/** @module log */

import { ContextResolver, IContext } from 'pip-services4-components-node';
import { StringConverter } from 'pip-services4-commons-node';

import { LogLevel } from './LogLevel';
import { Logger } from './Logger';
import { LogLevelConverter } from './LogLevelConverter';

/**
 * Logger that writes log messages to console.
 * 
 * Errors are written to standard err stream
 * and all other messages to standard out stream.
 * 
 * ### Configuration parameters ###
 * 
 * - level:             maximum log level to capture
 * - source:            source (context) name
 * 
 * ### References ###
 * 
 * - <code>\*:context-info:\*:\*:1.0</code>     (optional) [[ContextInfo]] to detect the context id and specify counters source
 * 
 * @see [[Logger]]
 * 
 * ### Example ###
 * 
 *     let logger = new ConsoleLogger();
 *     logger.setLevel(LogLevel.debug);
 *     
 *     logger.error("123", ex, "Error occured: %s", ex.message);
 *     logger.debug("123", "Everything is OK.");
 */
export class ConsoleLogger extends Logger {
    
    /**
     * Creates a new instance of the logger.
     */
    public constructor() {
        super();
    }

    /**
     * Writes a log message to the logger destination.
     * 
     * @param level             a log level.
     * @param context     (optional) a context to trace execution through call chain.
     * @param error             an error object associated with this message.
     * @param message           a human-readable message to log.
     */
    protected write(level: LogLevel, context: IContext, error: Error, message: string): void {
        if (this.getLevel() < level) return;

        let result = '[';
        result += context != null ? ContextResolver.getTraceId(context) : "---";
        result += ':';
        result += LogLevelConverter.toString(level);
        result += ':';
        result += StringConverter.toString(new Date());
        result += "] ";

        result += message;

        if (error != null) {
            if (message.length == 0) {
                result += "Error: ";
            } else {
                result += ": ";
            }

            result += this.composeError(error);
        }

        if (level == LogLevel.Fatal || level == LogLevel.Error || level == LogLevel.Warn) {
            console.error(result);
        } else {
            console.log(result);
        }
    }

}