feat: add Deepseek-backed lesson generation route

server/routes/generate.test.ts

@@ -0,0 +1,101 @@
+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 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)
+  })
+})

server/routes/generate.ts

@@ -0,0 +1,79 @@
+import { Hono } from 'hono'
+
+const SYSTEM_PROMPT = `你是一名教学设计专家，需要根据用户提供的主题生成一份 Markdown 格式的教案。
+请严格遵循以下结构（标题、表格列数、章节名称必须完全一致，便于程序解析），只输出 Markdown 正文本身，不要使用代码块包裹整篇文档，不要添加任何额外说明：
+
+1. 第一行是一级标题：\`# <课程标题> 教学设计\`
+2. 紧接着是一个两列表格（表头使用 \`|:---|:---|\`），依次包含以下行：
+   - \`| **课题** | **<课题名称>** |\`
+   - \`| **课时** | <课时说明，例如 1课时（40分钟）> |\`
+   - \`| **教学目标** | **知识目标**：...<br>**技能目标**：...<br>**素养目标**：... |\`
+   - \`| **教学重难点** | **重点**：...<br>**难点**：... |\`
+   - \`| **教学资源准备** | ... |\`
+3. 二级标题 \`## 教学过程\`，后接一个 5 列表格，表头固定为：
+   \`| 教学环节 | 教学内容 | 教师活动 | 学生活动 | 设计意图 |\`，分隔行 \`|:---|:---|:---|:---|:---|\`，
+   包含 4-6 个教学环节行，每个环节名称写作 \`**N. 环节名称**<br>（时长）\` 的格式。
+4. 二级标题 \`## 板书设计\`，内容放在 \`\`\`text 代码块中。
+5. 二级标题 \`## 教学成效与反思\`，后接一个两列表格：
+   - \`| **教学成效** | ... |\`
+   - \`| **教学反思** | ... |\`
+`
+
+function sanitizeFilename(topic: string): string {
+  const sanitized = topic.trim().replace(/[\\/:*?"<>|]/g, '_')
+  return sanitized || 'lesson'
+}
+
+export function createGenerateRouter(apiKey: string | undefined): Hono {
+  const app = new Hono()
+
+  app.post('/', async (c) => {
+    const body = (await c.req.json().catch(() => null)) as { topic?: unknown } | null
+    const topic = body?.topic
+
+    if (typeof topic !== 'string' || topic.trim() === '') {
+      return c.json({ error: '请提供教案主题。' }, 400)
+    }
+
+    if (!apiKey) {
+      return c.json({ error: '未配置 DEEPSEEK_API_KEY。' }, 500)
+    }
+
+    let response: Response
+    try {
+      response = await fetch('https://api.deepseek.com/chat/completions', {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          Authorization: `Bearer ${apiKey}`,
+        },
+        body: JSON.stringify({
+          model: 'deepseek-chat',
+          messages: [
+            { role: 'system', content: SYSTEM_PROMPT },
+            { role: 'user', content: `请围绕主题"${topic.trim()}"生成一份教案。` },
+          ],
+        }),
+      })
+    } catch {
+      return c.json({ error: 'Deepseek 请求失败，请检查网络后重试。' }, 502)
+    }
+
+    if (!response.ok) {
+      return c.json({ error: `Deepseek 请求失败（状态码 ${response.status}）。` }, 502)
+    }
+
+    const payload = (await response.json().catch(() => null)) as
+      | { choices?: Array<{ message?: { content?: string } }> }
+      | null
+    const markdown = payload?.choices?.[0]?.message?.content
+
+    if (!markdown) {
+      return c.json({ error: 'Deepseek 返回内容为空。' }, 502)
+    }
+
+    return c.json({ filename: `${sanitizeFilename(topic)}.md`, markdown })
+  })
+
+  return app
+}