<?php

use Monolog\Formatter\LineFormatter;
use Monolog\Handler\NullHandler;
use Monolog\Handler\RotatingFileHandler;
use Monolog\Level;
use Psr\Log\LoggerInterface;

/**
 * Central logger factory — provides named Monolog channel instances
 * backed by rotating JSON-line log files.
 *
 * Channels:
 *  - 'app'   → replaces AppLogger
 *  - 'admin' → replaces AdminLogger file output
 *  - 'error' → replaces ErrorHandler logging
 *  - 'audit' → replaces Audit file shadow (DB writes stay in Audit)
 *
 * Usage:
 *   Logger::get('app')->info('message', [...]);
 *   Logger::get('admin')->warning('message', [...]);
 */
class Logger
{
    /** @var array<string, LoggerInterface> */
    private static array $channels = [];

    /**
     * Get (or lazily create) a named Monolog channel.
     */
    public static function get(string $channel): LoggerInterface
    {
        if (!isset(self::$channels[$channel])) {
            self::$channels[$channel] = self::create($channel);
        }
        return self::$channels[$channel];
    }

    /**
     * Create a Monolog channel with rotating JSON file handler.
     *
     * Falls back to NullHandler if the log directory is not writable
     * (e.g. CLI scripts on a machine that doesn't have the production path).
     */
    private static function create(string $channel): \Monolog\Logger
    {
        $logDir = self::logDir();

        if (!is_dir($logDir) && !@mkdir($logDir, 0755, true) && !is_dir($logDir)) {
            // Directory can't be created — use null handler (graceful degradation)
            $logger = new \Monolog\Logger($channel);
            $logger->pushHandler(new NullHandler());
            return $logger;
        }

        try {
            $handler = new RotatingFileHandler(
                $logDir . '/' . $channel . '.log',
                30,          // keep 30 days of logs
                self::level()
            );
        } catch (\Throwable $e) {
            // Can't open log file — use null handler
            $logger = new \Monolog\Logger($channel);
            $logger->pushHandler(new NullHandler());
            return $logger;
        }

        // Pass-through formatter: the facades (AppLogger, AdminLogger, etc.)
        // construct their own JSON lines and pass them as the log message.
        // %message% preserves the existing JSON format contract exactly.
        $handler->setFormatter(new LineFormatter("%message%\n", null, true));

        $logger = new \Monolog\Logger($channel);
        $logger->pushHandler($handler);

        return $logger;
    }

    /**
     * Read the LOG_LEVEL env var with sensible defaults.
     */
    private static function level(): Level
    {
        $level = strtoupper(getenv('LOG_LEVEL') ?: '');

        // Default: WARNING in production (always set in .env), DEBUG otherwise
        if ($level === '') {
            return php_sapi_name() === 'cli-server' ? Level::Debug : Level::Warning;
        }

        return Level::fromName($level);
    }

    /**
     * Resolve the log directory.
     */
    private static function logDir(): string
    {
        if (defined('STORAGE_ROOT')) {
            return STORAGE_ROOT . '/logs';
        }
        return __DIR__ . '/../storage/logs';
    }
}