/*
 * 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 "shared-bindings/microcontroller/__init__.h"
#include "shared-bindings/busio/UART.h"

#include "mpconfigport.h"
#include "lib/utils/interrupt_char.h"
#include "py/gc.h"
#include "py/mperrno.h"
#include "py/runtime.h"
#include "py/stream.h"
#include "supervisor/shared/translate.h"

#include "tick.h"

void common_hal_busio_uart_construct(busio_uart_obj_t *self,
        const mcu_pin_obj_t * tx, const mcu_pin_obj_t * rx, uint32_t baudrate,
        uint8_t bits, uart_parity_t parity, uint8_t stop, mp_float_t timeout,
        uint8_t receiver_buffer_size) {
    // Sercom* sercom = NULL;
    // uint8_t sercom_index = 255; // Unset index
    // uint32_t rx_pinmux = 0;
    // uint8_t rx_pad = 255; // Unset pad
    // uint32_t tx_pinmux = 0;
    // uint8_t tx_pad = 255; // Unset pad

    // if (bits > 8) {
    //     mp_raise_NotImplementedError(translate("bytes > 8 bits not supported"));
    // }

    // bool have_tx = tx != mp_const_none;
    // bool have_rx = rx != mp_const_none;
    // if (!have_tx && !have_rx) {
    //     mp_raise_ValueError(translate("tx and rx cannot both be None"));
    // }

    // self->baudrate = baudrate;
    // self->character_bits = bits;
    // self->timeout_ms = timeout * 1000;

    // // This assignment is only here because the usart_async routines take a *const argument.
    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;

    // for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
    //     Sercom* potential_sercom = NULL;
    //     if (have_tx) {
    //         sercom_index = tx->sercom[i].index;
    //         if (sercom_index >= SERCOM_INST_NUM) {
    //             continue;
    //         }
    //         potential_sercom = sercom_insts[sercom_index];
    //         if (potential_sercom->USART.CTRLA.bit.ENABLE != 0 ||
    //             !(tx->sercom[i].pad == 0 ||
    //               tx->sercom[i].pad == 2)) {
    //             continue;
    //         }
    //         tx_pinmux = PINMUX(tx->number, (i == 0) ? MUX_C : MUX_D);
    //         tx_pad = tx->sercom[i].pad;
    //         if (rx == mp_const_none) {
    //             sercom = potential_sercom;
    //             break;
    //         }
    //     }
    //     for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
    //         if (((!have_tx && rx->sercom[j].index < SERCOM_INST_NUM &&
    //               sercom_insts[rx->sercom[j].index]->USART.CTRLA.bit.ENABLE == 0) ||
    //              sercom_index == rx->sercom[j].index) &&
    //             rx->sercom[j].pad != tx_pad) {
    //             rx_pinmux = PINMUX(rx->number, (j == 0) ? MUX_C : MUX_D);
    //             rx_pad = rx->sercom[j].pad;
    //             sercom = sercom_insts[rx->sercom[j].index];
    //             sercom_index = rx->sercom[j].index;
    //             break;
    //         }
    //     }
    //     if (sercom != NULL) {
    //         break;
    //     }
    // }
    // if (sercom == NULL) {
    //     mp_raise_ValueError(translate("Invalid pins"));
    // }
    // if (!have_tx) {
    //     tx_pad = 0;
    //     if (rx_pad == 0) {
    //         tx_pad = 2;
    //     }
    // }
    // if (!have_rx) {
    //     rx_pad = (tx_pad + 1) % 4;
    // }

    // // Set up clocks on SERCOM.
    // samd_peripherals_sercom_clock_init(sercom, sercom_index);

    // if (rx && receiver_buffer_size > 0) {
    //     self->buffer_length = receiver_buffer_size;
    //     // Initially allocate the UART's buffer in the long-lived part of the
    //     // heap.  UARTs are generally long-lived objects, but the "make long-
    //     // lived" machinery is incapable of moving internal pointers like
    //     // self->buffer, so do it manually.  (However, as long as internal
    //     // pointers like this are NOT moved, allocating the buffer
    //     // in the long-lived pool is not strictly necessary)
    //     self->buffer = (uint8_t *) gc_alloc(self->buffer_length * sizeof(uint8_t), false, true);
    //     if (self->buffer == NULL) {
    //         common_hal_busio_uart_deinit(self);
    //         mp_raise_msg(&mp_type_MemoryError, translate("Failed to allocate RX buffer"));
    //     }
    // } else {
    //     self->buffer_length = 0;
    //     self->buffer = NULL;
    // }

    // if (usart_async_init(usart_desc_p, sercom, self->buffer, self->buffer_length, NULL) != ERR_NONE) {
    //     mp_raise_ValueError(translate("Could not initialize UART"));
    // }

    // // usart_async_init() sets a number of defaults based on a prototypical SERCOM
    // // which don't necessarily match what we need. After calling it, set the values
    // // specific to this instantiation of UART.

    // // Set pads computed for this SERCOM.
    // // TXPO:
    // // 0x0: TX pad 0; no RTS/CTS
    // // 0x1: TX pad 2; no RTS/CTS
    // // 0x2: TX pad 0; RTS: pad 2, CTS: pad 3 (not used by us right now)
    // // So divide by 2 to map pad to value.
    // // RXPO:
    // // 0x0: RX pad 0
    // // 0x1: RX pad 1
    // // 0x2: RX pad 2
    // // 0x3: RX pad 3

    // // Doing a group mask and set of the registers saves 60 bytes over setting the bitfields individually.

    // sercom->USART.CTRLA.reg &= ~(SERCOM_USART_CTRLA_TXPO_Msk |
    //                              SERCOM_USART_CTRLA_RXPO_Msk |
    //                              SERCOM_USART_CTRLA_FORM_Msk);
    // sercom->USART.CTRLA.reg |= SERCOM_USART_CTRLA_TXPO(tx_pad / 2) |
    //                            SERCOM_USART_CTRLA_RXPO(rx_pad) |
    //                            (parity == PARITY_NONE ? 0 : SERCOM_USART_CTRLA_FORM(1));

    // // Enable tx and/or rx based on whether the pins were specified.
    // // CHSIZE is 0 for 8 bits, 5, 6, 7 for 5, 6, 7 bits. 1 for 9 bits, but we don't support that.
    // sercom->USART.CTRLB.reg &= ~(SERCOM_USART_CTRLB_TXEN |
    //                              SERCOM_USART_CTRLB_RXEN |
    //                              SERCOM_USART_CTRLB_PMODE |
    //                              SERCOM_USART_CTRLB_SBMODE |
    //                              SERCOM_USART_CTRLB_CHSIZE_Msk);
    // sercom->USART.CTRLB.reg |= (have_tx ? SERCOM_USART_CTRLB_TXEN : 0) |
    //                            (have_rx ? SERCOM_USART_CTRLB_RXEN : 0) |
    //                            (parity == PARITY_ODD ? SERCOM_USART_CTRLB_PMODE : 0) |
    //                            (stop > 1 ? SERCOM_USART_CTRLB_SBMODE : 0) |
    //                            SERCOM_USART_CTRLB_CHSIZE(bits % 8);

    // // Set baud rate
    // common_hal_busio_uart_set_baudrate(self, baudrate);

    // // Turn on rx interrupt handling. The UART async driver has its own set of internal callbacks,
    // // which are set up by uart_async_init(). These in turn can call user-specified callbacks.
    // // In fact, the actual interrupts are not enabled unless we set up a user-specified callback.
    // // This is confusing. It's explained in the Atmel START User Guide -> Implementation Description ->
    // // Different read function behavior in some asynchronous drivers. As of this writing:
    // // http://start.atmel.com/static/help/index.html?GUID-79201A5A-226F-4FBB-B0B8-AB0BE0554836
    // // Look at the ASFv4 code example for async USART.
    // usart_async_register_callback(usart_desc_p, USART_ASYNC_RXC_CB, usart_async_rxc_callback);


    // if (have_tx) {
    //     gpio_set_pin_direction(tx->number, GPIO_DIRECTION_OUT);
    //     gpio_set_pin_pull_mode(tx->number, GPIO_PULL_OFF);
    //     gpio_set_pin_function(tx->number, tx_pinmux);
    //     self->tx_pin  = tx->number;
    //     claim_pin(tx);
    // } else {
    //     self->tx_pin = NO_PIN;
    // }

    // if (have_rx) {
    //     gpio_set_pin_direction(rx->number, GPIO_DIRECTION_IN);
    //     gpio_set_pin_pull_mode(rx->number, GPIO_PULL_OFF);
    //     gpio_set_pin_function(rx->number, rx_pinmux);
    //     self->rx_pin  = rx->number;
    //     claim_pin(rx);
    // } else {
    //     self->rx_pin = NO_PIN;
    // }

    // usart_async_enable(usart_desc_p);
}

bool common_hal_busio_uart_deinited(busio_uart_obj_t *self) {
    return 0;//self->rx_pin == NO_PIN && self->tx_pin == NO_PIN;
}

void common_hal_busio_uart_deinit(busio_uart_obj_t *self) {
    // if (common_hal_busio_uart_deinited(self)) {
    //     return;
    // }
    // // This assignment is only here because the usart_async routines take a *const argument.
    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
    // usart_async_disable(usart_desc_p);
    // usart_async_deinit(usart_desc_p);
    // reset_pin_number(self->rx_pin);
    // reset_pin_number(self->tx_pin);
    // self->rx_pin = NO_PIN;
    // self->tx_pin = NO_PIN;
}

// Read characters.
size_t common_hal_busio_uart_read(busio_uart_obj_t *self, uint8_t *data, size_t len, int *errcode) {
//     if (self->rx_pin == NO_PIN) {
//         mp_raise_ValueError(translate("No RX pin"));
//     }

//     // This assignment is only here because the usart_async routines take a *const argument.
//     struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;

//     if (len == 0) {
//         // Nothing to read.
//         return 0;
//     }

//     struct io_descriptor *io;
//     usart_async_get_io_descriptor(usart_desc_p, &io);

//     size_t total_read = 0;
//     uint64_t start_ticks = ticks_ms;

//     // Busy-wait until timeout or until we've read enough chars.
//     while (ticks_ms - start_ticks <= self->timeout_ms) {
//         // Read as many chars as we can right now, up to len.
//         size_t num_read = io_read(io, data, len);

//         // Advance pointer in data buffer, and decrease how many chars left to read.
//         data += num_read;
//         len -= num_read;
//         total_read += num_read;
//         if (len == 0) {
//             // Don't need to read any more: data buf is full.
//             break;
//         }
//         if (num_read > 0) {
//             // Reset the timeout on every character read.
//             start_ticks = ticks_ms;
//         }
// #ifdef MICROPY_VM_HOOK_LOOP
//         MICROPY_VM_HOOK_LOOP ;
//         // Allow user to break out of a timeout with a KeyboardInterrupt.
//         if (mp_hal_is_interrupted()) {
//             break;
//         }
// #endif
//         // If we are zero timeout, make sure we don't loop again (in the event
//         // we read in under 1ms)
//         if (self->timeout_ms == 0) {
//             break;
//         }
//     }

//     if (total_read == 0) {
//         *errcode = EAGAIN;
//         return MP_STREAM_ERROR;
//     }

    return 0;//total_read;
}

// Write characters.
size_t common_hal_busio_uart_write(busio_uart_obj_t *self, const uint8_t *data, size_t len, int *errcode) {
    // if (self->tx_pin == NO_PIN) {
    //     mp_raise_ValueError(translate("No TX pin"));
    // }

    // // This assignment is only here because the usart_async routines take a *const argument.
    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;

    // struct io_descriptor *io;
    // usart_async_get_io_descriptor(usart_desc_p, &io);

    // if (io_write(io, data, len) < 0) {
    //     *errcode = MP_EAGAIN;
    //     return MP_STREAM_ERROR;
    // }

    // // Wait until write is complete or timeout.
    // bool done = false;
    // uint64_t start_ticks = ticks_ms;
    // // Busy-wait for timeout.
    // while (ticks_ms - start_ticks < self->timeout_ms) {
    //     if (usart_async_is_tx_empty(usart_desc_p)) {
    //         done = true;
    //         break;
    //     }
    //     #ifdef MICROPY_VM_HOOK_LOOP
    //         MICROPY_VM_HOOK_LOOP
    //     #endif
    // }

    // if (!done) {
    //     *errcode = MP_EAGAIN;
    //     return MP_STREAM_ERROR;
    // }

    // // All the characters got written.
    return 0;//len;
}

uint32_t common_hal_busio_uart_get_baudrate(busio_uart_obj_t *self) {
    return 0;//self->baudrate;
}

void common_hal_busio_uart_set_baudrate(busio_uart_obj_t *self, uint32_t baudrate) {
    // This assignment is only here because the usart_async routines take a *const argument.
    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
    // usart_async_set_baud_rate(usart_desc_p,
    //                           // Samples and ARITHMETIC vs FRACTIONAL must correspond to USART_SAMPR in
    //                           // hpl_sercom_config.h.
    //                           _usart_async_calculate_baud_rate(baudrate,  // e.g. 9600 baud
    //                                                            PROTOTYPE_SERCOM_USART_ASYNC_CLOCK_FREQUENCY,
    //                                                            16,   // samples
    //                                                            USART_BAUDRATE_ASYNCH_ARITHMETIC,
    //                                                            0  // fraction - not used for ARITHMETIC
    //                                                            ));
    // self->baudrate = baudrate;
}

uint32_t common_hal_busio_uart_rx_characters_available(busio_uart_obj_t *self) {
    // // This assignment is only here because the usart_async routines take a *const argument.
    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
    // struct usart_async_status async_status;
    // usart_async_get_status(usart_desc_p, &async_status);
    return 0;//async_status.rxcnt;
}

void common_hal_busio_uart_clear_rx_buffer(busio_uart_obj_t *self) {
    // This assignment is only here because the usart_async routines take a *const argument.
    // struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
    // usart_async_flush_rx_buffer(usart_desc_p);

}

bool common_hal_busio_uart_ready_to_tx(busio_uart_obj_t *self) {
    // if (self->tx_pin == NO_PIN) {
    //     return false;
    // }
    // // This assignment is only here because the usart_async routines take a *const argument.
    // const struct _usart_async_device * const usart_device_p =
    //     (struct _usart_async_device * const) &self->usart_desc.device;
    return 0;//_usart_async_is_byte_sent(usart_device_p);
}