/**
 * Marlin 3D Printer Firmware
 * Copyright (C) 2019 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
#ifdef ARDUINO_ARCH_ESP32

#include "../../inc/MarlinConfig.h"

#if ENABLED(WIFISUPPORT)

#include "WebSocketSerial.h"

extern WebSocketSerial webSocketSerial;

#include "wifi.h"
#include <AsyncTCP.h>
#include <ESPAsyncWebServer.h>

struct ring_buffer_r {
  unsigned char buffer[RX_BUFFER_SIZE];
  volatile ring_buffer_pos_t head, tail;
};

struct ring_buffer_t {
  unsigned char buffer[256];
  volatile uint8_t head, tail;
};

ring_buffer_r rx_buffer = { { 0 }, 0, 0 };
ring_buffer_t tx_buffer = { { 0 }, 0, 0 };

static bool _written;

#if ENABLED(EMERGENCY_PARSER)
  static EmergencyParser::State emergency_state; // = EP_RESET
#endif

AsyncWebSocket ws("/ws"); // access at ws://[esp ip]/ws

FORCE_INLINE int next_rx_index(const int i) { return (ring_buffer_pos_t)(i + 1) & (ring_buffer_pos_t)(RX_BUFFER_SIZE - 1); }
FORCE_INLINE int next_tx_index(const int i) { return (ring_buffer_pos_t)(i + 1) & (ring_buffer_pos_t)(TX_BUFFER_SIZE - 1); }

static void addToBuffer(uint8_t * const data, const size_t len) {
  for (size_t i = 0; i < len; i++) {
    ring_buffer_pos_t h = rx_buffer.head;
    const ring_buffer_pos_t t = rx_buffer.tail, n = next_rx_index(h);

    if (n != t) { rx_buffer.buffer[h] = data[i]; h = n; }

    // TODO: buffer is full, handle?

    rx_buffer.head = h;
  }
}

// Handle WebSocket event
static void onEvent(AsyncWebSocket * server, AsyncWebSocketClient * client, AwsEventType type, void * arg, uint8_t *data, size_t len) {
  switch (type) {
    case WS_EVT_CONNECT: client->ping(); break; // client connected
    case WS_EVT_DISCONNECT:                     // client disconnected
    case WS_EVT_ERROR:                          // error was received from the other end
    case WS_EVT_PONG: break;                    // pong message was received (in response to a ping request maybe)
    case WS_EVT_DATA: {                         // data packet
      AwsFrameInfo * info = (AwsFrameInfo*)arg;
      if (info->opcode == WS_TEXT || info->message_opcode == WS_TEXT)
        addToBuffer(data, len);
    }
  }
}

// Public Methods
void WebSocketSerial::begin(const long baud_setting) {
  ws.onEvent(onEvent);
  server.addHandler(&ws); // attach AsyncWebSocket
}

void WebSocketSerial::end() { }

int WebSocketSerial::peek(void) {
  const int v = rx_buffer.head == rx_buffer.tail ? -1 : rx_buffer.buffer[rx_buffer.tail];
  return v;
}

int WebSocketSerial::read(void) {
  const ring_buffer_pos_t h = rx_buffer.head, t = rx_buffer.tail;
  if (h == t) return -1;  // Nothing to read? Return now

  const int v = rx_buffer.buffer[t];

  rx_buffer.tail = (ring_buffer_pos_t)(t + 1) & (RX_BUFFER_SIZE - 1); // Advance tail

  return v;
}

bool WebSocketSerial::available(void) {
  const ring_buffer_pos_t h = rx_buffer.head, t = rx_buffer.tail;
  return (ring_buffer_pos_t)(RX_BUFFER_SIZE + h - t) & (RX_BUFFER_SIZE - 1);
}

void WebSocketSerial::flush(void) {
  ws.textAll("flush");
  rx_buffer.tail = rx_buffer.head;
}

#if TX_BUFFER_SIZE

  void WebSocketSerial::write(const uint8_t c) {
    _written = true;

    const uint8_t i = (tx_buffer.head + 1) & (TX_BUFFER_SIZE - 1);

    // Store new char. head is always safe to move
    tx_buffer.buffer[tx_buffer.head] = c;
    tx_buffer.head = i;

    if (c == '\n') {
      ws.textAll(tx_buffer.buffer, tx_buffer.head);
      tx_buffer.head = 0;
    }
  }

  void WebSocketSerial::flushTx(void) {
    ws.textAll("flushTx");
    if (!_written) return;
  }

#else

 //void WebSocketSerial::write(const uint8_t c) { _written = true; }
 //void WebSocketSerial::flushTx(void) { if (!_written) return; }

#endif

/**
 * Imports from print.h
 */

void WebSocketSerial::print(char c, int base) { print((long)c, base); }
void WebSocketSerial::print(unsigned char b, int base) { print((unsigned long)b, base); }
void WebSocketSerial::print(int n, int base) { print((long)n, base); }
void WebSocketSerial::print(unsigned int n, int base) { print((unsigned long)n, base); }
void WebSocketSerial::print(long n, int base) {
  if (base == 0)
    write(n);
  else if (base == 10) {
    if (n < 0) { print('-'); n = -n; }
    printNumber(n, 10);
  }
  else
    printNumber(n, base);
}

void WebSocketSerial::print(unsigned long n, int base) {
  if (base == 0) write(n); else printNumber(n, base);
}

void WebSocketSerial::print(double n, int digits)         { printFloat(n, digits); }

void WebSocketSerial::println(void)                       { print('\r'); print('\n'); }
void WebSocketSerial::println(const String& s)            { print(s); println(); }
void WebSocketSerial::println(const char c[])             { print(c); println(); }
void WebSocketSerial::println(char c, int base)           { print(c, base); println(); }
void WebSocketSerial::println(unsigned char b, int base)  { print(b, base); println(); }
void WebSocketSerial::println(int n, int base)            { print(n, base); println(); }
void WebSocketSerial::println(unsigned int n, int base)   { print(n, base); println(); }
void WebSocketSerial::println(long n, int base)           { print(n, base); println(); }
void WebSocketSerial::println(unsigned long n, int base)  { print(n, base); println(); }
void WebSocketSerial::println(double n, int digits)       { print(n, digits); println(); }

// Private Methods

void WebSocketSerial::printNumber(unsigned long n, uint8_t base) {
  if (n) {
    unsigned char buf[8 * sizeof(long)]; // Enough space for base 2
    int8_t i = 0;
    while (n) {
      buf[i++] = n % base;
      n /= base;
    }
    while (i--)
      print((char)(buf[i] + (buf[i] < 10 ? '0' : 'A' - 10)));
  }
  else
    print('0');
}

void WebSocketSerial::printFloat(double number, uint8_t digits) {
  // Handle negative numbers
  if (number < 0.0) { print('-'); number = -number; }

  // Round correctly so that print(1.999, 2) prints as "2.00"
  // Use a lookup table for performance
  constexpr double rounds[] = { 0.5, 0.05, 0.005, 0.0005, 0.00005, 0.000005, 0.0000005, 0.00000005 };
  number += rounds[digits];

  //number += pow(10, -(digits + 1)); // slower single-line equivalent

  // Extract the integer part of the number and print it
  unsigned long int_part = (unsigned long)number;
  print(int_part);

  // Print the decimal point, but only if there are digits beyond
  double remainder = number - (double)int_part;
  if (digits) {
    print('.');
    // Extract digits from the remainder one at a time
    while (digits--) {
      remainder *= 10.0;
      const int toPrint = int(remainder);
      print(toPrint);
      remainder -= toPrint;
    }
  }
}

#endif // WIFISUPPORT
#endif // ARDUINO_ARCH_ESP32