var startTime = Date.now();
var fs = require("fs");
var ueberDB = require("../src/node_modules/ueberDB");
var mysql = require("../src/node_modules/ueberDB/node_modules/mysql");
var async = require("../src/node_modules/async");
var Changeset = require("ep_etherpad-lite/static/js/Changeset");
var randomString = require('ep_etherpad-lite/static/js/pad_utils').randomString;
var AttributePool = require("ep_etherpad-lite/static/js/AttributePool");

var settingsFile = process.argv[2];
var sqlOutputFile = process.argv[3];

//stop if the settings file is not set
if(!settingsFile || !sqlOutputFile)
{
  console.error("Use: node convert.js $SETTINGSFILE $SQLOUTPUT");
  process.exit(1);
}

log("read settings file...");
//read the settings file and parse the json
var settings = JSON.parse(fs.readFileSync(settingsFile, "utf8"));
log("done");

log("open output file...");
var sqlOutput = fs.openSync(sqlOutputFile, "w");
var sql = "SET CHARACTER SET UTF8;\n" +
          "CREATE TABLE IF NOT EXISTS `store` ( \n" +
          "`key` VARCHAR( 100 ) NOT NULL , \n" + 
          "`value` LONGTEXT NOT NULL , \n" + 
          "PRIMARY KEY (  `key` ) \n" +
          ") ENGINE = INNODB;\n" + 
          "START TRANSACTION;\n\n";
fs.writeSync(sqlOutput, sql);
log("done");

var etherpadDB = mysql.createConnection({
  host     : settings.etherpadDB.host,
  user     : settings.etherpadDB.user,
  password : settings.etherpadDB.password,
  database : settings.etherpadDB.database,
  port     : settings.etherpadDB.port
});

//get the timestamp once
var timestamp = Date.now();

var padIDs;

async.series([
  //get all padids out of the database...
  function(callback)
  {
    log("get all padIds out of the database...");
    
    etherpadDB.query("SELECT ID FROM PAD_META", [], function(err, _padIDs)
    {
      padIDs = _padIDs;
      callback(err);
    });
  },
  function(callback)
  {
    log("done");
    
    //create a queue with a concurrency 100
    var queue = async.queue(function (padId, callback) 
    {
      convertPad(padId, function(err)
      {
        incrementPadStats();
        callback(err);
      });
    }, 100);
    
    //set the step callback as the queue callback
    queue.drain = callback;
    
    //add the padids to the worker queue
    for(var i=0,length=padIDs.length;i<length;i++)
    {
      queue.push(padIDs[i].ID);
    }
  }
], function(err)
{
  if(err) throw err;
  
  //write the groups
  var sql = "";
  for(var proID in proID2groupID)
  {
    var groupID = proID2groupID[proID];
    var subdomain = proID2subdomain[proID];
    
    sql+="REPLACE INTO store VALUES (" + etherpadDB.escape("group:" + groupID) + ", " + etherpadDB.escape(JSON.stringify(groups[groupID]))+ ");\n";
    sql+="REPLACE INTO store VALUES (" + etherpadDB.escape("mapper2group:subdomain:" + subdomain) + ", " + etherpadDB.escape(groupID)+ ");\n";
  }
  
  //close transaction
  sql+="COMMIT;";
  
  //end the sql file
  fs.writeSync(sqlOutput, sql, undefined, "utf-8");
  fs.closeSync(sqlOutput);
  
  log("finished.");
  process.exit(0);
});

function log(str)
{
  console.log((Date.now() - startTime)/1000 + "\t" + str);
}

var padsDone = 0;

function incrementPadStats()
{
  padsDone++;
  
  if(padsDone%100 == 0)
  {
    var averageTime = Math.round(padsDone/((Date.now() - startTime)/1000));
    log(padsDone + "/" + padIDs.length + "\t" + averageTime + " pad/s")
  }
}

var proID2groupID = {};
var proID2subdomain = {};
var groups = {};

function convertPad(padId, callback)
{
  var changesets = [];
  var changesetsMeta = [];
  var chatMessages = [];
  var authors = [];
  var apool;
  var subdomain;
  var padmeta;

  async.series([
    //get all needed db values
    function(callback)
    {
      async.parallel([
        //get the pad revisions
        function(callback)
        {
          var sql = "SELECT * FROM `PAD_CHAT_TEXT` WHERE NUMID = (SELECT `NUMID` FROM `PAD_CHAT_META` WHERE ID=?)";
          
          etherpadDB.query(sql, [padId], function(err, results)
          {
            if(!err) 
            {
              try
              {
                //parse the pages
                for(var i=0,length=results.length;i<length;i++)
                {
                  parsePage(chatMessages, results[i].PAGESTART, results[i].OFFSETS, results[i].DATA, true);
                }
              }catch(e) {err = e}
            }
            
            callback(err);
          });
        },
        //get the chat entries
        function(callback)
        {
          var sql = "SELECT * FROM `PAD_REVS_TEXT` WHERE NUMID = (SELECT `NUMID` FROM `PAD_REVS_META` WHERE ID=?)";
          
          etherpadDB.query(sql, [padId], function(err, results)
          {
            if(!err) 
            {
              try
              {
                //parse the pages
                for(var i=0,length=results.length;i<length;i++)
                {
                  parsePage(changesets, results[i].PAGESTART, results[i].OFFSETS, results[i].DATA, false);
                }
              }catch(e) {err = e}
            }
            
            callback(err);
          });
        },
        //get the pad revisions meta data
        function(callback)
        {
          var sql = "SELECT * FROM `PAD_REVMETA_TEXT` WHERE NUMID = (SELECT `NUMID` FROM `PAD_REVMETA_META` WHERE ID=?)";
          
          etherpadDB.query(sql, [padId], function(err, results)
          {
            if(!err) 
            {
              try
              {
                //parse the pages
                for(var i=0,length=results.length;i<length;i++)
                {
                  parsePage(changesetsMeta, results[i].PAGESTART, results[i].OFFSETS, results[i].DATA, true);
                }
              }catch(e) {err = e}
            }
            
            callback(err);
          });
        },
        //get the attribute pool of this pad
        function(callback)
        {
          var sql = "SELECT `JSON` FROM `PAD_APOOL` WHERE `ID` = ?";
          
          etherpadDB.query(sql, [padId], function(err, results)
          {
            if(!err)
            {
              try
              {
                apool=JSON.parse(results[0].JSON).x;
              }catch(e) {err = e}
            }
            
            callback(err);
          });
        },
        //get the authors informations
        function(callback)
        {
          var sql = "SELECT * FROM `PAD_AUTHORS_TEXT` WHERE NUMID = (SELECT `NUMID` FROM `PAD_AUTHORS_META` WHERE ID=?)";
          
          etherpadDB.query(sql, [padId], function(err, results)
          {
            if(!err) 
            {
              try
              {
                //parse the pages
                for(var i=0, length=results.length;i<length;i++)
                {
                  parsePage(authors, results[i].PAGESTART, results[i].OFFSETS, results[i].DATA, true);
                }
              }catch(e) {err = e}
            }
            
            callback(err);
          });
        },
        //get the pad information
        function(callback)
        {
          var sql = "SELECT JSON FROM `PAD_META` WHERE ID=?";
          
          etherpadDB.query(sql, [padId], function(err, results)
          {
            if(!err) 
            {
              try
              {
                padmeta = JSON.parse(results[0].JSON).x;
              }catch(e) {err = e}
            }
            
            callback(err);
          });
        },
        //get the subdomain
        function(callback)
        {
          //skip if this is no proPad
          if(padId.indexOf("$") == -1)
          {
            callback();
            return;
          }
          
          //get the proID out of this padID
          var proID = padId.split("$")[0];
        
          var sql = "SELECT subDomain FROM pro_domains WHERE ID = ?";
          
          etherpadDB.query(sql, [proID], function(err, results)
          {
            if(!err)
            {
              subdomain = results[0].subDomain;
            }
            
            callback(err);
          });
        }
      ], callback);
    },
    function(callback)
    {
      //saves all values that should be written to the database
      var values = {};
      
      //this is a pro pad, let's convert it to a group pad
      if(padId.indexOf("$") != -1)
      {
        var padIdParts = padId.split("$");
        var proID = padIdParts[0];
        var padName = padIdParts[1];
        
        var groupID
        
        //this proID is not converted so far, do it
        if(proID2groupID[proID] == null)
        {
          groupID = "g." + randomString(16);
          
          //create the mappers for this new group
          proID2groupID[proID] = groupID;
          proID2subdomain[proID] = subdomain;
          groups[groupID] = {pads: {}};
        }
        
        //use the generated groupID;
        groupID = proID2groupID[proID];
        
        //rename the pad
        padId = groupID + "$" + padName;
        
        //set the value for this pad in the group
        groups[groupID].pads[padId] = 1;
      }
      
      try
      {
        var newAuthorIDs = {};
        var oldName2newName = {};
        
        //replace the authors with generated authors
        // we need to do that cause where the original etherpad saves pad local authors, the new (lite) etherpad uses them global
        for(var i in apool.numToAttrib)
        {
          var key = apool.numToAttrib[i][0];
          var value = apool.numToAttrib[i][1];
          
          //skip non authors and anonymous authors
          if(key != "author" || value == "")
            continue;
            
          //generate new author values
          var authorID = "a." + randomString(16);
          var authorColorID = authors[i].colorId || Math.floor(Math.random()*32);
          var authorName = authors[i].name || null;
          
          //overwrite the authorID of the attribute pool
          apool.numToAttrib[i][1] = authorID;
          
          //write the author to the database
          values["globalAuthor:" + authorID] = {"colorId" : authorColorID, "name": authorName, "timestamp": timestamp};
          
          //save in mappers
          newAuthorIDs[i] = authorID;
          oldName2newName[value] = authorID;
        }
        
        //save all revisions
        for(var i=0;i<changesets.length;i++)
        {
          values["pad:" + padId + ":revs:" + i] = {changeset: changesets[i], 
                                                   meta : {
                                                     author: newAuthorIDs[changesetsMeta[i].a],
                                                     timestamp: changesetsMeta[i].t,
                                                     atext: changesetsMeta[i].atext || undefined
                                                   }};
        }
        
        //save all chat messages
        for(var i=0;i<chatMessages.length;i++)
        {
          values["pad:" + padId + ":chat:" + i] = {"text": chatMessages[i].lineText, 
                                                   "userId": oldName2newName[chatMessages[i].userId], 
                                                   "time": chatMessages[i].time}
        }
        
        //generate the latest atext
        var fullAPool = (new AttributePool()).fromJsonable(apool);
        var keyRev = Math.floor(padmeta.head / padmeta.keyRevInterval) * padmeta.keyRevInterval;
        var atext = changesetsMeta[keyRev].atext;
        var curRev = keyRev;
        while (curRev < padmeta.head) 
        {
          curRev++;
          var changeset = changesets[curRev];
          atext = Changeset.applyToAText(changeset, atext, fullAPool);
        }
        
        values["pad:" + padId] = {atext: atext, 
                                  pool: apool, 
                                  head: padmeta.head, 
                                  chatHead: padmeta.numChatMessages }
      
      }
      catch(e)
      {
        console.error("Error while converting pad " + padId + ", pad skipped");
        console.error(e.stack ? e.stack : JSON.stringify(e));
        callback();
        return;
      }
      
      var sql = "";
      for(var key in values)
      {
        sql+="REPLACE INTO store VALUES (" + etherpadDB.escape(key) + ", " + etherpadDB.escape(JSON.stringify(values[key]))+ ");\n";
      }
      
      fs.writeSync(sqlOutput, sql, undefined, "utf-8");
      callback();
    }
  ], callback);
}

/**
 * This parses a Page like Etherpad uses them in the databases
 * The offsets describes the length of a unit in the page, the data are
 * all values behind each other
 */
function parsePage(array, pageStart, offsets, data, json)
{
  var start = 0;
  var lengths = offsets.split(",");
  
  for(var i=0;i<lengths.length;i++)
  {
    var unitLength = lengths[i];
    
    //skip empty units
    if(unitLength == "")
      continue;
    
    //parse the number
    unitLength = Number(unitLength);
      
    //cut the unit out of data
    var unit = data.substr(start, unitLength);
    
    //put it into the array
    array[pageStart + i] = json ? JSON.parse(unit) : unit;
    
    //update start
    start+=unitLength;
  }
}