/* 
  ESP8266WebServer.cpp - Dead simple web-server.
  Supports only one simultaneous client, knows how to handle GET and POST.

  Copyright (c) 2014 Ivan Grokhotkov. All rights reserved.
 
  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/


#include <Arduino.h>
#include "WiFiServer.h"
#include "WiFiClient.h"
#include "ESP8266WebServer.h"

// #define DEBUG

struct ESP8266WebServer::RequestHandler {
  RequestHandler(ESP8266WebServer::THandlerFunction fn, const char* uri, HTTPMethod method)
  : fn(fn)
  , uri(uri)
  , method(method)
  , next(NULL)
  {
  }

  ESP8266WebServer::THandlerFunction fn;
  String uri;
  HTTPMethod method;
  RequestHandler* next;

};

ESP8266WebServer::ESP8266WebServer(int port)
: _server(port)
, _firstHandler(0)
, _lastHandler(0)
, _currentArgCount(0)
, _currentArgs(0)
{
}

ESP8266WebServer::~ESP8266WebServer()
{
  if (!_firstHandler)
    return;
  RequestHandler* handler = _firstHandler;
  while (handler) {
    RequestHandler* next = handler->next;
    delete handler;
    handler = next;
  }
}

void ESP8266WebServer::begin() {
  _server.begin();
}


void ESP8266WebServer::on(const char* uri, ESP8266WebServer::THandlerFunction handler)
{
  on(uri, HTTP_ANY, handler);
}

void ESP8266WebServer::on(const char* uri, HTTPMethod method, ESP8266WebServer::THandlerFunction fn)
{
  RequestHandler* handler = new RequestHandler(fn, uri, method);
  if (!_lastHandler) {
    _firstHandler = handler;
    _lastHandler = handler;
  }
  else {
    _lastHandler->next = handler;
    _lastHandler = handler;
  }
}

void ESP8266WebServer::handleClient()
{
  WiFiClient client = _server.available();
  if (!client) {
    return;
  }

#ifdef DEBUG
  Serial.println("New client");
#endif
  // Wait for data from client to become available
  while(client.connected() && !client.available()){
    delay(1);
  }

  // Read the first line of HTTP request
  String req = client.readStringUntil('\r');
  client.readStringUntil('\n');

  HTTPMethod method = HTTP_GET;
  if (req.startsWith("POST")) {
    method = HTTP_POST;
  }

  // First line of HTTP request looks like "GET /path HTTP/1.1"
  // Retrieve the "/path" part by finding the spaces
  int addr_start = req.indexOf(' ');
  int addr_end = req.indexOf(' ', addr_start + 1);
  if (addr_start == -1 || addr_end == -1) {
#ifdef DEBUG
    Serial.print("Invalid request: ");
    Serial.println(req);
#endif
    return;
  }

  req = req.substring(addr_start + 1, addr_end);

  String formData;
  if (method == HTTP_POST) {
    int contentLength = -1;
    int headerCount = 0;
    while(headerCount < 1024) { // there shouldn't be that much really
      String line = client.readStringUntil('\r');
      client.readStringUntil('\n');

      if (line.length() > 0) {  // this is a header
        ++headerCount;
        if (contentLength < 0 && line.startsWith("Content-Length")) {
          // get content length from the header
          int valuePos = line.indexOf(' ', 14);
          if (valuePos > 0) {
            String valueStr = line.substring(valuePos+1);
            contentLength = valueStr.toInt();
#ifdef DEBUG
            Serial.print("Content-Length: ");
            Serial.println(contentLength);
#endif
          }
        }
      }
      else {
        break;
      }
    }
#ifdef DEBUG
    Serial.print("headerCount=");
    Serial.println(headerCount);
#endif
    if (contentLength >= 0) {
      formData = "";
      int n = 0;   // timeout counter
      while (formData.length() < contentLength && ++n < 3)
        formData += client.readString();
    }
    else {
      formData = client.readStringUntil('\r'); // will return after timing out once
    }
  }
  else if (method == HTTP_GET) {
    int args_start = req.indexOf('?');
    if (args_start != -1) {
      formData = req.substring(args_start + 1);
      req = req.substring(0, args_start);
    }
  }

  client.flush();

#ifdef DEBUG
  Serial.print("Request: ");
  Serial.println(req);
  Serial.print("Args: ");
  Serial.println(formData);
#endif

  _parseArguments(formData);
  _handleRequest(client, req, method);

}

void ESP8266WebServer::send(int code, const char* content_type, String content) {
  String response = "HTTP/1.1 ";
  response += String(code);
  response += " ";
  response += _responseCodeToString(code);
  response += "\r\n";

  if (!content_type)
    content_type = "text/html";
  _appendHeader(response, "Content-Type", content_type);
  
  response += "\r\n";
  response += content;
  _currentClient.print(response);
}

String ESP8266WebServer::arg(const char* name) {
  for (int i = 0; i < _currentArgCount; ++i) {
    if (_currentArgs[i].key == name)
      return _currentArgs[i].value;
  }
  return String();
}

String ESP8266WebServer::arg(int i) {
  if (i < _currentArgCount)
    return _currentArgs[i].value;
  return String();
}

String ESP8266WebServer::argName(int i) {
  if (i < _currentArgCount)
    return _currentArgs[i].key;
  return String();
}

int ESP8266WebServer::args() {
  return _currentArgCount;
}

bool ESP8266WebServer::hasArg(const char* name) {
  for (int i = 0; i < _currentArgCount; ++i) {
    if (_currentArgs[i].key == name)
      return true;
  }
  return false;
}

void ESP8266WebServer::_parseArguments(String data) {
  if (_currentArgs)
    delete[] _currentArgs;
  _currentArgs = 0;
  if (data.length() == 0) {
    _currentArgCount = 0;
    return;
  }
  _currentArgCount = 1;

  for (int i = 0; i < data.length(); ) {
    i = data.indexOf('&', i);
    if (i == -1)
      break;
    ++i;
    ++_currentArgCount;
  }
#ifdef DEBUG
  Serial.print("args count: ");
  Serial.println(_currentArgCount);
#endif

  _currentArgs = new RequestArgument[_currentArgCount];
  int pos = 0;
  int iarg;
  for (iarg = 0; iarg < _currentArgCount;) {
    int equal_sign_index = data.indexOf('=', pos);
    int next_arg_index = data.indexOf('&', pos);
#ifdef DEBUG
    Serial.print("pos ");
    Serial.print(pos);
    Serial.print("=@ ");
    Serial.print(equal_sign_index);
    Serial.print(" &@ ");
    Serial.println(next_arg_index);
#endif
    if ((equal_sign_index == -1) || ((equal_sign_index > next_arg_index) && (next_arg_index != -1))) {
#ifdef DEBUG
      Serial.print("arg missing value: ");
      Serial.println(iarg);
#endif
      if (next_arg_index == -1)
        break;
      pos = next_arg_index + 1;
      continue;
    }
    RequestArgument& arg = _currentArgs[iarg];
    arg.key = data.substring(pos, equal_sign_index);
    arg.value = data.substring(equal_sign_index + 1, next_arg_index);
#ifdef DEBUG
    Serial.print("arg ");
    Serial.print(iarg);
    Serial.print(" key: ");
    Serial.print(arg.key);
    Serial.print(" value: ");
    Serial.println(arg.value);
#endif
    ++iarg;
    if (next_arg_index == -1)
      break;
    pos = next_arg_index + 1;
  }
  _currentArgCount = iarg;
#ifdef DEBUG
  Serial.print("args count: ");
  Serial.println(_currentArgCount);
#endif

}

void ESP8266WebServer::onNotFound(THandlerFunction fn) {
  _notFoundHandler = fn;
}

void ESP8266WebServer::_handleRequest(WiFiClient& client, String uri, HTTPMethod method) {
  _currentClient   = client;
  _currentUri      = uri;
  _currentMethod   = method;

  RequestHandler* handler;
  for (handler = _firstHandler; handler; handler = handler->next)
  {
    if (handler->method != HTTP_ANY && handler->method != method)
      continue;

    if (handler->uri != uri)
      continue;

    handler->fn();
    break;
  }

  if (!handler){
#ifdef DEBUG
    Serial.println("request handler not found");
#endif

    if(_notFoundHandler) {
      _notFoundHandler();
    }
    else {
      send(404, "text/plain", String("Not found: ") + uri);
    }
  }

  _currentClient   = WiFiClient();
  _currentUri      = String();
  
}

const char* ESP8266WebServer::_responseCodeToString(int code) {
  switch (code) {
    case 200: return "OK";
    case 404: return "Not found";
    default:  return "";
  }
}

void ESP8266WebServer::_appendHeader(String& response, const char* name, const char* value) {
  response += name;
  response += ": ";
  response += value;
  response += "\r\n";
}