/*
  This is a repair tool. It rebuilds an old pad at a new pad location up to a
  known "good" revision.
*/

if(process.argv.length != 4 && process.argv.length != 5) {
  console.error("Use: node bin/repairPad.js $PADID $REV [$NEWPADID]");
  process.exit(1);
}

var npm = require("../src/node_modules/npm");
var async = require("../src/node_modules/async");
var ueberDB = require("../src/node_modules/ueberDB");

var padId = process.argv[2];
var newRevHead = process.argv[3];
var newPadId = process.argv[4] || padId + "-rebuilt";

var db, oldPad, newPad, settings;
var AuthorManager, ChangeSet, Pad, PadManager;

async.series([
  function(callback) {
    npm.load({}, function(err) {
      if(err) {
        console.error("Could not load NPM: " + err)
        process.exit(1);
      } else {
        callback();
      }
    })
  },
  function(callback) {
    // Get a handle into the database
    db = require('../src/node/db/DB');
    db.init(callback);
  }, function(callback) {
     PadManager = require('../src/node/db/PadManager');
     Pad = require('../src/node/db/Pad').Pad;
     // Get references to the original pad and to a newly created pad
     // HACK: This is a standalone script, so we want to write everything
     // out to the database immediately.  The only problem with this is
     // that a driver (like the mysql driver) can hardcode these values.
     db.db.db.settings = {cache: 0, writeInterval: 0, json: true};
     // Validate the newPadId if specified and that a pad with that ID does
     // not already exist to avoid overwriting it.
     if (!PadManager.isValidPadId(newPadId)) {
       console.error("Cannot create a pad with that id as it is invalid");
       process.exit(1);
     }
     PadManager.doesPadExists(newPadId, function(err, exists) {
       if (exists) {
         console.error("Cannot create a pad with that id as it already exists");
         process.exit(1);
       }
     });
     PadManager.getPad(padId, function(err, pad)  {
       oldPad = pad;
       newPad = new Pad(newPadId);
       callback();
     });
  }, function(callback) {
    // Clone all Chat revisions
    var chatHead = oldPad.chatHead;
    for(var i = 0, curHeadNum = 0; i <= chatHead; i++) {
      db.db.get("pad:" + padId + ":chat:" + i, function (err, chat) {
        db.db.set("pad:" + newPadId + ":chat:" + curHeadNum++, chat);
        console.log("Created: Chat Revision: pad:" + newPadId + ":chat:" + curHeadNum);
      });
    }
    callback();
  }, function(callback) {
    // Rebuild Pad from revisions up to and including the new revision head
    AuthorManager = require("../src/node/db/AuthorManager");
    Changeset = require("ep_etherpad-lite/static/js/Changeset");
    // Author attributes are derived from changesets, but there can also be
    // non-author attributes with specific mappings that changesets depend on
    // and, AFAICT, cannot be recreated any other way
    newPad.pool.numToAttrib = oldPad.pool.numToAttrib;
    for(var curRevNum = 0; curRevNum <= newRevHead; curRevNum++) {
      db.db.get("pad:" + padId + ":revs:" + curRevNum, function(err, rev) {
        if (rev.meta) {
          throw "The specified revision number could not be found.";
        }
        var newRevNum = ++newPad.head;
        var newRevId = "pad:" + newPad.id + ":revs:" + newRevNum;
        db.db.set(newRevId, rev);
        AuthorManager.addPad(rev.meta.author, newPad.id);
        newPad.atext = Changeset.applyToAText(rev.changeset, newPad.atext, newPad.pool);
        console.log("Created: Revision: pad:" + newPad.id + ":revs:" + newRevNum);
        if (newRevNum == newRevHead) {
          callback();
        }
      });
    }
  }, function(callback) {
    // Add saved revisions up to the new revision head
    console.log(newPad.head);
    var newSavedRevisions = [];
    for(var i in oldPad.savedRevisions) {
      savedRev = oldPad.savedRevisions[i]
      if (savedRev.revNum <= newRevHead) {
        newSavedRevisions.push(savedRev);
        console.log("Added: Saved Revision: " + savedRev.revNum);
      }
    }
    newPad.savedRevisions = newSavedRevisions;
    callback();
  }, function(callback) {
    // Save the source pad
    db.db.set("pad:"+newPadId, newPad, function(err) {
      console.log("Created: Source Pad: pad:" + newPadId);
      newPad.saveToDatabase();
      callback();
    });
  }
], function (err) {
  if(err) throw err;
  else {
    console.info("finished");
    process.exit(0);
  }
});