import { Provide, Config } from "@midwayjs/core";
import { S3Client, PutObjectCommand, GetObjectCommand } from "@aws-sdk/client-s3";
import { getSignedUrl } from "@aws-sdk/s3-request-presigner";
import { createReadStream, statSync } from "fs";
import { randomUUID } from "crypto";
import { extname } from "path";
import { UploadFileInfo } from "@midwayjs/upload";

// RustFS 配置结构（见 config.default.ts 的 rustfs 段）
interface RustFsConfig {
	endpoint: string;
	port: number;
	useSSL: boolean;
	accessKey: string;
	secretKey: string;
	region: string;
	bucket: string;
	bucketProd: string;
	bucketTest: string;
	forcePathStyle: boolean;
	presignExpires: number;
	keyPrefix: string;
}

export interface UploadResult {
	key: string;
	url: string;
	name: string;
	size: number;
}

@Provide()
export class UploadService {
	@Config("rustfs")
	rustfsConfig!: RustFsConfig;

	private client: S3Client | null = null;

	private getClient(): S3Client {
		if (!this.client) {
			const protocol = this.rustfsConfig.useSSL ? "https" : "http";
			this.client = new S3Client({
				endpoint: `${protocol}://${this.rustfsConfig.endpoint}:${this.rustfsConfig.port}`,
				region: this.rustfsConfig.region,
				credentials: {
					accessKeyId: this.rustfsConfig.accessKey,
					secretAccessKey: this.rustfsConfig.secretKey
				},
				// RustFS 仅支持 path-style 访问
				forcePathStyle: this.rustfsConfig.forcePathStyle
			});
		}
		return this.client;
	}

	private get bucket(): string {
		return this.rustfsConfig.bucket;
	}

	/**
	 * 上传单个文件到 RustFS，返回对象 key 与预签名访问 URL
	 */
	async uploadFile(file: UploadFileInfo<string>): Promise<UploadResult> {
		if (!file || !file.data) {
			throw new Error("上传文件为空");
		}
		const ext = extname(file.filename || "").toLowerCase();
		const now = new Date();
		const yyyymm = `${now.getFullYear()}${String(now.getMonth() + 1).padStart(2, "0")}`;
		const key = `${this.rustfsConfig.keyPrefix}/${yyyymm}/${randomUUID()}${ext}`;

		await this.getClient().send(
			new PutObjectCommand({
				Bucket: this.bucket,
				Key: key,
				Body: createReadStream(file.data),
				ContentType: file.mimeType || "application/octet-stream"
			})
		);

		let size = 0;
		try {
			size = statSync(file.data).size;
		} catch {
			size = 0;
		}

		return {
			key,
			url: await this.getPresignedUrl(key),
			name: file.filename,
			size
		};
	}

	/**
	 * 按对象 key 生成预签名访问 URL（默认 1 小时有效）
	 */
	async getPresignedUrl(key: string): Promise<string> {
		if (!key) return "";
		return getSignedUrl(
			this.getClient(),
			new GetObjectCommand({ Bucket: this.bucket, Key: key }),
			{ expiresIn: this.rustfsConfig.presignExpires }
		);
	}

	/**
	 * 批量把对象 key 转成预签名 URL，返回 key → url 映射（key 非法时返回空串）
	 */
	async getPresignedUrlMap(keys: string[]): Promise<Record<string, string>> {
		const map: Record<string, string> = {};
		for (const key of keys) {
			try {
				map[key] = await this.getPresignedUrl(key);
			} catch {
				map[key] = "";
			}
		}
		return map;
	}
}