<?php
declare(strict_types=1);

namespace NeonBlog;

final class Config
{
    /** @var array<string, mixed> */
    private array $data;

    private string $path;

    /** @param array<string, mixed> $data */
    private function __construct(string $path, array $data)
    {
        $this->path = $path;
        $this->data = array_replace_recursive(self::defaults(), $data);
    }

    public static function load(string $path): self
    {
        $data = [];
        if (is_file($path)) {
            $decoded = json_decode((string) file_get_contents($path), true);
            if (is_array($decoded)) {
                $data = $decoded;
            }
        }

        return new self($path, $data);
    }

    /** @return mixed */
    public function get(string $key, mixed $default = null): mixed
    {
        $segments = explode('.', $key);
        $value = $this->data;
        foreach ($segments as $segment) {
            if (!is_array($value) || !array_key_exists($segment, $value)) {
                return $default;
            }
            $value = $value[$segment];
        }

        return $value;
    }

    public function set(string $key, mixed $value): void
    {
        $segments = explode('.', $key);
        $cursor = &$this->data;
        foreach ($segments as $segment) {
            if (!isset($cursor[$segment]) || !is_array($cursor[$segment])) {
                $cursor[$segment] = [];
            }
            $cursor = &$cursor[$segment];
        }
        $cursor = $value;
    }

    /** @return array<string, mixed> */
    public function all(): array
    {
        return $this->data;
    }

    public function save(): void
    {
        $dir = dirname($this->path);
        if (!is_dir($dir)) {
            mkdir($dir, 0775, true);
        }

        file_put_contents(
            $this->path,
            json_encode($this->data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES) . PHP_EOL
        );
    }

    public function baseUrl(): string
    {
        $configured = trim((string) $this->get('base_url', ''));
        if ($configured !== '') {
            $parts = parse_url($configured);
            if (is_array($parts) && isset($parts['scheme'], $parts['host'])) {
                $port = isset($parts['port']) ? ':' . $parts['port'] : '';
                return $parts['scheme'] . '://' . $parts['host'] . $port;
            }

            return rtrim($configured, '/');
        }

        if (PHP_SAPI === 'cli') {
            return '';
        }

        $https = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off')
            || (($_SERVER['HTTP_X_FORWARDED_PROTO'] ?? '') === 'https');
        $scheme = $https ? 'https' : 'http';
        $host = $_SERVER['HTTP_HOST'] ?? 'localhost';

        return $scheme . '://' . $host;
    }

    public function basePath(): string
    {
        $configured = trim((string) $this->get('base_path', ''));
        if ($configured !== '') {
            return self::normalizeBasePath($configured);
        }

        $baseUrl = trim((string) $this->get('base_url', ''));
        if ($baseUrl !== '') {
            $path = parse_url($baseUrl, PHP_URL_PATH);
            if (is_string($path) && $path !== '') {
                return self::normalizeBasePath($path);
            }
        }

        if (PHP_SAPI === 'cli') {
            return '';
        }

        $scriptName = str_replace('\\', '/', (string) ($_SERVER['SCRIPT_NAME'] ?? ''));
        $scriptDir = dirname($scriptName);
        if ($scriptDir === '.' || $scriptDir === '/') {
            return '';
        }

        return self::normalizeBasePath($scriptDir);
    }

    /** @return array<string, mixed> */
    private static function defaults(): array
    {
        return [
            'site' => [
                'title' => 'Neon Notes',
                'tagline' => 'A fast file-first blog CMS',
                'description' => 'A Markdown blog powered by PHP, SQLite, JSON, and plain files.',
                'author' => 'Editor',
                'language' => 'en',
            ],
            'base_url' => '',
            'base_path' => '',
            'timezone' => 'UTC',
            'theme' => 'neon',
            'posts_per_page' => 6,
            'comments' => [
                'enabled' => true,
                'moderate' => true,
                'captcha' => true,
                'honeypot_field' => 'website_url',
            ],
            'stats' => [
                'enabled' => true,
                'hash_salt' => 'change-me',
            ],
            'social' => [],
        ];
    }

    private static function normalizeBasePath(string $path): string
    {
        $path = '/' . trim($path, '/');
        return $path === '/' ? '' : $path;
    }
}