/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2020-2021 Damien P. George
 *
 * 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 <string.h>

#include "py/runtime.h"
#include "extmod/vfs.h"
#include "modrp2.h"
#include "hardware/flash.h"
#include "pico/binary_info.h"

#define BLOCK_SIZE_BYTES (FLASH_SECTOR_SIZE)

#ifndef MICROPY_HW_FLASH_STORAGE_BYTES
#define MICROPY_HW_FLASH_STORAGE_BYTES (1408 * 1024)
#endif
static_assert(MICROPY_HW_FLASH_STORAGE_BYTES % 4096 == 0, "Flash storage size must be a multiple of 4K");

#ifndef MICROPY_HW_FLASH_STORAGE_BASE
#define MICROPY_HW_FLASH_STORAGE_BASE (PICO_FLASH_SIZE_BYTES - MICROPY_HW_FLASH_STORAGE_BYTES)
#endif

static_assert(MICROPY_HW_FLASH_STORAGE_BYTES <= PICO_FLASH_SIZE_BYTES, "MICROPY_HW_FLASH_STORAGE_BYTES too big");
static_assert(MICROPY_HW_FLASH_STORAGE_BASE + MICROPY_HW_FLASH_STORAGE_BYTES <= PICO_FLASH_SIZE_BYTES, "MICROPY_HW_FLASH_STORAGE_BYTES too big");

typedef struct _rp2_flash_obj_t {
    mp_obj_base_t base;
    uint32_t flash_base;
    uint32_t flash_size;
} rp2_flash_obj_t;

STATIC rp2_flash_obj_t rp2_flash_obj = {
    .base = { &rp2_flash_type },
    .flash_base = MICROPY_HW_FLASH_STORAGE_BASE,
    .flash_size = MICROPY_HW_FLASH_STORAGE_BYTES,
};

// Tag the flash drive in the binary as readable/writable (but not reformatable)
bi_decl(bi_block_device(
    BINARY_INFO_TAG_MICROPYTHON,
    "MicroPython",
    XIP_BASE + MICROPY_HW_FLASH_STORAGE_BASE,
    MICROPY_HW_FLASH_STORAGE_BYTES,
    NULL,
    BINARY_INFO_BLOCK_DEV_FLAG_READ |
    BINARY_INFO_BLOCK_DEV_FLAG_WRITE |
    BINARY_INFO_BLOCK_DEV_FLAG_PT_UNKNOWN));

STATIC mp_obj_t rp2_flash_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    // Check args.
    mp_arg_check_num(n_args, n_kw, 0, 0, false);

    #ifndef NDEBUG
    extern char __flash_binary_end;
    assert((uintptr_t)&__flash_binary_end - XIP_BASE <= MICROPY_HW_FLASH_STORAGE_BASE);
    #endif

    // Return singleton object.
    return MP_OBJ_FROM_PTR(&rp2_flash_obj);
}

STATIC mp_obj_t rp2_flash_readblocks(size_t n_args, const mp_obj_t *args) {
    rp2_flash_obj_t *self = MP_OBJ_TO_PTR(args[0]);
    uint32_t offset = mp_obj_get_int(args[1]) * BLOCK_SIZE_BYTES;
    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(args[2], &bufinfo, MP_BUFFER_WRITE);
    if (n_args == 4) {
        offset += mp_obj_get_int(args[3]);
    }
    memcpy(bufinfo.buf, (void *)(XIP_BASE + self->flash_base + offset), bufinfo.len);
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(rp2_flash_readblocks_obj, 3, 4, rp2_flash_readblocks);

STATIC mp_obj_t rp2_flash_writeblocks(size_t n_args, const mp_obj_t *args) {
    rp2_flash_obj_t *self = MP_OBJ_TO_PTR(args[0]);
    uint32_t offset = mp_obj_get_int(args[1]) * BLOCK_SIZE_BYTES;
    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(args[2], &bufinfo, MP_BUFFER_READ);
    if (n_args == 3) {
        // Flash erase/program must run in an atomic section because the XIP bit gets disabled.
        mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
        flash_range_erase(self->flash_base + offset, bufinfo.len);
        MICROPY_END_ATOMIC_SECTION(atomic_state);
        MICROPY_EVENT_POLL_HOOK
        // TODO check return value
    } else {
        offset += mp_obj_get_int(args[3]);
    }
    // Flash erase/program must run in an atomic section because the XIP bit gets disabled.
    mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
    flash_range_program(self->flash_base + offset, bufinfo.buf, bufinfo.len);
    MICROPY_END_ATOMIC_SECTION(atomic_state);
    MICROPY_EVENT_POLL_HOOK
    // TODO check return value
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(rp2_flash_writeblocks_obj, 3, 4, rp2_flash_writeblocks);

STATIC mp_obj_t rp2_flash_ioctl(mp_obj_t self_in, mp_obj_t cmd_in, mp_obj_t arg_in) {
    rp2_flash_obj_t *self = MP_OBJ_TO_PTR(self_in);
    mp_int_t cmd = mp_obj_get_int(cmd_in);
    switch (cmd) {
        case MP_BLOCKDEV_IOCTL_INIT:
            return MP_OBJ_NEW_SMALL_INT(0);
        case MP_BLOCKDEV_IOCTL_DEINIT:
            return MP_OBJ_NEW_SMALL_INT(0);
        case MP_BLOCKDEV_IOCTL_SYNC:
            return MP_OBJ_NEW_SMALL_INT(0);
        case MP_BLOCKDEV_IOCTL_BLOCK_COUNT:
            return MP_OBJ_NEW_SMALL_INT(self->flash_size / BLOCK_SIZE_BYTES);
        case MP_BLOCKDEV_IOCTL_BLOCK_SIZE:
            return MP_OBJ_NEW_SMALL_INT(BLOCK_SIZE_BYTES);
        case MP_BLOCKDEV_IOCTL_BLOCK_ERASE: {
            uint32_t offset = mp_obj_get_int(arg_in) * BLOCK_SIZE_BYTES;
            // Flash erase/program must run in an atomic section because the XIP bit gets disabled.
            mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
            flash_range_erase(self->flash_base + offset, BLOCK_SIZE_BYTES);
            MICROPY_END_ATOMIC_SECTION(atomic_state);
            // TODO check return value
            return MP_OBJ_NEW_SMALL_INT(0);
        }
        default:
            return mp_const_none;
    }
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(rp2_flash_ioctl_obj, rp2_flash_ioctl);

STATIC const mp_rom_map_elem_t rp2_flash_locals_dict_table[] = {
    { MP_ROM_QSTR(MP_QSTR_readblocks), MP_ROM_PTR(&rp2_flash_readblocks_obj) },
    { MP_ROM_QSTR(MP_QSTR_writeblocks), MP_ROM_PTR(&rp2_flash_writeblocks_obj) },
    { MP_ROM_QSTR(MP_QSTR_ioctl), MP_ROM_PTR(&rp2_flash_ioctl_obj) },
};
STATIC MP_DEFINE_CONST_DICT(rp2_flash_locals_dict, rp2_flash_locals_dict_table);

const mp_obj_type_t rp2_flash_type = {
    { &mp_type_type },
    .name = MP_QSTR_Flash,
    .make_new = rp2_flash_make_new,
    .locals_dict = (mp_obj_dict_t *)&rp2_flash_locals_dict,
};
