/**
 * Todo Service Unit Tests
 * TDD: Test-Driven Development
 */

import { describe, it, expect, beforeEach, afterEach } from '@jest/globals';
import { TodoService } from '../../../src/services/todo.service';
import { prisma } from '../../../src/lib/prisma';

describe('TodoService', () => {
  // @ralph 我要测试什么？
  // - 创建待办事项
  // - 更新待办状态 (pending -> completed -> confirmed)
  // - 软删除待办
  // - 按状态筛选
  // - 优先级排序
  // - 到期日期处理

  let userId: string;
  let categoryId: string;
  let documentId: string;

  beforeEach(async () => {
    // Create test user, category and document
    const user = await prisma.user.create({
      data: {
        username: `testuser_${Date.now()}`,
        email: `test_${Date.now()}@example.com`,
        password_hash: '$2a$10$test',
      },
    });
    userId = user.id;

    const category = await prisma.category.create({
      data: {
        user_id: userId,
        name: 'Work',
        type: 'todo',
      },
    });
    categoryId = category.id;

    const document = await prisma.document.create({
      data: {
        user_id: userId,
        content: 'Related document',
      },
    });
    documentId = document.id;
  });

  afterEach(async () => {
    // Clean up
    await prisma.todo.deleteMany({ where: { user_id: userId } });
    await prisma.document.deleteMany({ where: { user_id: userId } });
    await prisma.category.deleteMany({ where: { user_id: userId } });
    await prisma.user.delete({ where: { id: userId } });
  });

  describe('create', () => {
    it('should create a new todo with required fields', async () => {
      // @ralph 正常路径是否覆盖？
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Test todo',
      });

      expect(todo).toBeDefined();
      expect(todo.id).toBeDefined();
      expect(todo.title).toBe('Test todo');
      expect(todo.status).toBe('pending');
      expect(todo.priority).toBe('medium');
      expect(todo.user_id).toBe(userId);
    });

    it('should create todo with all fields', async () => {
      // @ralph 完整创建是否支持？
      const dueDate = new Date('2025-12-31');
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Complete task',
        description: 'Task description',
        priority: 'high',
        due_date: dueDate,
        category_id: categoryId,
        document_id: documentId,
      });

      expect(todo.title).toBe('Complete task');
      expect(todo.description).toBe('Task description');
      expect(todo.priority).toBe('high');
      expect(new Date(todo.due_date!)).toEqual(dueDate);
      expect(todo.category_id).toBe(categoryId);
      expect(todo.document_id).toBe(documentId);
    });

    it('should reject empty title', async () => {
      // @ralph 验证是否正确？
      await expect(
        TodoService.create({
          user_id: userId,
          title: '',
        })
      ).rejects.toThrow('title');
    });

    it('should reject invalid priority', async () => {
      // @ralph 枚举验证是否正确？
      await expect(
        TodoService.create({
          user_id: userId,
          title: 'Test',
          priority: 'invalid' as any,
        })
      ).rejects.toThrow();
    });

    it('should reject invalid status', async () => {
      // @ralph 状态验证是否正确？
      await expect(
        TodoService.create({
          user_id: userId,
          title: 'Test',
          status: 'invalid' as any,
        })
      ).rejects.toThrow();
    });
  });

  describe('findById', () => {
    it('should find todo by id', async () => {
      // @ralph 查找功能是否正常？
      const created = await TodoService.create({
        user_id: userId,
        title: 'Find me',
      });

      const found = await TodoService.findById(created.id, userId);

      expect(found).toBeDefined();
      expect(found!.id).toBe(created.id);
      expect(found!.title).toBe('Find me');
    });

    it('should return null for non-existent todo', async () => {
      // @ralph 未找到时是否返回null？
      const found = await TodoService.findById('00000000-0000-0000-0000-000000000000', userId);
      expect(found).toBeNull();
    });

    it('should not return todo from different user', async () => {
      // @ralph 数据隔离是否正确？
      const otherUser = await prisma.user.create({
        data: {
          username: 'otheruser',
          password_hash: '$2a$10$test',
        },
      });

      const todo = await TodoService.create({
        user_id: userId,
        title: 'Private todo',
      });

      const found = await TodoService.findById(todo.id, otherUser.id);
      expect(found).toBeNull();

      await prisma.user.delete({ where: { id: otherUser.id } });
    });
  });

  describe('update', () => {
    it('should update todo title', async () => {
      // @ralph 更新功能是否正常？
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Old title',
      });

      const updated = await TodoService.update(todo.id, userId, {
        title: 'New title',
      });

      expect(updated.title).toBe('New title');
    });

    it('should update todo description', async () => {
      // @ralph 部分更新是否支持？
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Test',
      });

      const updated = await TodoService.update(todo.id, userId, {
        description: 'New description',
      });

      expect(updated.description).toBe('New description');
    });

    it('should update status and set completed_at', async () => {
      // @ralph 状态转换是否正确？
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Task',
        status: 'pending',
      });

      const updated = await TodoService.update(todo.id, userId, {
        status: 'completed',
      });

      expect(updated.status).toBe('completed');
      expect(updated.completed_at).toBeDefined();
    });

    it('should set confirmed_at when status changes to confirmed', async () => {
      // @ralph 三态流程是否正确？
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Task',
        status: 'completed',
      });

      const updated = await TodoService.update(todo.id, userId, {
        status: 'confirmed',
      });

      expect(updated.status).toBe('confirmed');
      expect(updated.confirmed_at).toBeDefined();
    });

    it('should clear completed_at when reverting to pending', async () => {
      // @ralph 状态回退是否正确？
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Task',
        status: 'completed',
      });

      const updated = await TodoService.update(todo.id, userId, {
        status: 'pending',
      });

      expect(updated.status).toBe('pending');
      expect(updated.completed_at).toBeNull();
    });

    it('should update priority', async () => {
      // @ralph 优先级更新是否正确？
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Task',
      });

      const updated = await TodoService.update(todo.id, userId, {
        priority: 'urgent',
      });

      expect(updated.priority).toBe('urgent');
    });

    it('should update due_date', async () => {
      // @ralph 到期日期更新是否正确？
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Task',
      });

      const newDate = new Date('2025-12-31');
      const updated = await TodoService.update(todo.id, userId, {
        due_date: newDate,
      });

      expect(new Date(updated.due_date!)).toEqual(newDate);
    });

    it('should reject update for non-existent todo', async () => {
      // @ralph 错误处理是否正确？
      await expect(
        TodoService.update('00000000-0000-0000-0000-000000000000', userId, {
          title: 'Updated',
        })
      ).rejects.toThrow();
    });
  });

  describe('delete', () => {
    it('should delete todo', async () => {
      // @ralph 删除功能是否正常？
      const todo = await TodoService.create({
        user_id: userId,
        title: 'Delete me',
      });

      await TodoService.delete(todo.id, userId);

      const found = await TodoService.findById(todo.id, userId);
      expect(found).toBeNull();
    });

    it('should reject delete for non-existent todo', async () => {
      // @ralph 错误处理是否正确？
      await expect(
        TodoService.delete('00000000-0000-0000-0000-000000000000', userId)
      ).rejects.toThrow();
    });
  });

  describe('findByUser', () => {
    beforeEach(async () => {
      // Create multiple todos
      await TodoService.create({
        user_id: userId,
        title: 'Pending task 1',
        status: 'pending',
        priority: 'high',
      });
      await TodoService.create({
        user_id: userId,
        title: 'Completed task',
        status: 'completed',
        priority: 'medium',
      });
      await TodoService.create({
        user_id: userId,
        title: 'Confirmed task',
        status: 'confirmed',
        priority: 'low',
      });
      await TodoService.create({
        user_id: userId,
        title: 'Pending task 2',
        status: 'pending',
        priority: 'urgent',
      });
    });

    it('should return all user todos', async () => {
      // @ralph 列表查询是否正确？
      const todos = await TodoService.findByUser(userId);

      expect(todos).toHaveLength(4);
      expect(todos.every(t => t.user_id === userId)).toBe(true);
    });

    it('should filter by status', async () => {
      // @ralph 状态筛选是否正确？
      const pending = await TodoService.findByUser(userId, { status: 'pending' });
      expect(pending).toHaveLength(2);
      expect(pending.every(t => t.status === 'pending')).toBe(true);

      const completed = await TodoService.findByUser(userId, { status: 'completed' });
      expect(completed).toHaveLength(1);

      const confirmed = await TodoService.findByUser(userId, { status: 'confirmed' });
      expect(confirmed).toHaveLength(1);
    });

    it('should filter by priority', async () => {
      // @ralph 优先级筛选是否正确？
      const high = await TodoService.findByUser(userId, { priority: 'high' });
      expect(high).toHaveLength(1);
      expect(high[0].priority).toBe('high');

      const urgent = await TodoService.findByUser(userId, { priority: 'urgent' });
      expect(urgent).toHaveLength(1);
      expect(urgent[0].priority).toBe('urgent');
    });

    it('should filter by category', async () => {
      // @ralph 分类筛选是否正确？
      const todoWithCategory = await TodoService.create({
        user_id: userId,
        title: 'Categorized task',
        category_id: categoryId,
      });

      const categorized = await TodoService.findByUser(userId, { category_id: categoryId });
      expect(categorized.length).toBeGreaterThanOrEqual(1);
      expect(categorized.some(t => t.id === todoWithCategory.id)).toBe(true);
    });

    it('should filter by document', async () => {
      // @ralph 文档筛选是否正确？
      const todoWithDocument = await TodoService.create({
        user_id: userId,
        title: 'Document task',
        document_id: documentId,
      });

      const withDocument = await TodoService.findByUser(userId, { document_id: documentId });
      expect(withDocument.length).toBeGreaterThanOrEqual(1);
      expect(withDocument.some(t => t.id === todoWithDocument.id)).toBe(true);
    });

    it('should support pagination', async () => {
      // @ralph 分页是否支持？
      const page1 = await TodoService.findByUser(userId, { page: 1, limit: 2 });
      expect(page1).toHaveLength(2);
    });

    it('should sort by priority by default', async () => {
      // @ralph 排序是否正确？
      const todos = await TodoService.findByUser(userId, { limit: 10 });

      // Check that urgent comes before high, and high before medium
      const priorities = todos.map(t => {
        const order = { urgent: 0, high: 1, medium: 2, low: 3 };
        return order[t.priority as keyof typeof order];
      });

      for (let i = 1; i < priorities.length; i++) {
        expect(priorities[i]).toBeGreaterThanOrEqual(priorities[i - 1]);
      }
    });

    it('should return overdue todos', async () => {
      // @ralph 过期筛选是否正确？
      const pastDate = new Date();
      pastDate.setDate(pastDate.getDate() - 10);

      await TodoService.create({
        user_id: userId,
        title: 'Overdue task',
        due_date: pastDate,
        status: 'pending',
      });

      const overdue = await TodoService.findByUser(userId, { overdue: true });
      expect(overdue.length).toBeGreaterThanOrEqual(1);
      expect(overdue.every(t => t.due_date && new Date(t.due_date) < new Date())).toBe(true);
    });
  });

  describe('getPendingTodos', () => {
    it('should return only pending todos', async () => {
      // @ralph 待办列表是否正确？
      await TodoService.create({ user_id: userId, title: 'Pending 1', status: 'pending' });
      await TodoService.create({ user_id: userId, title: 'Pending 2', status: 'pending' });
      await TodoService.create({ user_id: userId, title: 'Completed', status: 'completed' });
      await TodoService.create({ user_id: userId, title: 'Confirmed', status: 'confirmed' });

      const pending = await TodoService.getPendingTodos(userId);
      expect(pending).toHaveLength(2);
      expect(pending.every(t => t.status === 'pending')).toBe(true);
    });
  });

  describe('getCompletedTodos', () => {
    it('should return only completed todos', async () => {
      // @ralph 已完成列表是否正确？
      await TodoService.create({ user_id: userId, title: 'Pending', status: 'pending' });
      await TodoService.create({ user_id: userId, title: 'Completed 1', status: 'completed' });
      await TodoService.create({ user_id: userId, title: 'Completed 2', status: 'completed' });
      await TodoService.create({ user_id: userId, title: 'Confirmed', status: 'confirmed' });

      const completed = await TodoService.getCompletedTodos(userId);
      expect(completed).toHaveLength(2);
      expect(completed.every(t => t.status === 'completed')).toBe(true);
    });
  });

  describe('getConfirmedTodos', () => {
    it('should return only confirmed todos', async () => {
      // @ralph 已确认列表是否正确？
      await TodoService.create({ user_id: userId, title: 'Pending', status: 'pending' });
      await TodoService.create({ user_id: userId, title: 'Completed', status: 'completed' });
      await TodoService.create({ user_id: userId, title: 'Confirmed 1', status: 'confirmed' });
      await TodoService.create({ user_id: userId, title: 'Confirmed 2', status: 'confirmed' });

      const confirmed = await TodoService.getConfirmedTodos(userId);
      expect(confirmed).toHaveLength(2);
      expect(confirmed.every(t => t.status === 'confirmed')).toBe(true);
    });
  });
});