import { StatusMap } from "elysia";
import { fileTypeFromFile } from "file-type";
import type { Directory, FileListing } from "music-server-shared/types";
import { readdir, stat } from "node:fs/promises";
import path from "node:path";
import { coverRegex, fileTypeCache, mediaTypes, musicRoot, PathInfo, probeCache, ServerError } from "./shared";

export async function findAsync<T>(arr: Array<T>, asyncCallback: (value: T) => Promise<boolean>) {
	const promises = arr.map(asyncCallback);
	const results = await Promise.all(promises);
	const index = results.findIndex((result) => result);
	return arr[index];
}

type CoverResult = { path: string; info: PathInfo } | { info: ServerError };

export async function findCover(dirPath: string): Promise<CoverResult> {
	let coverFile: string | undefined;
	try {
		coverFile = await findAsync(await readdir(dirPath), async (file) => {
			return file.match(coverRegex) != null && (await stat(path.join(dirPath, file))).isFile();
		});
		const above = path.dirname(dirPath);
		if (!coverFile && isBelow(musicRoot, above)) {
			return findCover(above);
		}
		// biome-ignore lint/suspicious/noExplicitAny:
	} catch (error: any) {
		if (error?.code !== "ENOENT") {
			console.error("error getting cover: readdirSync failed:", error);
			return { info: new ServerError(StatusMap["Internal Server Error"], "error getting cover: readdirSync failed") };
		}
		return { info: new ServerError(StatusMap["Not Found"], "Directory not found") };
	}
	if (coverFile) {
		const info = (await getPathInfo(path.join(dirPath, coverFile))) as PathInfo | ServerError;
		if (info instanceof ServerError) {
			return { info: info };
		}
		return { path: path.join(dirPath, coverFile), info };
	}
	return { info: new ServerError(StatusMap["Not Found"], "Cover not found") };
}

export type FfprobeData = {
	format: {
		duration: number;
		bit_rate: number;
	};
};

// Rewritten to spawn ffprobe via bun.spawn
export async function probeFile(filePath: string): Promise<FfprobeData> {
	const cached = probeCache.get(filePath);
	if (cached) {
		return cached;
	}

	const ffprobeArgs = ["-v", "quiet", "-print_format", "json", "-show_format", "-show_streams", filePath];

	const proc = Bun.spawn(["ffprobe", ...ffprobeArgs], {
		stdout: "pipe",
		stderr: "pipe",
	});
	const text = await new Response(proc.stdout).text();
	let json: FfprobeData;
	try {
		json = JSON.parse(text);
	} catch (e) {
		const errText = await new Response(proc.stderr).text();
		throw new ServerError(StatusMap["Internal Server Error"], `ffprobe failed: ${errText || text}`);
	}

	probeCache.set(filePath, json);
	return json;
}

export async function getPathInfo(filePath: string): Promise<PathInfo | ServerError | undefined> {
	try {
		const stats = await stat(filePath);
		if (stats.isDirectory()) {
			return undefined;
		}
		let mimeType = fileTypeCache.get(filePath);
		if (!mimeType) {
			const type = await fileTypeFromFile(filePath);
			mimeType = type?.mime;
			if (mimeType) {
				fileTypeCache.set(filePath, mimeType);
			} else {
				console.error("Failed to determine MIME type for:", filePath);
				return new ServerError(StatusMap["Internal Server Error"], "Filetype scan failed");
			}
		}
		return new PathInfo(mimeType);
		// biome-ignore lint/suspicious/noExplicitAny:
	} catch (error: any) {
		if (error?.code === "ENOENT") {
			return new ServerError(StatusMap["Not Found"], "File not found");
		}
		console.error("Error scanning file:", filePath, error.message);
		return new ServerError(StatusMap["Internal Server Error"], "Internal Server Error");
	}
}

export function matchesType(mimeType: string, types: string[]): boolean {
	return types.includes(mimeType.split("/", 1)[0]);
}

export function needsTranscoding(probe: FfprobeData, requestBitrate?: unknown) {
	const bitrate = Number(requestBitrate);
	return probe.format.bit_rate && bitrate > 0 && bitrate < probe.format.bit_rate;
}

export function isBelow(basePath: string, targetPath: string) {
	const relativePath = path.relative(basePath, targetPath);
	return relativePath && !relativePath.startsWith("..");
}

export async function listFiles(subPath: string, recursive: boolean): Promise<Directory | ServerError> {
	const files: FileListing = [];

	try {
		for (const file of await readdir(subPath)) {
			const itemPath = path.join(subPath, file);
			if (!isBelow(musicRoot, itemPath)) {
				console.log(`Skipping ${itemPath} as it is outside the base path.`);
				continue;
			}

			const pathInfoResult = await getPathInfo(itemPath);
			if (!pathInfoResult) {
				if (recursive) {
					const subListing = await listFiles(itemPath, true);
					if (subListing instanceof ServerError) throw subListing;
					files.push({ name: file, files: subListing.files });
				} else {
					files.push({ name: file, files: [] });
				}
			} else if (pathInfoResult instanceof PathInfo && matchesType(pathInfoResult.mimeType, mediaTypes)) {
				let duration = 0;
				try {
					const probe = await probeFile(itemPath);
					duration = probe.format.duration || 0;
				} catch (probeError) {
					console.error("ffprobe error:", probeError);
				}
				files.push({ name: file, duration: duration });
			}
		}
		files.sort((a, b) => a.name.localeCompare(b.name));
		return { name: path.basename(path.relative(musicRoot, subPath)), files };
		// biome-ignore lint/suspicious/noExplicitAny: <explanation>
	} catch (error: any) {
		if (error?.code === "ENOENT") {
			return new ServerError(StatusMap["Not Found"], "Directory not found");
		}
		console.error("Error listing path:", subPath, error.message);
		return new ServerError(StatusMap["Internal Server Error"], "Internal Server Error");
	}
}

async function streamToString(stream: ReadableStream<Uint8Array>): Promise<string> {
	const reader = stream.getReader();
	const chunks: Uint8Array[] = [];

	try {
		while (true) {
			const { done, value } = await reader.read();
			if (done) break;
			if (value) chunks.push(value);
		}

		const combined = new Uint8Array(chunks.reduce((acc, chunk) => acc + chunk.length, 0));
		let offset = 0;
		for (const chunk of chunks) {
			combined.set(chunk, offset);
			offset += chunk.length;
		}

		return new TextDecoder().decode(combined);
	} finally {
		reader.releaseLock();
	}
}

export function convertWithFFmpeg(filePath: string, bitrate: number) {
	const cmd = Bun.spawn(["ffmpeg", "-i", filePath, "-f", "opus", "-b:a", bitrate.toString(), "-"], {
		stdin: "ignore",
		stdout: "pipe",
		stderr: "pipe",
		onExit: async (subprocess: Bun.Subprocess, exitCode: number | null) => {
			if (exitCode !== 0 && exitCode !== null) {
				console.error("ffmpeg failed with status code", exitCode);
				console.error(await streamToString(subprocess.stderr as ReadableStream));
			}
		},
	});
	return cmd;
}