/*
 * SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <string.h>
#include "common/tusb_common.h"
#include "diskio.h"
#include "esp_log.h"
#include "esp_err.h"
#include "esp_check.h"
#include "esp_vfs_fat.h"
#include "diskio_impl.h"
#include "esp_partition.h"
#include "tusb_msc_psram.h"
#include "vfs_fat_internal.h"
#include "tinyusb.h"
#include "class/msc/msc_device.h"
#include "tusb_msc_storage.h"
#include "esp_vfs_fat.h"

static const char *TAG = "tinyusb_msc_psram";

typedef struct {
    bool is_fat_mounted;
    const char *base_path;
    uint8_t* memory;
    size_t sectors;
    uint8_t pdrv;
    esp_err_t (*mount)(BYTE pdrv);
    esp_err_t (*unmount)(void);
    tusb_msc_callback_t callback_mount_changed;
    tusb_msc_callback_t callback_premount_changed;
    int max_files;
} tinyusb_msc_psram_handle_s; /*!< MSC object */

/* handle of tinyusb driver connected to application */
static tinyusb_msc_psram_handle_s *s_storage_handle;


static bool _psram_read (uint32_t lba, uint32_t offset,size_t size, uint8_t *dest) {
    /*!< sector read function */
    if(!s_storage_handle || !s_storage_handle->memory){
        return false;
    }
    
    memcpy(dest, s_storage_handle->memory + lba * FF_MAX_SS + offset, size);
    return true;
}

static bool _psram_write (uint32_t lba, uint32_t offset,size_t size, const uint8_t *src) {
   /*!< sector write function */
    if(!s_storage_handle || !s_storage_handle->memory){
        return false;
    }

    memcpy(s_storage_handle->memory + lba * FF_MAX_SS + offset, src, size);
    return true;
}



static DSTATUS _diskio_psram_status (unsigned char pdrv);

static DSTATUS _diskio_psram_init (unsigned char pdrv) {
    /*!< disk initialization function */
    return _diskio_psram_status(pdrv);
}

static DSTATUS _diskio_psram_status (unsigned char pdrv) {
    /*!< disk status check function */
    if(s_storage_handle && s_storage_handle->memory && s_storage_handle->pdrv == pdrv) {
        return 0;
    }
    return STA_NOINIT;
}

static DRESULT _diskio_psram_read (unsigned char pdrv, unsigned char* buff, uint32_t sector, unsigned count) {
    /*!< sector read function */
    if(!s_storage_handle || !s_storage_handle->memory || pdrv!=s_storage_handle->pdrv){
        return RES_NOTRDY;
    }
    if(_psram_read(sector, 0, FF_MAX_SS*count, buff)){
        return RES_OK;
    }
    return RES_NOTRDY;
}

static DRESULT _diskio_psram_write (unsigned char pdrv, const unsigned char* buff, uint32_t sector, unsigned count) {
   /*!< sector write function */
    if(!s_storage_handle || !s_storage_handle->memory || pdrv!=s_storage_handle->pdrv){
        return RES_NOTRDY;
    }

    if(_psram_write(sector, 0, FF_MAX_SS*count, buff)){
        return RES_OK;
    }
    return RES_NOTRDY;
}

static DRESULT _diskio_psram_ioctl(unsigned char pdrv, unsigned char cmd,
                                   void *buff) {
    /*!< function to get info about disk and do some misc operations */
    if (!s_storage_handle || !s_storage_handle->memory ||
        pdrv != s_storage_handle->pdrv) {
        return RES_NOTRDY;
    }

    switch (cmd) {
    case CTRL_SYNC:
        /*nothing to do*/
        break;
    case GET_SECTOR_COUNT:
        ((unsigned int *)buff)[0] = s_storage_handle->sectors;
        break;
    case GET_SECTOR_SIZE:
        ((unsigned int *)buff)[0] = FF_MAX_SS;
        break;
    case GET_BLOCK_SIZE:
        ((unsigned int *)buff)[0] =
            1; // byte access. todo: check if 4 makes sense
        break;
    case CTRL_TRIM:
        /*nothing to do*/
        break;
    default:
        return RES_PARERR;
    }
    return RES_OK;
}

static ff_diskio_impl_t *s_diskio_psram;



static esp_err_t _mount_psram(BYTE pdrv)
{
    ff_diskio_register(pdrv, s_diskio_psram);
    s_storage_handle->pdrv = pdrv;
    return ESP_OK;
}

static esp_err_t _unmount_psram(void)
{
    if (s_storage_handle->pdrv == 0xff) {
        ESP_LOGE(TAG, "Invalid state");
        return ESP_ERR_INVALID_STATE;
    }

    char drv[3] = {(char)('0' + s_storage_handle->pdrv), ':', 0};
    f_mount(0, drv, 0);
    ff_diskio_unregister(s_storage_handle->pdrv);

    return ESP_OK;
}

static esp_err_t msc_psram_read_sector(uint32_t lba,
        uint32_t offset,
        size_t size,
        void *dest)
{
    assert(s_storage_handle);

    if (_psram_read(lba, offset, size, dest)) {
        return ESP_OK;
    }
    return ESP_FAIL;
}

static esp_err_t msc_psram_write_sector(uint32_t lba,
        uint32_t offset,
        size_t size,
        const void *src)
{
    assert(s_storage_handle);
    if (s_storage_handle->is_fat_mounted) {
        ESP_LOGE(TAG, "can't write, FAT mounted");
        return ESP_ERR_INVALID_STATE;
    }
    size_t sector_size = tinyusb_msc_psram_get_sector_size();
    size_t temp = 0;
    size_t addr = 0; // Address of the data to be read, relative to the beginning of the partition.
    ESP_RETURN_ON_FALSE(!__builtin_umul_overflow(lba, sector_size, &temp), ESP_ERR_INVALID_SIZE, TAG, "overflow lba %lu sector_size %u", lba, sector_size);
    ESP_RETURN_ON_FALSE(!__builtin_uadd_overflow(temp, offset, &addr), ESP_ERR_INVALID_SIZE, TAG, "overflow addr %u offset %lu", temp, offset);

    if (addr % sector_size != 0 || size % sector_size != 0) {
        ESP_LOGE(TAG, "Invalid Argument lba(%lu) offset(%lu) size(%u) sector_size(%u)", lba, offset, size, sector_size);
        return ESP_ERR_INVALID_ARG;
    }


    if (_psram_write(lba, offset, size, src)) {
        return ESP_OK;
    }
    return ESP_FAIL;

}

static esp_err_t _mount(char *drv, FATFS *fs)
{
    void *workbuf = NULL;
    const size_t workbuf_size = 4096;
    esp_err_t ret;
    // Try to mount partition
    FRESULT fresult = f_mount(fs, drv, 1);
    if (fresult != FR_OK) {
        ESP_LOGW(TAG, "f_mount failed (%d)", fresult);
        if (!((fresult == FR_NO_FILESYSTEM || fresult == FR_INT_ERR))) {
            ret = ESP_FAIL;
            goto fail;
        }
        workbuf = ff_memalloc(workbuf_size);
        if (workbuf == NULL) {
            ret = ESP_ERR_NO_MEM;
            goto fail;
        }
        size_t alloc_unit_size = esp_vfs_fat_get_allocation_unit_size(
                                     CONFIG_WL_SECTOR_SIZE,
                                     4096);
        ESP_LOGW(TAG, "formatting card, allocation unit size=%d", alloc_unit_size);
        const MKFS_PARM opt = {(BYTE)FM_FAT, 0, 0, 0, alloc_unit_size};
        fresult = f_mkfs("", &opt, workbuf, workbuf_size); // Use default volume
        if (fresult != FR_OK) {
            ret = ESP_FAIL;
            ESP_LOGE(TAG, "f_mkfs failed (%d)", fresult);
            goto fail;
        }
        free(workbuf);
        workbuf = NULL;
        fresult = f_mount(fs, drv, 0);
        if (fresult != FR_OK) {
            ret = ESP_FAIL;
            ESP_LOGE(TAG, "f_mount failed after formatting (%d)", fresult);
            goto fail;
        }
    }
    return ESP_OK;
fail:
    if (workbuf) {
        free(workbuf);
    }
    return ret;
}

esp_err_t tinyusb_msc_psram_mount(const char *base_path)
{
    esp_err_t ret = ESP_OK;
    assert(s_storage_handle);

    if (s_storage_handle->is_fat_mounted) {
        return ESP_OK;
    }

    tusb_msc_callback_t cb = s_storage_handle->callback_premount_changed;
    if (cb) {
        tinyusb_msc_event_t event = {
            .type = TINYUSB_MSC_EVENT_PREMOUNT_CHANGED,
            .mount_changed_data = {
                .is_mounted = s_storage_handle->is_fat_mounted
            }
        };
        cb(&event);
    }

    if (!base_path) {
        base_path = CONFIG_TINYUSB_MSC_MOUNT_PATH;
    }

    // connect driver to FATFS
    BYTE pdrv = 0xFF;
    ESP_RETURN_ON_ERROR(ff_diskio_get_drive(&pdrv), TAG,
                        "The maximum count of volumes is already mounted");
    char drv[3] = {(char)('0' + pdrv), ':', 0};

    ESP_GOTO_ON_ERROR((s_storage_handle->mount)(pdrv), fail, TAG, "Failed pdrv=%d", pdrv);

    FATFS *fs = NULL;
    ret = esp_vfs_fat_register(base_path, drv, s_storage_handle->max_files, &fs);
    if (ret == ESP_ERR_INVALID_STATE) {
        ESP_LOGD(TAG, "it's okay, already registered with VFS");
    } else if (ret != ESP_OK) {
        ESP_LOGE(TAG, "esp_vfs_fat_register failed (0x%x)", ret);
        goto fail;
    }

    ESP_GOTO_ON_ERROR(_mount(drv, fs), fail, TAG, "Failed _mount");

    s_storage_handle->is_fat_mounted = true;
    s_storage_handle->base_path = base_path;

    cb = s_storage_handle->callback_mount_changed;
    if (cb) {
        tinyusb_msc_event_t event = {
            .type = TINYUSB_MSC_EVENT_MOUNT_CHANGED,
            .mount_changed_data = {
                .is_mounted = s_storage_handle->is_fat_mounted
            }
        };
        cb(&event);
    }

    return ret;

fail:
    if (fs) {
        esp_vfs_fat_unregister_path(base_path);
    }
    ff_diskio_unregister(pdrv);
    s_storage_handle->is_fat_mounted = false;
    ESP_LOGW(TAG, "Failed to mount storage (0x%x)", ret);
    return ret;
}

esp_err_t tinyusb_msc_psram_unmount(void)
{
    if (!s_storage_handle) {
        return ESP_FAIL;
    }

    if (!s_storage_handle->is_fat_mounted) {
        return ESP_OK;
    }

    tusb_msc_callback_t cb = s_storage_handle->callback_premount_changed;
    if (cb) {
        tinyusb_msc_event_t event = {
            .type = TINYUSB_MSC_EVENT_PREMOUNT_CHANGED,
            .mount_changed_data = {
                .is_mounted = s_storage_handle->is_fat_mounted
            }
        };
        cb(&event);
    }

    esp_err_t err = (s_storage_handle->unmount)();
    if (err) {
        return err;
    }
    err = esp_vfs_fat_unregister_path(s_storage_handle->base_path);
    s_storage_handle->base_path = NULL;
    s_storage_handle->is_fat_mounted = false;

    cb = s_storage_handle->callback_mount_changed;
    if (cb) {
        tinyusb_msc_event_t event = {
            .type = TINYUSB_MSC_EVENT_MOUNT_CHANGED,
            .mount_changed_data = {
                .is_mounted = s_storage_handle->is_fat_mounted
            }
        };
        cb(&event);
    }

    return err;
}

uint32_t tinyusb_msc_psram_get_sector_count(void)
{
    assert(s_storage_handle);
    return s_storage_handle->sectors;
}

uint32_t tinyusb_msc_psram_get_sector_size(void)
{
    return FF_MAX_SS;
}

esp_err_t tinyusb_msc_storage_init_psram(const tinyusb_msc_psram_config_t *config)
{
    assert(!s_storage_handle);
    assert(!s_diskio_psram);
    assert(config);
    assert(config->memory);

    s_diskio_psram = (ff_diskio_impl_t *)malloc(sizeof(ff_diskio_impl_t));
    ESP_RETURN_ON_FALSE(s_diskio_psram, ESP_ERR_NO_MEM, TAG, "could not allocate new handle for diskio_psram");    

    s_diskio_psram->init = &_diskio_psram_init;
    s_diskio_psram->status = &_diskio_psram_status;
    s_diskio_psram->read = &_diskio_psram_read;
    s_diskio_psram->write = &_diskio_psram_write;
    s_diskio_psram->ioctl = &_diskio_psram_ioctl;

    s_storage_handle = (tinyusb_msc_psram_handle_s *)malloc(sizeof(tinyusb_msc_psram_handle_s));
    ESP_RETURN_ON_FALSE(s_storage_handle, ESP_ERR_NO_MEM, TAG, "could not allocate new handle for storage");    

    s_storage_handle->mount = &_mount_psram;
    s_storage_handle->unmount = &_unmount_psram;
    s_storage_handle->is_fat_mounted = false;
    s_storage_handle->base_path = NULL;
    s_storage_handle->memory = config->memory;
    s_storage_handle->sectors = config->memory_size / FF_MAX_SS;
    // In case the user does not set mount_config.max_files
    // and for backward compatibility with versions <1.4.2
    // max_files is set to 2
    const int max_files = config->mount_config.max_files;
    s_storage_handle->max_files = max_files > 0 ? max_files : 2;

    /* Callbacks setting up*/
    if (config->callback_mount_changed) {
        tinyusb_msc_register_callback(TINYUSB_MSC_EVENT_MOUNT_CHANGED, config->callback_mount_changed);
    } else {
        tinyusb_msc_unregister_callback(TINYUSB_MSC_EVENT_MOUNT_CHANGED);
    }
    if (config->callback_premount_changed) {
        tinyusb_msc_register_callback(TINYUSB_MSC_EVENT_PREMOUNT_CHANGED, config->callback_premount_changed);
    } else {
        tinyusb_msc_unregister_callback(TINYUSB_MSC_EVENT_PREMOUNT_CHANGED);
    }

    return ESP_OK;
}

void tinyusb_msc_psram_deinit(void)
{
    assert(s_storage_handle);
    free(s_storage_handle);
    s_storage_handle = NULL;
}

esp_err_t tinyusb_msc_register_callback(tinyusb_msc_event_type_t event_type,
                                        tusb_msc_callback_t callback)
{
    assert(s_storage_handle);
    switch (event_type) {
    case TINYUSB_MSC_EVENT_MOUNT_CHANGED:
        s_storage_handle->callback_mount_changed = callback;
        return ESP_OK;
    case TINYUSB_MSC_EVENT_PREMOUNT_CHANGED:
        s_storage_handle->callback_premount_changed = callback;
        return ESP_OK;
    default:
        ESP_LOGE(TAG, "Wrong event type");
        return ESP_ERR_INVALID_ARG;
    }
}

esp_err_t tinyusb_msc_unregister_callback(tinyusb_msc_event_type_t event_type)
{
    assert(s_storage_handle);
    switch (event_type) {
    case TINYUSB_MSC_EVENT_MOUNT_CHANGED:
        s_storage_handle->callback_mount_changed = NULL;
        return ESP_OK;
    case TINYUSB_MSC_EVENT_PREMOUNT_CHANGED:
        s_storage_handle->callback_premount_changed = NULL;
        return ESP_OK;
    default:
        ESP_LOGE(TAG, "Wrong event type");
        return ESP_ERR_INVALID_ARG;
    }
}

bool tinyusb_msc_psram_in_use_by_usb_host(void)
{
    assert(s_storage_handle);
    return !s_storage_handle->is_fat_mounted;
}


/* TinyUSB MSC callbacks
   ********************************************************************* */

/** SCSI ASC/ASCQ codes. **/
/** User can add and use more codes as per the need of the application **/
#define SCSI_CODE_ASC_MEDIUM_NOT_PRESENT 0x3A /** SCSI ASC code for 'MEDIUM NOT PRESENT' **/
#define SCSI_CODE_ASC_INVALID_COMMAND_OPERATION_CODE 0x20 /** SCSI ASC code for 'INVALID COMMAND OPERATION CODE' **/
#define SCSI_CODE_ASCQ 0x00

// Invoked when received SCSI_CMD_INQUIRY
// Application fill vendor id, product id and revision with string up to 8, 16, 4 characters respectively
void tud_msc_inquiry_cb(uint8_t lun, uint8_t vendor_id[8], uint8_t product_id[16], uint8_t product_rev[4])
{
    (void) lun;
    const char vid[] = "TinyUSB";
    const char pid[] = "Flash Storage";
    const char rev[] = "0.1";

    memcpy(vendor_id, vid, strlen(vid));
    memcpy(product_id, pid, strlen(pid));
    memcpy(product_rev, rev, strlen(rev));
}

// Invoked when received Test Unit Ready command.
// return true allowing host to read/write this LUN e.g SD card inserted
bool tud_msc_test_unit_ready_cb(uint8_t lun)
{
    (void) lun;
    bool result = false;

    if (s_storage_handle->is_fat_mounted) {
        tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, SCSI_CODE_ASC_MEDIUM_NOT_PRESENT, SCSI_CODE_ASCQ);
        result = false;
    } else {
        if (tinyusb_msc_psram_unmount() != ESP_OK) {
            ESP_LOGW(TAG, "tud_msc_test_unit_ready_cb() unmount Fails");
        }
        result = true;
    }
    return result;
}

// Invoked when received SCSI_CMD_READ_CAPACITY_10 and SCSI_CMD_READ_FORMAT_CAPACITY to determine the disk size
// Application update block count and block size
void tud_msc_capacity_cb(uint8_t lun, uint32_t *block_count, uint16_t *block_size)
{
    (void) lun;

    uint32_t sec_count = tinyusb_msc_psram_get_sector_count();
    uint32_t sec_size = tinyusb_msc_psram_get_sector_size();
    *block_count = sec_count;
    *block_size  = (uint16_t)sec_size;
}

// Invoked when received Start Stop Unit command
// - Start = 0 : stopped power mode, if load_eject = 1 : unload disk storage
// - Start = 1 : active mode, if load_eject = 1 : load disk storage
bool tud_msc_start_stop_cb(uint8_t lun, uint8_t power_condition, bool start, bool load_eject)
{
    (void) lun;
    (void) power_condition;

    if (load_eject && !start) {
        if (tinyusb_msc_psram_mount(s_storage_handle->base_path) != ESP_OK) {
            ESP_LOGW(TAG, "tud_msc_start_stop_cb() mount Fails");
        }
    }
    return true;
}

// Invoked when received SCSI READ10 command
// - Address = lba * BLOCK_SIZE + offset
// - Application fill the buffer (up to bufsize) with address contents and return number of read byte.
int32_t tud_msc_read10_cb(uint8_t lun, uint32_t lba, uint32_t offset, void *buffer, uint32_t bufsize)
{
    esp_err_t err = msc_psram_read_sector(lba, offset, bufsize, buffer);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "msc_psram_read_sector failed: 0x%x", err);
        return 0;
    }
    return bufsize;
}

// Invoked when received SCSI WRITE10 command
// - Address = lba * BLOCK_SIZE + offset
// - Application write data from buffer to address contents (up to bufsize) and return number of written byte.
int32_t tud_msc_write10_cb(uint8_t lun, uint32_t lba, uint32_t offset, uint8_t *buffer, uint32_t bufsize)
{
    esp_err_t err = msc_psram_write_sector(lba, offset, bufsize, buffer);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "msc_psram_write_sector failed: 0x%x", err);
        return 0;
    }
    return bufsize;
}

/**
 * Invoked when received an SCSI command not in built-in list below.
 * - READ_CAPACITY10, READ_FORMAT_CAPACITY, INQUIRY, TEST_UNIT_READY, START_STOP_UNIT, MODE_SENSE6, REQUEST_SENSE
 * - READ10 and WRITE10 has their own callbacks
 *
 * \param[in]   lun         Logical unit number
 * \param[in]   scsi_cmd    SCSI command contents which application must examine to response accordingly
 * \param[out]  buffer      Buffer for SCSI Data Stage.
 *                            - For INPUT: application must fill this with response.
 *                            - For OUTPUT it holds the Data from host
 * \param[in]   bufsize     Buffer's length.
 *
 * \return      Actual bytes processed, can be zero for no-data command.
 * \retval      negative    Indicate error e.g unsupported command, tinyusb will \b STALL the corresponding
 *                          endpoint and return failed status in command status wrapper phase.
 */
int32_t tud_msc_scsi_cb(uint8_t lun, uint8_t const scsi_cmd[16], void *buffer, uint16_t bufsize)
{
    int32_t ret;

    switch (scsi_cmd[0]) {
    case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
        /* SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL is the Prevent/Allow Medium Removal
        command (1Eh) that requests the library to enable or disable user access to
        the storage media/partition. */
        ret = 0;
        break;
    default:
        ESP_LOGW(TAG, "tud_msc_scsi_cb() invoked: %d", scsi_cmd[0]);
        tud_msc_set_sense(lun, SCSI_SENSE_ILLEGAL_REQUEST, SCSI_CODE_ASC_INVALID_COMMAND_OPERATION_CODE, SCSI_CODE_ASCQ);
        ret = -1;
        break;
    }
    return ret;
}

// Invoked when device is unmounted
void tud_umount_cb(void)
{
    if (tinyusb_msc_psram_mount(s_storage_handle->base_path) != ESP_OK) {
        ESP_LOGW(TAG, "tud_umount_cb() mount Fails");
    }
}

// Invoked when device is mounted (configured)
void tud_mount_cb(void)
{
    tinyusb_msc_psram_unmount();
}
/*********************************************************************** TinyUSB MSC callbacks*/