#include <sys/types.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <getopt.h>
#include <unistd.h>
#include <microhttpd.h>
#include <iostream>
#include <string>
#include <iostream>
#include <sstream>
#include <zim/zim.h>
#include <zim/file.h>
#include <zim/article.h>
#include <zim/fileiterator.h>
#include <pthread.h>
#include <regex.h>
#include <kiwix/reader.h>
#include <kiwix/searcher.h>

using namespace std;

static const string HTMLScripts = " \
<style type=\"text/css\"> \n \
\n \
#topbar{ \n \
//  position: absolute; \n \
//  right: 0%; \n \
  border: 1px solid #BBBBBB; \n \
  border-radius: 5px; \n \
  -moz-border-radius: 5px; \n \
  -webkit-border-radius: 5px; \n \
//  margin-top: 0px; \n \
//  margin-right: 5px;  \n \
  margin: 5px;  \n \
  padding: 5px; \n \
  background: #FFFFFF; \n \
//  visibility: hidden; \n \
//  z-index: 100; \n \
} \n \
\n \
</style> \n \
<script type=\"text/javascript\"> \n \
var persistclose=0 //set to 0 or 1. 1 means once the bar is manually closed, it will remain closed for browser session \n \
//var startX = 30 //set x offset of bar in pixels \n \
var startY = 5 //set y offset of bar in pixels \n \
var verticalpos=\"fromtop\" //enter \"fromtop\" or \"frombottom\" \n \
 \n \
function iecompattest(){ \n \
  return (document.compatMode && document.compatMode!=\"BackCompat\")? document.documentElement : document.body \n \
} \n \
\n \
function staticbar(){ \n \
  barheight=document.getElementById(\"topbar\").offsetHeight \n \
  var ns = (navigator.appName.indexOf(\"Netscape\") != -1) || window.opera; \n \
  var d = document; \n \
  \n \
  function ml(id){ \n \
    var el=d.getElementById(id); \n \
    if (!persistclose || persistclose && get_cookie(\"remainclosed\")==\"\") \n \
      el.style.visibility=\"visible\" \n \
    if(d.layers) \n \
      el.style=el; \n \
    el.sP=function(x,y) { \n \
      this.style.left=x+\"px\"; \n \
      this.style.top=y+\"px\"; \n \
    }; \n \
    el.x = window.innerWidth - el.width - 5; \n \
    if (verticalpos==\"fromtop\") \n \
      el.y = startY; \n \
    else{ \n \
      el.y = ns ? pageYOffset + innerHeight : iecompattest().scrollTop + iecompattest().clientHeight; \n \
      el.y -= startY; \n \
    } \n \
    return el; \n \
  } \n \
  window.stayTopLeft=function(){ \n \
  if (verticalpos==\"fromtop\"){ \n \
    var pY = ns ? pageYOffset : iecompattest().scrollTop; \n \
    ftlObj.y += (pY + startY - ftlObj.y)/8; \n \
  } \n \
  else{ \n \
    var pY = ns ? pageYOffset + innerHeight - barheight: iecompattest().scrollTop + iecompattest().clientHeight - barheight; \n \
    ftlObj.y += (pY - startY - ftlObj.y)/8; \n \
  } \n \
  ftlObj.sP(ftlObj.x, ftlObj.y); \n \
  setTimeout(\"stayTopLeft()\", 10); \n \
} \n \
ftlObj = ml(\"topbar\"); \n \
stayTopLeft(); \n \
} \n \
\n \
/* if (window.addEventListener) \n \
  window.addEventListener(\"load\", staticbar, false) \n \
else if (window.attachEvent) \n \
  window.attachEvent(\"onload\", staticbar) \n \
else if (document.getElementById) \n \
  window.onload=staticbar */\n	     \
</script> \n \
";

static const string HTMLDiv = " \
<div id=\"topbar\"><form method=\"GET\" action=\"/search\"><input type=\"textbox\" name=\"pattern\" /><input type=\"submit\" value=\"Search\" /></form></div> \n \
";

static bool verboseFlag = false;
static kiwix::Reader* reader;
static kiwix::Searcher* searcher;
static pthread_mutex_t readerLock = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t searcherLock = PTHREAD_MUTEX_INITIALIZER;
static bool hasSearchIndex = false;

static void appendToFirstOccurence(string &content, const string regex, const string &replacement) {
  regmatch_t matchs[1];
  regex_t regexp;

  regcomp(&regexp, regex.data(), REG_ICASE);
  if (!regexec(&regexp, content.data(), 1, matchs, 0)) {
    if (matchs[0].rm_so > 0)
      content.insert(matchs[0].rm_eo, replacement);
  }

  regfree(&regexp);
}

static char charFromHex(std::string a) {
  std::istringstream Blat (a);
  int Z;
  Blat >> std::hex >> Z;
  return char (Z);
}

static void unescapeUrl(string &url) {
  std::string::size_type pos;
  std::string hex;
  while (std::string::npos != (pos = url.find('%'))) {
      hex = url.substr(pos + 1, 2);
      url.replace(pos, 3, 1, charFromHex(hex));
  }
  return;
}

static int accessHandlerCallback(void *cls,
				 struct MHD_Connection * connection,
				 const char * url,
				 const char * method,
				 const char * version,
				 const char * upload_data,
				 size_t * upload_data_size,
				 void ** ptr) {

  /* Unexpected method */
  if (0 != strcmp(method, "GET"))
    return MHD_NO;
  
  /* The first time only the headers are valid, do not respond in the first round... */
  static int dummy;
  if (&dummy != *ptr) {
    *ptr = &dummy;
    return MHD_YES;
  }

  /* Prepare the variables */
  struct MHD_Response *response;
  string content = "";
  string mimeType = "";
  unsigned int contentLength = 0;

  if (!strcmp(url, "/search") && hasSearchIndex) {
    const char* pattern = MHD_lookup_connection_value(connection, MHD_GET_ARGUMENT_KIND, "pattern");
    std::string urlStr;
    std::string titleStr;
    unsigned int scoreInt;
    char scoreStr[4];

    /* Mutex lock */
    pthread_mutex_lock(&searcherLock);

    searcher->search(pattern, 30);
    content = "<html><head><title>Kiwix search results</title></head><body><h1>Results</h1><hr/><ol>\n";
    while (searcher->getNextResult(urlStr, titleStr, scoreInt)) {
      sprintf(scoreStr, "%d", scoreInt);
      content += "<li><a href=\"" + urlStr + "\">" + titleStr+ "</a> - " + scoreStr + "%</li>\n";

    }
    content += "</ol></body></html>\n";

    mimeType = "text/html; charset=utf-8";
    contentLength = content.size();

    /* Mutex unlock */
    pthread_mutex_unlock(&searcherLock);

  } else {
    
    /* urlstr */
    std::string urlStr = string(url);
    unescapeUrl(urlStr);

    /* Mutex Lock */
    pthread_mutex_lock(&readerLock);
    
    /* Load the article from the ZIM file */
    if (verboseFlag)
      cout << "Loading '" << urlStr << "'... " << endl;

    try {
      reader->getContent(urlStr, content, contentLength, mimeType);

      if (verboseFlag) {
	cout << "content size: " << contentLength << endl;
	cout << "mimeType: " << mimeType << endl;
      }
    } catch (const std::exception& e) {
      std::cerr << e.what() << std::endl;
    }
    
    /* Mutex unlock */
    pthread_mutex_unlock(&readerLock);
  }
  
  /* Rewrite the content (add the search box) */
  if (hasSearchIndex && mimeType.find("text/html") != string::npos) {
    appendToFirstOccurence(content, "<head>", HTMLScripts);
    appendToFirstOccurence(content, "<body[^>]*>", HTMLDiv);
    contentLength = content.size();
  }

  /* clear context pointer */
  *ptr = NULL;
  
  /* Create the response */
  response = MHD_create_response_from_data(contentLength,
					   (void *)content.data(),
					   MHD_NO,
					   MHD_YES);

  /* Specify the mime type */
  MHD_add_response_header(response, "Content-Type", mimeType.c_str());

  /* Queue the response */
  int ret = MHD_queue_response(connection,
			   MHD_HTTP_OK,
			   response);
  MHD_destroy_response(response);

  return ret;
}

int main(int argc, char **argv) {
  struct MHD_Daemon *daemon;
  string zimPath = "";

  string indexPath = "";
  int serverPort = 80;
  int daemonFlag = false;

  /* Argument parsing */
  while (42) {

    static struct option long_options[] = {
      {"daemon", no_argument, 0, 'd'},
      {"verbose", no_argument, 0, 'v'},
      {"index", required_argument, 0, 'i'},
      {"port", required_argument, 0, 'p'},
      {0, 0, 0, 0}
    };
    
    int option_index = 0;
    int c = getopt_long(argc, argv, "dvi:p:", long_options, &option_index);

    if (c != -1) {

      switch (c) {
	
      case 'd':
	daemonFlag = true;
	break;
	
      case 'v':
	verboseFlag = true;
	break;
	
      case 'i':
	indexPath = optarg;
	break;
	
      case 'p':
	serverPort = atoi(optarg);
	break;
	
      }
    } else {
      if (optind < argc) {
	zimPath = argv[optind++];
	break;
      }
    }

  }

  /* Print usage)) if necessary */
  if (zimPath == "") {
    cerr << "Usage: kiwix-serve [--index=ZIM_PATH] [--port=PORT] [--verbose] [--daemon] ZIM_PATH" << endl;
    exit(1);
  }
  
  void *page;

  /* Instanciate the ZIM file handler */
  try {
    reader = new kiwix::Reader(zimPath);
  } catch (...) {
    cerr << "Unable to open the ZIM file '" << zimPath << "'." << endl; 
    exit(1);
  }

  /* Instanciate the ZIM index (if necessary) */
  if (indexPath != "") {
    try {
      searcher = new kiwix::Searcher(indexPath);
      hasSearchIndex = true;
    } catch (...) {
      cerr << "Unable to open the search index '" << zimPath << "'." << endl; 
      exit(1);
    }
  } else {
    hasSearchIndex = false;
  }

  /* Fork if necessary */
  if (daemonFlag) {
    pid_t pid;
    
    /* Fork off the parent process */       
    pid = fork();
    if (pid < 0) {
      exit(1);
    }
    /* If we got a good PID, then
       we can exit the parent process. */
    if (pid > 0) {
      exit(0);
    }
  }

  /* Mutex init */
  pthread_mutex_init(&readerLock, NULL);
  pthread_mutex_init(&searcherLock, NULL);

  /* Start the HTTP daemon */
  daemon = MHD_start_daemon(MHD_USE_THREAD_PER_CONNECTION,
			    serverPort,
			    NULL,
			    NULL,
			    &accessHandlerCallback,
			    page,
			    MHD_OPTION_END);
  
  if (daemon == NULL) {
    cerr << "Unable to instanciate the HTTP daemon."<< endl;
    exit(1);
  }

  /* Run endless */
  while (42) sleep(1);
  
  /* Stop the daemon */
  MHD_stop_daemon(daemon);

  /* Mutex destroy */
  pthread_mutex_destroy(&readerLock);
  pthread_mutex_destroy(&searcherLock);

  exit(0);
}