/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2018 hathach for Adafruit Industries
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "tusb.h"
#include "internal_flash.h"

// For updating fatfs's cache
#include "extmod/vfs.h"
#include "extmod/vfs_fat.h"
#include "lib/oofatfs/ff.h"
#include "py/mpstate.h"

#include "supervisor/shared/autoreload.h"

/*------------------------------------------------------------------*/
/* MACRO TYPEDEF CONSTANT ENUM
 *------------------------------------------------------------------*/
#define MSC_FLASH_ADDR_END      0xED000
#define MSC_FLASH_SIZE          (256*1024)
#define MSC_FLASH_ADDR_START    (MSC_FLASH_ADDR_END-MSC_FLASH_SIZE)
#define MSC_FLASH_BLOCK_SIZE    512

#define FL_PAGE_SZ              4096

// Callback invoked when received an SCSI command not in built-in list below
// - READ_CAPACITY10, READ_FORMAT_CAPACITY, INQUIRY, MODE_SENSE6, REQUEST_SENSE
// - READ10 and WRITE10 has their own callbacks
int32_t tud_msc_scsi_cb (uint8_t lun, const uint8_t scsi_cmd[16], void* buffer, uint16_t bufsize) {
    const void* response = NULL;
    uint16_t resplen = 0;

    switch ( scsi_cmd[0] ) {
        case SCSI_CMD_TEST_UNIT_READY:
            // Command that host uses to check our readiness before sending other commands
            resplen = 0;
        break;

        case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
            // Host is about to read/write etc ... better not to disconnect disk
            resplen = 0;
        break;

        case SCSI_CMD_START_STOP_UNIT:
            // Host try to eject/safe remove/poweroff us. We could safely disconnect with disk storage, or go into lower power
            /* scsi_start_stop_unit_t const * start_stop = (scsi_start_stop_unit_t const *) scsi_cmd;
            // Start bit = 0 : low power mode, if load_eject = 1 : unmount disk storage as well
            // Start bit = 1 : Ready mode, if load_eject = 1 : mount disk storage
            start_stop->start;
            start_stop->load_eject;
            */
            resplen = 0;
        break;

        default:
          // Set Sense = Invalid Command Operation
          tud_msc_set_sense(lun, SCSI_SENSE_ILLEGAL_REQUEST, 0x20, 0x00);

          // negative means error -> tinyusb could stall and/or response with failed status
          resplen = -1;
        break;
    }

    // return len must not larger than bufsize
    if ( resplen > bufsize ) {
        resplen = bufsize;
    }

    // copy response to stack's buffer if any
    if ( response && resplen ) {
        memcpy(buffer, response, resplen);
    }

    return resplen;
}

// Callback invoked when received READ10 command.
// Copy disk's data to buffer (up to bufsize) and return number of copied bytes.
int32_t tud_msc_read10_cb (uint8_t lun, uint32_t lba, uint32_t offset, void* buffer, uint32_t bufsize) {
    (void) lun;
    (void) offset;

    const uint32_t block_count = bufsize / MSC_FLASH_BLOCK_SIZE;

    internal_flash_read_blocks(buffer, lba, block_count);

    return block_count * MSC_FLASH_BLOCK_SIZE;
}

// Callback invoked when received WRITE10 command.
// Process data in buffer to disk's storage and return number of written bytes
int32_t tud_msc_write10_cb (uint8_t lun, uint32_t lba, uint32_t offset, void* buffer, uint32_t bufsize) {
    (void) lun;
    (void) offset;

    const uint32_t block_count = bufsize / MSC_FLASH_BLOCK_SIZE;

    // bufsize <= CFG_TUD_MSC_BUFSIZE (4096)
    internal_flash_write_blocks(buffer, lba, block_count);

    // update fatfs's cache if address matches
    fs_user_mount_t* vfs = MP_STATE_VM(vfs_mount_table)->obj;

    if ( (lba <= vfs->fatfs.winsect) && (vfs->fatfs.winsect <= (lba + bufsize / MSC_FLASH_BLOCK_SIZE)) ) {
        memcpy(vfs->fatfs.win, buffer + MSC_FLASH_BLOCK_SIZE * (vfs->fatfs.winsect - lba), MSC_FLASH_BLOCK_SIZE);
    }

    return block_count * MSC_FLASH_BLOCK_SIZE;
}

// Callback invoked when WRITE10 command is completed (status received and accepted by host).
// used to flush any pending cache.
void tud_msc_write10_complete_cb (uint8_t lun) {
    (void) lun;

    // flush pending cache when write10 is complete
    internal_flash_flush();

    // This write is complete, start the autoreload clock.
    autoreload_start();
}