import {LoggingLevel, LogMessage} from './types.ts'
import Logger from './Logger.ts'
import {Service} from '../../../../di/src/decorator/Service.ts'
import {make} from '../../../../di/src/global.ts'
import {isInstantiable} from '../../../../di/src/type/Instantiable.ts'

/**
 * Service for managing application logging.
 */
@Service()
class Logging {
    /**
     * The current logging level.
     * @type LoggingLevel
     */
    private _level = LoggingLevel.Warning

    /**
     * Loggers registered with this service.
     * @type Array<Logger>
     */
    private _loggers: Logger[] = []

    /**
     * Get the current logging level.
     * @type LoggingLevel
     */
    public get level() {
        return this._level
    }

    /**
     * Set the new logging level.
     * @param {LoggingLevel} level
     */
    public set level(level) {
        this._level = level
    }

    /**
     * Write an output with the success level.
     * @param output
     * @param {boolean} [force = false] - if true, the output will be written, regardless of the output level
     */
    public success(output: any, force = false) {
        this.write_log(LoggingLevel.Success, output, force)
    }

    /**
     * Write an output with the error level.
     * @param output
     * @param {boolean} [force = false] - if true, the output will be written, regardless of the output level
     */
    public error(output: any, force = false) {
        this.write_log(LoggingLevel.Error, output, force)
    }

    /**
     * Write an output with the warning level.
     * @param output
     * @param {boolean} [force = false] - if true, the output will be written, regardless of the output level
     */
    public warn(output: any, force = false) {
        this.write_log(LoggingLevel.Warning, output, force)
    }

    /**
     * Write an output with the info level.
     * @param output
     * @param {boolean} [force = false] - if true, the output will be written, regardless of the output level
     */
    public info(output: any, force = false) {
        this.write_log(LoggingLevel.Info, output, force)
    }

    /**
     * Write an output with the debug level.
     * @param output
     * @param {boolean} [force = false] - if true, the output will be written, regardless of the output level
     */
    public debug(output: any, force = false) {
        this.write_log(LoggingLevel.Debug, output, force)
    }

    /**
     * Write an output with the verbose level.
     * @param output
     * @param {boolean} [force = false] - if true, the output will be written, regardless of the output level
     */
    public verbose(output: any, force = false) {
        this.write_log(LoggingLevel.Verbose, output, force)
    }

    /**
     * Writes the output at the given logging level.
     * @param {LoggingLevel} level
     * @param output
     * @param {boolean} [force = false]
     */
    protected write_log(level: LoggingLevel, output: any, force = false) {
        const message = this.build_message(level, output)
        if ( this._level >= level || force ) {
            for ( const logger of this._loggers ) {
                try {
                    logger.write(message)
                } catch (e) {
                    console.error('logging error', e)
                }
            }
        }
    }

    /**
     * Given an output and level, build a log message object.
     * @param {LoggingLevel} level
     * @param output
     * @return LogMessage
     */
    protected build_message(level: LoggingLevel, output: any): LogMessage {
        return {
            level,
            output,
            date: new Date,
            caller_name: this.get_caller_info(),
        }
    }

    /**
     * Register a logger with this class.
     * @param {typeof Logger} logger_class
     */
    public register_logger(logger_class: typeof Logger) {
        if ( isInstantiable(logger_class) ) {
            const logger = make(logger_class)
            if ( !this._loggers.includes(logger) )
                this._loggers.push(logger)
        }
    }

    /**
     * Remove a logger from this class.
     * @param {typeof Logger} logger_class
     */
    public remove_logger(logger_class: typeof Logger) {
        this._loggers = this._loggers.filter(x => !(x instanceof logger_class))
    }

    /**
     * Get the information about the caller of a given context.
     * @param {number} [level = 5] - how far up in the stacktrace to go
     */
    protected get_caller_info(level = 5): string {
        let e = new Error
        if ( !e.stack ) return 'Unknown'
        return e.stack.split('    at ')
            .slice(level)
            .map((x: string): string => x.trim().split(' (')[0].split('.')[0].split(':')[0])[0]
    }
}

export { Logging }