<?php
/**
 * 本地磁盘驱动 —— 也是云端失败时的**回退目标**。
 * 绝不因为云配置出问题就让用户丢文件。
 */

declare(strict_types=1);

namespace App\Storage;

final class LocalDriver implements StorageDriver
{
    private string $root;

    public function __construct(string $root)
    {
        $this->root = rtrim($root, '/');
    }

    public function id(): string
    {
        return 'local';
    }

    public function validateConfig(): string
    {
        return is_dir($this->root) || @mkdir($this->root, 0755, true)
            ? ''
            : '本地存储目录不可写';
    }

    private function abs(string $key): string
    {
        // 挡目录穿越：.. 一律拒绝
        $key = ltrim(str_replace('\\', '/', $key), '/');
        if (strpos($key, '..') !== false) {
            return $this->root . '/__invalid__';
        }
        return $this->root . '/' . $key;
    }

    public function putFile(string $srcPath, string $key, ?string $mime = null): array
    {
        $dst = $this->abs($key);
        $dir = dirname($dst);
        if (!is_dir($dir) && !@mkdir($dir, 0755, true)) {
            return ['ok' => false, 'error' => '建不了目录：' . $dir];
        }
        if (!@copy($srcPath, $dst)) {
            return ['ok' => false, 'error' => '复制文件失败'];
        }
        @chmod($dst, 0644);
        return ['ok' => true, 'error' => ''];
    }

    public function putContents(string $binary, string $key, ?string $mime = null): array
    {
        $dst = $this->abs($key);
        $dir = dirname($dst);
        if (!is_dir($dir) && !@mkdir($dir, 0755, true)) {
            return ['ok' => false, 'error' => '建不了目录：' . $dir];
        }
        if (@file_put_contents($dst, $binary) === false) {
            return ['ok' => false, 'error' => '写入文件失败'];
        }
        @chmod($dst, 0644);
        return ['ok' => true, 'error' => ''];
    }

    public function delete(string $key): array
    {
        $p = $this->abs($key);
        if (is_file($p) && !@unlink($p)) {
            return ['ok' => false, 'error' => '删不掉：' . $key];
        }
        return ['ok' => true, 'error' => ''];
    }

    public function get(string $key, array $extra = []): array
    {
        $p = $this->abs($key);
        if (!is_file($p)) {
            return ['ok' => false, 'status' => 404, 'headers' => [], 'body' => '', 'error' => '文件不存在'];
        }
        $body = (string)@file_get_contents($p);
        return ['ok' => true, 'status' => 200, 'headers' => [], 'body' => $body, 'error' => ''];
    }

    public function exists(string $key): bool
    {
        return is_file($this->abs($key));
    }

    /** 本地文件返回站点相对路径（相对站点根，前面带 /） */
    public function url(string $key): string
    {
        return '/' . ltrim(str_replace('\\', '/', $key), '/');
    }
}