import { getRelatedNotes } from '@/lib/related'

// Mock prisma and usage before importing related module
jest.mock('@/lib/prisma', () => ({
  prisma: {
    note: {
      findUnique: jest.fn(),
      findMany: jest.fn(),
    },
  },
}))

jest.mock('@/lib/usage', () => ({
  getUsageStats: jest.fn(),
}))

import { prisma } from '@/lib/prisma'
import { getUsageStats } from '@/lib/usage'

describe('related.ts', () => {
  const createMockNote = (overrides = {}) => ({
    id: 'note-1',
    title: 'Docker Commands',
    content: 'docker build and docker run commands',
    type: 'command',
    isFavorite: false,
    isPinned: false,
    createdAt: new Date('2024-01-01'),
    updatedAt: new Date('2024-01-15'),
    tags: [
      { tag: { id: 'tag-1', name: 'docker' } },
      { tag: { id: 'tag-2', name: 'containers' } },
    ],
    ...overrides,
  })

  const createMockOtherNote = (overrides = {}) => ({
    id: 'note-other',
    title: 'Other Note Title',
    content: 'other content xyz123',
    type: 'snippet',
    tags: [] as { tag: { id: string; name: string } }[],
    ...overrides,
  })

  beforeEach(() => {
    jest.clearAllMocks()
    // Default usage stats - no usage
    ;(getUsageStats as jest.Mock).mockResolvedValue({ views: 0, clicks: 0, relatedClicks: 0 })
  })

  describe('getRelatedNotes', () => {
    it('should return empty array when note not found', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(null)

      const result = await getRelatedNotes('non-existent')

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

    it('should return empty array when no related notes found', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote())
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({ id: 'note-x', title: 'Completely Different', content: 'xyz abc def' }),
      ])

      const result = await getRelatedNotes('note-1')

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

    it('should return related notes sorted by score', async () => {
      const mockNote = createMockNote()
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(mockNote)
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({ id: 'note-2', type: 'command', title: 'Docker Compose', tags: [{ tag: { id: 't1', name: 'docker' } }] }),
        createMockOtherNote({ id: 'note-3', title: 'React Hooks', content: 'react hooks' }),
      ])

      const result = await getRelatedNotes('note-1')

      expect(result.length).toBeGreaterThan(0)
      // First result should have highest score
      for (let i = 0; i < result.length - 1; i++) {
        expect(result[i].score).toBeGreaterThanOrEqual(result[i + 1].score)
      }
    })

    it('should give +3 for same type', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote())
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({ id: 'note-2', type: 'command', title: 'XYZ', content: 'different' }),
      ])

      const result = await getRelatedNotes('note-1')

      const note2 = result.find((n) => n.id === 'note-2')
      expect(note2).toBeDefined()
      expect(note2!.score).toBe(3) // only type match
      expect(note2!.reason).toContain('Same type')
    })

    it('should give +3 per shared tag', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote())
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({
          id: 'note-2',
          type: 'snippet', // different type to isolate tag scoring
          title: 'XYZ Title',
          content: 'different content',
          tags: [
            { tag: { id: 'tag-1', name: 'docker' } },
            { tag: { id: 'tag-2', name: 'containers' } },
          ],
        }),
      ])

      const result = await getRelatedNotes('note-1')

      const note2 = result.find((n) => n.id === 'note-2')
      expect(note2).toBeDefined()
      expect(note2!.score).toBe(6) // 2 tags * 3 = 6
      expect(note2!.reason).toContain('Tags: docker, containers')
    })

    it('should cap title keyword boost at +3', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote({ title: 'Docker Kubernetes', content: 'different' }))
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({
          id: 'note-2',
          type: 'snippet',
          title: 'Docker Kubernetes Python Ruby', // 4 shared keywords but capped at 3
          content: 'different',
          tags: [],
        }),
      ])

      const result = await getRelatedNotes('note-1')

      const note2 = result.find((n) => n.id === 'note-2')
      expect(note2).toBeDefined()
      // Type mismatch = 0, Tags = 0, Title keywords capped at +3
      expect(note2!.score).toBeLessThanOrEqual(3)
    })

    it('should cap content keyword boost at +2', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote({ title: 'Different', content: 'docker kubernetes python ruby' }))
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({
          id: 'note-2',
          type: 'snippet',
          title: 'Title',
          content: 'docker kubernetes python', // 3 shared but capped at 2
          tags: [],
        }),
      ])

      const result = await getRelatedNotes('note-1')

      const note2 = result.find((n) => n.id === 'note-2')
      expect(note2).toBeDefined()
    })

    it('should add usage-based boost with view count', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote())
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({ id: 'note-2', type: 'command', title: 'XYZ', content: 'different', tags: [] }),
      ])
      ;(getUsageStats as jest.Mock).mockResolvedValue({ views: 15, clicks: 0, relatedClicks: 0 })

      const result = await getRelatedNotes('note-1')

      const note2 = result.find((n) => n.id === 'note-2')
      // Base: 3 (type) + floor(15/5)=3 + 2 (recency) = 8
      expect(note2!.score).toBe(8)
    })

    it('should cap usage view boost at +3', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote())
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({ id: 'note-2', type: 'command', title: 'XYZ', content: 'different', tags: [] }),
      ])
      ;(getUsageStats as jest.Mock).mockResolvedValue({ views: 50, clicks: 0, relatedClicks: 0 })

      const result = await getRelatedNotes('note-1')

      const note2 = result.find((n) => n.id === 'note-2')
      // Base: 3 (type) + min(floor(50/5),3)=3 + 2 (recency) = 8
      expect(note2!.score).toBe(8)
    })

    it('should add +2 recency boost when note has any views', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote())
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({ id: 'note-2', type: 'command', title: 'XYZ', content: 'different', tags: [] }),
      ])
      ;(getUsageStats as jest.Mock).mockResolvedValue({ views: 5, clicks: 0, relatedClicks: 0 })

      const result = await getRelatedNotes('note-1')

      const note2 = result.find((n) => n.id === 'note-2')
      // Base: 3 (type) + floor(5/5)=1 + 2 (recency) = 6
      expect(note2!.score).toBe(6)
    })

    it('should use relatedClicks for recency boost', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote())
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({ id: 'note-2', type: 'command', title: 'XYZ', content: 'different', tags: [] }),
      ])
      ;(getUsageStats as jest.Mock).mockResolvedValue({ views: 0, clicks: 0, relatedClicks: 3 })

      const result = await getRelatedNotes('note-1')

      const note2 = result.find((n) => n.id === 'note-2')
      // Base: 3 (type) + 0 (views) + 2 (related clicks recency) = 5
      expect(note2!.score).toBe(5)
    })

    it('should respect limit parameter', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote())
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({ id: 'note-2', type: 'command', title: 'Docker', tags: [{ tag: { id: 't1', name: 'docker' } }] }),
        createMockOtherNote({ id: 'note-3', type: 'command', title: 'Kubernetes', tags: [{ tag: { id: 't2', name: 'kubernetes' } }] }),
        createMockOtherNote({ id: 'note-4', type: 'command', title: 'Git', tags: [{ tag: { id: 't3', name: 'git' } }] }),
      ])

      const result = await getRelatedNotes('note-1', 2)

      expect(result).toHaveLength(2)
    })

    it('should include reason field', async () => {
      ;(prisma.note.findUnique as jest.Mock).mockResolvedValue(createMockNote())
      ;(prisma.note.findMany as jest.Mock).mockResolvedValue([
        createMockOtherNote({ id: 'note-2', type: 'command', title: 'Docker', tags: [{ tag: { id: 't1', name: 'docker' } }] }),
      ])

      const result = await getRelatedNotes('note-1')

      expect(result[0].reason).toBeDefined()
      expect(typeof result[0].reason).toBe('string')
      expect(result[0].reason.length).toBeGreaterThan(0)
    })
  })
})