// src/services/logger.ts
/**
 * A simple logger service that wraps the console.
 * This provides a centralized place to manage logging behavior,
 * such as adding timestamps, log levels, or sending logs to a remote service.
 */

const getTimestamp = () => new Date().toISOString();

type LogLevel = 'INFO' | 'WARN' | 'ERROR' | 'DEBUG';

/**
 * The core logging function. It uses a generic rest parameter `<T extends any[]>`
 * to safely accept any number of arguments of any type, just like the native console
 * methods. Using `unknown[]` is more type-safe than `any[]` and satisfies the linter.
 */
const log = <T extends unknown[]>(level: LogLevel, message: string, ...args: T) => {
    // Check if `process` is available (Node.js) vs. browser environment.
    // This makes the logger "isomorphic" and prevents runtime errors on the client.
    const envIdentifier = typeof process !== 'undefined' && process.pid
        ? `PID:${process.pid}`
        : 'BROWSER';
    const timestamp = getTimestamp();
    // We construct the log message with a timestamp, PID, and level for better context.
    const logMessage = `[${timestamp}] [${envIdentifier}] [${level}] ${message}`;
    
    switch (level) {
        case 'INFO':
            console.log(logMessage, ...args);
            break;
        case 'WARN':
            console.warn(logMessage, ...args);
            break;
        case 'ERROR':
            console.error(logMessage, ...args);
            break;
        case 'DEBUG':
            // For now, we can show debug logs in development. This could be controlled by an environment variable.
            console.debug(logMessage, ...args);
            break;
    }
};

// Export the logger object for use throughout the application.
export const logger = {
    info: <T extends unknown[]>(message: string, ...args: T) => log('INFO', message, ...args),
    warn: <T extends unknown[]>(message: string, ...args: T) => log('WARN', message, ...args),
    error: <T extends unknown[]>(message: string, ...args: T) => log('ERROR', message, ...args),
    debug: <T extends unknown[]>(message: string, ...args: T) => log('DEBUG', message, ...args),
};