<?php
/**
 * Configuration Management Class
 * Loads and manages application configuration from .env files
 */

class Config
{
    private static $config = [];
    private static $loaded = false;

    /**
     * Load configuration from environment and .env files
     */
    public static function load()
    {
        if (self::$loaded) {
            return self::$config;
        }

        // Load environment variables
        self::loadEnvironment();

        // Load .env file if it exists
        self::loadDotEnv();

        self::$loaded = true;
        return self::$config;
    }

    /**
     * Get a configuration value
     */
    public static function get($key, $default = null)
    {
        $config = self::load();

        // Support dot notation (e.g., 'database.host')
        $keys = explode('.', $key);
        $value = $config;

        foreach ($keys as $k) {
            if (!isset($value[$k])) {
                return $default;
            }
            $value = $value[$k];
        }

        return $value;
    }

    /**
     * Set a configuration value (runtime only)
     */
    public static function set($key, $value)
    {
        $keys = explode('.', $key);
        $config = &self::$config;

        foreach ($keys as $i => $k) {
            if ($i === count($keys) - 1) {
                $config[$k] = $value;
            } else {
                if (!isset($config[$k]) || !is_array($config[$k])) {
                    $config[$k] = [];
                }
                $config = &$config[$k];
            }
        }
    }

    /**
     * Load system environment variables
     */
    private static function loadEnvironment()
    {
        // System environment variables get precedence
        foreach ($_ENV as $key => $value) {
            self::setFromEnv($key, $value);
        }

        foreach ($_SERVER as $key => $value) {
            if (strpos($key, 'APP_') === 0 || strpos($key, 'DB_') === 0 ||
                strpos($key, 'STREAM_') === 0 || strpos($key, 'ADMIN_') === 0) {
                self::setFromEnv($key, $value);
            }
        }
    }

    /**
     * Load .env file
     */
    private static function loadDotEnv()
    {
        $envFile = __DIR__ . '/../.env';

        if (!file_exists($envFile)) {
            error_log("Warning: .env file not found. Using default configuration.");
            return;
        }

        $lines = file($envFile, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);

        foreach ($lines as $line) {
            $line = trim($line);

            // Skip comments
            if (strpos($line, '#') === 0) {
                continue;
            }

            // Parse key=value pairs
            if (strpos($line, '=') !== false) {
                list($key, $value) = explode('=', $line, 2);
                $key = trim($key);
                $value = trim($value);

                // Remove quotes if present
                if ((strpos($value, '"') === 0 && strrpos($value, '"') === strlen($value) - 1) ||
                    (strpos($value, "'") === 0 && strrpos($value, "'") === strlen($value) - 1)) {
                    $value = substr($value, 1, -1);
                }

                self::setFromEnv($key, $value);
            }
        }
    }

    /**
     * Set configuration value from environment variable
     */
    private static function setFromEnv($key, $value)
    {
        // Convert environment naming to configuration naming
        $configKey = strtolower(str_replace('_', '.', $key));

        // Type coercion for boolean values
        if (in_array($value, ['true', 'false'])) {
            $value = $value === 'true';
        }

        // Type coercion for numeric values
        if (is_numeric($value) && !is_string($value)) {
            $value = strpos($value, '.') !== false ? (float)$value : (int)$value;
        }

        // Handle arrays (comma-separated)
        if (strpos($value, ',') !== false) {
            $value = array_map('trim', explode(',', $value));
        }

        self::set($configKey, $value);
    }

    /**
     * Get all configuration as a flattened array
     */
    public static function all()
    {
        return self::load();
    }

    /**
     * Check if we are in a specific environment
     */
    public static function isEnvironment($env)
    {
        return self::get('app.env') === $env;
    }

    /**
     * Check if debug mode is enabled
     */
    public static function isDebug()
    {
        return self::get('app.debug', false);
    }
}