/**
 * @sh-mcp/tasks — unit tests
 *
 * All tests use:
 *   - A mock AuthContext (no real JWT; the auth layer is DEFERRED — see TODO
 *     in src/client.ts). requireScope() from @sh-mcp/shared is exercised as
 *     the live implementation so that scope-guard behaviour is tested.
 *   - A mock TasksClient (no DynamoDB, no AWS credentials, no network).
 *
 * Coverage targets:
 *   - Happy path for each of the four tools.
 *   - Empty result from listTasks.
 *   - Client error propagation (the tool must not swallow errors).
 *   - Throttle / transient-error retry surface (the tool propagates the error
 *     upward; retry policy lives at the transport layer, not in tool handlers).
 *   - Scope guard: a caller without ops:tasks is rejected before the client
 *     is ever called.
 *   - ABAC isolation: the client always receives ctx.sub, not an override from
 *     the input payload.
 */

import { describe, it, expect, vi, beforeEach } from 'vitest';
import { buildTaskTools } from '../src/tools.js';
import type { TasksClient, Task } from '../src/client.js';
import type { AuthContext } from '@sh-mcp/shared';

// ---------------------------------------------------------------------------
// Test fixtures
// ---------------------------------------------------------------------------

const MOCK_CTX: AuthContext = {
  sub: 'lauren@seahavenind.com',
  scopes: ['ops:read', 'ops:tasks'],
  aud: 'sh-mcp-ops',
};

const CTX_NO_TASKS: AuthContext = {
  sub: 'staff@seahavenind.com',
  scopes: ['ops:read'], // no ops:tasks
  aud: 'sh-mcp-ops',
};

const TASK_1: Task = {
  taskId: 'task-001',
  sub: 'lauren@seahavenind.com',
  title: 'Review vendor invoices',
  description: 'Check against PO log before EOD',
  completed: false,
  createdAt: '2026-06-11T09:00:00.000Z',
};

const TASK_1_COMPLETED: Task = {
  ...TASK_1,
  completed: true,
  completedAt: '2026-06-11T10:00:00.000Z',
};

// ---------------------------------------------------------------------------
// Mock client factory
// ---------------------------------------------------------------------------

function makeMockClient(overrides: Partial<TasksClient> = {}): TasksClient {
  return {
    createTask: vi.fn().mockResolvedValue(TASK_1),
    listTasks: vi.fn().mockResolvedValue([TASK_1]),
    completeTask: vi.fn().mockResolvedValue(TASK_1_COMPLETED),
    deleteTask: vi.fn().mockResolvedValue(undefined),
    ...overrides,
  };
}

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

function getHandler(tools: ReturnType<typeof buildTaskTools>, name: string) {
  const tool = tools.find((t) => t.name === name);
  if (!tool) throw new Error(`Tool '${name}' not found`);
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  return (input: any, ctx: AuthContext) => tool.handler(input, ctx);
}

// ---------------------------------------------------------------------------
// create_task
// ---------------------------------------------------------------------------

describe('create_task', () => {
  let client: TasksClient;
  let tools: ReturnType<typeof buildTaskTools>;

  beforeEach(() => {
    client = makeMockClient();
    tools = buildTaskTools(client);
  });

  it('happy path: creates a task and returns the expected shape', async () => {
    const call = getHandler(tools, 'create_task');
    const result = await call({ title: 'Review vendor invoices', description: 'Check against PO log' }, MOCK_CTX);

    expect(result).toMatchObject({
      task: {
        taskId: 'task-001',
        title: 'Review vendor invoices',
        completed: false,
        createdAt: '2026-06-11T09:00:00.000Z',
      },
    });
  });

  it('passes ctx.sub as the owner, not any caller-supplied override', async () => {
    const call = getHandler(tools, 'create_task');
    await call({ title: 'Test ABAC' }, MOCK_CTX);

    expect(client.createTask).toHaveBeenCalledWith(
      expect.objectContaining({ sub: MOCK_CTX.sub }),
    );
  });

  it('propagates client errors without swallowing them', async () => {
    client = makeMockClient({
      createTask: vi.fn().mockRejectedValue(new Error('DynamoDB write failed')),
    });
    tools = buildTaskTools(client);
    const call = getHandler(tools, 'create_task');

    await expect(call({ title: 'Failing task' }, MOCK_CTX)).rejects.toThrow('DynamoDB write failed');
  });

  it('scope guard: rejects callers without ops:tasks before touching the client', async () => {
    const call = getHandler(tools, 'create_task');

    await expect(call({ title: 'Sneaky task' }, CTX_NO_TASKS)).rejects.toThrow();
    expect(client.createTask).not.toHaveBeenCalled();
  });

  it('tool metadata: name, tier, requiredScope are correct', () => {
    const tool = tools.find((t) => t.name === 'create_task')!;
    expect(tool.tier).toBe('ops');
    expect(tool.requiredScope).toBe('ops:tasks');
  });
});

// ---------------------------------------------------------------------------
// list_tasks
// ---------------------------------------------------------------------------

describe('list_tasks', () => {
  let client: TasksClient;
  let tools: ReturnType<typeof buildTaskTools>;

  beforeEach(() => {
    client = makeMockClient();
    tools = buildTaskTools(client);
  });

  it('happy path: returns tasks with expected fields', async () => {
    const call = getHandler(tools, 'list_tasks');
    const result = await call({}, MOCK_CTX);

    expect(result.tasks).toHaveLength(1);
    expect(result.tasks[0]).toMatchObject({
      taskId: 'task-001',
      title: 'Review vendor invoices',
      completed: false,
    });
  });

  it('empty result: returns an empty array without error', async () => {
    client = makeMockClient({ listTasks: vi.fn().mockResolvedValue([]) });
    tools = buildTaskTools(client);
    const call = getHandler(tools, 'list_tasks');
    const result = await call({}, MOCK_CTX);

    expect(result.tasks).toEqual([]);
  });

  it('passes includeCompleted: false by default', async () => {
    const call = getHandler(tools, 'list_tasks');
    await call({}, MOCK_CTX);

    expect(client.listTasks).toHaveBeenCalledWith(
      expect.objectContaining({ includeCompleted: false }),
    );
  });

  it('passes includeCompleted: true when requested', async () => {
    const call = getHandler(tools, 'list_tasks');
    await call({ includeCompleted: true }, MOCK_CTX);

    expect(client.listTasks).toHaveBeenCalledWith(
      expect.objectContaining({ includeCompleted: true }),
    );
  });

  it('always passes ctx.sub to the client for ABAC', async () => {
    const call = getHandler(tools, 'list_tasks');
    await call({}, MOCK_CTX);

    expect(client.listTasks).toHaveBeenCalledWith(
      expect.objectContaining({ sub: MOCK_CTX.sub }),
    );
  });

  it('propagates client errors', async () => {
    client = makeMockClient({
      listTasks: vi.fn().mockRejectedValue(new Error('DynamoDB query failed')),
    });
    tools = buildTaskTools(client);
    const call = getHandler(tools, 'list_tasks');

    await expect(call({}, MOCK_CTX)).rejects.toThrow('DynamoDB query failed');
  });

  it('simulates a throttle error (ProvisionedThroughputExceededException)', async () => {
    const throttleError = Object.assign(
      new Error('ProvisionedThroughputExceededException: rate exceeded'),
      { name: 'ProvisionedThroughputExceededException', $retryable: { throttling: true } },
    );
    client = makeMockClient({ listTasks: vi.fn().mockRejectedValue(throttleError) });
    tools = buildTaskTools(client);
    const call = getHandler(tools, 'list_tasks');

    // The tool handler propagates the error; retry logic belongs at the transport layer.
    const err = await call({}, MOCK_CTX).catch((e) => e);
    expect(err.name).toBe('ProvisionedThroughputExceededException');
  });

  it('scope guard: rejects callers without ops:tasks', async () => {
    const call = getHandler(tools, 'list_tasks');

    await expect(call({}, CTX_NO_TASKS)).rejects.toThrow();
    expect(client.listTasks).not.toHaveBeenCalled();
  });

  it('tool metadata: name, tier, requiredScope are correct', () => {
    const tool = tools.find((t) => t.name === 'list_tasks')!;
    expect(tool.tier).toBe('ops');
    expect(tool.requiredScope).toBe('ops:tasks');
  });
});

// ---------------------------------------------------------------------------
// complete_task
// ---------------------------------------------------------------------------

describe('complete_task', () => {
  let client: TasksClient;
  let tools: ReturnType<typeof buildTaskTools>;

  beforeEach(() => {
    client = makeMockClient();
    tools = buildTaskTools(client);
  });

  it('happy path: returns the completed task shape', async () => {
    const call = getHandler(tools, 'complete_task');
    const result = await call({ taskId: 'task-001' }, MOCK_CTX);

    expect(result.task).toMatchObject({
      taskId: 'task-001',
      completed: true,
      completedAt: '2026-06-11T10:00:00.000Z',
    });
  });

  it('passes ctx.sub for ownership enforcement (ABAC)', async () => {
    const call = getHandler(tools, 'complete_task');
    await call({ taskId: 'task-001' }, MOCK_CTX);

    expect(client.completeTask).toHaveBeenCalledWith(
      expect.objectContaining({ sub: MOCK_CTX.sub, taskId: 'task-001' }),
    );
  });

  it('propagates a ConditionalCheckFailedException (task not owned by caller)', async () => {
    const ownershipError = Object.assign(
      new Error('ConditionalCheckFailedException: condition not met'),
      { name: 'ConditionalCheckFailedException' },
    );
    client = makeMockClient({ completeTask: vi.fn().mockRejectedValue(ownershipError) });
    tools = buildTaskTools(client);
    const call = getHandler(tools, 'complete_task');

    const err = await call({ taskId: 'task-999' }, MOCK_CTX).catch((e) => e);
    expect(err.name).toBe('ConditionalCheckFailedException');
  });

  it('propagates a throttle error', async () => {
    const throttleError = Object.assign(
      new Error('ProvisionedThroughputExceededException'),
      { name: 'ProvisionedThroughputExceededException', $retryable: { throttling: true } },
    );
    client = makeMockClient({ completeTask: vi.fn().mockRejectedValue(throttleError) });
    tools = buildTaskTools(client);
    const call = getHandler(tools, 'complete_task');

    const err = await call({ taskId: 'task-001' }, MOCK_CTX).catch((e) => e);
    expect(err.name).toBe('ProvisionedThroughputExceededException');
  });

  it('scope guard: rejects callers without ops:tasks', async () => {
    const call = getHandler(tools, 'complete_task');

    await expect(call({ taskId: 'task-001' }, CTX_NO_TASKS)).rejects.toThrow();
    expect(client.completeTask).not.toHaveBeenCalled();
  });

  it('tool metadata: tier and requiredScope', () => {
    const tool = tools.find((t) => t.name === 'complete_task')!;
    expect(tool.tier).toBe('ops');
    expect(tool.requiredScope).toBe('ops:tasks');
  });
});

// ---------------------------------------------------------------------------
// delete_task
// ---------------------------------------------------------------------------

describe('delete_task', () => {
  let client: TasksClient;
  let tools: ReturnType<typeof buildTaskTools>;

  beforeEach(() => {
    client = makeMockClient();
    tools = buildTaskTools(client);
  });

  it('happy path: returns deleted: true and the taskId', async () => {
    const call = getHandler(tools, 'delete_task');
    const result = await call({ taskId: 'task-001' }, MOCK_CTX);

    expect(result).toEqual({ deleted: true, taskId: 'task-001' });
  });

  it('passes ctx.sub for ownership enforcement (ABAC)', async () => {
    const call = getHandler(tools, 'delete_task');
    await call({ taskId: 'task-001' }, MOCK_CTX);

    expect(client.deleteTask).toHaveBeenCalledWith(
      expect.objectContaining({ sub: MOCK_CTX.sub, taskId: 'task-001' }),
    );
  });

  it('propagates client errors', async () => {
    client = makeMockClient({
      deleteTask: vi.fn().mockRejectedValue(new Error('DynamoDB delete failed')),
    });
    tools = buildTaskTools(client);
    const call = getHandler(tools, 'delete_task');

    await expect(call({ taskId: 'task-001' }, MOCK_CTX)).rejects.toThrow('DynamoDB delete failed');
  });

  it('propagates a throttle error', async () => {
    const throttleError = Object.assign(
      new Error('ProvisionedThroughputExceededException'),
      { name: 'ProvisionedThroughputExceededException', $retryable: { throttling: true } },
    );
    client = makeMockClient({ deleteTask: vi.fn().mockRejectedValue(throttleError) });
    tools = buildTaskTools(client);
    const call = getHandler(tools, 'delete_task');

    const err = await call({ taskId: 'task-001' }, MOCK_CTX).catch((e) => e);
    expect(err.name).toBe('ProvisionedThroughputExceededException');
  });

  it('scope guard: rejects callers without ops:tasks', async () => {
    const call = getHandler(tools, 'delete_task');

    await expect(call({ taskId: 'task-001' }, CTX_NO_TASKS)).rejects.toThrow();
    expect(client.deleteTask).not.toHaveBeenCalled();
  });

  it('tool metadata: tier and requiredScope', () => {
    const tool = tools.find((t) => t.name === 'delete_task')!;
    expect(tool.tier).toBe('ops');
    expect(tool.requiredScope).toBe('ops:tasks');
  });
});