/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 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 <stdio.h>
#include <stdint.h>
#include <string.h>

#include "ets_sys.h"
#include "uart.h"

#include "py/runtime.h"
#include "py/stream.h"
#include "py/mperrno.h"
#include "modpyb.h"

// baudrate is currently fixed to this value
#define UART_BAUDRATE (115200)

typedef struct _pyb_uart_obj_t {
    mp_obj_base_t base;
    uint8_t uart_id;
    uint16_t timeout;       // timeout waiting for first char (in ms)
    uint16_t timeout_char;  // timeout waiting between chars (in ms)
} pyb_uart_obj_t;

/******************************************************************************/
// MicroPython bindings for UART

STATIC void pyb_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    pyb_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
    mp_printf(print, "UART(%u, baudrate=%u, timeout=%u, timeout_char=%u)",
        self->uart_id, UART_BAUDRATE, self->timeout, self->timeout_char);
}

STATIC void pyb_uart_init_helper(pyb_uart_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
    enum { ARG_timeout, ARG_timeout_char };
    static const mp_arg_t allowed_args[] = {
        //{ MP_QSTR_baudrate, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 9600} },
        //{ MP_QSTR_bits, MP_ARG_INT, {.u_int = 8} },
        //{ MP_QSTR_parity, MP_ARG_OBJ, {.u_obj = mp_const_none} },
        //{ MP_QSTR_stop, MP_ARG_INT, {.u_int = 1} },
        //{ MP_QSTR_tx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
        //{ MP_QSTR_rx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
        { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
        { MP_QSTR_timeout_char, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
    };
    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

    // set timeout
    self->timeout = args[ARG_timeout].u_int;

    // set timeout_char
    // make sure it is at least as long as a whole character (13 bits to be safe)
    self->timeout_char = args[ARG_timeout_char].u_int;
    uint32_t min_timeout_char = 13000 / UART_BAUDRATE + 1;
    if (self->timeout_char < min_timeout_char) {
        self->timeout_char = min_timeout_char;
    }
}

STATIC mp_obj_t pyb_uart_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);

    // get uart id
    mp_int_t uart_id = mp_obj_get_int(args[0]);
    if (uart_id != 0 && uart_id != 1) {
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "UART(%d) does not exist", uart_id));
    }

    // create instance
    pyb_uart_obj_t *self = m_new_obj(pyb_uart_obj_t);
    self->base.type = &pyb_uart_type;
    self->uart_id = uart_id;

    // init the peripheral
    mp_map_t kw_args;
    mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
    pyb_uart_init_helper(self, n_args - 1, args + 1, &kw_args);

    return MP_OBJ_FROM_PTR(self);
}

STATIC mp_obj_t pyb_uart_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    pyb_uart_init_helper(args[0], n_args - 1, args + 1, kw_args);
    return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_KW(pyb_uart_init_obj, 1, pyb_uart_init);

STATIC const mp_rom_map_elem_t pyb_uart_locals_dict_table[] = {
    { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&pyb_uart_init_obj) },

    { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
    { MP_ROM_QSTR(MP_QSTR_readall), MP_ROM_PTR(&mp_stream_readall_obj) },
    { MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
    { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
    { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
};

STATIC MP_DEFINE_CONST_DICT(pyb_uart_locals_dict, pyb_uart_locals_dict_table);

STATIC mp_uint_t pyb_uart_read(mp_obj_t self_in, void *buf_in, mp_uint_t size, int *errcode) {
    pyb_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);

    if (self->uart_id == 1) {
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "UART(1) can't read"));
    }

    // make sure we want at least 1 char
    if (size == 0) {
        return 0;
    }

    // wait for first char to become available
    if (!uart_rx_wait(self->timeout * 1000)) {
        *errcode = MP_EAGAIN;
        return MP_STREAM_ERROR;
    }

    // read the data
    uint8_t *buf = buf_in;
    for (;;) {
        *buf++ = uart_rx_char();
        if (--size == 0 || !uart_rx_wait(self->timeout_char * 1000)) {
            // return number of bytes read
            return buf - (uint8_t*)buf_in;
        }
    }
}

STATIC mp_uint_t pyb_uart_write(mp_obj_t self_in, const void *buf_in, mp_uint_t size, int *errcode) {
    pyb_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
    const byte *buf = buf_in;

    /* TODO implement non-blocking
    // wait to be able to write the first character
    if (!uart_tx_wait(self, timeout)) {
        *errcode = EAGAIN;
        return MP_STREAM_ERROR;
    }
    */

    // write the data
    for (size_t i = 0; i < size; ++i) {
        uart_tx_one_char(self->uart_id, *buf++);
    }

    // return number of bytes written
    return size;
}

STATIC mp_uint_t pyb_uart_ioctl(mp_obj_t self_in, mp_uint_t request, mp_uint_t arg, int *errcode) {
    *errcode = MP_EINVAL;
    return MP_STREAM_ERROR;
}

STATIC const mp_stream_p_t uart_stream_p = {
    .read = pyb_uart_read,
    .write = pyb_uart_write,
    .ioctl = pyb_uart_ioctl,
    .is_text = false,
};

const mp_obj_type_t pyb_uart_type = {
    { &mp_type_type },
    .name = MP_QSTR_UART,
    .print = pyb_uart_print,
    .make_new = pyb_uart_make_new,
    .getiter = mp_identity,
    .iternext = mp_stream_unbuffered_iter,
    .protocol = &uart_stream_p,
    .locals_dict = (mp_obj_dict_t*)&pyb_uart_locals_dict,
};