/*
 * Copyright (C) OpenTX
 *
 * Based on code named
 *   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.
 */

#include "opentx.h"

Fifo<uint8_t, 64> btTxFifo;
Fifo<uint8_t, 64> btRxFifo;

#if defined(PCBX7) || defined(PCBXLITE)
volatile uint8_t btChipPresent = 0;
#endif

enum BluetoothWriteState
{
  BLUETOOTH_WRITE_IDLE,
  BLUETOOTH_WRITE_INIT,
  BLUETOOTH_WRITING,
  BLUETOOTH_WRITE_DONE
};

volatile uint8_t bluetoothWriteState = BLUETOOTH_WRITE_IDLE;

void bluetoothInit(uint32_t baudrate)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  GPIO_InitStructure.GPIO_Pin = BT_EN_GPIO_PIN;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
  GPIO_Init(BT_EN_GPIO, &GPIO_InitStructure);

#if defined(BT_BRTS_GPIO_PIN)
  GPIO_InitStructure.GPIO_Pin = BT_BRTS_GPIO_PIN;
  GPIO_Init(BT_BRTS_GPIO, &GPIO_InitStructure);
  GPIO_SetBits(BT_BRTS_GPIO, BT_BRTS_GPIO_PIN);
#endif

#if defined(BT_BCTS_GPIO_PIN)
  GPIO_InitStructure.GPIO_Pin = BT_BCTS_GPIO_PIN;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_Init(BT_BCTS_GPIO, &GPIO_InitStructure);
#endif

  GPIO_PinAFConfig(BT_GPIO_TXRX, BT_TX_GPIO_PinSource, BT_GPIO_AF);
  GPIO_PinAFConfig(BT_GPIO_TXRX, BT_RX_GPIO_PinSource, BT_GPIO_AF);

  GPIO_InitStructure.GPIO_Pin = BT_TX_GPIO_PIN | BT_RX_GPIO_PIN;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(BT_GPIO_TXRX, &GPIO_InitStructure);

  USART_DeInit(BT_USART);
  USART_InitTypeDef USART_InitStructure;
  USART_InitStructure.USART_BaudRate = baudrate;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
  USART_Init(BT_USART, &USART_InitStructure);
  USART_Cmd(BT_USART, ENABLE);

  USART_ITConfig(BT_USART, USART_IT_RXNE, ENABLE);
  NVIC_SetPriority(BT_USART_IRQn, 6);
  NVIC_EnableIRQ(BT_USART_IRQn);

  btRxFifo.clear();
  btTxFifo.clear();
  bluetoothWriteState = BLUETOOTH_WRITE_IDLE;

  GPIO_ResetBits(BT_EN_GPIO, BT_EN_GPIO_PIN); // open bluetooth
}

void bluetoothDone()
{
  GPIO_SetBits(BT_EN_GPIO, BT_EN_GPIO_PIN); // close bluetooth
}

extern "C" void BT_USART_IRQHandler(void)
{
  DEBUG_INTERRUPT(INT_BLUETOOTH);
  if (USART_GetITStatus(BT_USART, USART_IT_RXNE) != RESET) {
    USART_ClearITPendingBit(BT_USART, USART_IT_RXNE);
    uint8_t byte = USART_ReceiveData(BT_USART);
    btRxFifo.push(byte);
#if defined(PCBX7) || defined(PCBXLITE)
    if (!btChipPresent) {
      // This is to differentiate X7 and X7S and X-Lite with/without BT
      btChipPresent = 1;
      bluetoothDone();
    }
#endif
  }

  if (USART_GetITStatus(BT_USART, USART_IT_TXE) != RESET) {
    uint8_t byte;
    bool result = btTxFifo.pop(byte);
    if (result) {
      USART_SendData(BT_USART, byte);
    }
    else {
      USART_ITConfig(BT_USART, USART_IT_TXE, DISABLE);
      bluetoothWriteState = BLUETOOTH_WRITE_DONE;
    }
  }
}

void bluetoothWriteWakeup(void)
{
  if (bluetoothWriteState == BLUETOOTH_WRITE_IDLE) {
    if (!btTxFifo.isEmpty()) {
      bluetoothWriteState = BLUETOOTH_WRITE_INIT;
#if defined(BT_BRTS_GPIO_PIN)
      GPIO_ResetBits(BT_BRTS_GPIO, BT_BRTS_GPIO_PIN);
#endif
    }
  }
  else if (bluetoothWriteState == BLUETOOTH_WRITE_INIT) {
    bluetoothWriteState = BLUETOOTH_WRITING;
    USART_ITConfig(BT_USART, USART_IT_TXE, ENABLE);
  }
  else if (bluetoothWriteState == BLUETOOTH_WRITE_DONE) {
    bluetoothWriteState = BLUETOOTH_WRITE_IDLE;
#if defined(BT_BRTS_GPIO_PIN)
    GPIO_SetBits(BT_BRTS_GPIO, BT_BRTS_GPIO_PIN);
#endif
  }
}

uint8_t bluetoothIsWriting(void)
{
  return bluetoothWriteState != BLUETOOTH_WRITE_IDLE;
}