import { fileURLToPath } from 'node:url';
import { dirname } from 'node:path';
import { test } from 'node:test';

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
const indexPath = __filename.replace('/test/index.js', '/index.js');
const indexUrl = `file://${indexPath}`;

let takeUntil;

test('setup', async () => {
  const mod = await import(indexUrl);
  takeUntil = mod.takeUntil || mod.default || mod;
});

function createAsyncSource(values, delay = 5) {
  let index = 0;
  return {
    pipe(s) {
      this.sink = s;
      try { s.source = this; } catch (e) {}
      this.resume();
      return s;
    },
    resume() { this.writeNext(); },
    writeNext() {
      if (index >= values.length) {
        if (this.sink && this.sink.end) {
          this.sink.end();
        }
        return;
      }
      if (!this.sink) return;
      this.sink.write(values[index++]);
      setTimeout(() => this.writeNext(), delay);
    },
    write() {},
    end() {},
    abort() {},
    get sink() { return this._sink; },
    set sink(s) { this._sink = s; },
    get paused() { return this._sink ? this._sink.paused : true; },
    get ended() { return false; }
  };
}

function createSignalStream(delay) {
  return {
    pipe(s) {
      this.sink = s;
      try { s.source = this; } catch (e) {}
      if (delay === 0) {
        if (this.sink && this.sink.end) {
          this.sink.end();
        }
      } else {
        setTimeout(() => {
          if (this.sink && this.sink.end) {
            this.sink.end();
          }
        }, delay);
      }
      return s;
    },
    resume() {},
    write() {},
    end() {},
    abort() {},
    get sink() { return this._sink; },
    set sink(s) { this._sink = s; },
    get paused() { return this._sink ? this._sink.paused : true; },
    get ended() { return false; }
  };
}

test('ends when signal emits', async () => {
  const results = [];
  let streamEnded = false;
  let endTime = 0;
  const startTime = Date.now();

  const signalStream = createSignalStream(30);
  const { sink, pipe } = takeUntil(signalStream);

  const finalSink = {
    write: (v) => results.push(v),
    end: (err) => { streamEnded = true; endTime = Date.now() - startTime; },
    get paused() { return false; }
  };

  pipe(finalSink);
  createAsyncSource([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 5).pipe(sink);

  let waited = 0;
  while (!streamEnded && waited < 200) {
    await new Promise(resolve => setTimeout(resolve, 10));
    waited++;
  }

  if (streamEnded === false) {
    throw new Error('Stream should have ended');
  }
  if (endTime < 20) {
    throw new Error(`Stream ended too quickly (${endTime}ms) - signal may not be working`);
  }
  if (endTime > 100) {
    throw new Error(`Stream took too long to end (${endTime}ms)`);
  }
  if (results.length >= 10) {
    throw new Error(`Expected fewer than 10 values (signal should have stopped it), got ${results.length}`);
  }
});

test('signal immediately ends', async () => {
  const results = [];
  let streamEnded = false;

  const signalStream = createSignalStream(0);
  const { sink, pipe } = takeUntil(signalStream);

  const finalSink = {
    write: (v) => results.push(v),
    end: () => { streamEnded = true; },
    get paused() { return false; }
  };

  pipe(finalSink);
  createAsyncSource([1, 2, 3, 4, 5], 5).pipe(sink);

  let waited = 0;
  while (!streamEnded && waited < 100) {
    await new Promise(resolve => setTimeout(resolve, 10));
    waited++;
  }

  if (results.length !== 0) {
    throw new Error(`Expected 0 values (immediate signal), got ${results.length}`);
  }
});

test('signal never emits', async () => {
  const results = [];
  let streamEnded = false;

  const signalStream = {
    pipe(s) {
      this.sink = s;
      try { s.source = this; } catch (e) {}
      return s;
    },
    resume() {},
    write() {},
    end() {},
    abort() {},
    get sink() { return this._sink; },
    set sink(s) { this._sink = s; },
    get paused() { return this._sink ? this._sink.paused : true; },
    get ended() { return false; }
  };

  const takeUntilStream = takeUntil(signalStream);

  const finalSink = {
    write: (v) => results.push(v),
    end: () => { streamEnded = true; },
    get paused() { return false; }
  };

  takeUntilStream.pipe(finalSink);
  createAsyncSource([1, 2, 3], 5).pipe(takeUntilStream);

  let waited = 0;
  while (!streamEnded && waited < 200) {
    await new Promise(resolve => setTimeout(resolve, 10));
    waited++;
  }

  if (results.length !== 3) {
    throw new Error(`Expected 3 values, got ${results.length}`);
  }
});

test('passes through all values before signal', async () => {
  const results = [];
  let streamEnded = false;

  const signalStream = createSignalStream(100);
  const takeUntilStream = takeUntil(signalStream);

  const finalSink = {
    write: (v) => results.push(v),
    end: () => { streamEnded = true; },
    get paused() { return false; }
  };

  takeUntilStream.pipe(finalSink);
  createAsyncSource([1, 2], 5).pipe(takeUntilStream);

  let waited = 0;
  while (!streamEnded && waited < 200) {
    await new Promise(resolve => setTimeout(resolve, 10));
    waited++;
  }

  if (results.length !== 2) {
    throw new Error(`Expected 2 values before signal, got ${results.length}`);
  }
  if (results[0] !== 1 || results[1] !== 2) {
    throw new Error(`Values wrong: ${JSON.stringify(results)}`);
  }
});