// epd7in5_v3.c

#include "epd7in5.h"
#include "driver/gpio.h"

#define TIMEOUT_MS     1000

static esp_err_t gpio_setup(int pin, gpio_mode_t mode)
{
    gpio_config_t io_conf = {
        .pin_bit_mask = 1ULL << pin,
        .mode = mode,
        .pull_up_en = GPIO_PULLUP_DISABLE,
        .pull_down_en = GPIO_PULLDOWN_DISABLE,
        .intr_type = GPIO_INTR_DISABLE
    };
    return gpio_config(&io_conf);
}

#define ESP_RETURN_ON_ERROR(x, y, z) x

esp_err_t epd7in5_v3_create(epd7in5_v3_t *epd, spi_host_device_t host)
{
    esp_err_t ret;

    epd->pin_rst  = EPD_RST_PIN;
    epd->pin_dc   = EPD_DC_PIN;
    epd->pin_cs   = EPD_CS_PIN;
    epd->pin_busy = EPD_BUSY_PIN;
    epd->width    = EPD_WIDTH;
    epd->height   = EPD_HEIGHT;
    epd->spi_host = host;

    // 1) configure GPIOs
    ESP_RETURN_ON_ERROR(gpio_setup(epd->pin_rst, GPIO_MODE_OUTPUT), "rst gpio", ret);
    ESP_RETURN_ON_ERROR(gpio_setup(epd->pin_dc,  GPIO_MODE_OUTPUT), "dc gpio", ret);
    ESP_RETURN_ON_ERROR(gpio_setup(epd->pin_cs,  GPIO_MODE_OUTPUT), "cs gpio", ret);
    ESP_RETURN_ON_ERROR(gpio_setup(epd->pin_busy,GPIO_MODE_INPUT),  "busy gpio", ret);

    // 2) initialize SPI bus if needed, then add device
    spi_bus_config_t buscfg = {
        .mosi_io_num = 11/* your MOSI pin */,
        .miso_io_num = 13/* your MISO pin */,
        .sclk_io_num = 12/* your SCLK pin */,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
        .max_transfer_sz = epd->width * epd->height / 8 + 16
    };
    ESP_RETURN_ON_ERROR(spi_bus_initialize(epd->spi_host, &buscfg, SPI_DMA_CH_AUTO), "bus init", ret);

    return ESP_OK;
}

esp_err_t epd7in5_v3_init(epd7in5_v3_t *epd)
{
    spi_device_interface_config_t devcfg = {
        .clock_speed_hz = 20 * 1000 * 1000,      // 2 MHz
        .mode = 0,                              // SPI mode 0
        .spics_io_num = epd->pin_cs,
        .queue_size = 1,
        .flags = SPI_DEVICE_HALFDUPLEX           // use .flags |= SPI_DEVICE_3WIRE if necessary
    };
    ESP_RETURN_ON_ERROR(spi_bus_add_device(epd->spi_host, &devcfg, &epd->spi), "add device", ret);

    // 3) reset panel
    gpio_set_level(epd->pin_rst, 1);
    vTaskDelay(pdMS_TO_TICKS(20));
    gpio_set_level(epd->pin_rst, 0);
    vTaskDelay(pdMS_TO_TICKS(4));
    gpio_set_level(epd->pin_rst, 1);
    vTaskDelay(pdMS_TO_TICKS(20));

    // 4) initial sequence (matches epd7in5_v3::Init)
    epd7in5_v3_send_command(epd, CMD_BOOSTER_SOFT_START);
    epd7in5_v3_send_data(epd, 0x17);
    epd7in5_v3_send_data(epd, 0x17);
    epd7in5_v3_send_data(epd, 0x28);
    epd7in5_v3_send_data(epd, 0x17);

    epd7in5_v3_send_command(epd, CMD_POWER_SETTING);
    epd7in5_v3_send_data(epd, 0x07);
    epd7in5_v3_send_data(epd, 0x07);
    epd7in5_v3_send_data(epd, 0x28);
    epd7in5_v3_send_data(epd, 0x17);

    epd7in5_v3_send_command(epd, CMD_POWER_ON);
    vTaskDelay(pdMS_TO_TICKS(100));
    epd7in5_v3_busy_wait(epd);

    epd7in5_v3_send_command(epd, CMD_PANEL_SETTING);
    epd7in5_v3_send_data(epd, 0x1F);

    epd7in5_v3_send_command(epd, CMD_RESOLUTION_SETTING);
    epd7in5_v3_send_data(epd, 0x03);
    epd7in5_v3_send_data(epd, 0x20);
    epd7in5_v3_send_data(epd, 0x01);
    epd7in5_v3_send_data(epd, 0xE0);

    epd7in5_v3_send_command(epd, CMD_DUAL_SPI);
    epd7in5_v3_send_data(epd, 0x00);

    epd7in5_v3_send_command(epd, CMD_VCOM_AND_DATA_INTERVAL_SETTING);
    epd7in5_v3_send_data(epd, 0x10);
    epd7in5_v3_send_data(epd, 0x07);

    epd7in5_v3_send_command(epd, CMD_TCON_SETTING);
    epd7in5_v3_send_data(epd, 0x22);

    return ESP_OK;
}

esp_err_t epd7in5_v3_send_command(epd7in5_v3_t *epd, uint8_t cmd)
{
    esp_err_t ret;
    spi_transaction_t t = {
        .flags = SPI_TRANS_USE_TXDATA,
        .tx_data = { cmd, 0, 0, 0 },
        .length   = 8,
    };
    gpio_set_level(epd->pin_dc, 0);
    ret = spi_device_polling_transmit(epd->spi, &t);
    return ret;
}

esp_err_t epd7in5_v3_send_data(epd7in5_v3_t *epd, uint8_t data)
{
    esp_err_t ret;
    spi_transaction_t t = {
        .flags = SPI_TRANS_USE_TXDATA,
        .tx_data = { data, 0, 0, 0 },
        .length   = 8,
    };
    gpio_set_level(epd->pin_dc, 1);
    ret = spi_device_polling_transmit(epd->spi, &t);
    return ret;
}

esp_err_t epd7in5_v3_send_data_block(epd7in5_v3_t *epd, const uint8_t *data, size_t len)
{
    esp_err_t ret;
    spi_transaction_t t = {
        .tx_buffer = data,
        .length    = len * 8,
    };
    gpio_set_level(epd->pin_dc, 1);
    ret = spi_device_polling_transmit(epd->spi, &t);
    return ret;
}

void epd7in5_v3_busy_wait(epd7in5_v3_t *epd)
{
    // send dummy 0x71 until BUSY goes high
    do {
        epd7in5_v3_send_command(epd, 0x71);
        vTaskDelay(pdMS_TO_TICKS(10));
    } while (gpio_get_level(epd->pin_busy) == 0);
    vTaskDelay(pdMS_TO_TICKS(20));
}

esp_err_t epd7in5_v3_display(epd7in5_v3_t *epd, const uint8_t *image)
{
    size_t width_bytes = (epd->width + 7) / 8;
    size_t img_size = width_bytes * epd->height;

    epd7in5_v3_send_command(epd, CMD_DISPLAY_START_TRANSMISSION_1);
    // white buffer:
    for (size_t i = 0; i < img_size; i++) {
        epd7in5_v3_send_data(epd, 0xFF);
    }

    epd7in5_v3_send_command(epd, CMD_DISPLAY_START_TRANSMISSION_2);
    for (size_t i = 0; i < img_size; i += width_bytes) {
        epd7in5_v3_send_data_block(epd, &image[i], width_bytes);
    }

    epd7in5_v3_send_command(epd, CMD_DISPLAY_REFRESH);
    vTaskDelay(pdMS_TO_TICKS(100));
    epd7in5_v3_busy_wait(epd);

    return ESP_OK;
}

esp_err_t epd7in5_v3_clear(epd7in5_v3_t *epd)
{
    size_t len = (epd->width + 7) / 8 * epd->height;
    // Stage 1: paint white
    epd7in5_v3_send_command(epd, CMD_DISPLAY_START_TRANSMISSION_1);
    for (size_t i = 0; i < len; i++) {
        epd7in5_v3_send_data(epd, 0xFF);
    }
    // Stage 2: paint black
    epd7in5_v3_send_command(epd, CMD_DISPLAY_START_TRANSMISSION_2);
    for (size_t i = 0; i < len; i++) {
        epd7in5_v3_send_data(epd, 0x00);
    }
    // Refresh
    epd7in5_v3_send_command(epd, CMD_DISPLAY_REFRESH);
    vTaskDelay(pdMS_TO_TICKS(100));
    epd7in5_v3_busy_wait(epd);
    return ESP_OK;
}

esp_err_t epd7in5_v3_sleep(epd7in5_v3_t *epd)
{
    epd7in5_v3_send_command(epd, 0x50);
    epd7in5_v3_send_data(epd, 0xF7);
    epd7in5_v3_send_command(epd, CMD_POWER_OFF);
    epd7in5_v3_busy_wait(epd);
    epd7in5_v3_send_command(epd, 0x07);
    epd7in5_v3_send_data(epd, 0xA5);
    vTaskDelay(pdMS_TO_TICKS(2000));

    spi_bus_remove_device(epd->spi);
    
    gpio_set_level(epd->pin_rst, 0);
    gpio_set_level(epd->pin_dc, 0);

    return ESP_OK;
}