const logger = require("logops")
    , config = require('../../config')
    , { Builder, Capabilities } = require('selenium-webdriver')
    , pool = require('generic-pool')
    , { Options } = require('selenium-webdriver/chrome');

class PoolingService {
    constructor() {        
        this.config = {
            pool: { max: 10, min: 1, testOnBorrow: true },
            browser: 'chrome',
            browserArgs: ['--no-sandbox', '--headless', '--disable-dev-shm-usage', '--proxy-server=spiduler-tor:8118']
        }
        this.pool = this.createPool()
    }

    createPool() {
        setInterval(() => this.debugPoolStatus(), 1000 * 60 * 5)
        return pool.createPool({
            create: () => this.create(),
            destroy: (driver) => this.destroy(driver),
            validate: (driver) => this.validate(driver)
        }, this.config.pool);
    }

    create() {
        logger.info('Create new driver instance')
        return this.getDriver();
    }

    destroy(driver) {
        logger.info('Quitting driver')
        return driver.quit().catch(err => {
            logger.debug({ message: err.message }, 'Quitting error')
            this.pool.release(driver)
        })
    }

    validate(driver) {
        return driver.getSession().then(s => {
            logger.info('Driver session validation checked (id: %s)', s.getId())
            return true
        }).catch(err => {
            this.pool.destroy(driver)
            logger.debug({ message: err.message }, 'Driver session expired and destroy it')
            return false
        })
    }

    getDriver() {
        let opts = new Options;
        let capabilities = Capabilities.chrome()
        opts.addArguments(this.config.browserArgs)
        return new Builder()
            .usingServer('http://spiduler-chrome:4444/wd/hub')
            .withCapabilities(capabilities)
            .forBrowser(this.config.browser)
            .setChromeOptions(opts)
            .build();
    }

    debugPoolStatus() {
        logger.debug({
            spare: this.pool.spareResourceCapacity,
            size: this.pool.size,
            available: this.pool.available,
            borrowed: this.pool.borrowed,
            pending: this.pool.pending
        }, 'Pool status')
    }
}

module.exports = new PoolingService