/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import { describe, it, expect, vi, beforeEach, type Mock } from 'vitest';
import { CoderAgentExecutor } from './executor.js';
import type {
  ExecutionEventBus,
  RequestContext,
  TaskStore,
} from '@a2a-js/sdk/server';
import { EventEmitter } from 'node:events';
import { requestStorage } from '../http/requestStorage.js';

vi.mock('../utils/path_utils.js', () => ({
  validateWorkspacePath: vi
    .fn()
    .mockImplementation(async (path?: string) => path || process.cwd()),
}));

// Mocks for constructor dependencies
vi.mock('@google/gemini-cli-core', () => ({
  GeminiEventType: {
    PRIMARY_TURN_STARTED: 'PRIMARY_TURN_STARTED',
    SECONDARY_TURN_STARTED: 'SECONDARY_TURN_STARTED',
  },
  SimpleExtensionLoader: vi.fn(),
  checkPathTrust: vi.fn().mockReturnValue({ isTrusted: false }),
  isHeadlessMode: vi.fn().mockReturnValue(true),
  resolveToRealPath: vi.fn().mockImplementation((p) => p),
}));

vi.mock('../config/config.js', () => ({
  loadConfig: vi.fn().mockReturnValue({
    getSessionId: () => 'test-session',
    getTargetDir: () => '/tmp',
    getCheckpointingEnabled: () => false,
  }),
  loadEnvironment: vi.fn(),
  setIsTrusted: vi.fn().mockReturnValue(false),
  setTargetDir: vi.fn().mockReturnValue('/tmp'),
  envStorage: {
    run: (env: Record<string, string>, cb: () => unknown) => cb(),
  },
  cwdSymbol: Symbol('cwd'),
}));

vi.mock('../config/settings.js', () => ({
  loadSettings: vi.fn().mockReturnValue({}),
}));

vi.mock('../config/extension.js', () => ({
  loadExtensions: vi.fn().mockReturnValue([]),
}));

vi.mock('../http/requestStorage.js', () => ({
  requestStorage: {
    getStore: vi.fn(),
  },
}));

vi.mock('./task.js', () => {
  const mockTaskInstance = (taskId: string, contextId: string) => ({
    id: taskId,
    contextId,
    taskState: 'working',
    acceptUserMessage: vi
      .fn()
      .mockImplementation(async function* (context, aborted) {
        const isConfirmation = (
          context.userMessage.parts as Array<{ kind: string }>
        ).some((p) => p.kind === 'confirmation');
        // Hang only for main user messages (text), allow confirmations to finish quickly
        if (!isConfirmation && aborted) {
          await new Promise((resolve) => {
            aborted.addEventListener('abort', resolve, { once: true });
          });
        }
        yield { type: 'content', value: 'hello' };
      }),
    acceptAgentMessage: vi.fn().mockResolvedValue(undefined),
    scheduleToolCalls: vi.fn().mockResolvedValue(undefined),
    waitForPendingTools: vi.fn().mockResolvedValue(undefined),
    getAndClearCompletedTools: vi.fn().mockReturnValue([]),
    get hasPendingTools() {
      return false;
    },
    get pendingToolsCount() {
      return 0;
    },
    addToolResponsesToHistory: vi.fn(),
    sendCompletedToolsToLlm: vi.fn().mockImplementation(async function* () {}),
    cancelPendingTools: vi.fn(),
    setTaskStateAndPublishUpdate: vi.fn(),
    dispose: vi.fn(),
    getMetadata: vi.fn().mockResolvedValue({}),
    geminiClient: {
      initialize: vi.fn().mockResolvedValue(undefined),
    },
    toSDKTask: () => ({
      id: taskId,
      contextId,
      kind: 'task',
      status: { state: 'working', timestamp: new Date().toISOString() },
      metadata: {},
      history: [],
      artifacts: [],
    }),
  });

  const MockTask = vi.fn().mockImplementation(mockTaskInstance);
  (MockTask as unknown as { create: Mock }).create = vi
    .fn()
    .mockImplementation(async (taskId: string, contextId: string) =>
      mockTaskInstance(taskId, contextId),
    );

  return { Task: MockTask };
});

describe('CoderAgentExecutor', () => {
  let executor: CoderAgentExecutor;
  let mockTaskStore: TaskStore;
  let mockEventBus: ExecutionEventBus;

  beforeEach(() => {
    vi.clearAllMocks();
    mockTaskStore = {
      save: vi.fn().mockResolvedValue(undefined),
      load: vi.fn().mockResolvedValue(undefined),
      delete: vi.fn().mockResolvedValue(undefined),
      list: vi.fn().mockResolvedValue([]),
    } as unknown as TaskStore;

    mockEventBus = new EventEmitter() as unknown as ExecutionEventBus;
    mockEventBus.publish = vi.fn();
    mockEventBus.finished = vi.fn();

    executor = new CoderAgentExecutor(mockTaskStore);
  });

  it('should distinguish between primary and secondary execution', async () => {
    const taskId = 'test-task';
    const contextId = 'test-context';

    const mockSocket = new EventEmitter();
    const requestContext = {
      userMessage: {
        messageId: 'msg-1',
        taskId,
        contextId,
        parts: [{ kind: 'text', text: 'hi' }],
        metadata: {
          coderAgent: { kind: 'agent-settings', workspacePath: '/tmp' },
        },
      },
    } as unknown as RequestContext;

    // Mock requestStorage for primary
    (requestStorage.getStore as Mock).mockReturnValue({
      req: { socket: mockSocket },
    });

    // First execution (Primary)
    const primaryPromise = executor.execute(requestContext, mockEventBus);

    // Give it enough time to reach line 490 in executor.ts
    await new Promise((resolve) => setTimeout(resolve, 50));

    expect(
      (
        executor as unknown as { executingTasks: Set<string> }
      ).executingTasks.has(taskId),
    ).toBe(true);
    const wrapper = executor.getTask(taskId);
    expect(wrapper).toBeDefined();

    // Mock requestStorage for secondary
    const secondarySocket = new EventEmitter();
    (requestStorage.getStore as Mock).mockReturnValue({
      req: { socket: secondarySocket },
    });

    const secondaryRequestContext = {
      userMessage: {
        messageId: 'msg-2',
        taskId,
        contextId,
        parts: [{ kind: 'confirmation', callId: '1', outcome: 'proceed' }],
        metadata: {
          coderAgent: { kind: 'agent-settings', workspacePath: '/tmp' },
        },
      },
    } as unknown as RequestContext;

    const secondaryPromise = executor.execute(
      secondaryRequestContext,
      mockEventBus,
    );

    // Secondary execution should NOT add to executingTasks (already there)
    // and should return early after its loop
    await secondaryPromise;

    // Task should still be in executingTasks and NOT disposed
    expect(
      (
        executor as unknown as { executingTasks: Set<string> }
      ).executingTasks.has(taskId),
    ).toBe(true);
    expect(wrapper?.task.dispose).not.toHaveBeenCalled();

    // Now simulate secondary socket closure - it should NOT affect primary
    secondarySocket.emit('end');
    expect(
      (
        executor as unknown as { executingTasks: Set<string> }
      ).executingTasks.has(taskId),
    ).toBe(true);
    expect(wrapper?.task.dispose).not.toHaveBeenCalled();

    // Set to terminal state to verify disposal on finish
    wrapper!.task.taskState = 'completed';

    // Now close primary socket
    mockSocket.emit('end');

    await primaryPromise;

    expect(
      (
        executor as unknown as { executingTasks: Set<string> }
      ).executingTasks.has(taskId),
    ).toBe(false);
    expect(wrapper?.task.dispose).toHaveBeenCalled();
  });

  it('should evict task from cache when it reaches terminal state', async () => {
    const taskId = 'test-task-terminal';
    const contextId = 'test-context';

    const mockSocket = new EventEmitter();
    (requestStorage.getStore as Mock).mockReturnValue({
      req: { socket: mockSocket },
    });

    const requestContext = {
      userMessage: {
        messageId: 'msg-1',
        taskId,
        contextId,
        parts: [{ kind: 'text', text: 'hi' }],
        metadata: {
          coderAgent: { kind: 'agent-settings', workspacePath: '/tmp' },
        },
      },
    } as unknown as RequestContext;

    const primaryPromise = executor.execute(requestContext, mockEventBus);
    await new Promise((resolve) => setTimeout(resolve, 50));

    const wrapper = executor.getTask(taskId)!;
    expect(wrapper).toBeDefined();
    // Simulate terminal state
    wrapper.task.taskState = 'completed';

    // Finish primary execution
    mockSocket.emit('end');
    await primaryPromise;

    expect(executor.getTask(taskId)).toBeUndefined();
    expect(wrapper.task.dispose).toHaveBeenCalled();
  });

  it('should yield the turn and transition to input-required if tools are pending', async () => {
    const taskId = 'test-task-pending-tools';
    const contextId = 'test-context';

    const mockSocket = new EventEmitter();
    (requestStorage.getStore as Mock).mockReturnValue({
      req: { socket: mockSocket },
    });

    // Pre-create the task to safely modify its mocked methods before execution
    const wrapper = await executor.createTask(
      taskId,
      contextId,
      undefined,
      mockEventBus,
    );
    const hasPendingToolsSpy = vi
      .spyOn(wrapper.task, 'hasPendingTools', 'get')
      .mockReturnValue(true);
    vi.spyOn(wrapper.task, 'pendingToolsCount', 'get').mockReturnValue(1);

    const requestContext = {
      userMessage: {
        messageId: 'msg-1',
        taskId,
        contextId,
        parts: [{ kind: 'confirmation', callId: '1', outcome: 'proceed' }],
        metadata: {
          coderAgent: { kind: 'agent-settings', workspacePath: '/tmp' },
        },
      },
    } as unknown as RequestContext;

    await executor.execute(requestContext, mockEventBus);

    // Assert that the executor yielded the turn correctly without further progression
    expect(hasPendingToolsSpy).toHaveBeenCalled();
    expect(wrapper.task.getAndClearCompletedTools).not.toHaveBeenCalled();
    expect(wrapper.task.sendCompletedToolsToLlm).not.toHaveBeenCalled();
    expect(wrapper.task.setTaskStateAndPublishUpdate).toHaveBeenCalledWith(
      'input-required',
      expect.any(Object),
      undefined,
      undefined,
      true,
    );
  });

  it('cancelTask should abort the active execution loop', async () => {
    const abortSpy = vi.spyOn(AbortController.prototype, 'abort');
    const taskId = 'test-task-to-cancel';
    const contextId = 'test-context';

    const mockSocket = new EventEmitter();
    (requestStorage.getStore as Mock).mockReturnValue({
      req: { socket: mockSocket },
    });

    const requestContext = {
      userMessage: {
        messageId: 'msg-1',
        taskId,
        contextId,
        parts: [{ kind: 'text', text: 'a long running prompt' }],
        metadata: {
          coderAgent: { kind: 'agent-settings', workspacePath: '/tmp' },
        },
      },
    } as unknown as RequestContext;

    // Don't await this, let it run in the background.
    let primaryError: Error | null = null;
    const primaryPromise = executor.execute(requestContext, mockEventBus);
    primaryPromise.catch((err) => {
      primaryError = err as Error;
    });

    // Poll until the task is registered in the executor to avoid flaky timeouts in slow CI environments.
    let attempts = 0;
    while (!executor.getTask(taskId)) {
      if (primaryError) {
        throw new Error(`Primary execution failed early: ${primaryError}`);
      }
      if (attempts++ > 100) {
        // 100 * 5ms = 500ms timeout
        throw new Error('Timed out waiting for task to be registered');
      }
      await new Promise((resolve) => setTimeout(resolve, 5));
    }

    const wrapper = executor.getTask(taskId);
    expect(wrapper).toBeDefined();
    const setTaskStateSpy = vi
      .spyOn(wrapper!.task, 'setTaskStateAndPublishUpdate')
      .mockImplementation((newState) => {
        // Make the mock realistic: actually update the state when called.
        wrapper!.task.taskState = newState;
      });

    // Now, cancel the task.
    await executor.cancelTask(taskId, mockEventBus);

    // Verify that the abort method on the controller was called and state was updated.
    expect(abortSpy).toHaveBeenCalledOnce();
    expect(setTaskStateSpy).toHaveBeenCalledWith(
      'canceled',
      expect.any(Object),
      'Task canceled by user request.',
      undefined,
      true,
    );

    // Clean up the test by allowing the promise to resolve.
    // The abort call should have unblocked the acceptUserMessage generator.
    await primaryPromise;

    // Verify task is evicted from cache
    expect(executor.getTask(taskId)).toBeUndefined();

    abortSpy.mockRestore();
  });

  it('cancelTask should explicitly save task state to TaskStore and evict task during active aborts', async () => {
    const taskId = 'test-task-active-abort-save';
    const contextId = 'test-context';

    const mockSocket = new EventEmitter();
    (requestStorage.getStore as Mock).mockReturnValue({
      req: { socket: mockSocket },
    });

    const requestContext = {
      userMessage: {
        messageId: 'msg-1',
        taskId,
        contextId,
        parts: [{ kind: 'text', text: 'a long running prompt' }],
        metadata: {
          coderAgent: { kind: 'agent-settings', workspacePath: '/tmp' },
        },
      },
    } as unknown as RequestContext;

    const primaryPromise = executor.execute(requestContext, mockEventBus);

    // Wait for task to be registered
    let attempts = 0;
    while (!executor.getTask(taskId)) {
      if (attempts++ > 100) {
        throw new Error('Timed out waiting for task to be registered');
      }
      await new Promise((resolve) => setTimeout(resolve, 5));
    }

    const wrapper = executor.getTask(taskId)!;
    const saveSpy = vi.spyOn(mockTaskStore, 'save');

    // Now, cancel the task.
    await executor.cancelTask(taskId, mockEventBus);

    // Verify that the task state was saved to TaskStore during cancelTask
    expect(saveSpy).toHaveBeenCalled();
    expect(wrapper.task.dispose).toHaveBeenCalled();
    expect(executor.getTask(taskId)).toBeUndefined();

    // Clean up the test by allowing the promise to resolve.
    await primaryPromise;
  });
});