/*
 * This is a debug tool. It checks all revisions for data corruption
 */

if (process.argv.length != 3) {
  console.error("Use: node bin/checkPad.js $PADID");
  process.exit(1);
}

//get the padID
var padId = process.argv[2];

// initialize the variables
var db, settings, padManager;
var npm = require('../src/node_modules/npm');
var async = require('../src/node_modules/async');

var Changeset = require('ep_etherpad-lite/static/js/Changeset');

async.series([
  // load npm
  function(callback) {
    npm.load({}, function(er) {
      callback(er);
    });
  },

  // load modules
  function(callback) {
    settings = require('../src/node/utils/Settings');
    db = require('../src/node/db/DB');

    // initialize the database
    db.init(callback);
  },

  // get the pad
  function (callback) {
    padManager = require('../src/node/db/PadManager');

    padManager.doesPadExists(padId, function(err, exists) {
      if (!exists) {
        console.error("Pad does not exist");
        process.exit(1);
      }

      padManager.getPad(padId, function(err, _pad) {
        pad = _pad;
        callback(err);
      });
    });
  },

  function (callback) {
    // create an array with key revisions
    // key revisions always save the full pad atext
    var head = pad.getHeadRevisionNumber();
    var keyRevisions = [];
    for (var i = 0; i < head; i += 100) {
      keyRevisions.push(i);
    }

    // run through all key revisions
    async.forEachSeries(keyRevisions, function(keyRev, callback) {
      // create an array of revisions we need till the next keyRevision or the End
      var revisionsNeeded = [];
      for(var i = keyRev; i <= keyRev + 100 && i <= head; i++) {
        revisionsNeeded.push(i);
      }

      // this array will hold all revision changesets
      var revisions = [];

      // run through all needed revisions and get them from the database
      async.forEach(revisionsNeeded, function(revNum, callback) {
        db.db.get("pad:" + padId + ":revs:" + revNum, function(err, revision) {
          revisions[revNum] = revision;
          callback(err);
        });
      },
      function(err) {
        if (err) {
          callback(err);
          return;
        }

        // check if the pad has a pool
        if (pad.pool === undefined) {
          console.error("Attribute pool is missing");
          process.exit(1);
        }

        // check if there is an atext in the keyRevisions
        if (revisions[keyRev] === undefined || revisions[keyRev].meta === undefined || revisions[keyRev].meta.atext === undefined) {
          console.error("No atext in key revision " + keyRev);
          callback();
          return;
        }

        var apool = pad.pool;
        var atext = revisions[keyRev].meta.atext;

        for (var i = keyRev + 1; i <= keyRev + 100 && i <= head; i++) {
          try {
            // console.log("check revision " + i);
            var cs = revisions[i].changeset;
            atext = Changeset.applyToAText(cs, atext, apool);
          } catch(e) {
            console.error("Bad changeset at revision " + i + " - " + e.message);
            callback();
            return;
          }
        }

        callback();
      });
    }, callback);
  }
],
function (err) {
  if(err) {
    throw err;
  } else {
    console.log("finished");
    process.exit(0);
  }
});