/*
 * SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Unlicense OR CC0-1.0
 */

#include <errno.h>
#include <dirent.h>
#include <sys/stat.h>
#include "esp_partition.h"
#include "esp_check.h"
#include "tinyusb.h"
#include "tusb_msc_storage.h"
#include "tusb_cdc_acm.h"

#define BASE_PATH "/usb" // base path to mount the partition

static const char *TAG = "example_main";
static uint8_t buf[CONFIG_TINYUSB_CDC_RX_BUFSIZE + 1];

void tinyusb_cdc_rx_callback(int itf, cdcacm_event_t *event)
{
    /* initialization */
    size_t rx_size = 0;

    /* read */
    esp_err_t ret = tinyusb_cdcacm_read(itf, buf, CONFIG_TINYUSB_CDC_RX_BUFSIZE, &rx_size);
    if (ret == ESP_OK) {
        ESP_LOGI(TAG, "Data from channel %d:", itf);
        ESP_LOG_BUFFER_HEXDUMP(TAG, buf, rx_size, ESP_LOG_INFO);
    } else {
        ESP_LOGE(TAG, "Read error");
    }

    /* write back */
    tinyusb_cdcacm_write_queue(itf, buf, rx_size);
    tinyusb_cdcacm_write_flush(itf, 0);
}

void tinyusb_cdc_line_state_changed_callback(int itf, cdcacm_event_t *event)
{
    int dtr = event->line_state_changed_data.dtr;
    int rts = event->line_state_changed_data.rts;
    ESP_LOGI(TAG, "Line state changed on channel %d: DTR:%d, RTS:%d", itf, dtr, rts);
}

static bool file_exists(const char *file_path)
{
    struct stat buffer;
    return stat(file_path, &buffer) == 0;
}

static void file_operations(void)
{
    const char *directory = "/usb/esp";
    const char *file_path = "/usb/esp/test.txt";

    struct stat s = {0};
    bool directory_exists = stat(directory, &s) == 0;
    if (!directory_exists) {
        if (mkdir(directory, 0775) != 0) {
            ESP_LOGE(TAG, "mkdir failed with errno: %s", strerror(errno));
        }
    }

    if (!file_exists(file_path)) {
        ESP_LOGI(TAG, "Creating file");
        FILE *f = fopen(file_path, "w");
        if (f == NULL) {
            ESP_LOGE(TAG, "Failed to open file for writing");
            return;
        }
        fprintf(f, "Hello World!\n");
        fclose(f);
    }

    FILE *f;
    ESP_LOGI(TAG, "Reading file");
    f = fopen(file_path, "r");
    if (f == NULL) {
        ESP_LOGE(TAG, "Failed to open file for reading");
        return;
    }
    char line[64];
    fgets(line, sizeof(line), f);
    fclose(f);
    // strip newline
    char *pos = strchr(line, '\n');
    if (pos) {
        *pos = '\0';
    }
    ESP_LOGI(TAG, "Read from file: '%s'", line);
}

static esp_err_t storage_init_spiflash(wl_handle_t *wl_handle)
{
    ESP_LOGI(TAG, "Initializing wear levelling");

    const esp_partition_t *data_partition = esp_partition_find_first(ESP_PARTITION_TYPE_DATA, ESP_PARTITION_SUBTYPE_DATA_FAT, NULL);
    if (data_partition == NULL) {
        ESP_LOGE(TAG, "Failed to find FATFS partition. Check the partition table.");
        return ESP_ERR_NOT_FOUND;
    }

    return wl_mount(data_partition, wl_handle);
}

void app_main(void)
{
    ESP_LOGI(TAG, "Initializing storage...");

    static wl_handle_t wl_handle = WL_INVALID_HANDLE;
    ESP_ERROR_CHECK(storage_init_spiflash(&wl_handle));

    const tinyusb_msc_spiflash_config_t config_spi = {
        .wl_handle = wl_handle
    };
    ESP_ERROR_CHECK(tinyusb_msc_storage_init_spiflash(&config_spi));
    ESP_ERROR_CHECK(tinyusb_msc_storage_mount(BASE_PATH));
    file_operations();

    ESP_LOGI(TAG, "USB Composite initialization");
    const tinyusb_config_t tusb_cfg = {
        .device_descriptor = NULL,
        .string_descriptor = NULL,
        .string_descriptor_count = 0,
        .external_phy = false,
        .configuration_descriptor = NULL,
    };
    ESP_ERROR_CHECK(tinyusb_driver_install(&tusb_cfg));

    tinyusb_config_cdcacm_t acm_cfg = {
        .usb_dev = TINYUSB_USBDEV_0,
        .cdc_port = TINYUSB_CDC_ACM_0,
        .rx_unread_buf_sz = 64,
        .callback_rx = &tinyusb_cdc_rx_callback, // the first way to register a callback
        .callback_rx_wanted_char = NULL,
        .callback_line_state_changed = NULL,
        .callback_line_coding_changed = NULL
    };

    ESP_ERROR_CHECK(tusb_cdc_acm_init(&acm_cfg));
    /* the second way to register a callback */
    ESP_ERROR_CHECK(tinyusb_cdcacm_register_callback(
                        TINYUSB_CDC_ACM_0,
                        CDC_EVENT_LINE_STATE_CHANGED,
                        &tinyusb_cdc_line_state_changed_callback));

    ESP_LOGI(TAG, "USB Composite initialization DONE");
}