import { afterEach, beforeEach, describe, expect, it, mock } from 'bun:test'
import { Hono } from 'hono'
import { createGenerateRouter } from './generate'

describe('generate route', () => {
  let originalFetch: typeof fetch

  beforeEach(() => {
    originalFetch = globalThis.fetch
  })

  afterEach(() => {
    globalThis.fetch = originalFetch
  })

  it('returns 400 when topic is missing', async () => {
    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))

    const res = await app.request('/api/generate', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({}),
    })

    expect(res.status).toBe(400)
  })

  it('returns 500 when DEEPSEEK_API_KEY is not configured', async () => {
    const app = new Hono().route('/api/generate', createGenerateRouter(undefined))

    const res = await app.request('/api/generate', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ topic: 'CSS 弹性布局' }),
    })

    expect(res.status).toBe(500)
  })

  it('returns parsed markdown on success', async () => {
    globalThis.fetch = mock(async () =>
      new Response(
        JSON.stringify({ choices: [{ message: { content: '# CSS 弹性布局 教学设计' } }] }),
        { status: 200 },
      ),
    ) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    const res = await app.request('/api/generate', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ topic: 'CSS 弹性布局' }),
    })

    expect(res.status).toBe(200)
    const body = (await res.json()) as { filename: string; markdown: string }
    expect(body.filename).toBe('CSS 弹性布局.md')
    expect(body.markdown).toContain('# CSS 弹性布局 教学设计')
  })

  it('returns 502 when Deepseek responds with an error status', async () => {
    globalThis.fetch = mock(async () => new Response('', { status: 401 })) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    const res = await app.request('/api/generate', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ topic: 'CSS 弹性布局' }),
    })

    expect(res.status).toBe(502)
  })

  it('returns 502 when fetch throws', async () => {
    globalThis.fetch = mock(async () => {
      throw new Error('network error')
    }) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    const res = await app.request('/api/generate', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ topic: 'CSS 弹性布局' }),
    })

    expect(res.status).toBe(502)
  })

  it('returns 400 when theme is missing on outline', async () => {
    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))

    const res = await app.request('/api/generate/outline', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({}),
    })

    expect(res.status).toBe(400)
  })

  it('uses the requested count in the outline prompt', async () => {
    let sentBody = ''
    globalThis.fetch = mock(async (_url: unknown, init: { body?: string } = {}) => {
      sentBody = init.body ?? ''
      return new Response(
        JSON.stringify({ choices: [{ message: { content: 'A\nB\nC' } }] }),
        { status: 200 },
      )
    }) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    const res = await app.request('/api/generate/outline', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ theme: 'Web 前端', count: 25 }),
    })

    expect(res.status).toBe(200)
    expect(sentBody).toContain('共约25条')
    const body = (await res.json()) as { titles: string[] }
    expect(body.titles).toEqual(['A', 'B', 'C'])
  })

  it('defaults the outline count to 18 and clamps out-of-range values', async () => {
    const captured: string[] = []
    globalThis.fetch = mock(async (_url: unknown, init: { body?: string } = {}) => {
      captured.push(init.body ?? '')
      return new Response(
        JSON.stringify({ choices: [{ message: { content: 'A' } }] }),
        { status: 200 },
      )
    }) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))

    await app.request('/api/generate/outline', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ theme: 'Web 前端' }),
    })
    await app.request('/api/generate/outline', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ theme: 'Web 前端', count: 999 }),
    })

    expect(captured[0]).toContain('共约18条')
    expect(captured[1]).toContain('共约50条')
  })

  it('returns 502 when Deepseek response has no content', async () => {
    globalThis.fetch = mock(async () => new Response(JSON.stringify({ choices: [] }), { status: 200 })) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    const res = await app.request('/api/generate', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ topic: 'CSS 弹性布局' }),
    })

    expect(res.status).toBe(502)
  })

  it('does not add content to the prompt when topic is sent alone', async () => {
    let sentBody = ''
    globalThis.fetch = mock(async (_url: unknown, init: { body?: string } = {}) => {
      sentBody = init.body ?? ''
      return new Response(
        JSON.stringify({ choices: [{ message: { content: '# x 教学设计' } }] }),
        { status: 200 },
      )
    }) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    await app.request('/api/generate', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ topic: 'CSS 弹性布局' }),
    })

    expect(sentBody).not.toContain('作为编写依据')
    expect(sentBody).toContain('请围绕主题')
    expect(sentBody).toContain('生成一份教案。')
  })

  it('injects chapter content into the prompt when content is provided', async () => {
    let sentBody = ''
    globalThis.fetch = mock(async (_url: unknown, init: { body?: string } = {}) => {
      sentBody = init.body ?? ''
      return new Response(
        JSON.stringify({ choices: [{ message: { content: '# x 教学设计' } }] }),
        { status: 200 },
      )
    }) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    const res = await app.request('/api/generate', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ topic: 'CSS 弹性布局', content: '弹性盒模型的正文内容片段' }),
    })

    expect(res.status).toBe(200)
    expect(sentBody).toContain('作为编写依据')
    expect(sentBody).toContain('弹性盒模型的正文内容片段')
  })

  it('returns 400 when entries are missing on lessons-from-book', async () => {
    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))

    const res = await app.request('/api/generate/lessons-from-book', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({}),
    })

    expect(res.status).toBe(400)
  })

  it('parses lessons with sourceIndexes from lessons-from-book', async () => {
    globalThis.fetch = mock(async () =>
      new Response(
        JSON.stringify({
          choices: [
            {
              message: {
                content:
                  '{"lessons":[{"title":"C# 入门——搭建环境","sourceIndexes":[0]},{"title":"变量与类型","sourceIndexes":[1,2]}]}',
              },
            },
          ],
        }),
        { status: 200 },
      ),
    ) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    const res = await app.request('/api/generate/lessons-from-book', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        entries: [
          { index: 0, title: '第1章 C# 入门', charCount: 5000 },
          { index: 1, title: '第2章 变量', charCount: 3000 },
          { index: 2, title: '第3章 类型', charCount: 2000 },
        ],
      }),
    })

    expect(res.status).toBe(200)
    const body = (await res.json()) as {
      lessons: { title: string; sourceIndexes: number[] }[]
    }
    expect(body.lessons).toEqual([
      { title: 'C# 入门——搭建环境', sourceIndexes: [0] },
      { title: '变量与类型', sourceIndexes: [1, 2] },
    ])
  })

  it('strips code fences and drops out-of-range sourceIndexes on lessons-from-book', async () => {
    globalThis.fetch = mock(async () =>
      new Response(
        JSON.stringify({
          choices: [
            {
              message: {
                content:
                  '```json\n{"lessons":[{"title":"课时一","sourceIndexes":[0,9]}]}\n```',
              },
            },
          ],
        }),
        { status: 200 },
      ),
    ) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    const res = await app.request('/api/generate/lessons-from-book', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ entries: [{ index: 0, title: '第1章', charCount: 100 }] }),
    })

    expect(res.status).toBe(200)
    const body = (await res.json()) as {
      lessons: { title: string; sourceIndexes: number[] }[]
    }
    expect(body.lessons).toEqual([{ title: '课时一', sourceIndexes: [0] }])
  })

  it('returns 502 when lessons-from-book JSON is malformed', async () => {
    globalThis.fetch = mock(async () =>
      new Response(
        JSON.stringify({ choices: [{ message: { content: '这不是 JSON' } }] }),
        { status: 200 },
      ),
    ) as unknown as typeof fetch

    const app = new Hono().route('/api/generate', createGenerateRouter('test-key'))
    const res = await app.request('/api/generate/lessons-from-book', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ entries: [{ index: 0, title: '第1章', charCount: 100 }] }),
    })

    expect(res.status).toBe(502)
  })
})