX_TRANSFER_SIZE,
        .flags = SPICOMMON_BUSFLAG_SCLK | SPICOMMON_BUSFLAG_MISO |
                 SPICOMMON_BUSFLAG_MOSI | SPICOMMON_BUSFLAG_MASTER,
        .isr_cpu_id = ESP_INTR_CPU_AFFINITY_AUTO,
        .intr_flags = ESP_INTR_FLAG_LOWMED | ESP_INTR_FLAG_IRAM
    };

    ESP_ERROR_CHECK(spi_bus_initialize(SPI2_HOST, &bus, SPI_DMA_CH_AUTO));
}

static void initialize_display() {
    const esp_lcd_panel_io_spi_config_t io_config = {
        .cs_gpio_num = TFT_PIN_CS,
        .dc_gpio_num = TFT_PIN_DC,
        .spi_mode = 0,
        .pclk_hz = DISPLAY_REFRESH_HZ,
        .trans_queue_depth = DISPLAY_SPI_QUEUE_LEN,
        .on_color_trans_done = notify_lvgl_flush_ready,
        .user_ctx = &lv_disp_drv,
        .lcd_cmd_bits = DISPLAY_COMMAND_BITS,
        .lcd_param_bits = DISPLAY_PARAMETER_BITS,
        .flags = {
            .dc_high_on_cmd = 0,  /*!< If enabled, DC level = 1 indicates command transfer */
            .dc_low_on_data = 0,  /*!< If enabled, DC level = 0 indicates color data transfer */
            .dc_low_on_param = 0, /*!< If enabled, DC level = 0 indicates parameter transfer */
            .octal_mode = 0,      /*!< transmit with octal mode (8 data lines), this mode is used to simulate Intel 8080 timing */
            .quad_mode = 0,       /*!< transmit with quad mode (4 data lines), this mode is useful when transmitting LCD parameters (Only use one line for command) */
            .sio_mode = 0,        /*!< Read and write through a single data line (MOSI) */
            .lsb_first = 0,       /*!< transmit LSB bit first */
            .cs_high_active = 0,  /*!< CS line is high active */
        }
    };

    const esp_lcd_panel_dev_config_t lcd_config = {
        .reset_gpio_num = TFT_PIN_RESET,
        .color_space = LCD_RGB_ELEMENT_ORDER_BGR,
        .data_endian = LCD_RGB_DATA_ENDIAN_BIG,
        .bits_per_pixel = 18,
        .flags = {
            .reset_active_high = 0
        },
        .vendor_config = NULL
    };

    ESP_ERROR_CHECK(
        esp_lcd_new_panel_io_spi((esp_lcd_spi_bus_handle_t)SPI2_HOST, &io_config, &lcd_io_handle)); 

    ESP_ERROR_CHECK(esp_lcd_new_panel_ili9488(lcd_io_handle, &lcd_config, LV_BUFFER_SIZE, &lcd_handle));
    
    ESP_ERROR_CHECK(esp_lcd_panel_reset(lcd_handle));
    ESP_ERROR_CHECK(esp_lcd_panel_init(lcd_handle));
    ESP_ERROR_CHECK(esp_lcd_panel_invert_color(lcd_handle, true));
    ESP_ERROR_CHECK(esp_lcd_panel_swap_xy(lcd_handle, true));
    ESP_ERROR_CHECK(esp_lcd_panel_mirror(lcd_handle, false, true));
    ESP_ERROR_CHECK(esp_lcd_panel_set_gap(lcd_handle, 0, 0));
#if ESP_IDF_VERSION < ESP_IDF_VERSION_VAL(5, 0, 0)
    ESP_ERROR_CHECK(esp_lcd_panel_disp_off(lcd_handle, false));
#else
    ESP_ERROR_CHECK(esp_lcd_panel_disp_on_off(lcd_handle, true));
#endif
}

static void guiTask(void *pvParameter) {
    xGuiSemaphore = xSemaphoreCreateMutex();
    ESP_LOGI(TAG, "Initializing LVGL");
    lv_init();
    ESP_LOGI(TAG, "Allocating %zu bytes for LVGL buffer", LV_BUFFER_SIZE * sizeof(lv_color_t));
    lv_buf_1 = (lv_color_t *)heap_caps_malloc(LV_BUFFER_SIZE * sizeof(lv_color_t), MALLOC_CAP_DMA);
#if USE_DOUBLE_BUFFERING
    ESP_LOGI(TAG, "Allocating %zu bytes for second LVGL buffer", LV_BUFFER_SIZE * sizeof(lv_color_t));
    lv_buf_2 = (lv_color_t *)heap_caps_malloc(LV_BUFFER_SIZE * sizeof(lv_color_t), MALLOC_CAP_DMA);
#endif
    ESP_LOGI(TAG, "Creating LVLG display buffer");
    lv_disp_draw_buf_init(&lv_disp_buf, lv_buf_1, lv_buf_2, LV_BUFFER_SIZE);

    ESP_LOGI(TAG, "Initializing %dx%d display", DISPLAY_HORIZONTAL_PIXELS, DISPLAY_VERTICAL_PIXELS);
    lv_disp_drv_init(&lv_disp_drv);
    lv_disp_drv.hor_res = DISPLAY_HORIZONTAL_PIXELS;
    lv_disp_drv.ver_res = DISPLAY_VERTICAL_PIXELS;
    lv_disp_drv.flush_cb = lvgl_flush_cb;
    lv_disp_drv.draw_buf = &lv_disp_buf;
    lv_disp_drv.user_data = lcd_handle;
    // lv_disp_drv.rotated = LV_DISP_ROT_90;
    lv_display = lv_disp_drv_register(&lv_disp_drv);

    ESP_LOGI(TAG, "Creating LVGL tick timer");
    const esp_timer_create_args_t lvgl_tick_timer_args = {
        .callback = &lv_tick_task,
        // .dispatch_method = ESP_TIMER_TASK,
        .name = "periodic_gui",
        // .skip_unhandled_events = false
    };
    esp_timer_handle_t periodic_timer;
    ESP_ERROR_CHECK(esp_timer_create(&lvgl_tick_timer_args, &periodic_timer));
    ESP_ERROR_CHECK(esp_timer_start_periodic(periodic_timer, LVGL_UPDATE_PERIOD_MS * 1000));

    screen = lv_scr_act();
    lv_style_init(&style_screen);
    lv_style_set_bg_color(&style_screen, lv_color_black());
    lv_obj_add_style(screen, &style_screen, LV_STATE_DEFAULT);

    while (1) {
        /* Delay 1 tick (assumes FreeRTOS tick is 10ms */
        vTaskDelay(pdMS_TO_TICKS(10));

        /* Try to take the semaphore, call lvgl related function on success */
        if (pdTRUE == xSemaphoreTake(xGuiSemaphore, portMAX_DELAY)) {
            lv_task_handler();
            xSemaphoreGive(xGuiSemaphore);
       }
    }

    vTaskDelete(NULL);
}

void init_tft() {
    ESP_LOGI(TAG, "Initializing TFT...");

    initialize_spi();
    initialize_display();
    xTaskCreatePinnedToCore(guiTask, "gui", 4096*2, NULL, 5, NULL, 1);

    register_replay_fn(replay_handler);

    ESP_LOGI(TAG, "TFT initialized!");
}