const Promise = require('bluebird');
const Sequelize = require('sequelize');

let sequelize = new Sequelize('maydb', 'myuser', 'a-secure-password',
  {
    host: 'localhost',
    dialect: 'mysql',
    retry: {
      match: /Deadlock/i,
      max: 5
    },
    logging: console.log
  });

/*
    CREATE TABLE foo (col1 TEXT);
    CREATE TABLE tableA (col1 INT);
    INSERT INTO tableA VALUES (0);
    CREATE TABLE tableB (col1 INT);
    INSERT INTO  tableB VALUES (0);
     */

let update = (t, table, value, delay) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      console.log(`${table} -> ${value};`);
      sequelize
      .query(`UPDATE ${table} SET col1 = ${value};`, {transaction: t})
      .then(resolve)
      .catch(reject);
    }, delay);
  });
};

let process1 = () => {
  return sequelize.transaction((t1) => {
    return writeInFoo("Process1 has started", t1).then(()=> {
      return update(t1, 'tableA', 1, 0);//first update: timer to keep the right order to force a dead lock
    }).then(() => {
      return writeInFoo("Process1 changed tableA", t1);
    }).then(() => {
      return update(t1, 'tableB', 1, 10);//fourth update: timer to keep the right order to force a dead lock
    }).then(() => {
      return writeInFoo("Process1 changed tableB", t1);
    });
  }).then(() => {
    return true;
  }).catch((err) => {
    console.error(err);
    return false;
  });
};

let process2 = () => {
  return sequelize.transaction((t2) => {
    return writeInFoo("Process2 has started", t2).then(()=> {
      return update(t2, 'tableB', 2, 5);//second update: timer to keep the right order to force a dead lock
    }).then(() => {
      return writeInFoo("Process2 changed tableB", t2);
    }).then(() => {
      return update(t2, 'tableA', 2, 0);//third to keep the right order to force a dead lock
    }).then(() => {
      return writeInFoo("Process2 changed tableA", t2);
    });
  }).then(() => {
    return true;
  }).catch((err) => {
    console.error(err);
    return false;
  });
};

let writeInFoo = (message, t) => {
  return sequelize.query(`INSERT INTO foo VALUES (:msg);`, {
    replacements: {msg: message},
    type: sequelize.QueryTypes.INSERT,
    transaction: t
  });
};

Promise.all([process1(), process2()]).then((r) => {
  console.log(r);
  process.exit()
});