'use strict';

const _ = require('lodash');

const requireConnector = require('./require-connector');
const { createQuery } = require('./queries');

class DatabaseManager {
  constructor(strapi) {
    this.strapi = strapi;

    // throw if connections and schemas aren't arrays
    this.initialized = false;
    this.queries = new Map();
    this.connectors = new Map();
  }

  async initialize() {
    if (this.initialized === true) {
      throw new Error('Database manager already initialized');
    }

    this.initialized = true;

    const connectorsToInitialize = [];
    for (const connection of Object.values(this.strapi.config.connections)) {
      const { connector } = connection;
      if (!connectorsToInitialize.includes(connector)) {
        connectorsToInitialize.push(connector);
      }
    }

    for (const connectorToInitialize of connectorsToInitialize) {
      const connector = requireConnector(connectorToInitialize)(strapi);

      this.connectors.set(connectorToInitialize, connector);

      await connector.initialize();
    }

    return this;
  }

  query(entity, plugin) {
    if (!entity) {
      throw new Error(`argument entity is required`);
    }

    const normalizedName = entity.toLowerCase();

    const model = this.getModel(normalizedName, plugin);

    if (!model) {
      throw new Error(`The model ${entity} can't be found.`);
    }

    if (this.queries.has(model.uid)) {
      return this.queries.get(model.uid);
    }

    const connectorQuery = this.connectors
      .get(model.orm)
      .queries({ model, modelKey: normalizedName, strapi });

    const query = createQuery({ connectorQuery, model });
    this.queries.set(model.uid, query);
    return query;
  }

  getModel(name, plugin) {
    const key = _.toLower(name);

    if (plugin === 'admin') {
      return _.get(strapi.admin, ['models', key]);
    }

    return (
      _.get(strapi.plugins, [plugin, 'models', key]) ||
      _.get(strapi, ['models', key]) ||
      _.get(strapi, ['groups', key])
    );
  }
}

function createDatabaseManager(strapi) {
  return new DatabaseManager(strapi);
}

module.exports = {
  createDatabaseManager,
};