import "server-only";

import { S3Client, PutObjectCommand } from "@aws-sdk/client-s3";
import { put } from "@vercel/blob";
import {
  getDefaultStorageConfig,
  getStorageConfigById,
  getSystemSetting,
} from "@/lib/db/queries";

type S3UploadConfig = {
  endpoint: string;
  region: string;
  bucket: string;
  accessKeyId: string;
  secretAccessKey: string;
  publicUrl?: string;
};

let lastKnownGoodDbS3Config: S3UploadConfig | null = null;
const STORAGE_FAILOVER_CONFIG_KEY = "storage_failover_config";

// 获取文件的 Content-Type
function getContentType(filename: string): string {
  const ext = filename.toLowerCase().split(".").pop();
  const types: Record<string, string> = {
    jpg: "image/jpeg",
    jpeg: "image/jpeg",
    png: "image/png",
    gif: "image/gif",
    webp: "image/webp",
    svg: "image/svg+xml",
    pdf: "application/pdf",
    json: "application/json",
    txt: "text/plain",
    html: "text/html",
    css: "text/css",
    js: "application/javascript",
  };
  return types[ext ?? ""] ?? "application/octet-stream";
}

// S3/MinIO 上传函数（使用 AWS SDK）
async function uploadToS3(
  filename: string,
  buffer: ArrayBuffer,
  config: S3UploadConfig
) {
  const { endpoint, region, bucket, accessKeyId, secretAccessKey, publicUrl } = config;

  // 生成唯一的文件名
  const timestamp = Date.now();
  const randomString = Math.random().toString(36).slice(2, 8);
  const ext = filename.split(".").pop();
  const key = `uploads/${timestamp}-${randomString}.${ext}`;

  const contentType = getContentType(filename);

  try {
    // 创建 S3 客户端（支持 MinIO）
    const s3Client = new S3Client({
      endpoint: endpoint,
      region: region || "auto",
      credentials: {
        accessKeyId: accessKeyId,
        secretAccessKey: secretAccessKey,
      },
      // 关键：MinIO 需要使用 path-style URL
      forcePathStyle: true,
    });

    console.log(`[S3 Upload] Uploading to: ${endpoint}/${bucket}/${key}`);

    // 上传文件
    const command = new PutObjectCommand({
      Bucket: bucket,
      Key: key,
      Body: Buffer.from(buffer),
      ContentType: contentType,
      // 设置为公开可读（如果您的 MinIO 桶支持）
      ACL: "public-read",
    });

    await s3Client.send(command);

    console.log(`[S3 Upload] Upload successful: ${key}`);

    // 返回文件的公开 URL
    // MinIO 的公开 URL 格式通常是: http://endpoint:port/bucket/key
    let fileUrl: string;
    if (publicUrl) {
      // 如果用户配置了自定义公开 URL，使用它
      fileUrl = `${publicUrl}/${key}`;
    } else {
      // 否则使用 endpoint + bucket + key
      const cleanEndpoint = endpoint.replace(/\/$/, ""); // 移除末尾的斜杠
      fileUrl = `${cleanEndpoint}/${bucket}/${key}`;
    }

    console.log(`[S3 Upload] File URL: ${fileUrl}`);

    return {
      url: fileUrl,
      pathname: key,
      contentType,
    };
  } catch (error) {
    console.error("[S3 Upload] Error:", error);
    throw error;
  }
}

function toDbS3UploadConfig(raw: unknown): S3UploadConfig | null {
  const value = raw as Record<string, unknown> | null | undefined;
  if (
    !value ||
    value.type !== "s3" ||
    !value.isEnabled ||
    !value.endpoint ||
    !value.bucket ||
    !value.accessKeyId ||
    !value.secretAccessKey
  ) {
    return null;
  }

  return {
    endpoint: String(value.endpoint),
    region: String(value.region || "auto"),
    bucket: String(value.bucket),
    accessKeyId: String(value.accessKeyId),
    secretAccessKey: String(value.secretAccessKey),
    publicUrl: value.publicUrl ? String(value.publicUrl) : undefined,
  };
}

function buildEnvS3Config(): S3UploadConfig | null {
  if (
    process.env.S3_ENDPOINT &&
    process.env.S3_BUCKET &&
    process.env.S3_ACCESS_KEY_ID &&
    process.env.S3_SECRET_ACCESS_KEY
  ) {
    return {
      endpoint: process.env.S3_ENDPOINT,
      region: process.env.S3_REGION ?? "auto",
      bucket: process.env.S3_BUCKET,
      accessKeyId: process.env.S3_ACCESS_KEY_ID,
      secretAccessKey: process.env.S3_SECRET_ACCESS_KEY,
      publicUrl: process.env.S3_PUBLIC_URL,
    };
  }
  return null;
}

function normalizeStorageFailoverConfig(value: unknown): {
  enabled: boolean;
  backupStorageConfigId: string;
} {
  const raw =
    value && typeof value === "object" && !Array.isArray(value)
      ? (value as Record<string, unknown>)
      : {};
  return {
    enabled: raw.enabled === true,
    backupStorageConfigId: String(raw.backupStorageConfigId || "").trim(),
  };
}

async function uploadWithBackupStorageConfig(
  filename: string,
  buffer: ArrayBuffer,
  primaryStorageConfigId?: string
): Promise<{ url: string; pathname: string; contentType: string } | null> {
  try {
    const setting = await getSystemSetting({ key: STORAGE_FAILOVER_CONFIG_KEY });
    const failover = normalizeStorageFailoverConfig(setting?.value);

    if (!failover.enabled || !failover.backupStorageConfigId) {
      return null;
    }

    if (
      primaryStorageConfigId &&
      failover.backupStorageConfigId === primaryStorageConfigId
    ) {
      console.warn(
        "[Upload] Backup storage config equals default storage config, skipping failover retry"
      );
      return null;
    }

    const backupStorageConfig = await getStorageConfigById({
      id: failover.backupStorageConfigId,
    });
    const backupS3Config = toDbS3UploadConfig(backupStorageConfig);

    if (!backupS3Config) {
      console.warn(
        "[Upload] Backup storage config is invalid, disabled, or not S3 compatible"
      );
      return null;
    }

    console.log(
      `[Upload] Retrying with backup S3 config: ${backupStorageConfig?.name ?? failover.backupStorageConfigId}`
    );

    const uploaded = await uploadToS3(filename, buffer, backupS3Config);
    lastKnownGoodDbS3Config = backupS3Config;
    return uploaded;
  } catch (error) {
    console.error("[Upload] Backup storage config retry failed:", error);
    return null;
  }
}

// 上传文件到存储服务
export async function uploadFile(
  filename: string,
  buffer: ArrayBuffer
): Promise<{ url: string; pathname: string; contentType: string }> {
  console.log(`[Upload] Starting upload for file: ${filename}`);

  let dbS3Config: S3UploadConfig | null = null;
  let primaryStorageConfigId: string | undefined;
  try {
    const storageConfig = await getDefaultStorageConfig();
    primaryStorageConfigId = storageConfig?.id;
    dbS3Config = toDbS3UploadConfig(storageConfig);
    if (dbS3Config) {
      console.log(`[Upload] Using database S3 config: ${storageConfig?.name}`);
      console.log(`[Upload] Endpoint: ${dbS3Config.endpoint}`);
      console.log(`[Upload] Bucket: ${dbS3Config.bucket}`);
      const uploaded = await uploadToS3(filename, buffer, dbS3Config);
      lastKnownGoodDbS3Config = dbS3Config;
      return uploaded;
    }
    console.warn("[Upload] No valid S3 config in database");
  } catch (error) {
    console.error("[Upload] Database storage path failed:", error);

    const uploadedFromBackup = await uploadWithBackupStorageConfig(
      filename,
      buffer,
      primaryStorageConfigId
    );
    if (uploadedFromBackup) {
      return uploadedFromBackup;
    }

    if (lastKnownGoodDbS3Config) {
      try {
        console.log("[Upload] Retrying with last known good database S3 config");
        return await uploadToS3(filename, buffer, lastKnownGoodDbS3Config);
      } catch (retryError) {
        console.error("[Upload] Last known S3 config upload failed:", retryError);
      }
    }
  }

  if (!dbS3Config) {
    const uploadedFromBackup = await uploadWithBackupStorageConfig(
      filename,
      buffer,
      primaryStorageConfigId
    );
    if (uploadedFromBackup) {
      return uploadedFromBackup;
    }
  }

  const envS3Config = buildEnvS3Config();
  if (envS3Config) {
    console.log("[Upload] Using environment variable S3 config");
    return await uploadToS3(filename, buffer, envS3Config);
  }

  if (!process.env.BLOB_READ_WRITE_TOKEN) {
    throw new Error(
      "No available storage backend: database S3 failed, env S3 missing, and BLOB_READ_WRITE_TOKEN is not configured."
    );
  }

  // 最终回退到 Vercel Blob
  console.log("[Upload] Falling back to Vercel Blob");
  const data = await put(filename, buffer, {
    access: "public",
  });

  return {
    url: data.url,
    pathname: data.pathname,
    contentType: getContentType(filename),
  };
}

// 获取当前使用的存储类型
export async function getStorageType(): Promise<
  "database-s3" | "env-s3" | "vercel-blob"
> {
  try {
    const storageConfig = await getDefaultStorageConfig();
    if (
      storageConfig &&
      storageConfig.type === "s3" &&
      storageConfig.endpoint &&
      storageConfig.bucket
    ) {
      return "database-s3";
    }
  } catch (error) {
    // ignore
  }

  if (process.env.S3_ENDPOINT && process.env.S3_BUCKET) {
    return "env-s3";
  }

  return "vercel-blob";
}