/*
 * Copyright (C) EdgeTx
 *
 * Based on code named
 *   opentx - https://github.com/opentx/opentx
 *   th9x - http://code.google.com/p/th9x
 *   er9x - http://code.google.com/p/er9x
 *   gruvin9x - http://code.google.com/p/gruvin9x
 *
 * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#pragma once

#include <stdint.h>


enum SerialEncoding {
  ETX_Encoding_8N1,
  ETX_Encoding_8E2,
  ETX_Encoding_PXX1_PWM,
};

enum SerialDirection {
  ETX_Dir_None = 0,
  ETX_Dir_RX = 1,
  ETX_Dir_TX = 2,
  ETX_Dir_TX_RX = 3,
};

enum SerialPolarity {
  ETX_Pol_Normal,
  ETX_Pol_Inverted,
};

typedef struct {
  uint32_t baudrate;    // = 0;
  uint8_t encoding;     // = ETX_Encoding_8N1;
  uint8_t direction;    // = ETX_Dir_None;
  uint8_t polarity;     // = ETX_Pol_Normal;
} etx_serial_init;

// TODO: move somewhere else
struct etx_serial_callbacks_t {
  uint8_t (*on_send)(uint8_t* data);
  void (*on_receive)(uint8_t data);

  void* on_idle_ctx;
  void (*on_idle)(void* ctx);

  void (*on_error)();
};

enum SerialHWOption {
  ETX_HWOption_OVER8,  // oversampling by 8
  ETX_HWOption_ONEBIT, // one-bit sampling
};

typedef struct {

  // Init serial communication
  void* (*init)(void* hw_def, const etx_serial_init* params);

  // De-Init serial communication
  void (*deinit)(void* ctx);

  // Send a single byte
  void (*sendByte)(void* ctx, uint8_t byte);

  // Send a buffer
  void (*sendBuffer)(void* ctx, const uint8_t* data, uint32_t size);

  // Is TX phase completed
  uint8_t (*txCompleted)(void* ctx);
  
  // Wait for last send operation to complete
  void (*waitForTxCompleted)(void* ctx);
  
  // 2-wire half-duplex
  void (*enableRx)(void* ctx);
  
  // Fetch next available byte from internal buffer
  int (*getByte)(void* ctx, uint8_t* data);

  // Fetch a byte by its index from the end of the buffer
  int (*getLastByte)(void* ctx, uint32_t idx, uint8_t* data);

  // Return the number of unread bytes
  int (*getBufferedBytes)(void* ctx);

  int (*copyRxBuffer)(void* ctx, uint8_t* buf, uint32_t len);

  // Clear internal buffer
  void (*clearRxBuffer)(void* ctx);

  // Get current baudrate
  uint32_t (*getBaudrate)(void*);

  // Set baudrate
  void (*setBaudrate)(void*, uint32_t baudrate);

  // Configure inverter
  void (*setPolarity)(void*, uint8_t polarity);
  
  // Set a HW specific option (SerialHWOption; possibly unsupported by the driver)
  void (*setHWOption)(void*, uint32_t option);
  
  // Callbacks
  void (*setReceiveCb)(void* ctx, void (*on_receive)(uint8_t*, uint32_t));
  void (*setIdleCb)(void* ctx, void (*on_idle)(void*), void* param);
  void (*setBaudrateCb)(void* ctx, void (*on_set_baudrate)(uint32_t));

} etx_serial_driver_t;