package main

import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/joho/godotenv"

	ctxbuild "github.com/yourname/cyrene-ai/ai-core/internal/context"
	"github.com/yourname/cyrene-ai/ai-core/internal/llm"
	"github.com/yourname/cyrene-ai/ai-core/internal/memory"
	"github.com/yourname/cyrene-ai/ai-core/internal/model"
	"github.com/yourname/cyrene-ai/ai-core/internal/orchestrator"
	"github.com/yourname/cyrene-ai/ai-core/internal/persona"
)

func main() {
	// 自动加载 .env 文件（来自 backend/.env）
	if err := godotenv.Load("../.env"); err != nil {
		log.Println("ℹ 未找到 .env 文件，将使用环境变量或默认值")
	}

	log.SetFlags(log.LstdFlags | log.Lshortfile)
	log.Println("🧠 AI-Core 服务启动中...")

	// 加载配置
	cfg := loadConfig()

	// 初始化人格加载器
	personaDir := cfg.PersonaDir
	if personaDir == "" {
		personaDir = "./internal/persona"
	}
	personaLoader, err := persona.NewLoader(personaDir)
	if err != nil {
		log.Fatalf("加载人格配置失败: %v", err)
	}
	log.Printf("已加载 %d 个人格: %v", len(personaLoader.List()), personaLoader.List())

	// 初始化LLM适配器
	llmProvider := llm.NewOpenAIProvider(llm.OpenAIConfig{
		BaseURL:       cfg.LLMBaseURL,
		APIKey:        cfg.LLMAPIKey,
		Model:         cfg.LLMModel,
		FallbackModel: cfg.LLMFallbackModel,
		Timeout:       120 * time.Second,
	})
	llmAdapter := llm.NewAdapter(llmProvider)
	log.Printf("LLM适配器已就绪: 模型=%s", llmAdapter.ModelName())

	// 初始化记忆系统
	var memStore *memory.Store
	var memRetriever *memory.Retriever
	var memExtractor *memory.Extractor

	if cfg.DatabaseURL != "" {
		memStore, err = memory.NewStore(cfg.DatabaseURL)
		if err != nil {
			log.Printf("⚠ 记忆存储初始化失败 (将跳过记忆功能): %v", err)
		} else {
			defer memStore.Close()
			log.Println("记忆存储已就绪")

			memRetriever = memory.NewRetriever(memStore, nil)

			// 记忆提取器使用LLM
			memExtractor = memory.NewExtractor(memStore, func(ctx context.Context, messages []model.LLMMessage) (*model.LLMResponse, error) {
				return llmAdapter.Chat(ctx, messages)
			})
			log.Println("记忆提取器已就绪")
		}
	}

	// 初始化上下文构建器
	ctxBuilder := &ctxbuild.Builder{}

	// 健康检查与对话API的HTTP mux
	mux := http.NewServeMux()

	// 手动构建 orchestrator 用于处理（因为现有orchestrator结构体已定义但未导出构造函数）
	orch := &orchestrator.Orchestrator{}

	// 注册对话API端点
	mux.HandleFunc("/api/v1/chat", func(w http.ResponseWriter, r *http.Request) {
		handleChat(w, r, orch, ctxBuilder, llmAdapter, personaLoader, memRetriever, memExtractor)
	})

	// 注册记忆API端点
	mux.HandleFunc("/api/v1/memory/search", func(w http.ResponseWriter, r *http.Request) {
		handleMemorySearch(w, r, memRetriever)
	})
	mux.HandleFunc("/api/v1/memory", func(w http.ResponseWriter, r *http.Request) {
		handleMemoryCRUD(w, r, memStore, memExtractor)
	})

	mux.HandleFunc("/api/v1/health", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		w.Write([]byte(`{"status":"ok","service":"ai-core","model":"` + llmAdapter.ModelName() + `"}`))
	})

	// 启动HTTP服务
	srv := &http.Server{
		Addr:    ":" + cfg.Port,
		Handler: mux,
	}

	go func() {
		log.Printf("🚀 AI-Core 服务已启动在端口 %s", cfg.Port)
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatalf("服务启动失败: %v", err)
		}
	}()

	// 优雅关闭
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit
	log.Println("正在关闭 AI-Core 服务...")

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	srv.Shutdown(ctx)
	log.Println("AI-Core 服务已关闭")
}

// Config AI-Core配置
type Config struct {
	Port             string
	PersonaDir       string
	LLMBaseURL       string
	LLMAPIKey        string
	LLMModel         string
	LLMFallbackModel string
	DatabaseURL      string
}

func loadConfig() Config {
	return Config{
		Port:             getEnv("AI_CORE_PORT", "8081"),
		PersonaDir:       getEnv("PERSONA_DIR", "./internal/persona"),
		LLMBaseURL:       getEnv("LLM_API_URL", "https://api.openai.com/v1"),
		LLMAPIKey:        getEnv("LLM_API_KEY", ""),
		LLMModel:         getEnv("LLM_MODEL", "gpt-4o"),
		LLMFallbackModel: getEnv("LLM_FALLBACK_MODEL", "gpt-4o-mini"),
		DatabaseURL: buildDatabaseURL(),
	}
}

func buildDatabaseURL() string {
	host := getEnv("POSTGRES_HOST", "localhost")
	port := getEnv("POSTGRES_PORT", "5432")
	user := getEnv("POSTGRES_USER", "cyrene")
	password := getEnv("POSTGRES_PASSWORD", "change_me")
	dbname := getEnv("POSTGRES_DB", "cyrene_ai")
	sslmode := getEnv("POSTGRES_SSLMODE", "disable")

	return fmt.Sprintf("postgres://%s:%s@%s:%s/%s?sslmode=%s",
		user, password, host, port, dbname, sslmode)
}

func getEnv(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}

// handleChat 处理对话请求（SSE 流式响应）
func handleChat(
	w http.ResponseWriter,
	r *http.Request,
	_ *orchestrator.Orchestrator,
	ctxBuilder *ctxbuild.Builder,
	llmAdapter *llm.Adapter,
	personaLoader *persona.Loader,
	memRetriever *memory.Retriever,
	memExtractor *memory.Extractor,
) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	// 解析请求
	var req struct {
		UserID    string `json:"user_id"`
		SessionID string `json:"session_id"`
		Message   string `json:"message"`
		Mode      string `json:"mode"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "无效的请求体", http.StatusBadRequest)
		return
	}

	if req.Mode == "" {
		req.Mode = "text"
	}

	ctx := r.Context()

	// 1. 检索相关记忆
	var memories []memory.MemoryEntry
	if memRetriever != nil {
		var err error
		memories, err = memRetriever.Retrieve(ctx, req.UserID, req.Message)
		if err != nil {
			log.Printf("[chat] 记忆检索失败: %v", err)
		}
	}

	// 2. 加载人格配置
	personaConfig, err := personaLoader.Get("cyrene")
	if err != nil {
		http.Error(w, fmt.Sprintf("加载人格失败: %v", err), http.StatusInternalServerError)
		return
	}

	// 3. 构建对话上下文
	llmMessages, err := ctxBuilder.Build(ctx, ctxbuild.BuildParams{
		UserID:       req.UserID,
		SessionID:    req.SessionID,
		UserMessage:  req.Message,
		Persona:      personaConfig,
		Memories:     memories,
		HistoryLimit: 20,
	})
	if err != nil {
		http.Error(w, fmt.Sprintf("构建上下文失败: %v", err), http.StatusInternalServerError)
		return
	}

	// 4. 设置 SSE 响应头
	w.Header().Set("Content-Type", "text/event-stream")
	w.Header().Set("Cache-Control", "no-cache")
	w.Header().Set("Connection", "keep-alive")
	w.Header().Set("X-Accel-Buffering", "no")

	flusher, ok := w.(http.Flusher)
	if !ok {
		http.Error(w, "Streaming not supported", http.StatusInternalServerError)
		return
	}

	// 5. 调用LLM流式接口
	chunkCh, err := llmAdapter.ChatStream(ctx, llmMessages)
	if err != nil {
		// 流式初始化失败，返回 SSE 格式错误
		errData, _ := json.Marshal(map[string]string{"delta": "", "error": fmt.Sprintf("LLM调用失败: %v", err)})
		fmt.Fprintf(w, "data: %s\n\n", errData)
		flusher.Flush()
		fmt.Fprintf(w, "data: [DONE]\n\n")
		flusher.Flush()
		return
	}

	messageID := fmt.Sprintf("msg-%d", time.Now().UnixNano())

	// 6. 逐 token 推送 SSE
	var fullContent string
	var segments []llm.Segment
	segmenter := llm.NewSegmenter()

	for chunk := range chunkCh {
		if chunk.Error != nil {
			log.Printf("[chat] 流式错误: %v", chunk.Error)
			errData, _ := json.Marshal(map[string]string{"delta": "", "error": chunk.Error.Error()})
			fmt.Fprintf(w, "data: %s\n\n", errData)
			flusher.Flush()
			fmt.Fprintf(w, "data: [DONE]\n\n")
			flusher.Flush()
			return
		}

		if chunk.Done {
			// 流结束，flush 剩余片段
			if remaining := segmenter.Flush(); remaining != nil {
				segments = append(segments, *remaining)
			}
			break
		}

		if chunk.Content != "" {
			fullContent += chunk.Content

			// 实时断句
			newSegs := segmenter.Feed(chunk.Content)
			segments = append(segments, newSegs...)

			deltaData, _ := json.Marshal(map[string]string{
				"delta":      chunk.Content,
				"message_id": messageID,
			})
			fmt.Fprintf(w, "data: %s\n\n", deltaData)
			flusher.Flush()
		}
	}

	// 7. 发送结束标记（附带元数据）
	endData, _ := json.Marshal(map[string]interface{}{
		"message_id": messageID,
		"mode":       req.Mode,
		"segments":   segments,
		"done":       true,
	})
	fmt.Fprintf(w, "data: %s\n\n", endData)
	flusher.Flush()
	fmt.Fprintf(w, "data: [DONE]\n\n")
	flusher.Flush()

	// 8. 异步提取记忆
	if memExtractor != nil && fullContent != "" {
		go memExtractor.ExtractAndStore(context.Background(), req.UserID, req.SessionID, req.Message, fullContent)
	}

	// Ensure unused variables don't cause compile errors
	_ = personaLoader
	_ = memRetriever
	_ = memExtractor
	_ = messageID
}

// handleMemorySearch 处理记忆搜索请求
func handleMemorySearch(
w http.ResponseWriter,
r *http.Request,
memRetriever *memory.Retriever,
) {
if r.Method != http.MethodGet {
	http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
	return
}

userID := r.URL.Query().Get("user_id")
if userID == "" {
	http.Error(w, "缺少 user_id 参数", http.StatusBadRequest)
	return
}

query := r.URL.Query().Get("q")
if query == "" {
	http.Error(w, "缺少 q 参数", http.StatusBadRequest)
	return
}

if memRetriever == nil {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"user_id":  userID,
		"query":    query,
		"memories": []interface{}{},
		"message":  "记忆系统未就绪",
	})
	return
}

ctx := r.Context()
memories, err := memRetriever.Retrieve(ctx, userID, query)
if err != nil {
	log.Printf("[memory] 检索失败: %v", err)
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"user_id":  userID,
		"query":    query,
		"memories": []interface{}{},
		"error":    "检索失败",
	})
	return
}

if memories == nil {
	memories = []memory.MemoryEntry{}
}

w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(map[string]interface{}{
	"user_id":  userID,
	"query":    query,
	"memories": memories,
	"total":    len(memories),
})
}

// handleMemoryCRUD 处理记忆的 CRUD 操作
func handleMemoryCRUD(
w http.ResponseWriter,
r *http.Request,
memStore *memory.Store,
memExtractor *memory.Extractor,
) {
switch r.Method {
case http.MethodGet:
	// 列出用户的所有记忆
	userID := r.URL.Query().Get("user_id")
	if userID == "" {
		http.Error(w, "缺少 user_id 参数", http.StatusBadRequest)
		return
	}

	if memStore == nil {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"user_id":  userID,
			"memories": []interface{}{},
			"message":  "记忆系统未就绪",
		})
		return
	}

	ctx := r.Context()
	memories, err := memStore.Query(ctx, model.MemoryQuery{
		UserID: userID,
		Limit:  50,
	})
	if err != nil {
		log.Printf("[memory] 查询失败: %v", err)
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"user_id":  userID,
			"memories": []interface{}{},
			"error":    "查询失败",
		})
		return
	}

	if memories == nil {
		memories = []model.MemoryEntry{}
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"user_id":  userID,
		"memories": memories,
		"total":    len(memories),
	})

case http.MethodDelete:
	// 删除单条记忆: DELETE /api/v1/memory?id=xxx
	memoryID := r.URL.Query().Get("id")
	if memoryID == "" {
		http.Error(w, "缺少 id 参数", http.StatusBadRequest)
		return
	}

	if memStore == nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusServiceUnavailable)
		json.NewEncoder(w).Encode(map[string]interface{}{
			"error": "记忆系统未就绪",
		})
		return
	}

	ctx := r.Context()
	if err := memStore.Delete(ctx, memoryID); err != nil {
		log.Printf("[memory] 删除失败: %v", err)
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(map[string]interface{}{
			"error": "删除失败",
		})
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]interface{}{
		"status":    "deleted",
		"memory_id": memoryID,
	})

case http.MethodPost:
	// 手动添加记忆
	var req struct {
		UserID   string `json:"user_id"`
		Content  string `json:"content"`
		Category string `json:"category"`
		Priority int    `json:"priority"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "无效的请求体", http.StatusBadRequest)
		return
	}

	if req.UserID == "" || req.Content == "" {
		http.Error(w, "缺少 user_id 或 content", http.StatusBadRequest)
		return
	}

	if req.Category == "" {
		req.Category = "other"
	}
	if req.Priority <= 0 {
		req.Priority = 1
	}

	if memStore == nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusServiceUnavailable)
		json.NewEncoder(w).Encode(map[string]interface{}{
			"error": "记忆系统未就绪",
		})
		return
	}

	entry := &model.MemoryEntry{
		UserID:   req.UserID,
		Content:  req.Content,
		Category: model.MemoryCategory(req.Category),
		Priority: model.MemoryPriority(req.Priority),
	}

	ctx := r.Context()
	if err := memStore.Save(ctx, entry); err != nil {
		log.Printf("[memory] 保存失败: %v", err)
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(map[string]interface{}{
			"error": "保存失败",
		})
		return
	}

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusCreated)
	json.NewEncoder(w).Encode(map[string]interface{}{
		"status":   "saved",
		"memory":   entry,
	})

default:
	http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
}

// Ensure unused variables don't cause compile errors
_ = memExtractor
}