'use strict';
const debug = require('debug')('strapi-database:migration');
const { isFunction } = require('lodash/fp');

class MigrationManager {
  constructor(db) {
    debug('Initialize migration manager');
    this.db = db;
    this.migrations = [];
  }

  register(migration) {
    debug('Register migration');
    this.migrations.push(migration);
  }

  async runMigration(fn, options, context = {}) {
    debug('Run migration');
    await this.runBefore(options, context);
    await await fn(options, context);
    await this.runAfter(options, context);
  }

  async runBefore(options, context) {
    debug('Run before migrations');

    for (const migration of this.migrations) {
      if (isFunction(migration.before)) {
        await migration.before(options, context);
      }
    }
  }

  async runAfter(options, context) {
    debug('Run after migrations');

    for (const migration of this.migrations.slice(0).reverse()) {
      if (isFunction(migration.after)) {
        await migration.after(options, context);
      }
    }
  }
}

module.exports = strapi => {
  return new MigrationManager(strapi);
};