import { describe, expect, it, vi, beforeEach, afterEach } from 'vitest';
import { writeFileSync, mkdirSync, unlinkSync, rmSync, readFileSync, existsSync } from 'node:fs';
import { resolve } from 'node:path';
import { tmpdir, homedir } from 'node:os';
import { execSync } from 'node:child_process';
import { HeartbeatService, type HeartbeatConfig } from './heartbeat.js';
import { buildCustomHeartbeatPrompt, SILENT_MODE_PREFIX } from '../core/prompts.js';
import type { AgentSession } from '../core/interfaces.js';
import { addTodo } from '../todo/store.js';
import { getCronLogPath } from '../utils/paths.js';

const HEARTBEAT_LOG_PATH = getCronLogPath();

// ── buildCustomHeartbeatPrompt ──────────────────────────────────────────

describe('buildCustomHeartbeatPrompt', () => {
  it('includes silent mode prefix', () => {
    const result = buildCustomHeartbeatPrompt('Do something', '12:00 PM', 'UTC', 60);
    expect(result).toContain(SILENT_MODE_PREFIX);
  });

  it('includes time and interval metadata', () => {
    const result = buildCustomHeartbeatPrompt('Do something', '3:30 PM', 'America/Los_Angeles', 45);
    expect(result).toContain('TIME: 3:30 PM (America/Los_Angeles)');
    expect(result).toContain('NEXT HEARTBEAT: in 45 minutes');
  });

  it('includes custom prompt text in body', () => {
    const result = buildCustomHeartbeatPrompt('Check your todo list.', '12:00 PM', 'UTC', 60);
    expect(result).toContain('Check your todo list.');
  });

  it('includes lettabot-message instructions', () => {
    const result = buildCustomHeartbeatPrompt('Custom task', '12:00 PM', 'UTC', 60);
    expect(result).toContain('lettabot-message send --text');
  });

  it('does NOT include default body text', () => {
    const result = buildCustomHeartbeatPrompt('Custom task', '12:00 PM', 'UTC', 60);
    expect(result).not.toContain('This is your time');
    expect(result).not.toContain('Pursue curiosities');
  });
});

// ── HeartbeatService prompt resolution ──────────────────────────────────

function createMockBot(): AgentSession {
  return {
    registerChannel: vi.fn(),
    setGroupBatcher: vi.fn(),
    processGroupBatch: vi.fn(),
    start: vi.fn(),
    stop: vi.fn(),
    sendToAgent: vi.fn().mockResolvedValue('ok'),
    streamToAgent: vi.fn().mockReturnValue((async function* () { yield { type: 'result', success: true }; })()),
    deliverToChannel: vi.fn(),
    getStatus: vi.fn().mockReturnValue({ agentId: 'test', conversationId: null, channels: [] }),
    setAgentId: vi.fn(),
    reset: vi.fn(),
    getLastMessageTarget: vi.fn().mockReturnValue(null),
    getLastUserMessageTime: vi.fn().mockReturnValue(null),
    invalidateSession: vi.fn(),
  };
}

function createConfig(overrides: Partial<HeartbeatConfig> = {}): HeartbeatConfig {
  return {
    enabled: true,
    intervalMinutes: 30,
    workingDir: tmpdir(),
    agentKey: 'test-agent',
    ...overrides,
  };
}

describe('HeartbeatService prompt resolution', () => {
  let tmpDir: string;
  let originalDataDir: string | undefined;

  beforeEach(() => {
    tmpDir = resolve(tmpdir(), `heartbeat-test-${Date.now()}`);
    mkdirSync(tmpDir, { recursive: true });
    originalDataDir = process.env.DATA_DIR;
    process.env.DATA_DIR = tmpDir;
  });

  afterEach(() => {
    if (originalDataDir === undefined) {
      delete process.env.DATA_DIR;
    } else {
      process.env.DATA_DIR = originalDataDir;
    }
    try { rmSync(tmpDir, { recursive: true, force: true }); } catch { /* ignore */ }
  });

  it('uses default prompt when no custom prompt is set', async () => {
    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({ workingDir: tmpDir }));

    await service.trigger();

    const sentMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[0][0] as string;
    expect(sentMessage).toContain('This is your time');
    expect(sentMessage).toContain(SILENT_MODE_PREFIX);
  });

  it('uses inline prompt when set', async () => {
    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      prompt: 'Check your todo list and work on the top item.',
    }));

    await service.trigger();

    const sentMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[0][0] as string;
    expect(sentMessage).toContain('Check your todo list and work on the top item.');
    expect(sentMessage).not.toContain('This is your time');
    expect(sentMessage).toContain(SILENT_MODE_PREFIX);
  });

  it('uses promptFile when no inline prompt is set', async () => {
    const promptPath = resolve(tmpDir, 'heartbeat-prompt.txt');
    writeFileSync(promptPath, 'Research quantum computing papers.');

    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      promptFile: 'heartbeat-prompt.txt',
    }));

    await service.trigger();

    const sentMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[0][0] as string;
    expect(sentMessage).toContain('Research quantum computing papers.');
    expect(sentMessage).not.toContain('This is your time');
  });

  it('inline prompt takes precedence over promptFile', async () => {
    const promptPath = resolve(tmpDir, 'heartbeat-prompt.txt');
    writeFileSync(promptPath, 'FROM FILE');

    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      prompt: 'FROM INLINE',
      promptFile: 'heartbeat-prompt.txt',
    }));

    await service.trigger();

    const sentMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[0][0] as string;
    expect(sentMessage).toContain('FROM INLINE');
    expect(sentMessage).not.toContain('FROM FILE');
  });

  it('re-reads promptFile on each tick (live reload)', async () => {
    const promptPath = resolve(tmpDir, 'heartbeat-prompt.txt');
    writeFileSync(promptPath, 'Version 1');

    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      promptFile: 'heartbeat-prompt.txt',
    }));

    // First tick
    await service.trigger();
    const firstMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[0][0] as string;
    expect(firstMessage).toContain('Version 1');

    // Update file
    writeFileSync(promptPath, 'Version 2');

    // Second tick
    await service.trigger();
    const secondMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[1][0] as string;
    expect(secondMessage).toContain('Version 2');
    expect(secondMessage).not.toContain('Version 1');
  });

  it('falls back to default when promptFile does not exist', async () => {
    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      promptFile: 'nonexistent.txt',
    }));

    await service.trigger();

    const sentMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[0][0] as string;
    // Should fall back to default since file doesn't exist
    expect(sentMessage).toContain('This is your time');
  });

  it('falls back to default when promptFile is empty', async () => {
    const promptPath = resolve(tmpDir, 'empty.txt');
    writeFileSync(promptPath, '   \n  ');

    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      promptFile: 'empty.txt',
    }));

    await service.trigger();

    const sentMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[0][0] as string;
    // Empty/whitespace file should fall back to default
    expect(sentMessage).toContain('This is your time');
  });

  it('injects actionable todos into default heartbeat prompt', async () => {
    addTodo('test', {
      text: 'Deliver morning report',
      due: '2026-02-13T08:00:00.000Z',
      recurring: 'daily 8am',
    });

    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({ workingDir: tmpDir }));

    await service.trigger();

    const sentMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[0][0] as string;
    expect(sentMessage).toContain('PENDING TO-DOS:');
    expect(sentMessage).toContain('Deliver morning report');
    expect(sentMessage).toContain('recurring: daily 8am');
    expect(sentMessage).toContain('manage_todo');
  });

  it('does not include snoozed todos that are not actionable yet', async () => {
    addTodo('test', {
      text: 'Follow up after trip',
      snoozed_until: '2099-01-01T00:00:00.000Z',
    });

    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({ workingDir: tmpDir }));

    await service.trigger();

    const sentMessage = (bot.sendToAgent as ReturnType<typeof vi.fn>).mock.calls[0][0] as string;
    expect(sentMessage).not.toContain('Follow up after trip');
  });

  it('skips automatic heartbeat when user messaged within skip window', async () => {
    const bot = createMockBot();
    (bot.getLastUserMessageTime as ReturnType<typeof vi.fn>).mockReturnValue(
      new Date(Date.now() - 2 * 60 * 1000),
    );

    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      skipRecentPolicy: 'fixed',
      skipRecentUserMinutes: 5,
    }));

    await (service as any).runHeartbeat(false);

    expect(bot.sendToAgent).not.toHaveBeenCalled();
  });

  it('does not skip automatic heartbeat when skipRecentUserMinutes is 0', async () => {
    const bot = createMockBot();
    (bot.getLastUserMessageTime as ReturnType<typeof vi.fn>).mockReturnValue(
      new Date(Date.now() - 1 * 60 * 1000),
    );

    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      skipRecentPolicy: 'fixed',
      skipRecentUserMinutes: 0,
    }));

    await (service as any).runHeartbeat(false);

    expect(bot.sendToAgent).toHaveBeenCalledTimes(1);
  });

  it('defaults to fraction policy (0.5 of interval) when no fixed window is configured', async () => {
    const bot = createMockBot();
    (bot.getLastUserMessageTime as ReturnType<typeof vi.fn>).mockReturnValue(
      new Date(Date.now() - 10 * 60 * 1000),
    );

    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      intervalMinutes: 30,
    }));

    await (service as any).runHeartbeat(false);

    // 30m * 0.5 => 15m skip window; 10m ago should skip.
    expect(bot.sendToAgent).not.toHaveBeenCalled();
  });

  it('does not skip when skipRecentPolicy is off', async () => {
    const bot = createMockBot();
    (bot.getLastUserMessageTime as ReturnType<typeof vi.fn>).mockReturnValue(
      new Date(Date.now() - 1 * 60 * 1000),
    );

    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      skipRecentPolicy: 'off',
      skipRecentUserMinutes: 60,
    }));

    await (service as any).runHeartbeat(false);

    expect(bot.sendToAgent).toHaveBeenCalledTimes(1);
  });
});

// ── Memfs health check ─────────────────────────────────────────────────

describe('HeartbeatService memfs health check', () => {
  let tmpDir: string;
  let memDir: string | undefined;
  let originalDataDir: string | undefined;
  let originalHome: string | undefined;
  let testHome: string;

  beforeEach(() => {
    tmpDir = resolve(tmpdir(), `heartbeat-memfs-test-${Date.now()}`);
    testHome = resolve(tmpDir, 'fake-home');
    mkdirSync(tmpDir, { recursive: true });
    mkdirSync(testHome, { recursive: true });
    originalDataDir = process.env.DATA_DIR;
    originalHome = process.env.HOME;
    process.env.DATA_DIR = tmpDir;
    process.env.HOME = testHome;
  });

  afterEach(() => {
    if (originalDataDir === undefined) {
      delete process.env.DATA_DIR;
    } else {
      process.env.DATA_DIR = originalDataDir;
    }
    if (originalHome === undefined) {
      delete process.env.HOME;
    } else {
      process.env.HOME = originalHome;
    }
    try { rmSync(tmpDir, { recursive: true, force: true }); } catch { /* ignore */ }
    memDir = undefined;
  });

  it('emits heartbeat_memfs_dirty when memfs directory has untracked files', async () => {
    // Set up a real git repo to act as the memory directory
    const agentId = 'agent-memfs-test-' + Date.now();
    memDir = resolve(homedir(), '.letta', 'agents', agentId, 'memory');
    mkdirSync(memDir, { recursive: true });
    execSync('git init', { cwd: memDir, stdio: 'ignore' });
    // Create an untracked file
    writeFileSync(resolve(memDir, 'untracked.md'), 'test');

    const bot = createMockBot();
    (bot.getStatus as ReturnType<typeof vi.fn>).mockReturnValue({
      agentId,
      conversationId: null,
      channels: [],
    });

    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      memfs: true,
    }));

    // Access private method for direct testing
    const checkMemfsHealth = (service as any).checkMemfsHealth.bind(service);

    expect(() => checkMemfsHealth()).not.toThrow();
    await new Promise((resolvePromise) => setTimeout(resolvePromise, 10));

    const logContents = existsSync(HEARTBEAT_LOG_PATH)
      ? readFileSync(HEARTBEAT_LOG_PATH, 'utf-8')
      : '';
    expect(logContents).toContain('heartbeat_memfs_dirty');
    expect(logContents).toContain(agentId);
  });

  it('skips memfs check when memfs is disabled', async () => {
    const bot = createMockBot();
    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      memfs: false,
    }));

    const getMemoryDir = (service as any).getMemoryDir.bind(service);
    expect(getMemoryDir()).toBeNull();
  });

  it('skips memfs check when agent ID is not available', async () => {
    const bot = createMockBot();
    (bot.getStatus as ReturnType<typeof vi.fn>).mockReturnValue({
      agentId: null,
      conversationId: null,
      channels: [],
    });

    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      memfs: true,
    }));

    const getMemoryDir = (service as any).getMemoryDir.bind(service);
    expect(getMemoryDir()).toBeNull();
  });

  it('resolves memory directory correctly when memfs is enabled', () => {
    const bot = createMockBot();
    (bot.getStatus as ReturnType<typeof vi.fn>).mockReturnValue({
      agentId: 'agent-abc123',
      conversationId: null,
      channels: [],
    });

    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      memfs: true,
    }));

    const getMemoryDir = (service as any).getMemoryDir.bind(service);
    expect(getMemoryDir()).toBe(resolve(homedir(), '.letta', 'agents', 'agent-abc123', 'memory'));
  });

  it('still calls sendToAgent even when memfs check finds dirty files', async () => {
    const agentId = 'agent-memfs-dirty-' + Date.now();
    memDir = resolve(homedir(), '.letta', 'agents', agentId, 'memory');
    mkdirSync(memDir, { recursive: true });
    execSync('git init', { cwd: memDir, stdio: 'ignore' });
    writeFileSync(resolve(memDir, 'dirty.md'), 'uncommitted content');

    const bot = createMockBot();
    (bot.getStatus as ReturnType<typeof vi.fn>).mockReturnValue({
      agentId,
      conversationId: null,
      channels: [],
    });

    const service = new HeartbeatService(bot, createConfig({
      workingDir: tmpDir,
      memfs: true,
    }));

    await service.trigger();

    // sendToAgent should still be called (memfs check is non-blocking)
    expect(bot.sendToAgent).toHaveBeenCalledTimes(1);
  });
});