/**
 * @file Database configuration and model initialization for Sequelize.
 * Initializes the Sequelize ORM based on environment settings and loads database models.
 * Provides access to the Sequelize instance and loaded models.
 */

'use strict';

const fs = require('fs');
const path = require('path');
const Sequelize = require('sequelize');
const process = require('process');

/**
 * Base filename of the current file
 * @type {string}
 */
const basename = path.basename(__filename);

/**
 * Current environment (development/production/test)
 * @type {string}
 */
const env = process.env.NODE_ENV || 'development';

/**
 * Database configuration for the current environment
 * @type {Object}
 */
const config = require(__dirname + '/../config/config.js')[env];

/**
 * Object containing all database models and Sequelize instances
 * @type {Object}
 */
const db = {};

/**
 * Sequelize instance for database connection
 * @type {Sequelize}
 */
let sequelize;

// Initialize Sequelize with environment config or direct config
if (config.use_env_variable) {
    sequelize = new Sequelize(process.env[config.use_env_variable], config);
} else {
    sequelize = new Sequelize(config.database, config.username, config.password, config);
}


/**
 * Load all model files from current directory and initialize them
 */
fs
    .readdirSync(__dirname)
    .filter(file => {
        return (
            file.indexOf('.') !== 0 &&
            file !== basename &&
            file.slice(-3) === '.js' &&
            file.indexOf('.test.js') === -1
        );
    })
    .forEach(file => {
        /**
         * Initialize model from file
         * @type {Sequelize.Model}
         */
        const model = require(path.join(__dirname, file))(sequelize, Sequelize.DataTypes);
        db[model.name] = model;
    });

/**
 * Set up model associations if defined
 */
Object.keys(db).forEach(modelName => {
    if (db[modelName].associate) {
        db[modelName].associate(db);
    }
});

// Add Sequelize instances to db object
db.sequelize = sequelize;
db.Sequelize = Sequelize;

module.exports = db;