#include <stdio.h>
#include <string.h>

#include "stm32f4xx_hal.h"

#include "mpconfig.h"
#include "nlr.h"
#include "misc.h"
#include "qstr.h"
#include "obj.h"
#include "runtime.h"
#include "bufhelper.h"
#include "uart.h"

/// \moduleref pyb
/// \class UART - duplex serial communication bus
///
/// UART implements the standard UART/USART duplex serial communications protocol.  At
/// the physical level it consists of 2 lines: RX and TX.
///
/// See usage model of I2C.  UART is very similar.  Main difference is
/// parameters to init the UART bus:
///
///     from pyb import UART
///
///     uart = UART(1, 9600)                         # init with given baudrate
///     uart.init(9600, bits=8, stop=1, parity=None) # init with given parameters
///
/// Bits can be 8 or 9, stop can be 1 or 2, parity can be None, 0 (even), 1 (odd).
///
/// Extra method:
///
///     uart.any()               # returns True if any characters waiting

struct _pyb_uart_obj_t {
    mp_obj_base_t base;
    pyb_uart_t uart_id;
    bool is_enabled;
    UART_HandleTypeDef uart;
};

pyb_uart_obj_t *pyb_uart_global_debug = NULL;

// assumes Init parameters have been set up correctly
bool uart_init2(pyb_uart_obj_t *uart_obj) {
    USART_TypeDef *UARTx = NULL;

    uint32_t GPIO_Pin = 0;
    uint8_t  GPIO_AF_UARTx = 0;
    GPIO_TypeDef* GPIO_Port = NULL;

    switch (uart_obj->uart_id) {
        // USART1 is on PA9/PA10 (CK on PA8), PB6/PB7
        case PYB_UART_1:
            UARTx = USART1;
            GPIO_AF_UARTx = GPIO_AF7_USART1;

#if defined (PYBV4) || defined(PYBV10)
            GPIO_Port = GPIOB;
            GPIO_Pin = GPIO_PIN_6 | GPIO_PIN_7;
#else
            GPIO_Port = GPIOA;
            GPIO_Pin = GPIO_PIN_9 | GPIO_PIN_10;
#endif

            __USART1_CLK_ENABLE();
            break;

        // USART2 is on PA2/PA3 (CK on PA4), PD5/PD6 (CK on PD7)
        case PYB_UART_2:
            UARTx = USART2;
            GPIO_AF_UARTx = GPIO_AF7_USART2;

            GPIO_Port = GPIOA;
            GPIO_Pin = GPIO_PIN_2 | GPIO_PIN_3;

            __USART2_CLK_ENABLE();
            break;

        // USART3 is on PB10/PB11 (CK on PB12), PC10/PC11 (CK on PC12), PD8/PD9 (CK on PD10)
        case PYB_UART_3:
            UARTx = USART3;
            GPIO_AF_UARTx = GPIO_AF7_USART3;

#if defined(PYBV3) || defined(PYBV4) | defined(PYBV10)
            GPIO_Port = GPIOB;
            GPIO_Pin = GPIO_PIN_10 | GPIO_PIN_11;
#else
            GPIO_Port = GPIOD;
            GPIO_Pin = GPIO_PIN_8 | GPIO_PIN_9;
#endif
            __USART3_CLK_ENABLE();
            break;

        // UART4 is on PA0/PA1, PC10/PC11
        case PYB_UART_4:
            UARTx = UART4;
            GPIO_AF_UARTx = GPIO_AF8_UART4;

            GPIO_Port = GPIOA;
            GPIO_Pin = GPIO_PIN_0 | GPIO_PIN_1;

            __UART4_CLK_ENABLE();
            break;

        // USART6 is on PC6/PC7 (CK on PC8)
        case PYB_UART_6:
            UARTx = USART6;
            GPIO_AF_UARTx = GPIO_AF8_USART6;

            GPIO_Port = GPIOC;
            GPIO_Pin = GPIO_PIN_6 | GPIO_PIN_7;

            __USART6_CLK_ENABLE();
            break;

        default:
            return false;
    }

    // init GPIO
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.Pin = GPIO_Pin;
    GPIO_InitStructure.Speed = GPIO_SPEED_HIGH;
    GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStructure.Pull = GPIO_PULLUP;
    GPIO_InitStructure.Alternate = GPIO_AF_UARTx;
    HAL_GPIO_Init(GPIO_Port, &GPIO_InitStructure);

    // init UARTx
    uart_obj->uart.Instance = UARTx;
    HAL_UART_Init(&uart_obj->uart);

    uart_obj->is_enabled = true;

    return true;
}

bool uart_init(pyb_uart_obj_t *uart_obj, uint32_t baudrate) {
    UART_HandleTypeDef *uh = &uart_obj->uart;
    memset(uh, 0, sizeof(*uh));
    uh->Init.BaudRate = baudrate;
    uh->Init.WordLength = UART_WORDLENGTH_8B;
    uh->Init.StopBits = UART_STOPBITS_1;
    uh->Init.Parity = UART_PARITY_NONE;
    uh->Init.Mode = UART_MODE_TX_RX;
    uh->Init.HwFlowCtl = UART_HWCONTROL_NONE;
    uh->Init.OverSampling = UART_OVERSAMPLING_16;
    return uart_init2(uart_obj);
}

void uart_deinit(pyb_uart_obj_t *uart_obj) {
    uart_obj->is_enabled = false;
    UART_HandleTypeDef *uart = &uart_obj->uart;
    HAL_UART_DeInit(uart);
    if (uart->Instance == USART1) {
        __USART1_FORCE_RESET();
        __USART1_RELEASE_RESET();
        __USART1_CLK_DISABLE();
    } else if (uart->Instance == USART2) {
        __USART2_FORCE_RESET();
        __USART2_RELEASE_RESET();
        __USART2_CLK_DISABLE();
    } else if (uart->Instance == USART3) {
        __USART3_FORCE_RESET();
        __USART3_RELEASE_RESET();
        __USART3_CLK_DISABLE();
    } else if (uart->Instance == UART4) {
        __UART4_FORCE_RESET();
        __UART4_RELEASE_RESET();
        __UART4_CLK_DISABLE();
    } else if (uart->Instance == USART6) {
        __USART6_FORCE_RESET();
        __USART6_RELEASE_RESET();
        __USART6_CLK_DISABLE();
    }
}

bool uart_rx_any(pyb_uart_obj_t *uart_obj) {
    return __HAL_UART_GET_FLAG(&uart_obj->uart, UART_FLAG_RXNE);
}

int uart_rx_char(pyb_uart_obj_t *uart_obj) {
    uint8_t ch;
    if (HAL_UART_Receive(&uart_obj->uart, &ch, 1, 0) != HAL_OK) {
        ch = 0;
    }
    return ch;
}

void uart_tx_char(pyb_uart_obj_t *uart_obj, int c) {
    uint8_t ch = c;
    HAL_UART_Transmit(&uart_obj->uart, &ch, 1, 100000);
}

void uart_tx_str(pyb_uart_obj_t *uart_obj, const char *str) {
    HAL_UART_Transmit(&uart_obj->uart, (uint8_t*)str, strlen(str), 100000);
}

void uart_tx_strn(pyb_uart_obj_t *uart_obj, const char *str, uint len) {
    HAL_UART_Transmit(&uart_obj->uart, (uint8_t*)str, len, 100000);
}

void uart_tx_strn_cooked(pyb_uart_obj_t *uart_obj, const char *str, uint len) {
    for (const char *top = str + len; str < top; str++) {
        if (*str == '\n') {
            uart_tx_char(uart_obj, '\r');
        }
        uart_tx_char(uart_obj, *str);
    }
}

/******************************************************************************/
/* Micro Python bindings                                                      */

STATIC void pyb_uart_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
    pyb_uart_obj_t *self = self_in;
    if (!self->is_enabled) {
        print(env, "UART(%lu)", self->uart_id);
    } else {
        print(env, "UART(%lu, baudrate=%u, bits=%u, stop=%u",
            self->uart_id, self->uart.Init.BaudRate,
            self->uart.Init.WordLength == UART_WORDLENGTH_8B ? 8 : 9,
            self->uart.Init.StopBits == UART_STOPBITS_1 ? 1 : 2);
        if (self->uart.Init.Parity == UART_PARITY_NONE) {
            print(env, ", parity=None)");
        } else {
            print(env, ", parity=%u)", self->uart.Init.Parity == UART_PARITY_EVEN ? 0 : 1);
        }
    }
}

/// \method init(baudrate, *, bits=8, stop=1, parity=None)
///
/// Initialise the SPI bus with the given parameters:
///
///   - `baudrate` is the clock rate.
///   - `bits` is the number of bits per byte, 8 or 9.
///   - `stop` is the number of stop bits, 1 or 2.
///   - `parity` is the parity, `None`, 0 (even) or 1 (odd).
STATIC const mp_arg_t pyb_uart_init_args[] = {
    { MP_QSTR_baudrate, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 9600} },
    { MP_QSTR_bits,     MP_ARG_KW_ONLY | MP_ARG_INT,  {.u_int = 8} },
    { MP_QSTR_stop,     MP_ARG_KW_ONLY | MP_ARG_INT,  {.u_int = 1} },
    { MP_QSTR_parity,   MP_ARG_KW_ONLY | MP_ARG_OBJ,  {.u_obj = mp_const_none} },
};
#define PYB_UART_INIT_NUM_ARGS ARRAY_SIZE(pyb_uart_init_args)

STATIC mp_obj_t pyb_uart_init_helper(pyb_uart_obj_t *self, uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    // parse args
    mp_arg_val_t vals[PYB_UART_INIT_NUM_ARGS];
    mp_arg_parse_all(n_args, args, kw_args, PYB_UART_INIT_NUM_ARGS, pyb_uart_init_args, vals);

    // set the UART configuration values
    memset(&self->uart, 0, sizeof(self->uart));
    UART_InitTypeDef *init = &self->uart.Init;
    init->BaudRate = vals[0].u_int;
    init->WordLength = vals[1].u_int == 8 ? UART_WORDLENGTH_8B : UART_WORDLENGTH_9B;
    switch (vals[2].u_int) {
        case 1: init->StopBits = UART_STOPBITS_1; break;
        default: init->StopBits = UART_STOPBITS_2; break;
    }
    if (vals[3].u_obj == mp_const_none) {
        init->Parity = UART_PARITY_NONE;
    } else {
        machine_int_t parity = mp_obj_get_int(vals[3].u_obj);
        init->Parity = (parity & 1) ? UART_PARITY_ODD : UART_PARITY_EVEN;
    }
    init->Mode = UART_MODE_TX_RX;
    init->HwFlowCtl = UART_HWCONTROL_NONE;
    init->OverSampling = UART_OVERSAMPLING_16;

    // init UART (if it fails, it's because the port doesn't exist)
    if (!uart_init2(self)) {
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "UART port %d does not exist", self->uart_id));
    }

    return mp_const_none;
}

/// \classmethod \constructor(bus, ...)
///
/// Construct a UART object on the given bus.  `bus` can be 1-6, or 'XA', 'XB', 'YA', or 'YB'.
/// With no additional parameters, the UART object is created but not
/// initialised (it has the settings from the last initialisation of
/// the bus, if any).  If extra arguments are given, the bus is initialised.
/// See `init` for parameters of initialisation.
STATIC mp_obj_t pyb_uart_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
    // check arguments
    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);

    // create object
    pyb_uart_obj_t *o = m_new_obj(pyb_uart_obj_t);
    o->base.type = &pyb_uart_type;

    // work out port
    o->uart_id = 0;
    if (MP_OBJ_IS_STR(args[0])) {
        const char *port = mp_obj_str_get_str(args[0]);
        if (0) {
#if defined(PYBV10)
        } else if (strcmp(port, "XA") == 0) {
            o->uart_id = PYB_UART_XA;
        } else if (strcmp(port, "XB") == 0) {
            o->uart_id = PYB_UART_XB;
        } else if (strcmp(port, "YA") == 0) {
            o->uart_id = PYB_UART_YA;
        } else if (strcmp(port, "YB") == 0) {
            o->uart_id = PYB_UART_YB;
#endif
        } else {
            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "UART port %s does not exist", port));
        }
    } else {
        o->uart_id = mp_obj_get_int(args[0]);
    }

    if (n_args > 1 || n_kw > 0) {
        // start the peripheral
        mp_map_t kw_args;
        mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
        pyb_uart_init_helper(o, n_args - 1, args + 1, &kw_args);
    }

    return o;
}

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

/// \method deinit()
/// Turn off the UART bus.
STATIC mp_obj_t pyb_uart_deinit(mp_obj_t self_in) {
    pyb_uart_obj_t *self = self_in;
    uart_deinit(self);
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_uart_deinit_obj, pyb_uart_deinit);

/// \method any()
/// Return `True` if any characters waiting, else `False`.
STATIC mp_obj_t pyb_uart_any(mp_obj_t self_in) {
    pyb_uart_obj_t *self = self_in;
    if (uart_rx_any(self)) {
        return mp_const_true;
    } else {
        return mp_const_false;
    }
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_uart_any_obj, pyb_uart_any);

/// \method send(send, *, timeout=5000)
/// Send data on the bus:
///
///   - `send` is the data to send (an integer to send, or a buffer object).
///   - `timeout` is the timeout in milliseconds to wait for the send.
///
/// Return value: `None`.
STATIC const mp_arg_t pyb_uart_send_args[] = {
    { MP_QSTR_send,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
    { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 5000} },
};
#define PYB_UART_SEND_NUM_ARGS ARRAY_SIZE(pyb_uart_send_args)

STATIC mp_obj_t pyb_uart_send(uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    // TODO assumes transmission size is 8-bits wide

    pyb_uart_obj_t *self = args[0];

    // parse args
    mp_arg_val_t vals[PYB_UART_SEND_NUM_ARGS];
    mp_arg_parse_all(n_args - 1, args + 1, kw_args, PYB_UART_SEND_NUM_ARGS, pyb_uart_send_args, vals);

    // get the buffer to send from
    mp_buffer_info_t bufinfo;
    uint8_t data[1];
    pyb_buf_get_for_send(vals[0].u_obj, &bufinfo, data);

    // send the data
    HAL_StatusTypeDef status = HAL_UART_Transmit(&self->uart, bufinfo.buf, bufinfo.len, vals[1].u_int);

    if (status != HAL_OK) {
        // TODO really need a HardwareError object, or something
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_Exception, "HAL_UART_Transmit failed with code %d", status));
    }

    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_uart_send_obj, 1, pyb_uart_send);

/// \method recv(recv, *, timeout=5000)
///
/// Receive data on the bus:
///
///   - `recv` can be an integer, which is the number of bytes to receive,
///     or a mutable buffer, which will be filled with received bytes.
///   - `timeout` is the timeout in milliseconds to wait for the receive.
///
/// Return value: if `recv` is an integer then a new buffer of the bytes received,
/// otherwise the same buffer that was passed in to `recv`.
STATIC const mp_arg_t pyb_uart_recv_args[] = {
    { MP_QSTR_recv,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
    { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 5000} },
};
#define PYB_UART_RECV_NUM_ARGS ARRAY_SIZE(pyb_uart_recv_args)

STATIC mp_obj_t pyb_uart_recv(uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    // TODO assumes transmission size is 8-bits wide

    pyb_uart_obj_t *self = args[0];

    // parse args
    mp_arg_val_t vals[PYB_UART_RECV_NUM_ARGS];
    mp_arg_parse_all(n_args - 1, args + 1, kw_args, PYB_UART_RECV_NUM_ARGS, pyb_uart_recv_args, vals);

    // get the buffer to receive into
    mp_buffer_info_t bufinfo;
    mp_obj_t o_ret = pyb_buf_get_for_recv(vals[0].u_obj, &bufinfo);

    // receive the data
    HAL_StatusTypeDef status = HAL_UART_Receive(&self->uart, bufinfo.buf, bufinfo.len, vals[1].u_int);

    if (status != HAL_OK) {
        // TODO really need a HardwareError object, or something
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_Exception, "HAL_UART_Receive failed with code %d", status));
    }

    // return the received data
    if (o_ret == MP_OBJ_NULL) {
        return vals[0].u_obj;
    } else {
        return mp_obj_str_builder_end(o_ret);
    }
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_uart_recv_obj, 1, pyb_uart_recv);

STATIC const mp_map_elem_t pyb_uart_locals_dict_table[] = {
    // instance methods
    { MP_OBJ_NEW_QSTR(MP_QSTR_init), (mp_obj_t)&pyb_uart_init_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_deinit), (mp_obj_t)&pyb_uart_deinit_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_any), (mp_obj_t)&pyb_uart_any_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_send), (mp_obj_t)&pyb_uart_send_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_recv), (mp_obj_t)&pyb_uart_recv_obj },
};

STATIC MP_DEFINE_CONST_DICT(pyb_uart_locals_dict, pyb_uart_locals_dict_table);

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,
    .locals_dict = (mp_obj_t)&pyb_uart_locals_dict,
};
