import * as fs from "node:fs";
import { fileURLToPath } from "node:url";
import { dirname } from "node:path";
import type Koa from "koa";
import send from "koa-send";
import rename from "rename";
import { serverLogger } from "../index.js";
import { contentDisposition } from "@/misc/content-disposition.js";
import { DriveFiles } from "@/models/index.js";
import { InternalStorage } from "@/services/drive/internal-storage.js";
import { createTemp } from "@/misc/create-temp.js";
import { downloadUrl } from "@/misc/download-url.js";
import { detectType } from "@/misc/get-file-info.js";
import { convertToWebp } from "@/services/drive/image-processor.js";
import { GenerateVideoThumbnail } from "@/services/drive/generate-video-thumbnail.js";
import { StatusError } from "@/misc/fetch.js";
import { FILE_TYPE_BROWSERSAFE, MINUTE } from "@/const.js";
import { IEndpointMeta } from "@/server/api/endpoints.js";
import { getIpHash } from "@/misc/get-ip-hash.js";
import { limiter } from "@/server/api/limiter.js";

const _filename = fileURLToPath(import.meta.url);
const _dirname = dirname(_filename);

const assets = `${_dirname}/../../server/file/assets/`;

const commonReadableHandlerGenerator =
	(ctx: Koa.Context) => (e: Error): void => {
		serverLogger.error(e);
		ctx.status = 500;
		ctx.set("Cache-Control", "max-age=300");
	};

export default async function (ctx: Koa.Context) {
	const key = ctx.params.key;

	// koa will automatically load the `X-Forwarded-For` header if `proxy: true` is configured in the app.
	let limitActor: string;
	limitActor = getIpHash(ctx.ip);

	const limit: IEndpointMeta["limit"] = {
		key: `drive-file:${key}`,
		duration: MINUTE * 10,
		max: 10
	}

	// Rate limit
	await limiter(
		limit as IEndpointMeta["limit"] & { key: NonNullable<string> },
		limitActor,
	).catch((e) => {
		const remainingTime = e.remainingTime
			? `Please try again in ${e.remainingTime}.`
			: "Please try again later.";

		ctx.status = 429;
		ctx.body = "Rate limit exceeded. " + remainingTime;
	});

	if (ctx.status == 429) return;

	// Fetch drive file
	const file = await DriveFiles.createQueryBuilder("file")
		.where("file.accessKey = :accessKey", { accessKey: key })
		.orWhere("file.thumbnailAccessKey = :thumbnailAccessKey", {
			thumbnailAccessKey: key,
		})
		.orWhere("file.webpublicAccessKey = :webpublicAccessKey", {
			webpublicAccessKey: key,
		})
		.getOne();

	if (file == null) {
		ctx.status = 404;
		ctx.set("Cache-Control", "max-age=86400");
		await send(ctx as any, "/dummy.png", { root: assets });
		return;
	}

	ctx.set("X-Content-Type-Options", "nosniff");

	const isThumbnail = file.thumbnailAccessKey === key;
	const isWebpublic = file.webpublicAccessKey === key;

	if (!file.storedInternal) {
		if (file.isLink && file.uri) {
			// 期限切れリモートファイル
			const [path, cleanup] = await createTemp();

			try {
				await downloadUrl(file.uri, path);

				const { mime, ext } = await detectType(path);

				const convertFile = async () => {
					if (isThumbnail) {
						if (
							[
								"image/jpeg",
								"image/webp",
								"image/png",
								"image/svg+xml",
								"image/avif",
							].includes(mime)
						) {
							return await convertToWebp(path, 996, 560);
						} else if (mime.startsWith("video/")) {
							return await GenerateVideoThumbnail(path);
						}
					}

					if (isWebpublic) {
						if (["image/svg+xml"].includes(mime)) {
							return await convertToWebp(path, 2048, 2048, 100);
						}
					}

					return {
						data: fs.readFileSync(path),
						ext,
						type: mime,
					};
				};

				const image = await convertFile();
				ctx.body = image.data;
				ctx.set(
					"Content-Type",
					FILE_TYPE_BROWSERSAFE.includes(image.type)
						? image.type
						: "application/octet-stream",
				);
				ctx.set("Cache-Control", "max-age=31536000, immutable");
			} catch (e) {
				serverLogger.error(`${e}`);

				if (e instanceof StatusError && !e.isRetryable) {
					ctx.status = e.statusCode;
					ctx.set("Cache-Control", "max-age=86400");
				} else {
					ctx.status = 500;
					ctx.set("Cache-Control", "max-age=300");
				}
			} finally {
				cleanup();
			}
			return;
		}

		ctx.status = 204;
		ctx.set("Cache-Control", "max-age=86400");
		return;
	}

	if (isThumbnail || isWebpublic) {
		const { mime, ext } = await detectType(InternalStorage.resolvePath(key));
		const filename = rename(file.name, {
			suffix: isThumbnail ? "-thumb" : "-web",
			extname: ext ? `.${ext}` : undefined,
		}).toString();

		ctx.body = InternalStorage.read(key);
		ctx.set(
			"Content-Type",
			FILE_TYPE_BROWSERSAFE.includes(mime) ? mime : "application/octet-stream",
		);
		ctx.set("Cache-Control", "max-age=31536000, immutable");
		ctx.set("Content-Disposition", contentDisposition("inline", filename));
	} else {
		const readable = InternalStorage.read(file.accessKey!);
		readable.on("error", commonReadableHandlerGenerator(ctx));
		ctx.body = readable;
		ctx.set(
			"Content-Type",
			FILE_TYPE_BROWSERSAFE.includes(file.type)
				? file.type
				: "application/octet-stream",
		);
		ctx.set("Cache-Control", "max-age=31536000, immutable");
		ctx.set("Content-Disposition", contentDisposition("inline", file.name));
	}
}
