import { type FileHandle, open } from "node:fs/promises";
import { orderBy } from "natural-orderby";
import { ZipReader, Reader, type Entry } from "@zip.js/zip.js";

class FileReader extends Reader<FileHandle> {
	private fd: FileHandle;
	private offset: number;
	constructor(fd: FileHandle) {
		super(fd);
		this.fd = fd;
		this.offset = 0;
	}

	async init(): Promise<void> {
		this.offset = 0;
		this.size = (await this.fd.stat()).size;
	}
	close(): void {
		this.fd.close();
	}

	async readUint8Array(index: number, length: number): Promise<Uint8Array> {
		const buffer = new Uint8Array(length);
		const buf = await this.fd.read(buffer, 0, length, index);
		if (buf.bytesRead !== length) {
			console.error(`read error: ${buf.bytesRead} !== ${length}`);
			throw new Error("read error");
		}
		return buffer;
	}
}

export async function readZip(path: string): Promise<{
	reader: ZipReader<FileHandle>
	handle: FileHandle
}> {
	const fd = await open(path);
	const reader = new ZipReader(new FileReader(fd), {
		useCompressionStream: true,
		preventClose: false,
	});
	return { reader, handle: fd };
}
export async function entriesByNaturalOrder(zip: ZipReader<FileHandle>) {
	// console.log(zip);
	const entries = await zip.getEntries();
	// console.log(entries.map((v) => v.filename));
	const ret = orderBy(entries, (v) => v.filename);
	return ret;
}

export async function createReadableStreamFromZip(_zip: ZipReader<FileHandle>, entry: Entry): Promise<ReadableStream> {
	if (entry.getData === undefined) {
		throw new Error("entry.getData is undefined");
	}
	const stream = new TransformStream<Uint8Array, Uint8Array>();
	entry.getData(stream.writable);
	return stream.readable;
}