const path = require('path');
const chalk = require('chalk');

const { Util } = require('../../../util/');

const MongodbTable = require('./MongodbTable.js');
const MariadbTable = require('./MariadbTable.js');

const Constants = {
    Tables: {
        'mongodb': MongodbTable,
        'mariadb': MariadbTable
    }
};

class Provider {

    constructor(client, opts) {

        if(!opts.config) throw new Error('No config file provided!');
        this.config = opts.config[opts.name];
        if(this.config && (!this.config.database || !this.config.host)) throw new Error('Invalid config file provided!' + JSON.stringify(this.config));

        this.client = client;
        this.storageManager = client.storageManager;

        this.name = opts.name;
        this.connection = null;
        this.db = null; 
        
        this.tables = {};

        this._initialized = false;
        this._class = Constants.Tables[opts.name];

    }

    async loadTables() {

        const directory = path.join(process.cwd(), 'structure/storage/');
        const files = await Util.readdirRecursive(path.join(directory, `tables/${this.name}`));

        const loaded = [];

        for(const file of files) {
            const func = require(file);
            if(typeof func !== 'function') {
                this.storageManager._error("Attempted to index an invalid function as a table.", this);
                delete require.cache[file];
                continue;
            }
            const table = new func(this.client, this);
            if(this._class && !(table instanceof this._class)) {
                this.storageManager._error("Attempted to load an invalid class as a table.", this);
                delete require.cache[file];
                continue;
            }

            loaded.push(await this.loadTable(table));

        }

        for(const table of this.config.tables) {
            if(this.tables[table]) continue;
            else loaded.push(await this.loadTable(new this._class(this.client, this, {
                name: table
            })));
        }

        return loaded;

    }

    async loadTable(table) {

        if(this.tables[table.name]) {
            this.storageManager._error("Attempted to load an existing table.", table);
            return null;
        }

        this.tables[table.name] = table;
        this.storageManager._log(`Table ${chalk.bold(table.name)} was ${chalk.bold('loaded')}.`, table);
        return table;

    }

    _error(err) {
        this.storageManager._error(err, this);
    }

}

module.exports = Provider;