/**
 * Regression tests for TSK-0237: single-claim semantics in the work loop.
 *
 * Bug (24.07. ~01:54): after the TSK-0230 auto-wake, an agent's waiting work
 * loop claimed EVERY task assigned to it in parallel (codex held TSK-0222 +
 * TSK-0235 at once) — the board lied about who works on what.
 *
 * Soll:
 *   (a) several assigned tasks ⇒ the loop claims exactly ONE (highest
 *       priority, oldest createdAt breaks ties); the rest stays open.
 *   (b) the next auto-claim happens only after the active task reaches
 *       review/done (or is reopened back).
 *   (c) server-side guard: a claim while holding an in_progress task → error
 *       (architect exempt, no --force for agents).
 *   (d) the TSK-0230 auto-wake suite keeps passing.
 */
import { describe, it, expect, beforeEach, afterEach } from 'vitest';
import { mkdtempSync, rmSync } from 'fs';
import { tmpdir } from 'os';
import { join } from 'path';
import { init } from '../src/cli/commands/init.js';
import { workAgent } from '../src/cli/commands/work.js';
import { startServer } from '../src/server/index.js';
import { createTask, claimTask, getTask } from '../src/core/services/taskService.js';
import type { Task } from '../src/core/schema.js';

const AGENT = 'kimi';

function sleep(ms: number): Promise<void> {
  return new Promise((r) => setTimeout(r, ms));
}

async function createAndAssign(serverUrl: string, title: string, priority: string): Promise<string> {
  const res = await fetch(`${serverUrl}/tasks`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ title, role: 'implementer', priority }),
  });
  const task = (await res.json()) as Task;
  await fetch(`${serverUrl}/tasks/${task.id}`, {
    method: 'PATCH',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ assignedTo: AGENT }),
  });
  return task.id;
}

async function taskViaApi(serverUrl: string, id: string): Promise<Task> {
  const res = (await fetch(`${serverUrl}/tasks/${id}`).then((r) => r.json())) as { task: Task };
  return res.task;
}

async function claimViaApi(serverUrl: string, id: string, agent: string): Promise<Response> {
  return fetch(`${serverUrl}/tasks/${id}`, {
    method: 'PATCH',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ status: 'in_progress', assignedTo: agent }),
  });
}

describe('single-claim semantics (TSK-0237)', () => {
  let cwd: string;
  let server: Awaited<ReturnType<typeof startServer>>;

  beforeEach(async () => {
    cwd = mkdtempSync(join(tmpdir(), 'ah-single-claim-'));
    init(cwd, { projectName: 'single-claim-test', yes: true });
    server = await startServer(cwd, { host: '127.0.0.1', port: 0 });
  });

  afterEach(async () => {
    await server.app.close().catch(() => undefined);
    rmSync(cwd, { recursive: true, force: true });
  });

  it('(a) claims exactly ONE of several assigned tasks — highest priority first', async () => {
    const low = await createAndAssign(server.url, 'kimi: low prio', 'low');
    await sleep(10);
    const high = await createAndAssign(server.url, 'kimi: high prio', 'high');

    await workAgent({ serverUrl: server.url, projectCwd: cwd, agent: AGENT, role: 'implementer', timeoutSec: 2 });

    const highTask = await taskViaApi(server.url, high);
    expect(highTask.status).toBe('in_progress');
    expect(highTask.assignedTo).toBe(AGENT);

    // The other task must stay open — no parallel claim.
    const lowTask = await taskViaApi(server.url, low);
    expect(lowTask.status).toBe('open');
    expect(lowTask.assignedTo).toBe(AGENT);

    // A second work run while busy claims nothing (single-claim), it just waits.
    await workAgent({ serverUrl: server.url, projectCwd: cwd, agent: AGENT, role: 'implementer', timeoutSec: 1 });
    expect((await taskViaApi(server.url, low)).status).toBe('open');
  }, 10_000);

  it('(a2) breaks priority ties by oldest createdAt', async () => {
    const older = await createAndAssign(server.url, 'kimi: older medium', 'medium');
    await sleep(10);
    const newer = await createAndAssign(server.url, 'kimi: newer medium', 'medium');

    await workAgent({ serverUrl: server.url, projectCwd: cwd, agent: AGENT, role: 'implementer', timeoutSec: 2 });

    expect((await taskViaApi(server.url, older)).status).toBe('in_progress');
    expect((await taskViaApi(server.url, newer)).status).toBe('open');
  }, 10_000);

  it('(b) auto-claims the next task only after the active one reaches review', async () => {
    const first = await createAndAssign(server.url, 'kimi: first', 'high');
    await sleep(10);
    const second = await createAndAssign(server.url, 'kimi: second', 'medium');

    await workAgent({ serverUrl: server.url, projectCwd: cwd, agent: AGENT, role: 'implementer', timeoutSec: 2 });
    expect((await taskViaApi(server.url, first)).status).toBe('in_progress');
    expect((await taskViaApi(server.url, second)).status).toBe('open');

    // Submit the active task for review → the agent is free for the next one.
    await fetch(`${server.url}/tasks/${first}`, {
      method: 'PATCH',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ status: 'review' }),
    });

    await workAgent({ serverUrl: server.url, projectCwd: cwd, agent: AGENT, role: 'implementer', timeoutSec: 2 });
    expect((await taskViaApi(server.url, second)).status).toBe('in_progress');
  }, 12_000);

  it('(c) server guard: claim while holding an in_progress task → 400, architect exempt', async () => {
    const t1 = await createAndAssign(server.url, 'kimi: held', 'medium');
    const t2 = await createAndAssign(server.url, 'kimi: blocked', 'medium');

    const ok = await claimViaApi(server.url, t1, AGENT);
    expect(ok.status).toBe(200);

    const blocked = await claimViaApi(server.url, t2, AGENT);
    expect(blocked.status).toBe(400);
    const body = (await blocked.json()) as { error?: string; message?: string };
    expect(JSON.stringify(body)).toContain(t1);
    // The blocked task stays open.
    expect((await taskViaApi(server.url, t2)).status).toBe('open');

    // Architect (default config: claude) may hold several threads.
    const t3 = await createAndAssign(server.url, 'claude: thread one', 'medium');
    const t4 = await createAndAssign(server.url, 'claude: thread two', 'medium');
    expect((await claimViaApi(server.url, t3, 'claude')).status).toBe(200);
    expect((await claimViaApi(server.url, t4, 'claude')).status).toBe(200);
  }, 10_000);

  it('(c2) claimTask unit: guard throws, same-task re-claim stays idempotent', () => {
    const a = createTask(cwd, { title: 'kimi: a', role: 'implementer' });
    const b = createTask(cwd, { title: 'kimi: b', role: 'implementer' });

    claimTask(cwd, a.id, AGENT);
    expect(() => claimTask(cwd, b.id, AGENT)).toThrowError(new RegExp(a.id));
    // Idempotent re-claim of the SAME task is still a no-op.
    expect(() => claimTask(cwd, a.id, AGENT)).not.toThrow();
    // Architect exempt.
    const c = createTask(cwd, { title: 'claude: x', role: 'architect' });
    const d = createTask(cwd, { title: 'claude: y', role: 'architect' });
    claimTask(cwd, c.id, 'claude');
    expect(() => claimTask(cwd, d.id, 'claude')).not.toThrow();

    const { task } = getTask(cwd, b.id);
    expect(task.status).toBe('open');
  });
});