<?php
declare(strict_types=1);

namespace Fendx\I18n\Config;

use Fendx\I18n\Config\Loader\ConfigLoader;
use Fendx\I18n\Config\Validator\ConfigValidator;
use Fendx\I18n\Config\Cache\ConfigCache;

class I18nConfigManager
{
    protected ConfigLoader $loader;
    protected ConfigValidator $validator;
    protected ConfigCache $cache;
    protected array $config = [];
    protected array $defaults = [];
    protected array $environments = [];
    protected string $currentEnvironment = 'production';
    protected bool $loaded = false;

    public function __construct(array $config = [])
    {
        $this->defaults = $this->getDefaultConfig();
        $this->config = array_merge($this->defaults, $config);
        $this->loader = new ConfigLoader($this->config);
        $this->validator = new ConfigValidator($this->config);
        $this->cache = new ConfigCache($this->config);
        
        $this->currentEnvironment = $this->config['environment'] ?? $this->detectEnvironment();
    }

    /**
     * Load I18n configuration.
     */
    public function load(): void
    {
        if ($this->loaded) {
            return;
        }

        // Load base configuration
        $baseConfig = $this->loader->loadBase();
        
        // Load environment-specific configuration
        $envConfig = $this->loader->loadEnvironment($this->currentEnvironment);
        
        // Load local configuration
        $localConfig = $this->loader->loadLocal();
        
        // Merge configurations
        $this->config = array_merge_recursive(
            $this->defaults,
            $baseConfig,
            $envConfig,
            $localConfig
        );
        
        // Validate configuration
        $validation = $this->validator->validate($this->config);
        if (!$validation['valid']) {
            throw new \InvalidArgumentException(
                'Invalid I18n configuration: ' . implode(', ', $validation['errors'])
            );
        }
        
        // Process configuration
        $this->processConfig();
        
        $this->loaded = true;
    }

    /**
     * Get configuration value.
     */
    public function get(string $key, mixed $default = null): mixed
    {
        $this->ensureLoaded();
        
        return $this->getNestedValue($this->config, $key, $default);
    }

    /**
     * Set configuration value.
     */
    public function set(string $key, mixed $value): void
    {
        $this->ensureLoaded();
        
        $this->setNestedValue($this->config, $key, $value);
        $this->cache->clear();
    }

    /**
     * Check if configuration key exists.
     */
    public function has(string $key): bool
    {
        $this->ensureLoaded();
        
        return $this->hasNestedValue($this->config, $key);
    }

    /**
     * Get all configuration.
     */
    public function all(): array
    {
        $this->ensureLoaded();
        
        return $this->config;
    }

    /**
     * Get supported languages.
     */
    public function getSupportedLanguages(): array
    {
        return $this->get('supported_languages', []);
    }

    /**
     * Get default language.
     */
    public function getDefaultLanguage(): string
    {
        return $this->get('default_language', 'en');
    }

    /**
     * Get fallback language.
     */
    public function getFallbackLanguage(): string
    {
        return $this->get('fallback_language', 'en');
    }

    /**
     * Get current language.
     */
    public function getCurrentLanguage(): string
    {
        return $this->get('current_language', $this->getDefaultLanguage());
    }

    /**
     * Set current language.
     */
    public function setCurrentLanguage(string $language): void
    {
        if (!in_array($language, $this->getSupportedLanguages())) {
            throw new \InvalidArgumentException("Language '{$language}' is not supported");
        }
        
        $this->set('current_language', $language);
    }

    /**
     * Get timezone configuration.
     */
    public function getTimezoneConfig(): array
    {
        return $this->get('timezone', [
            'default' => 'UTC',
            'allow_user_override' => true,
            'supported_timezones' => []
        ]);
    }

    /**
     * Get currency configuration.
     */
    public function getCurrencyConfig(): array
    {
        return $this->get('currency', [
            'default' => 'USD',
            'allow_user_override' => true,
            'supported_currencies' => [],
            'precision' => 2,
            'decimal_separator' => '.',
            'thousands_separator' => ','
        ]);
    }

    /**
     * Get date/time format configuration.
     */
    public function getDateTimeConfig(): array
    {
        return $this->get('datetime', [
            'date_format' => 'Y-m-d',
            'time_format' => 'H:i:s',
            'datetime_format' => 'Y-m-d H:i:s',
            'timezone' => 'UTC',
            'locale' => 'en'
        ]);
    }

    /**
     * Get number format configuration.
     */
    public function getNumberConfig(): array
    {
        return $this->get('number', [
            'decimal_separator' => '.',
            'thousands_separator' => ',',
            'precision' => 2
        ]);
    }

    /**
     * Get translation paths.
     */
    public function getTranslationPaths(): array
    {
        return $this->get('translation_paths', []);
    }

    /**
     * Get cache configuration.
     */
    public function getCacheConfig(): array
    {
        return $this->get('cache', [
            'enabled' => true,
            'driver' => 'file',
            'prefix' => 'i18n',
            'ttl' => 3600
        ]);
    }

    /**
     * Get language switcher configuration.
     */
    public function getSwitcherConfig(): array
    {
        return $this->get('switcher', [
            'strategies' => ['url', 'parameter', 'header', 'session', 'cookie'],
            'url_parameter' => 'lang',
            'cookie_name' => 'language',
            'cookie_expires' => 86400 * 30
        ]);
    }

    /**
     * Get fallback configuration.
     */
    public function getFallbackConfig(): array
    {
        return $this->get('fallback', [
            'enabled' => true,
            'chains' => [],
            'max_depth' => 5
        ]);
    }

    /**
     * Get validation configuration.
     */
    public function getValidationConfig(): array
    {
        return $this->get('validation', [
            'strict_mode' => false,
            'log_missing' => true,
            'throw_on_missing' => false
        ]);
    }

    /**
     * Add supported language.
     */
    public function addSupportedLanguage(string $code, string $name, array $options = []): void
    {
        $languages = $this->getSupportedLanguages();
        $languages[$code] = array_merge([
            'name' => $name,
            'native_name' => $name,
            'direction' => 'ltr',
            'enabled' => true
        ], $options);
        
        $this->set('supported_languages', $languages);
    }

    /**
     * Remove supported language.
     */
    public function removeSupportedLanguage(string $code): void
    {
        $languages = $this->getSupportedLanguages();
        unset($languages[$code]);
        $this->set('supported_languages', $languages);
    }

    /**
     * Add translation path.
     */
    public function addTranslationPath(string $path, int $priority = 0): void
    {
        $paths = $this->getTranslationPaths();
        $paths[] = ['path' => $path, 'priority' => $priority];
        
        // Sort by priority (higher first)
        usort($paths, fn($a, $b) => $b['priority'] - $a['priority']);
        
        $this->set('translation_paths', $paths);
    }

    /**
     * Remove translation path.
     */
    public function removeTranslationPath(string $path): void
    {
        $paths = $this->getTranslationPaths();
        $paths = array_filter($paths, fn($p) => $p['path'] !== $path);
        $this->set('translation_paths', array_values($paths));
    }

    /**
     * Set timezone configuration.
     */
    public function setTimezoneConfig(array $config): void
    {
        $this->set('timezone', array_merge($this->getTimezoneConfig(), $config));
    }

    /**
     * Set currency configuration.
     */
    public function setCurrencyConfig(array $config): void
    {
        $this->set('currency', array_merge($this->getCurrencyConfig(), $config));
    }

    /**
     * Set date/time format configuration.
     */
    public function setDateTimeConfig(array $config): void
    {
        $this->set('datetime', array_merge($this->getDateTimeConfig(), $config));
    }

    /**
     * Set number format configuration.
     */
    public function setNumberConfig(array $config): void
    {
        $this->set('number', array_merge($this->getNumberConfig(), $config));
    }

    /**
     * Enable/disable cache.
     */
    public function setCacheEnabled(bool $enabled): void
    {
        $this->set('cache.enabled', $enabled);
    }

    /**
     * Set cache TTL.
     */
    public function setCacheTtl(int $ttl): void
    {
        $this->set('cache.ttl', $ttl);
    }

    /**
     * Enable/disable strict validation.
     */
    public function setStrictValidation(bool $strict): void
    {
        $this->set('validation.strict_mode', $strict);
    }

    /**
     * Get environment-specific configuration.
     */
    public function getEnvironmentConfig(string $environment): array
    {
        return $this->environments[$environment] ?? [];
    }

    /**
     * Set environment-specific configuration.
     */
    public function setEnvironmentConfig(string $environment, array $config): void
    {
        $this->environments[$environment] = $config;
    }

    /**
     * Get current environment.
     */
    public function getCurrentEnvironment(): string
    {
        return $this->currentEnvironment;
    }

    /**
     * Set current environment.
     */
    public function setCurrentEnvironment(string $environment): void
    {
        $this->currentEnvironment = $environment;
        $this->loaded = false; // Force reload with new environment
    }

    /**
     * Detect current environment.
     */
    protected function detectEnvironment(): string
    {
        // Check environment variable
        $env = getenv('APP_ENV') ?: getenv('ENVIRONMENT');
        if ($env) {
            return $env;
        }
        
        // Check server variable
        if (isset($_SERVER['APP_ENV'])) {
            return $_SERVER['APP_ENV'];
        }
        
        // Check for common indicators
        if (isset($_SERVER['SERVER_NAME'])) {
            $serverName = $_SERVER['SERVER_NAME'];
            
            if (str_contains($serverName, 'localhost') || str_contains($serverName, 'dev')) {
                return 'development';
            } elseif (str_contains($serverName, 'staging') || str_contains($serverName, 'test')) {
                return 'staging';
            }
        }
        
        // Default to production
        return 'production';
    }

    /**
     * Process configuration after loading.
     */
    protected function processConfig(): void
    {
        // Set default timezone
        $timezone = $this->get('timezone.default', 'UTC');
        date_default_timezone_set($timezone);
        
        // Process supported languages
        $languages = $this->getSupportedLanguages();
        foreach ($languages as $code => $info) {
            if (!isset($info['name'])) {
                $languages[$code]['name'] = $code;
            }
            if (!isset($info['native_name'])) {
                $languages[$code]['native_name'] = $info['name'];
            }
            if (!isset($info['direction'])) {
                $languages[$code]['direction'] = 'ltr';
            }
            if (!isset($info['enabled'])) {
                $languages[$code]['enabled'] = true;
            }
        }
        $this->set('supported_languages', $languages);
        
        // Process translation paths
        $paths = $this->getTranslationPaths();
        foreach ($paths as $index => $path) {
            if (is_string($path)) {
                $paths[$index] = ['path' => $path, 'priority' => 0];
            }
        }
        usort($paths, fn($a, $b) => $b['priority'] - $a['priority']);
        $this->set('translation_paths', $paths);
        
        // Validate current language
        $currentLanguage = $this->getCurrentLanguage();
        if (!in_array($currentLanguage, array_keys($languages))) {
            $this->setCurrentLanguage($this->getDefaultLanguage());
        }
    }

    /**
     * Get nested value from array.
     */
    protected function getNestedValue(array $array, string $key, mixed $default = null): mixed
    {
        $keys = explode('.', $key);
        $current = $array;
        
        foreach ($keys as $k) {
            if (!is_array($current) || !array_key_exists($k, $current)) {
                return $default;
            }
            $current = $current[$k];
        }
        
        return $current;
    }

    /**
     * Set nested value in array.
     */
    protected function setNestedValue(array &$array, string $key, mixed $value): void
    {
        $keys = explode('.', $key);
        $current = &$array;
        
        foreach ($keys as $k) {
            if (!is_array($current)) {
                $current = [];
            }
            if (!array_key_exists($k, $current)) {
                $current[$k] = [];
            }
            $current = &$current[$k];
        }
        
        $current = $value;
    }

    /**
     * Check if nested value exists.
     */
    protected function hasNestedValue(array $array, string $key): bool
    {
        $keys = explode('.', $key);
        $current = $array;
        
        foreach ($keys as $k) {
            if (!is_array($current) || !array_key_exists($k, $current)) {
                return false;
            }
            $current = $current[$k];
        }
        
        return true;
    }

    /**
     * Ensure configuration is loaded.
     */
    protected function ensureLoaded(): void
    {
        if (!$this->loaded) {
            $this->load();
        }
    }

    /**
     * Reload configuration.
     */
    public function reload(): void
    {
        $this->loaded = false;
        $this->cache->clear();
        $this->load();
    }

    /**
     * Save configuration to file.
     */
    public function save(string $filename = null): bool
    {
        $this->ensureLoaded();
        
        $filename = $filename ?? $this->get('config_file', 'i18n.php');
        $content = '<?php return ' . var_export($this->config, true) . ';';
        
        return file_put_contents($filename, $content) !== false;
    }

    /**
     * Export configuration.
     */
    public function export(string $format = 'php'): string
    {
        $this->ensureLoaded();
        
        return match ($format) {
            'php' => '<?php return ' . var_export($this->config, true) . ';',
            'json' => json_encode($this->config, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE),
            'yaml' => $this->toYaml($this->config),
            default => throw new \InvalidArgumentException("Unsupported export format: {$format}")
        };
    }

    /**
     * Import configuration.
     */
    public function import(string $data, string $format = 'php'): void
    {
        $config = match ($format) {
            'php' => include 'data://text/plain,' . urlencode($data),
            'json' => json_decode($data, true),
            'yaml' => $this->fromYaml($data),
            default => throw new \InvalidArgumentException("Unsupported import format: {$format}")
        };
        
        if (!is_array($config)) {
            throw new \InvalidArgumentException('Invalid configuration data');
        }
        
        $this->config = array_merge($this->defaults, $config);
        $this->processConfig();
        $this->cache->clear();
    }

    /**
     * Convert to YAML.
     */
    protected function toYaml(array $data, int $depth = 0): string
    {
        $yaml = '';
        $indent = str_repeat('  ', $depth);
        
        foreach ($data as $key => $value) {
            if (is_array($value)) {
                $yaml .= "{$indent}{$key}:\n";
                $yaml .= $this->toYaml($value, $depth + 1);
            } else {
                $escapedValue = str_replace(["\n", "\r"], ['\\n', '\\r'], (string) $value);
                $yaml .= "{$indent}{$key}: \"{$escapedValue}\"\n";
            }
        }
        
        return $yaml;
    }

    /**
     * Parse from YAML.
     */
    protected function fromYaml(string $yaml): array
    {
        $data = [];
        $lines = explode("\n", $yaml);
        $stack = [&$data];
        $currentIndent = 0;
        
        foreach ($lines as $line) {
            $line = trim($line);
            if (empty($line) || str_starts_with($line, '#')) {
                continue;
            }
            
            $indent = strlen($line) - strlen(ltrim($line));
            $line = trim($line);
            
            if (preg_match('/^(\w+):\s*$/', $line, $matches)) {
                $key = $matches[1];
                $newArray = [];
                
                // Adjust stack depth
                while ($indent < $currentIndent) {
                    array_pop($stack);
                    $currentIndent -= 2;
                }
                
                $current = &$stack[count($stack) - 1];
                $current[$key] = &$newArray;
                $stack[] = &$newArray;
                $currentIndent = $indent;
            } elseif (preg_match('/^(\w+):\s*"(.*)"$/', $line, $matches)) {
                $key = $matches[1];
                $value = stripslashes($matches[2]);
                
                // Adjust stack depth
                while ($indent < $currentIndent) {
                    array_pop($stack);
                    $currentIndent -= 2;
                }
                
                $current = &$stack[count($stack) - 1];
                $current[$key] = $value;
            }
        }
        
        return $data;
    }

    /**
     * Validate configuration.
     */
    public function validate(): array
    {
        $this->ensureLoaded();
        return $this->validator->validate($this->config);
    }

    /**
     * Get configuration summary.
     */
    public function getSummary(): array
    {
        $this->ensureLoaded();
        
        return [
            'environment' => $this->currentEnvironment,
            'default_language' => $this->getDefaultLanguage(),
            'current_language' => $this->getCurrentLanguage(),
            'fallback_language' => $this->getFallbackLanguage(),
            'supported_languages' => count($this->getSupportedLanguages()),
            'translation_paths' => count($this->getTranslationPaths()),
            'cache_enabled' => $this->get('cache.enabled', false),
            'timezone' => $this->get('timezone.default', 'UTC'),
            'currency' => $this->get('currency.default', 'USD')
        ];
    }

    /**
     * Get default configuration.
     */
    protected function getDefaultConfig(): array
    {
        return [
            'environment' => 'production',
            'default_language' => 'en',
            'fallback_language' => 'en',
            'current_language' => 'en',
            'supported_languages' => [
                'en' => [
                    'name' => 'English',
                    'native_name' => 'English',
                    'direction' => 'ltr',
                    'enabled' => true
                ]
            ],
            'translation_paths' => [
                ['path' => 'resources/lang', 'priority' => 100]
            ],
            'cache' => [
                'enabled' => true,
                'driver' => 'file',
                'prefix' => 'i18n',
                'ttl' => 3600
            ],
            'switcher' => [
                'strategies' => ['url', 'parameter', 'header', 'session', 'cookie'],
                'url_parameter' => 'lang',
                'cookie_name' => 'language',
                'cookie_expires' => 86400 * 30,
                'track_switches' => true
            ],
            'fallback' => [
                'enabled' => true,
                'chains' => [],
                'max_depth' => 5
            ],
            'timezone' => [
                'default' => 'UTC',
                'allow_user_override' => true,
                'supported_timezones' => []
            ],
            'currency' => [
                'default' => 'USD',
                'allow_user_override' => true,
                'supported_currencies' => [],
                'precision' => 2,
                'decimal_separator' => '.',
                'thousands_separator' => ','
            ],
            'datetime' => [
                'date_format' => 'Y-m-d',
                'time_format' => 'H:i:s',
                'datetime_format' => 'Y-m-d H:i:s',
                'timezone' => 'UTC',
                'locale' => 'en'
            ],
            'number' => [
                'decimal_separator' => '.',
                'thousands_separator' => ',',
                'precision' => 2
            ],
            'validation' => [
                'strict_mode' => false,
                'log_missing' => true,
                'throw_on_missing' => false
            ]
        ];
    }

    /**
     * Create I18n config manager instance.
     */
    public static function create(array $config = []): self
    {
        return new self($config);
    }

    /**
     * Create for development environment.
     */
    public static function forDevelopment(): self
    {
        return new self([
            'environment' => 'development',
            'cache' => ['enabled' => false],
            'validation' => ['strict_mode' => true, 'log_missing' => true]
        ]);
    }

    /**
     * Create for testing environment.
     */
    public static function forTesting(): self
    {
        return new self([
            'environment' => 'testing',
            'cache' => ['enabled' => false],
            'validation' => ['strict_mode' => true]
        ]);
    }

    /**
     * Create for production environment.
     */
    public static function forProduction(): self
    {
        return new self([
            'environment' => 'production',
            'cache' => ['enabled' => true, 'ttl' => 7200],
            'validation' => ['strict_mode' => false, 'log_missing' => false]
        ]);
    }
}