#!/usr/bin/env node
'use strict';
var mongo = require('mongodb');

var cachedDb;
var cachedClient;

var posts;
var files;
var threads;
var references;

exports.secondFix = function(reference, callback) {

  var thumbPath = '/.media/t_' + reference.sha256;

  var path = '/.media/' + reference.sha256;

  if (reference.extension) {
    path += '.' + reference.extension;
  }

  var match = {
    'files.path' : path
  };

  var update = {
    $set : {
      'files.$[file].thumb' : thumbPath
    }
  };

  var ops = {
    arrayFilters : [ {
      'file.path' : path
    } ]
  };

  posts.updateMany(match, update, ops, function(error) {

    if (error) {
      callback(error);
    } else {
      threads.updateMany(match, update, ops, callback);
    }

  });

};

exports.fixPostings = function(reference, callback) {

  var path = '/.media/' + reference.sha256;

  if (reference.extension) {
    path += '.' + reference.extension;
  }

  var match = {
    'files.path' : path
  };

  var update = {
    $set : {
      'files.$[file].thumb' : reference.width ? path : '/audioGenericThumb.png'
    }
  };

  var ops = {
    arrayFilters : [ {
      'file.path' : path
    } ]
  };

  posts.updateMany(match, update, ops, function(error) {

    if (error) {
      callback(error);
    } else {
      threads.updateMany(match, update, ops, callback);
    }

  });

};

function checkThumb(reference, callback) {

  files.findOne({
    filename : '/.media/t_' + reference.sha256
  }, function(error, foundFile) {

    if (error) {
      return callback(error);
    } else if (!foundFile) {

      return exports.fixPostings(reference, callback);
    }

    // style exception, too simple
    references.updateOne({
      _id : reference._id
    }, {
      $set : {
        hasThumb : true
      }
    }, function(error) {

      if (error) {
        callback(error);
      } else {
        exports.secondFix(reference, callback);
      }

    });
    // style exception, too simple

  });

}

function startIteration(callback, lastId) {

  references.find({
    sha256 : {
      $exists : true
    },
    hasThumb : {
      $ne : true
    },
    _id : lastId ? {
      $gt : lastId
    } : {
      $exists : true
    }
  }).sort({
    _id : 1
  }).limit(1).toArray(function(error, foundReferences) {

    if (error || !foundReferences.length) {
      return callback(error);
    }

    checkThumb(foundReferences[0], function(error) {

      if (error) {
        callback(error);
      } else {
        startIteration(callback, foundReferences[0]._id);
      }

    });
  });

}

function connect(connectString, dbToUse, callback, attempts) {

  attempts = attempts || 0;

  mongo.MongoClient.connect(connectString, {
    useNewUrlParser : true,
    useUnifiedTopology : true
  }, function connectedDb(error, client) {

    if (error) {

      if (attempts > 9) {
        callback(error);
      } else {

        console.log(error);
        console.log('Retrying in 10 seconds');

        setTimeout(function() {
          connect(connectString, dbToUse, callback, ++attempts);
        }, 10000);
      }

    } else {

      cachedClient = client;
      cachedDb = client.db(dbToUse);

      files = cachedDb.collection('fs.files');
      posts = cachedDb.collection('posts');
      threads = cachedDb.collection('threads');
      references = cachedDb.collection('uploadReferences');

      startIteration(callback);
    }

  });

}

exports.init = function(callback) {

  var dbSettings = require('./settings/db.json');

  var connectString = 'mongodb://';

  if (dbSettings.user) {
    connectString += dbSettings.user + ':' + dbSettings.password + '@';
  }

  connectString += dbSettings.address + ':';
  connectString += dbSettings.port + '/' + dbSettings.db;

  if (dbSettings.ssl) {
    connectString += '?ssl=true';
  }

  connect(connectString, dbSettings.db, callback);

};

exports.init(function(error) {

  if (error) {
    console.log(error);
  }

  cachedClient.close();

});