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

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

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

// load and initialize NPM;
const expect = require('expect.js');
const diff = require('diff');
var async = require('async');

const npm = require('../src/node_modules/npm');
var async = require('ep_etherpad-lite/node_modules/async');
const Changeset = require('ep_etherpad-lite/static/js/Changeset');

npm.load({}, async () => {
  try {
    // initialize database
    const settings = require('../src/node/utils/Settings');
    const db = require('../src/node/db/DB');
    await db.init();

    // load modules
    const Changeset = require('ep_etherpad-lite/static/js/Changeset');
    const padManager = require('../src/node/db/PadManager');

    const exists = await padManager.doesPadExists(padId);
    if (!exists) {
      console.error('Pad does not exist');
      process.exit(1);
    }

    // get the pad
    const pad = await padManager.getPad(padId);

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

    // create an array with all revisions
    const revisions = [];
    for (var i = 0; i <= head; i++) {
      revisions.push(i);
    }

    let atext = Changeset.makeAText('\n');

    // run trough all revisions
    async.forEachSeries(revisions, (revNum, callback) => {
      // console.log('Fetching', revNum)
      db.db.get(`pad:${padId}:revs:${revNum}`, (err, revision) => {
        if (err) return callback(err);

        // check if there is a atext in the keyRevisions
        if (~keyRevisions.indexOf(revNum) && (revision === undefined || revision.meta === undefined || revision.meta.atext === undefined)) {
          console.error(`No atext in key revision ${revNum}`);
          callback();
          return;
        }

        try {
          // console.log("check revision ", revNum);
          const cs = revision.changeset;
          atext = Changeset.applyToAText(cs, atext, pad.pool);
        } catch (e) {
          console.error(`Bad changeset at revision ${revNum} - ${e.message}`);
          callback();
          return;
        }

        if (~keyRevisions.indexOf(revNum)) {
          try {
            expect(revision.meta.atext.text).to.eql(atext.text);
            expect(revision.meta.atext.attribs).to.eql(atext.attribs);
          } catch (e) {
            console.error(`Atext in key revision ${revNum} doesn't match computed one.`);
            console.log(diff.diffChars(atext.text, revision.meta.atext.text).map((op) => { if (!op.added && !op.removed) op.value = op.value.length; return op; }));
            // console.error(e)
            // console.log('KeyRev. :', revision.meta.atext)
            // console.log('Computed:', atext)
            callback();
            return;
          }
        }

        setImmediate(callback);
      });
    }, (er) => {
      if (pad.atext.text == atext.text) { console.log('ok'); } else {
        console.error('Pad AText doesn\'t match computed one! (Computed ', atext.text.length, ', db', pad.atext.text.length, ')');
        console.log(diff.diffChars(atext.text, pad.atext.text).map((op) => { if (!op.added && !op.removed) op.value = op.value.length; return op; }));
      }
      callback(er);
    });

    process.exit(0);
  } catch (e) {
    console.trace(e);
    process.exit(1);
  }
});