import { describe, expect, it } from 'vitest';
import {
  canStartQueuedPrompt,
  createIdleSessionRunState,
  didSuppressAbortError,
  isCurrentRunEvent,
  isSessionRunActive,
  takeNextQueuedPrompt,
  transitionSessionRunState,
} from '@/stores/opencode-session-run-machine';

type TestPrompt = {
  id: string;
  text: string;
};

describe('opencode session run machine', () => {
  it('starts a run and marks it active while posting or running', () => {
    const idle = createIdleSessionRunState<TestPrompt>();
    const posting = transitionSessionRunState(idle, {
      type: 'send_started',
      runId: 1,
      promptId: 'msg_1',
    });

    expect(posting).toMatchObject({
      phase: 'posting',
      runId: 1,
      promptId: 'msg_1',
      terminalReason: null,
      error: null,
      suppressNextAbortError: false,
    });
    expect(isSessionRunActive(posting)).toBe(true);

    const running = transitionSessionRunState(posting, {
      type: 'post_accepted',
      runId: 1,
    });

    expect(running.phase).toBe('running');
    expect(isSessionRunActive(running)).toBe(true);
  });

  it('queues and dequeues prompts without changing the current run', () => {
    const running = transitionSessionRunState(
      createIdleSessionRunState<TestPrompt>(),
      { type: 'send_started', runId: 2, promptId: 'msg_active' },
    );
    const withQueue = transitionSessionRunState(running, {
      type: 'queue_prompt',
      prompt: { id: 'queued_1', text: 'second' },
    });

    expect(withQueue.queue).toEqual([{ id: 'queued_1', text: 'second' }]);
    expect(withQueue.runId).toBe(2);
    expect(canStartQueuedPrompt(withQueue)).toBe(false);

    const completed = transitionSessionRunState(withQueue, {
      type: 'remote_idle',
      runId: 2,
    });
    const taken = takeNextQueuedPrompt(completed);

    expect(canStartQueuedPrompt(completed)).toBe(true);
    expect(taken.prompt).toEqual({ id: 'queued_1', text: 'second' });
    expect(taken.state.queue).toEqual([]);
  });

  it('clears queued prompts immediately when abort is requested', () => {
    const running = transitionSessionRunState(
      createIdleSessionRunState<TestPrompt>([{ id: 'queued_1', text: 'queued' }]),
      { type: 'send_started', runId: 3, promptId: 'msg_active' },
    );
    const aborting = transitionSessionRunState(running, {
      type: 'abort_requested',
      runId: 3,
    });

    expect(aborting).toMatchObject({
      phase: 'aborting',
      runId: 3,
      queue: [],
      terminalReason: 'aborted',
      error: null,
      suppressNextAbortError: true,
    });
    expect(isSessionRunActive(aborting)).toBe(false);
  });

  it('ignores stale run-scoped events from an older run after a new prompt starts', () => {
    const firstRun = transitionSessionRunState(
      createIdleSessionRunState<TestPrompt>(),
      { type: 'send_started', runId: 4, promptId: 'msg_first' },
    );
    const aborting = transitionSessionRunState(firstRun, {
      type: 'abort_requested',
      runId: 4,
    });
    const secondRun = transitionSessionRunState(aborting, {
      type: 'send_started',
      runId: 5,
      promptId: 'msg_second',
    });

    expect(isCurrentRunEvent(secondRun, 4)).toBe(false);
    expect(isCurrentRunEvent(secondRun, 5)).toBe(true);

    const afterStaleAbort = transitionSessionRunState(secondRun, {
      type: 'remote_aborted',
      runId: 4,
    });

    expect(afterStaleAbort).toEqual(secondRun);
  });

  it('suppresses one late abort-like error delivered to the new run after an explicit stop', () => {
    const firstRun = transitionSessionRunState(
      createIdleSessionRunState<TestPrompt>(),
      { type: 'send_started', runId: 7, promptId: 'msg_first' },
    );
    const aborting = transitionSessionRunState(firstRun, {
      type: 'abort_requested',
      runId: 7,
    });
    const secondRun = transitionSessionRunState(aborting, {
      type: 'send_started',
      runId: 8,
      promptId: 'msg_second',
    });

    expect(secondRun.suppressNextAbortError).toBe(true);

    const afterLateAbort = transitionSessionRunState(secondRun, {
      type: 'remote_aborted',
      runId: 8,
    });

    expect(afterLateAbort).toMatchObject({
      phase: 'posting',
      runId: 8,
      promptId: 'msg_second',
      terminalReason: null,
      error: null,
      suppressNextAbortError: false,
    });
    expect(didSuppressAbortError(secondRun, afterLateAbort)).toBe(true);
  });

  it('keeps provider failures visible but still makes the run inactive', () => {
    const running = transitionSessionRunState(
      createIdleSessionRunState<TestPrompt>(),
      { type: 'send_started', runId: 6, promptId: 'msg_fail' },
    );
    const failed = transitionSessionRunState(running, {
      type: 'remote_failed',
      runId: 6,
      error: 'Authentication failed',
    });

    expect(failed).toMatchObject({
      phase: 'idle',
      runId: 6,
      terminalReason: 'failed',
      error: 'Authentication failed',
    });
    expect(isSessionRunActive(failed)).toBe(false);
    expect(canStartQueuedPrompt(failed)).toBe(false);
  });

  it('does not let post acceptance reopen a terminal run', () => {
    const posting = transitionSessionRunState(
      createIdleSessionRunState<TestPrompt>(),
      { type: 'send_started', runId: 9, promptId: 'compact-ses_1' },
    );
    const completed = transitionSessionRunState(posting, {
      type: 'remote_idle',
      runId: 9,
    });
    const afterLatePost = transitionSessionRunState(completed, {
      type: 'post_accepted',
      runId: 9,
    });

    expect(afterLatePost).toEqual(completed);
    expect(afterLatePost).toMatchObject({
      phase: 'idle',
      terminalReason: 'completed',
    });
  });

  it.each([
    [
      'failure',
      { type: 'remote_failed' as const, runId: 10, error: 'POST failed after early idle' },
      {
        phase: 'idle',
        queue: [{ id: 'queued_1', text: 'second' }],
        terminalReason: 'failed',
        error: 'POST failed after early idle',
      },
    ],
    [
      'abort',
      { type: 'remote_aborted' as const, runId: 10 },
      {
        phase: 'idle',
        queue: [],
        terminalReason: 'aborted',
        error: null,
      },
    ],
  ])('lets authoritative %s override an early-idle completion', (
    _caseName,
    terminalEvent,
    expected,
  ) => {
    const posting = transitionSessionRunState(
      createIdleSessionRunState<TestPrompt>([{ id: 'queued_1', text: 'second' }]),
      { type: 'send_started', runId: 10, promptId: 'msg_first' },
    );
    const earlyIdle = transitionSessionRunState(posting, {
      type: 'remote_idle',
      runId: 10,
    });
    const terminal = transitionSessionRunState(earlyIdle, terminalEvent);

    expect(terminal).toMatchObject(expected);
    expect(canStartQueuedPrompt(terminal)).toBe(false);
  });
});