#!/usr/bin/env node

/**
 * Module dependencies.
 */

const util = require('./util');
const _ = require('lodash');
const program = require('commander');
const inquirer = require('inquirer');
const mongoose = require('../services/mongoose');
const MigrationService = require('../services/migration');

// Register shutdown hooks.
util.onshutdown([() => mongoose.disconnect()]);

async function createMigration(name) {
  try {
    // Create the migration.
    await MigrationService.create(name);

    util.shutdown();
  } catch (e) {
    console.error(e);
    util.shutdown(1);
  }
}

async function runMigrations(options) {
  const { yes, queryBatchSize, updateBatchSize } = options;
  try {
    if (!yes) {
      const { backedUp } = await inquirer.prompt([
        {
          type: 'confirm',
          name: 'backedUp',
          message: 'Did you perform a database backup',
          default: false,
        },
      ]);

      if (!backedUp) {
        throw new Error(
          'Please backup your databases prior to migrations occuring'
        );
      }
    }

    // Get the migrations to run.
    const migrations = await MigrationService.listPending();

    console.log('Now going to run the following migrations:\n');

    for (const { filename } of migrations) {
      console.log(`\tmigrations/${filename}`);
    }

    if (!yes) {
      const { confirm } = await inquirer.prompt([
        {
          type: 'confirm',
          name: 'confirm',
          message: 'Proceed with migrations',
          default: false,
        },
      ]);

      if (confirm) {
        // Run the migrations.
        await MigrationService.run(migrations, {
          queryBatchSize,
          updateBatchSize,
        });
      } else {
        console.warn('Skipping migrations');
      }
    } else {
      // Run the migrations.
      await MigrationService.run(migrations, {
        queryBatchSize,
        updateBatchSize,
      });
    }

    util.shutdown();
  } catch (e) {
    console.error(e);
    util.shutdown(1);
  }
}

//==============================================================================
// Setting up the program command line arguments.
//==============================================================================

program
  .command('create <name>')
  .description('creates a new migration')
  .action(createMigration);

// Bypasses issue that defaults + coercion doesn't work well together.
// Ref: https://github.com/tj/commander.js/issues/400#issuecomment-310860869
const parse10 = _.ary(_.partialRight(parseInt, 10), 1);

program
  .command('run')
  .option(
    '-q, --query-batch-size <n>',
    'change the size of queried documents that are batched at a time',
    parse10,
    10000
  )
  .option(
    '-u, --update-batch-size <n>',
    'change the size of documents that are batched before the update is sent',
    parse10,
    20000
  )
  .option('-y, --yes', 'will answer yes to all questions')
  .description('runs all pending migrations')
  .action(runMigrations);

program.parse(process.argv);

// If there is no command listed, output help.
if (process.argv.length <= 2) {
  program.outputHelp();
  util.shutdown();
}