import { describe, expect, it, vi, beforeEach, afterEach } from 'vitest';

/**
 * Regression for https://github.com/openchamber/openchamber/issues/2710
 * "Scheduled daily task executes twice at the configured time"
 *
 * Root cause: each OpenChamber server process keeps its own timers. Two
 * instances that share the same on-disk project config (CLI serve on port 3000
 * + Electron on 57123, or a startup login service + desktop) each arm a timer
 * for the same occurrence and both dispatch.
 *
 * Fix: scheduled runs claim the occurrence in shared project config
 * (`lastScheduledFor` + advanced `nextRunAt`) under a cross-process write lock
 * before creating a session, so the second instance skips.
 */

const sdk = vi.hoisted(() => ({
  sessionCreates: [],
  createOpencodeClient: () => ({
    session: {
      create: async () => {
        sdk.sessionCreates.push(Date.now());
        return { data: { id: `sess-${sdk.sessionCreates.length}` } };
      },
    },
    command: { list: async () => ({ data: [] }) },
  }),
}));

vi.mock('@opencode-ai/sdk/v2', () => ({
  createOpencodeClient: sdk.createOpencodeClient,
}));

import { createScheduledTasksRuntime } from './runtime.js';

const UTC = (y, mo, d, h, mi, s = 0) => Date.UTC(y, mo, d, h, mi, s);
const MINUTE = 60_000;
const HOUR = 3_600_000;

const makeTask = (schedule) => ({
  id: 'task-1',
  name: 'Daily Sync',
  enabled: true,
  schedule: { timezone: 'UTC', ...schedule },
  execution: { prompt: 'Summarize open issues', providerID: 'openai', modelID: 'gpt-4o' },
  state: { createdAt: UTC(2026, 0, 1, 0, 0, 0), updatedAt: UTC(2026, 0, 1, 0, 0, 0) },
});

/**
 * Shared on-disk store stand-in. Both runtimes must see the same task state so
 * occurrence claiming can serialize dispatches the way real project config does.
 */
const createSharedProjectConfigRuntime = (initialTask) => {
  let currentTask = structuredClone(initialTask);

  const applyPatch = (patch) => {
    const nextState = {
      ...(currentTask.state || {}),
      ...patch,
      updatedAt: Date.now(),
    };
    // Mirror normalizeState: explicit undefined clears optional numeric fields.
    for (const key of ['nextRunAt', 'lastRunAt', 'lastDurationMs', 'lastScheduledFor', 'lastError', 'lastSessionId']) {
      if (Object.prototype.hasOwnProperty.call(patch, key) && patch[key] === undefined) {
        delete nextState[key];
      }
    }
    currentTask = {
      ...currentTask,
      state: nextState,
    };
    return currentTask;
  };

  return {
    listScheduledTasks: vi.fn(async () => [structuredClone(currentTask)]),
    reconcileLoopTasks: vi.fn(async () => [structuredClone(currentTask)]),
    updateScheduledTaskState: vi.fn(async (_pid, _tid, patch) => {
      const task = applyPatch(patch);
      return { task: structuredClone(task), updated: true };
    }),
    updateScheduledTaskStateIf: vi.fn(async (_pid, _tid, predicate, patch) => {
      if (!predicate(currentTask)) {
        return { task: structuredClone(currentTask), updated: false };
      }
      const task = applyPatch(patch);
      return { task: structuredClone(task), updated: true };
    }),
    upsertScheduledTask: vi.fn(async (_pid, input) => {
      currentTask = structuredClone(input);
      return { task: structuredClone(currentTask) };
    }),
  };
};

const createRuntimeDeps = (projectConfigRuntime) => ({
  projectConfigRuntime,
  listProjects: vi.fn(async () => [{ id: 'p1', path: '/repo' }]),
  buildOpenCodeUrl: () => 'http://127.0.0.1:9999/',
  getOpenCodeAuthHeaders: () => ({}),
  waitForOpenCodeReady: async () => {},
  emitTaskRunEvent: vi.fn(),
  setSessionAutoAccept: async () => {},
  logger: { info: () => {}, warn: () => {}, error: () => {} },
});

const startInstances = async (count, task) => {
  const projectConfigRuntime = createSharedProjectConfigRuntime(task);
  const runtimes = [];
  for (let i = 0; i < count; i += 1) {
    const runtime = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtime.start();
    runtimes.push(runtime);
  }
  return { runtimes, projectConfigRuntime };
};

describe('issue 2710: daily scheduled task double execution at the configured time', () => {
  beforeEach(() => {
    vi.useFakeTimers();
    sdk.sessionCreates.length = 0;
    globalThis.fetch = vi.fn(async () => ({ ok: true, text: async () => '' }));
  });

  afterEach(() => {
    vi.useRealTimers();
    vi.restoreAllMocks();
  });

  it('ONE instance fires a daily 15:00 task exactly once at 15:00', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const { runtimes } = await startInstances(1, makeTask({ kind: 'daily', times: ['15:00'] }));
    await vi.advanceTimersByTimeAsync(HOUR + 3_000);

    expect(sdk.sessionCreates.length).toBe(1);
    const firedAt = new Date(sdk.sessionCreates[0]);
    expect(firedAt.getUTCHours()).toBe(15);

    runtimes.forEach((runtime) => runtime.stop());
  });

  it('ONE instance firing daily 15:00 across 4 days never double-fires', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const { runtimes } = await startInstances(1, makeTask({ kind: 'daily', times: ['15:00'] }));
    await vi.advanceTimersByTimeAsync((4 * 24 * HOUR) + 3_000);

    expect(sdk.sessionCreates.length).toBe(4);
    const byHourBucket = new Map();
    for (const timestamp of sdk.sessionCreates) {
      const date = new Date(timestamp);
      expect(date.getUTCHours()).toBe(15);
      expect(date.getUTCMinutes()).toBe(0);
      const bucket = Math.floor(timestamp / HOUR);
      byHourBucket.set(bucket, (byHourBucket.get(bucket) || 0) + 1);
    }
    for (const count of byHourBucket.values()) {
      expect(count).toBe(1);
    }

    runtimes.forEach((runtime) => runtime.stop());
  });

  it('TWO instances fire a daily 15:00 task exactly ONCE (occurrence claim)', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const { runtimes, projectConfigRuntime } = await startInstances(
      2,
      makeTask({ kind: 'daily', times: ['15:00'] }),
    );
    await vi.advanceTimersByTimeAsync(HOUR + 3_000);

    expect(sdk.sessionCreates.length).toBe(1);
    const firedAt = new Date(sdk.sessionCreates[0]);
    expect(firedAt.getUTCHours()).toBe(15);
    expect(firedAt.getUTCMinutes()).toBe(0);
    expect(projectConfigRuntime.updateScheduledTaskStateIf).toHaveBeenCalled();

    runtimes.forEach((runtime) => runtime.stop());
  });

  it('TWO instances fire a weekly task exactly once', async () => {
    // 2026-01-04 is a Sunday. Weekly Mon/Wed/Fri 09:00.
    vi.setSystemTime(UTC(2026, 0, 4, 8, 0, 0));
    const { runtimes } = await startInstances(2, makeTask({
      kind: 'weekly',
      times: ['09:00'],
      weekdays: [1, 3, 5],
    }));
    await vi.advanceTimersByTimeAsync((25 * HOUR) + 3_000);

    expect(sdk.sessionCreates.length).toBe(1);

    runtimes.forEach((runtime) => runtime.stop());
  });

  it('TWO instances fire a cron task exactly once', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 14, 3, 0));
    const { runtimes } = await startInstances(2, makeTask({ kind: 'cron', cron: '*/5 * * * *' }));
    await vi.advanceTimersByTimeAsync(3 * MINUTE);

    expect(sdk.sessionCreates.length).toBe(1);

    runtimes.forEach((runtime) => runtime.stop());
  });

  it('TWO instances fire a once task exactly once', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 8, 0, 0));
    const { runtimes } = await startInstances(2, makeTask({
      kind: 'once',
      date: '2026-01-01',
      time: '09:00',
    }));
    await vi.advanceTimersByTimeAsync(HOUR + 3_000);

    expect(sdk.sessionCreates.length).toBe(1);

    runtimes.forEach((runtime) => runtime.stop());
  });

  it('claim failure releases the running slot and does not reject unhandled', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const projectConfigRuntime = createSharedProjectConfigRuntime(
      makeTask({ kind: 'daily', times: ['15:00'] }),
    );
    projectConfigRuntime.updateScheduledTaskStateIf = vi.fn(async () => {
      throw new Error('timeout acquiring project config lock for p1');
    });
    const runtime = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtime.start();

    await vi.advanceTimersByTimeAsync(HOUR + 3_000);

    expect(sdk.sessionCreates.length).toBe(0);
    expect(runtime.getStatus().runningScheduledTasksCount).toBe(0);
    expect(runtime.getStatus().hasRunningScheduledTasks).toBe(false);

    // Manual runNow must not be stuck behind a permanently "running" claim failure.
    const manual = await runtime.runNow('p1', 'task-1');
    expect(manual.ok).toBe(true);
    expect(sdk.sessionCreates.length).toBe(1);

    runtime.stop();
  });

  it('completion state write failure releases the running slot', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const projectConfigRuntime = createSharedProjectConfigRuntime(
      makeTask({ kind: 'daily', times: ['15:00'] }),
    );
    const originalUpdate = projectConfigRuntime.updateScheduledTaskState;
    let completionWrites = 0;
    projectConfigRuntime.updateScheduledTaskState = vi.fn(async (pid, tid, patch) => {
      // syncTaskSchedule + claim path may write; fail the post-run completion write.
      if (patch?.lastStatus === 'success' || patch?.lastStatus === 'error') {
        completionWrites += 1;
        throw new Error('timeout acquiring project config lock for p1');
      }
      return originalUpdate(pid, tid, patch);
    });

    const runtime = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtime.start();
    await vi.advanceTimersByTimeAsync(HOUR + 3_000);

    // Initial completion write + best-effort retry.
    expect(completionWrites).toBeGreaterThanOrEqual(2);
    expect(sdk.sessionCreates.length).toBe(1);
    expect(runtime.getStatus().runningScheduledTasksCount).toBe(0);

    const manual = await runtime.runNow('p1', 'task-1');
    expect(manual.ok).toBe(true);
    expect(manual.sessionID).toBeTruthy();
    expect(runtime.getStatus().runningScheduledTasksCount).toBe(0);

    runtime.stop();
  });

  it('manual run completion write failure returns session and clears running status', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const projectConfigRuntime = createSharedProjectConfigRuntime(
      makeTask({ kind: 'daily', times: ['15:00'] }),
    );
    const runtime = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtime.start();

    const originalUpdate = projectConfigRuntime.updateScheduledTaskState;
    projectConfigRuntime.updateScheduledTaskState = vi.fn(async (pid, tid, patch) => {
      if (patch?.lastStatus === 'success' || patch?.lastStatus === 'error') {
        throw new Error('timeout acquiring project config lock for p1');
      }
      return originalUpdate(pid, tid, patch);
    });

    const manual = await runtime.runNow('p1', 'task-1');
    expect(manual.ok).toBe(true);
    expect(manual.sessionID).toBeTruthy();
    expect(manual.reason).toBe('completion-state-failed');
    expect(manual.persistError).toMatch(/timeout acquiring project config lock/);
    expect(manual.task?.state?.lastStatus).toBe('success');
    expect(runtime.getStatus().runningScheduledTasksCount).toBe(0);

    runtime.stop();
  });

  it('manual start state write failure releases the running slot', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const projectConfigRuntime = createSharedProjectConfigRuntime(
      makeTask({ kind: 'daily', times: ['15:00'] }),
    );
    const runtime = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtime.start();

    projectConfigRuntime.updateScheduledTaskState = vi.fn(async () => {
      throw new Error('timeout acquiring project config lock for p1');
    });

    const manual = await runtime.runNow('p1', 'task-1');
    expect(manual.ok).toBe(false);
    expect(manual.reason).toBe('start-state-failed');
    expect(sdk.sessionCreates.length).toBe(0);
    expect(runtime.getStatus().runningScheduledTasksCount).toBe(0);

    runtime.stop();
  });

  it('armed instance still fires when another instance syncs inside the due-slack window', async () => {
    // Instance A arms for 15:00 outside the slack window. Instance B then starts
    // inside TASK_DUE_SLACK_MS and syncTaskSchedule advances disk nextRunAt to
    // tomorrow. A must still claim today's occurrence.
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const task = makeTask({ kind: 'daily', times: ['15:00'] });
    const projectConfigRuntime = createSharedProjectConfigRuntime(task);

    const runtimeA = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtimeA.start();

    // Enter the due-slack window (T-5s .. T) and sync a second instance.
    await vi.advanceTimersByTimeAsync(HOUR - 2_000);
    const runtimeB = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtimeB.start();

    await vi.advanceTimersByTimeAsync(5_000);

    expect(sdk.sessionCreates.length).toBe(1);

    runtimeA.stop();
    runtimeB.stop();
  });

  it('armed instance still fires on a later day when lastScheduledFor is already set', async () => {
    // After day 1 has claimed, lastScheduledFor is finite. On day 2 a second
    // instance syncing inside the due-slack window must not suppress the armed fire.
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const task = makeTask({ kind: 'daily', times: ['15:00'] });
    const projectConfigRuntime = createSharedProjectConfigRuntime(task);

    const runtimeA = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtimeA.start();
    await vi.advanceTimersByTimeAsync(HOUR + 3_000);
    expect(sdk.sessionCreates.length).toBe(1);

    // Advance to day-2 afternoon, still outside slack, so A re-arms for 15:00.
    await vi.advanceTimersByTimeAsync((23 * HOUR) - 3_000);
    // Enter day-2 due-slack window and sync instance B (advances nextRunAt).
    await vi.advanceTimersByTimeAsync(HOUR - 2_000);
    const runtimeB = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtimeB.start();

    await vi.advanceTimersByTimeAsync(5_000);

    expect(sdk.sessionCreates.length).toBe(2);

    runtimeA.stop();
    runtimeB.stop();
  });

  it('once-task loser does not spin-rearm a past nextRunAt while the winner runs', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 8, 0, 0));

    let releaseFetch;
    const fetchGate = new Promise((resolve) => {
      releaseFetch = resolve;
    });
    globalThis.fetch = vi.fn(async () => {
      await fetchGate;
      return { ok: true, text: async () => '' };
    });

    const { runtimes, projectConfigRuntime } = await startInstances(2, makeTask({
      kind: 'once',
      date: '2026-01-01',
      time: '09:00',
    }));

    await vi.advanceTimersByTimeAsync(HOUR + 3_000);

    // Winner claimed and is blocked in prompt_async; exactly one session.
    expect(sdk.sessionCreates.length).toBe(1);
    const claimsAfterFire = projectConfigRuntime.updateScheduledTaskStateIf.mock.calls.length;
    expect(claimsAfterFire).toBeGreaterThanOrEqual(1);

    // Advance through many jitter windows. Loser must not keep re-entering claim.
    await vi.advanceTimersByTimeAsync(60_000);
    expect(projectConfigRuntime.updateScheduledTaskStateIf.mock.calls.length).toBe(claimsAfterFire);
    expect(sdk.sessionCreates.length).toBe(1);

    releaseFetch();
    await Promise.resolve();
    await vi.advanceTimersByTimeAsync(5_000);

    expect(sdk.sessionCreates.length).toBe(1);
    expect(runtimes.every((runtime) => runtime.getStatus().runningScheduledTasksCount === 0)).toBe(true);

    runtimes.forEach((runtime) => runtime.stop());
  });

  it('claim-failed re-arms the next occurrence, not an immediate retry of the past slot', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 14, 0, 0));
    const projectConfigRuntime = createSharedProjectConfigRuntime(
      makeTask({ kind: 'daily', times: ['15:00'] }),
    );

    let claimAttempts = 0;
    const originalClaim = projectConfigRuntime.updateScheduledTaskStateIf;
    projectConfigRuntime.updateScheduledTaskStateIf = vi.fn(async (pid, tid, predicate, patch) => {
      // Claim patches set lastScheduledFor; failure-recording patches set lastStatus error.
      if (Object.prototype.hasOwnProperty.call(patch || {}, 'lastScheduledFor')) {
        claimAttempts += 1;
        throw new Error('timeout acquiring project config lock for p1');
      }
      return originalClaim(pid, tid, predicate, patch);
    });

    const runtime = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtime.start();

    await vi.advanceTimersByTimeAsync(HOUR + 3_000);
    expect(claimAttempts).toBe(1);

    // Must not immediately retry the same past occurrence on a ~jitter cadence.
    await vi.advanceTimersByTimeAsync(30_000);
    expect(claimAttempts).toBe(1);

    // Next calendar occurrence (tomorrow 15:00) may attempt once more.
    await vi.advanceTimersByTimeAsync(24 * HOUR);
    expect(claimAttempts).toBe(2);

    runtime.stop();
  });

  it('once claim failure records an error status instead of leaving the task silently inert', async () => {
    vi.setSystemTime(UTC(2026, 0, 1, 8, 0, 0));
    const projectConfigRuntime = createSharedProjectConfigRuntime(makeTask({
      kind: 'once',
      date: '2026-01-01',
      time: '09:00',
    }));

    const originalClaim = projectConfigRuntime.updateScheduledTaskStateIf;
    projectConfigRuntime.updateScheduledTaskStateIf = vi.fn(async (pid, tid, predicate, patch) => {
      if (Object.prototype.hasOwnProperty.call(patch || {}, 'lastScheduledFor')) {
        throw new Error('timeout acquiring project config lock for p1');
      }
      return originalClaim(pid, tid, predicate, patch);
    });

    const runtime = createScheduledTasksRuntime(createRuntimeDeps(projectConfigRuntime));
    await runtime.start();
    await vi.advanceTimersByTimeAsync(HOUR + 3_000);

    expect(sdk.sessionCreates.length).toBe(0);
    const tasks = await projectConfigRuntime.listScheduledTasks('p1');
    expect(tasks[0].state.lastStatus).toBe('error');
    expect(tasks[0].state.lastError).toMatch(/Scheduled claim failed/);
    expect(tasks[0].enabled).toBe(true);

    // No silent delay-0 spin after the failed once claim.
    const errorWrites = projectConfigRuntime.updateScheduledTaskStateIf.mock.calls
      .filter(([, , , patch]) => patch?.lastStatus === 'error')
      .length;
    await vi.advanceTimersByTimeAsync(30_000);
    const errorWritesAfter = projectConfigRuntime.updateScheduledTaskStateIf.mock.calls
      .filter(([, , , patch]) => patch?.lastStatus === 'error')
      .length;
    expect(errorWritesAfter).toBe(errorWrites);

    runtime.stop();
  });
});