/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2017 Glenn Ruben Bakke
 *
 * 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 <string.h>

#include "py/nlr.h"
#include "py/runtime.h"
#include "py/mperrno.h"
#include "py/mphal.h"

#if MICROPY_PY_MACHINE_I2C

#include "extmod/modmachine.h"
#include "i2c.h"
#if NRFX_TWI_ENABLED
#include "nrfx_twi.h"
#else
#include "nrfx_twim.h"
#endif

#if NRFX_TWIM_ENABLED

#define nrfx_twi_t        nrfx_twim_t
#define nrfx_twi_config_t nrfx_twim_config_t

#define nrfx_twi_init     nrfx_twim_init
#define nrfx_twi_uninit   nrfx_twim_uninit
#define nrfx_twi_enable   nrfx_twim_enable
#define nrfx_twi_xfer     nrfx_twim_xfer
#define nrfx_twi_disable  nrfx_twim_disable

#define nrfx_twi_xfer_desc_t nrfx_twim_xfer_desc_t

#define nrfx_twi_evt_handler_t nrfx_twim_evt_handler_t
#define nrfx_twi_evt_t         nrfx_twim_evt_t
#define nrfx_twi_evt_type_t    nrfx_twim_evt_type_t

#define NRFX_TWI_XFER_DESC_RX NRFX_TWIM_XFER_DESC_RX
#define NRFX_TWI_XFER_DESC_TX NRFX_TWIM_XFER_DESC_TX

#define NRFX_TWI_INSTANCE NRFX_TWIM_INSTANCE

#define NRFX_TWI_EVT_DONE         NRFX_TWIM_EVT_DONE
#define NRFX_TWI_EVT_ADDRESS_NACK NRFX_TWIM_EVT_ADDRESS_NACK
#define NRFX_TWI_EVT_DATA_NACK    NRFX_TWIM_EVT_DATA_NACK
#define NRFX_TWI_EVT_BUS_ERROR    NRFX_TWIM_EVT_BUS_ERROR

#define NRFX_TWI_FLAG_TX_NO_STOP NRFX_TWIM_FLAG_TX_NO_STOP

#define NRF_TWI_FREQ_100K NRF_TWIM_FREQ_100K
#define NRF_TWI_FREQ_250K NRF_TWIM_FREQ_250K
#define NRF_TWI_FREQ_400K NRF_TWIM_FREQ_400K

#endif

typedef struct _machine_hard_i2c_obj_t {
    mp_obj_base_t base;
    nrfx_twi_t p_twi;     // Driver instance
    uint32_t timeout;
    volatile bool xfer_done;
    volatile nrfx_twi_evt_type_t xfer_evt;
} machine_hard_i2c_obj_t;

static machine_hard_i2c_obj_t machine_hard_i2c_obj[] = {
    {{&machine_i2c_type}, .p_twi = NRFX_TWI_INSTANCE(0)},
    {{&machine_i2c_type}, .p_twi = NRFX_TWI_INSTANCE(1)},
};

void i2c_init0(void) {
}

static void twi_event_handler(nrfx_twi_evt_t const *p_event, void *p_context) {
    machine_hard_i2c_obj_t *self = (machine_hard_i2c_obj_t *)p_context;
    self->xfer_evt = p_event->type;
    self->xfer_done = true;
}

static int i2c_find(mp_obj_t id) {
    // given an integer id
    int i2c_id = mp_obj_get_int(id);
    if (i2c_id >= 0 && i2c_id < MP_ARRAY_SIZE(machine_hard_i2c_obj)) {
        return i2c_id;
    }
    mp_raise_ValueError(MP_ERROR_TEXT("I2C doesn't exist"));
}

static void machine_hard_i2c_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    machine_hard_i2c_obj_t *self = self_in;
    mp_printf(print, "I2C(%u, timeout=%u)", self->p_twi.drv_inst_idx, self->timeout);
}

/******************************************************************************/
/* MicroPython bindings for machine API                                       */

mp_obj_t machine_hard_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    MP_MACHINE_I2C_CHECK_FOR_LEGACY_SOFTI2C_CONSTRUCTION(n_args, n_kw, all_args);

    enum { ARG_id, ARG_scl, ARG_sda, ARG_freq, ARG_timeout };
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_id,       MP_ARG_REQUIRED | MP_ARG_OBJ },
        { MP_QSTR_scl,      MP_ARG_REQUIRED | MP_ARG_OBJ },
        { MP_QSTR_sda,      MP_ARG_REQUIRED | MP_ARG_OBJ },
        { MP_QSTR_freq,     MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
        { MP_QSTR_timeout,  MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 50000} },
    };

    // parse args
    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
    mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

    // get static peripheral object
    int i2c_id = i2c_find(args[ARG_id].u_obj);
    machine_hard_i2c_obj_t *self = &machine_hard_i2c_obj[i2c_id];

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

    nrfx_twi_config_t config;
    memset(&config, 0, sizeof(config));
    #if NRFX_TWI_ENABLED
    config.scl = mp_hal_get_pin_obj(args[ARG_scl].u_obj)->pin;
    config.sda = mp_hal_get_pin_obj(args[ARG_sda].u_obj)->pin;
    #else
    config.scl_pin = mp_hal_get_pin_obj(args[ARG_scl].u_obj)->pin;
    config.sda_pin = mp_hal_get_pin_obj(args[ARG_sda].u_obj)->pin;
    #endif

    int freq = NRF_TWI_FREQ_400K;
    if (args[ARG_freq].u_int != -1) {
        if (args[ARG_freq].u_int <= 150000) {
            freq = NRF_TWI_FREQ_100K;
        } else if (args[ARG_freq].u_int < 320000) {
            freq = NRF_TWI_FREQ_250K;
        }
    }
    config.frequency = freq;

    config.hold_bus_uninit = false;
    config.interrupt_priority = 6;

    // First reset the TWI
    nrfx_twi_uninit(&self->p_twi);

    // Set context to this object, use non-blocking mode with event handler.
    nrfx_twi_init(&self->p_twi, &config, twi_event_handler, (void *)self);

    return MP_OBJ_FROM_PTR(self);
}

int machine_hard_i2c_transfer_single(mp_obj_base_t *self_in, uint16_t addr, size_t len, uint8_t *buf, unsigned int flags) {
    machine_hard_i2c_obj_t *self = (machine_hard_i2c_obj_t *)self_in;

    nrfx_twi_enable(&self->p_twi);

    self->xfer_done = false;
    self->xfer_evt = NRFX_TWI_EVT_DONE;

    nrfx_err_t err_code;
    int transfer_ret = 0;
    if (flags & MP_MACHINE_I2C_FLAG_READ) {
        nrfx_twi_xfer_desc_t desc = NRFX_TWI_XFER_DESC_RX(addr, buf, len);
        err_code = nrfx_twi_xfer(&self->p_twi, &desc, 0);
    } else {
        nrfx_twi_xfer_desc_t desc = NRFX_TWI_XFER_DESC_TX(addr, buf, len);
        uint32_t xfer_flags = (flags & MP_MACHINE_I2C_FLAG_STOP) ? 0 : NRFX_TWI_FLAG_TX_NO_STOP;
        err_code = nrfx_twi_xfer(&self->p_twi, &desc, xfer_flags);
        transfer_ret = len;
    }

    // In non-blocking mode, ANACK/DNACK are delivered via the event handler.
    // These checks handle transfer start failures (e.g. bus busy).
    if (err_code != NRFX_SUCCESS) {
        nrfx_twi_disable(&self->p_twi);
        if (err_code == NRFX_ERROR_DRV_TWI_ERR_ANACK) {
            return -MP_ENODEV;
        } else if (err_code == NRFX_ERROR_DRV_TWI_ERR_DNACK) {
            return -MP_EIO;
        }
        return -MP_ETIMEDOUT;
    }

    // Poll until xfer_done (timeout=0 means wait forever).
    mp_uint_t start = mp_hal_ticks_us();
    while (!self->xfer_done) {
        if (self->timeout > 0 && (mp_hal_ticks_us() - start) >= self->timeout) {
            nrfx_twi_disable(&self->p_twi);
            nrfx_twi_enable(&self->p_twi);
            return -MP_ETIMEDOUT;
        }
        mp_event_wait_ms(1);
    }

    // Leave the peripheral SUSPENDED (enabled, bus held) after a NOSTOP TX
    // so the next xfer issues a repeated START. Disabling would release SDA.
    if (flags & (MP_MACHINE_I2C_FLAG_READ | MP_MACHINE_I2C_FLAG_STOP)) {
        nrfx_twi_disable(&self->p_twi);
    }

    if (self->xfer_evt == NRFX_TWI_EVT_ADDRESS_NACK) {
        return -MP_ENODEV;
    } else if (self->xfer_evt == NRFX_TWI_EVT_DATA_NACK) {
        return -MP_EIO;
    } else if (self->xfer_evt != NRFX_TWI_EVT_DONE) {
        return -MP_EIO;
    }

    return transfer_ret;
}

static const mp_machine_i2c_p_t machine_hard_i2c_p = {
    .transfer = mp_machine_i2c_transfer_adaptor,
    .transfer_single = machine_hard_i2c_transfer_single,
};

MP_DEFINE_CONST_OBJ_TYPE(
    machine_i2c_type,
    MP_QSTR_I2C,
    MP_TYPE_FLAG_NONE,
    make_new, machine_hard_i2c_make_new,
    print, machine_hard_i2c_print,
    protocol, &machine_hard_i2c_p,
    locals_dict, &mp_machine_i2c_locals_dict
    );

#endif // MICROPY_PY_MACHINE_I2C
