import { Observable, from, map, mergeAll } from "rxjs";
import File from "vinyl";
import { Glob } from "glob";
import { readFile } from "node:fs/promises";
import { join, dirname } from "node:path";
import { existsSync, mkdirSync, writeFileSync } from "node:fs";

export function src(glob: string | string[]): Observable<File> {
    return from(new Glob(glob, {})).pipe(
        map(async (path) => new File({ path, contents: await readFile(path) })),
        map(from),
        mergeAll(),
    );
}

export function dist(prefix: string) {
    return (observable: Observable<File>): Observable<File> =>
        new Observable((subscriber) =>
            observable.subscribe({
                next(value) {
                    const actualPath = join(prefix, value.path);
                    if (!existsSync(dirname(actualPath))) {
                        mkdirSync(dirname(actualPath), { recursive: true });
                    }
                    writeFileSync(actualPath, value.contents as Buffer);
                    console.log("[-] Written", actualPath);

                    subscriber.next(value);
                },
                complete() {
                    subscriber.complete();
                },
            }),
        );
}

export function synchronise<T>() {
    return (observable: Observable<Promise<T>>): Observable<T> =>
        new Observable<T>((subscriber) => {
            const promiseArray = [];
            let done = false;

            observable.subscribe({
                next(value) {
                    const promise = value.then((v) => {
                        const i = promiseArray.findIndex((i) => i == promise);
                        promiseArray.splice(i, 1);

                        subscriber.next(v);
                        if (promiseArray.length === 0 && done) {
                            subscriber.complete();
                        }
                    });
                    promiseArray.push(promise);
                },
                complete() {
                    done = true;
                    if (promiseArray.length === 0) {
                        console.log("[synchronise] complete (from complete)");
                        subscriber.complete();
                    }
                },
            });
        });
}