<?php
declare(strict_types=1);

namespace Soon\Api\Services;

use Soon\Api\Core\Config;
use Soon\Api\Core\Db;
use Soon\Api\Core\Json;

/**
 * .soon 文件服务：JSON 数据流模型，乐观锁、配额、软删除。
 */
final class FileService
{
    public static function usersRoot(): string
    {
        $dir = (string)Config::get('storage.users_dir', SOON_SERVER_ROOT . '/storage/users');
        if (!is_dir($dir)) {
            @mkdir($dir, 0775, true);
        }
        return $dir;
    }

    public static function userDir(int $userId): string
    {
        $root = self::usersRoot();
        $dir = $root . '/' . $userId;
        if (!is_dir($dir)) {
            @mkdir($dir, 0775, true);
        }
        return $dir;
    }

    public static function quotaBytes(int $userId): int
    {
        $plan = MembershipService::currentPlan($userId);
        $planQuota = (int)($plan['quota_mb'] ?? 50);
        return $planQuota * 1024 * 1024;
    }

    public static function usedBytes(int $userId): int
    {
        $stmt = Db::pdo()->prepare('SELECT COALESCE(SUM(size),0) AS s FROM soon_files WHERE user_id = :u AND deleted_at IS NULL');
        $stmt->execute(['u' => $userId]);
        return (int)$stmt->fetchColumn();
    }

    public static function fileCount(int $userId): int
    {
        $stmt = Db::pdo()->prepare('SELECT COUNT(*) FROM soon_files WHERE user_id = :u AND deleted_at IS NULL');
        $stmt->execute(['u' => $userId]);
        return (int)$stmt->fetchColumn();
    }

    public static function list(int $userId, int $limit, int $offset): array
    {
        $stmt = Db::pdo()->prepare(
            'SELECT id, name, size, version, updated_at, created_at '
            . 'FROM soon_files WHERE user_id = :u AND deleted_at IS NULL '
            . 'ORDER BY updated_at DESC LIMIT :lim OFFSET :off'
        );
        $stmt->bindValue('u', $userId, \PDO::PARAM_INT);
        $stmt->bindValue('lim', $limit, \PDO::PARAM_INT);
        $stmt->bindValue('off', $offset, \PDO::PARAM_INT);
        $stmt->execute();
        return $stmt->fetchAll();
    }

    public static function create(int $userId, string $name, string $json): array
    {
        $maxFiles = MembershipService::maxFilesLimit($userId);
        if (self::fileCount($userId) >= $maxFiles) {
            Json::fail('file_limit_exceeded', '已达文件数量上限（' . $maxFiles . ' 个），请清理文件或续订', 413);
        }
        $size = strlen($json);
        $quota = self::quotaBytes($userId);
        $used = self::usedBytes($userId);
        if ($quota > 0 && $used + $size > $quota) {
            Json::fail('quota_exceeded', '存储空间已满，请清理文件或续订', 413);
        }
        $now = date('Y-m-d H:i:s');
        $stmt = Db::pdo()->prepare(
            'INSERT INTO soon_files (user_id, name, json, size, version, created_at, updated_at) '
            . 'VALUES (:u, :n, :j, :s, 1, :created_at, :updated_at)'
        );
        $stmt->execute(['u' => $userId, 'n' => $name, 'j' => $json, 's' => $size, 'created_at' => $now, 'updated_at' => $now]);
        $id = (int)Db::pdo()->lastInsertId();
        return ['id' => $id, 'name' => $name, 'size' => $size, 'version' => 1, 'updated_at' => $now];
    }

    public static function update(int $userId, int $id, string $name, string $json, ?int $expectedVersion): array
    {
        $newSize = strlen($json);
        $quota = self::quotaBytes($userId);
        $used = self::usedBytes($userId);
        $pdo = Db::pdo();
        $pdo->beginTransaction();
        try {
            $stmt = $pdo->prepare('SELECT * FROM soon_files WHERE id = :id AND user_id = :u AND deleted_at IS NULL FOR UPDATE');
            $stmt->execute(['id' => $id, 'u' => $userId]);
            $row = $stmt->fetch();
            if (!$row) {
                throw new \RuntimeException('not_found');
            }
            if ($expectedVersion !== null && (int)$row['version'] !== $expectedVersion) {
                throw new \RuntimeException('version_conflict');
            }
            $oldSize = (int)$row['size'];
            if ($quota > 0 && ($used - $oldSize + $newSize) > $quota) {
                throw new \RuntimeException('quota_exceeded');
            }
            $now = date('Y-m-d H:i:s');
            $newVersion = (int)$row['version'] + 1;
            $upd = $pdo->prepare(
                'UPDATE soon_files SET name = :n, json = :j, size = :s, version = :v, updated_at = :ts '
                . 'WHERE id = :id AND version = :cv'
            );
            $upd->execute([
                'n' => $name, 'j' => $json, 's' => $newSize, 'v' => $newVersion,
                'ts' => $now, 'id' => $id, 'cv' => (int)$row['version'],
            ]);
            if ($upd->rowCount() === 0) {
                throw new \RuntimeException('version_conflict');
            }
            $pdo->commit();
            return ['id' => $id, 'name' => $name, 'size' => $newSize, 'version' => $newVersion, 'updated_at' => $now];
        } catch (\RuntimeException $e) {
            if ($pdo->inTransaction()) $pdo->rollBack();
            if ($e->getMessage() === 'not_found') Json::fail('not_found', '文件不存在', 404);
            if ($e->getMessage() === 'version_conflict') Json::fail('conflict', '版本冲突，请刷新后重试', 409);
            if ($e->getMessage() === 'quota_exceeded') Json::fail('quota_exceeded', '存储空间已满', 413);
            throw $e;
        } catch (\Throwable $e) {
            if ($pdo->inTransaction()) $pdo->rollBack();
            throw $e;
        }
    }

    public static function softDelete(int $userId, int $id): void
    {
        $stmt = Db::pdo()->prepare('UPDATE soon_files SET deleted_at = :ts WHERE id = :id AND user_id = :u');
        $stmt->execute(['ts' => date('Y-m-d H:i:s'), 'id' => $id, 'u' => $userId]);
    }

    public static function fetch(int $userId, int $id): array
    {
        $stmt = Db::pdo()->prepare('SELECT * FROM soon_files WHERE id = :id AND user_id = :u AND deleted_at IS NULL');
        $stmt->execute(['id' => $id, 'u' => $userId]);
        $row = $stmt->fetch();
        if (!$row) {
            Json::fail('not_found', '文件不存在', 404);
        }
        return $row;
    }
}