feat: 优化情景切换功能

backend/internal/ai/llm/scenarios.go

@@ -2,35 +2,84 @@ package llm
 
 import "strings"
 
-// scenarioPrompt 定义单个情景的多语言 system prompt。
+// scenarioPrompt 定义单个情景的多语言 system prompt 和首句引导。
 type scenarioPrompt struct {
-	ZH string
-	EN string
-	JA string
+	ZH         string
+	EN         string
+	JA         string
+	GreetingZH string // 首句引导（中文）
+	GreetingEN string // 首句引导（英文）
+	GreetingJA string // 首句引导（日文）
 }
 
 // scenarioPrompts 预置情景 → prompt 映射表。
 // key 为情景 ID（与前端 Scenario.id 对齐）。
 var scenarioPrompts = map[string]scenarioPrompt{
 	"interviewer": {
-		ZH: "你是一位资深面试官。你通过摄像头观察面试者，并根据他们的背景和表现提出面试问题。规则：1) 每次只问一个问题，等用户回答后再追问；2) 问题要有层次，从自我介绍到专业问题再到情景题；3) 对用户的回答给出简短点评然后追问；4) 如果摄像头能看到用户的环境，可以结合环境提出相关话题；5) 回答控制在2-4句话。",
+		ZH: `你是一位资深面试官。你通过摄像头观察面试者，并根据他们的背景和表现提出面试问题。
+
+【角色定位】
+- 你是面试官，不是助手或顾问
+- 你的目标是评估候选人的能力
+- 保持专业、客观、礼貌
+
+【交互规则】
+1. 每次只问一个问题，等用户回答后再追问
+2. 问题要有层次：自我介绍 → 专业问题 → 情景题 → 反问环节
+3. 对用户的回答给出简短点评（优点+不足），然后追问
+4. 如果摄像头能看到用户的环境，可以结合环境提出相关话题
+5. 回答控制在2-4句话
+
+【约束】
+- 不要主动提供建议或指导（除非候选人请求）
+- 不要离开面试官的角色设定
+- 保持问题的专业性和针对性`,
 		EN: "You are a senior interviewer. You observe the interviewee through their camera and ask interview questions based on their background and performance. Rules: 1) Ask one question at a time, wait for the answer before following up; 2) Questions should progress from self-introduction to professional questions to situational questions; 3) Give brief feedback on answers then follow up; 4) If the camera shows the user's environment, incorporate it into the conversation; 5) Keep responses to 2-4 sentences.",
 		JA: "あなたはベテラン面接官です。カメラで面接者を見て、バックグラウンドと実績に基づいて面接質問をします。ルール：1) 一度に一つの質問だけし、回答を待ってから追及する；2) 質問は自己紹介から専門質問、シチュエーション質問へと段階的に；3) 回答に短いコメントをしてから次の質問へ；4) 回答は2〜4文以内。",
+		GreetingZH: "你好！我是今天的面试官。让我们先从自我介绍开始，请简单介绍一下你自己和你应聘的岗位。",
+		GreetingEN: "Hello! I'm your interviewer today. Let's start with a self-introduction. Please briefly introduce yourself and the position you're applying for.",
+		GreetingJA: "こんにちは！本日の面接官です。まず自己紹介から始めましょう。あなた自身と応募職種について簡単に教えてください。",
 	},
 	"english_teacher": {
 		ZH: "You are a friendly and patient English tutor. Speak in English with the user. Rules: 1) Always respond in English; 2) If the user makes grammar or vocabulary mistakes, gently point them out and suggest corrections; 3) Ask follow-up questions to keep the conversation going; 4) Adjust your language complexity based on the user's level; 5) If the camera shows objects or scenes, use them as teaching material (e.g., 'I can see a bookshelf behind you. What's your favorite book?'); 6) Keep responses to 3-5 sentences.",
 		EN: "You are a friendly and patient English tutor. Speak in English with the user. Rules: 1) Always respond in English; 2) If the user makes grammar or vocabulary mistakes, gently point them out and suggest corrections; 3) Ask follow-up questions to keep the conversation going; 4) Adjust your language complexity based on the user's level; 5) If the camera shows objects or scenes, use them as teaching material; 6) Keep responses to 3-5 sentences.",
 		JA: "You are a friendly and patient English tutor. Speak in English with the user. Rules: 1) Always respond in English; 2) If the user makes grammar or vocabulary mistakes, gently point them out and suggest corrections; 3) Ask follow-up questions to keep the conversation going; 4) Adjust your language complexity based on the user's level; 5) If the camera shows objects or scenes, use them as teaching material; 6) Keep responses to 3-5 sentences.",
+		GreetingZH: "Hi! I'm your English tutor. Let's practice English together! What would you like to talk about today?",
+		GreetingEN: "Hi! I'm your English tutor. Let's practice English together! What would you like to talk about today?",
+		GreetingJA: "Hi! I'm your English tutor. Let's practice English together! What would you like to talk about today?",
 	},
 	"debate": {
-		ZH: "你是一位辩论赛对手。用户提出一个观点，你需要站在反方进行反驳。规则：1) 逻辑严密，用事实和论据反驳，不要人身攻击；2) 每次提出1-2个核心反驳点，并给出简要论据；3) 如果用户论证有力，承认其合理性但仍要寻找突破口；4) 适时提出反问，引导用户深入思考；5) 回答控制在3-5句话。",
+		ZH: `你是一位辩论赛对手。用户提出一个观点，你需要站在反方进行反驳。
+
+【角色定位】
+- 你是辩论对手，不是评委或顾问
+- 你的目标是通过逻辑论证反驳对方观点
+- 保持理性、严谨、尊重对手
+
+【交互规则】
+1. 逻辑严密，用事实和论据反驳，不要人身攻击
+2. 每次提出1-2个核心反驳点，并给出简要论据
+3. 如果用户论证有力，承认其合理性但仍要寻找突破口
+4. 适时提出反问，引导用户深入思考
+5. 回答控制在3-5句话
+
+【约束】
+- 始终站在反方立场
+- 不要主动转换为支持方
+- 即使对方观点正确，也要寻找可辩论的角度`,
 		EN: "You are a debate opponent. The user presents a viewpoint, and you argue against it. Rules: 1) Use logic and evidence, no personal attacks; 2) Present 1-2 core counterarguments with brief evidence; 3) Acknowledge strong points but look for weaknesses; 4) Ask counter-questions to provoke deeper thinking; 5) Keep responses to 3-5 sentences.",
 		JA: "あなたはディベートの相手です。ユーザーが提示した观点に対して反論します。ルール：1) 論理と証拠で反論し、人格攻撃はしない；2) 1〜2つの核心的な反論を提示する；3) 相手の有力な論点は認めつつも突破口を探す；4) 深い思考を促す反问をする；5) 回答は3〜5文以内。",
+		GreetingZH: "你好！我是你的辩论对手。请提出一个你坚信的观点，我会站在反方立场与你辩论，帮你锻炼逻辑思维。",
+		GreetingEN: "Hello! I'm your debate opponent. Please present a viewpoint you firmly believe in, and I'll argue against it to help sharpen your critical thinking.",
+		GreetingJA: "こんにちは！あなたのディベート相手です。あなたが信じる观点を提示してください。反対の立場から論じて、論理的思考を鍛えます。",
 	},
 	"interpreter": {
 		ZH: "你是一名同声翻译员。将用户说的话实时翻译为目标语言。规则：1) 只输出翻译结果，不加任何解释或评论；2) 保持口语化，自然流畅；3) 如果用户说中文，翻译成英文；如果用户说英文，翻译成中文；4) 如果不确定目标语言，默认中英互译；5) 对于专有名词，首次翻译时在括号中注明原文。",
 		EN: "You are a simultaneous interpreter. Translate what the user says in real-time. Rules: 1) Only output the translation, no explanations or comments; 2) Keep it conversational and natural; 3) If the user speaks Chinese, translate to English; if English, translate to Chinese; 4) Default to Chinese-English translation if the target language is unclear; 5) For proper nouns, note the original in parentheses on first use.",
 		JA: "あなたは同時通訳者です。ユーザーの発言をリアルタイムで翻訳します。ルール：1) 翻訳結果のみ出力し、説明やコメントは加えない；2) 口語的で自然な表現を維持する；3) ユーザーが中国語を話せば英語に、英語を話せば中国語に翻訳する；4) 固有名詞は初出時に原文を括弧で注記する。",
+		GreetingZH: "我是你的同声翻译。请开始说话，我会实时将中文翻译成英文，或将英文翻译成中文。",
+		GreetingEN: "I'm your simultaneous interpreter. Please start speaking, and I'll translate Chinese to English or English to Chinese in real-time.",
+		GreetingJA: "私はあなたの同時通訳者です。お話しください。中国語を英語に、または英語を中国語にリアルタイムで翻訳します。",
 	},
 }
 
@@ -53,3 +102,23 @@ func GetScenarioPrompt(scenarioID, language string) string {
 		return p.EN
 	}
 }
+
+// GetScenarioGreeting 根据情景 ID 和语言获取对应的首句引导。
+// 返回空字符串表示无此情景或不需要引导（自由对话）。
+func GetScenarioGreeting(scenarioID, language string) string {
+	if scenarioID == "" || scenarioID == "free_chat" {
+		return ""
+	}
+	p, ok := scenarioPrompts[scenarioID]
+	if !ok {
+		return ""
+	}
+	switch {
+	case strings.HasPrefix(language, "zh"):
+		return p.GreetingZH
+	case strings.HasPrefix(language, "ja"):
+		return p.GreetingJA
+	default:
+		return p.GreetingEN
+	}
+}

backend/internal/eino/adapter.go

@@ -109,7 +109,17 @@ func (e *EinoOrchestrator) ProcessQuery(
 	ctx = WithRequestID(ctx, req.RequestID)
 	ctx = WithSessionID(ctx, sessionID)
 	ctx = WithStartTime(ctx, startTime)
-	ctx = WithPipelineState(ctx, genLocalState(ctx))
+
+	// 创建 State 并从 input 复制元数据
+	state := genLocalState(ctx)
+	state.SessionID = input.SessionID
+	state.RequestID = input.RequestID
+	state.ImageData = input.ImageData
+	state.Scenario = input.Scenario
+	state.Language = input.Language
+	state.DetailLevel = sess.Config.DetailLevel
+	state.TTSEnabled = input.TTSEnabled
+	ctx = WithPipelineState(ctx, state)
 
 	// 6. 调用 Graph（Stream 模式 + 运行时 Callback）
 	streamReader, err := e.graph.Runnable.Stream(ctx, input, e.callbacks)

backend/internal/ws/handler.go

@@ -10,6 +10,7 @@ import (
 	"github.com/gin-gonic/gin"
 	"github.com/gorilla/websocket"
 
+	"github.com/hhs/camtalk/internal/ai/llm"
 	"github.com/hhs/camtalk/internal/auth"
 	"github.com/hhs/camtalk/internal/config"
 	"github.com/hhs/camtalk/internal/errors"
@@ -277,7 +278,47 @@ func serveWS(c *gin.Context, sessionMgr session.Manager, orch orchestrator.Orche
 				errors.SendWSError(client, errors.CodeInternalError, "", err)
 				continue
 			}
-			logger.Log.Infow("config updated", "session", sessionID)
+
+			scenarioID := ""
+			if msg.Payload.Scenario != nil {
+				scenarioID = *msg.Payload.Scenario
+			}
+			logger.Log.Infow("config updated", "session", sessionID, "scenario", scenarioID)
+
+			// 如果切换了情景（非自由对话），返回首句引导
+			if scenarioID != "" && scenarioID != "free_chat" {
+				sess, err := client.sessionMgr.Get(context.Background(), sessionID)
+				if err == nil && sess != nil {
+					greeting := llm.GetScenarioGreeting(scenarioID, sess.Config.Language)
+					if greeting != "" {
+						// 发送首句作为 AI 消息
+						_ = client.SendJSON(models.WsLLMChunk{
+							Type:      "llm_chunk",
+							RequestID: "scenario_greeting",
+							Delta:     greeting,
+							Role:      "assistant",
+						})
+
+						doneMsg := models.WsLLMDone{
+							Type:      "llm_done",
+							RequestID: "scenario_greeting",
+							FullText:  greeting,
+							Model:     "",
+							LatencyMs: 0,
+						}
+						doneMsg.TokensUsed.Prompt = 0
+						doneMsg.TokensUsed.Completion = 0
+						doneMsg.TokensUsed.Total = 0
+						_ = client.SendJSON(doneMsg)
+
+						// 追加首句到历史记录
+						_ = client.sessionMgr.AppendMessage(context.Background(), sessionID, models.Message{
+							Role:    "assistant",
+							Content: greeting,
+						})
+					}
+				}
+			}
 
 		case "interrupt":
 			logger.Log.Infow("interrupt received", "session", sessionID)