import LifecycleUnit from '../lifecycle/Unit.ts'
import { Unit } from '../lifecycle/decorators.ts'
import { Logging } from '../service/logging/Logging.ts'
import StandardLogger from '../service/logging/StandardLogger.ts'
import { isLoggingLevel } from '../service/logging/types.ts'
import Utility from '../service/utility/Utility.ts'
import { make } from '../../../di/src/global.ts'
import 'https://deno.land/x/dotenv/load.ts'
import { Container } from '../../../di/src/Container.ts'
import { Inject } from '../../../di/src/decorator/Injection.ts'
import CacheFactory from '../support/CacheFactory.ts'

/**
 * Simple helper for loading ENV values with fallback.
 * @param {string} name - the environment variable name
 * @param fallback
 * @return any
 */
const env = (name: string, fallback?: any) => {
    const scaffolding = make(Scaffolding)
    return scaffolding.env(name) ?? fallback
}

export { env }

/**
 * Unit service responsible for getting basic essential scaffolding necessary for Daton.
 * @extends LifecycleUnit
 */
@Unit()
export default class Scaffolding extends LifecycleUnit {
    constructor(
        protected logger: Logging,
        protected utility: Utility,
        @Inject('injector') protected injector: Container,
    ) { super() }

    /**
     * Helper method for fetching environment variables.
     * @param {string} name
     * @return any
     */
    public env(name: string) {
        return this.utility.infer(Deno.env.get(name) ?? '')
    }

    public async up() {
        this.setup_logging()
        this.register_factories()
    }

    /**
     * Bootstrap the logging service, and set the appropriate logging level.
     */
    public setup_logging() {
        StandardLogger.register()

        try {
            this.logger.verbose('Attempting to load logging level from the environment')
            const env_level = this.env('DATON_LOGGING_LEVEL')
            this.logger.verbose(`Read logging level: ${env_level}`)
            if ( isLoggingLevel(env_level) ) {
                this.logger.verbose('Logging level is valid.')
                this.logger.level = env_level
                this.logger.debug(`Set logging level from environment: ${env_level}`)
            }
        } catch (e) {}

        this.logger.info('Logging initialized.', true)
    }

    /**
     * Register the necessary core factories with the IoC container.
     */
    public register_factories() {
        this.logger.verbose('Adding the cache production factory to the container...')
        this.injector.register_factory(new CacheFactory())
    }
}