// Command server 启动 sundynix-mcp-go —— 第 5 层 Go I/O 型 MCP 工具微服务。
package main

import (
	"context"
	"log"
	"os"
	"os/signal"
	"syscall"

	sharedbus "github.com/sundynix/sundynix-shared/bus"
	"github.com/sundynix/sundynix-shared/contract"

	"github.com/sundynix/sundynix-mcp-go/internal/history"
	"github.com/sundynix/sundynix-mcp-go/internal/mcp"
	"github.com/sundynix/sundynix-mcp-go/internal/memory"
	"github.com/sundynix/sundynix-mcp-go/internal/rag"
	"github.com/sundynix/sundynix-mcp-go/internal/search"

	"github.com/sundynix/sundynix-shared/otelx"
	"github.com/sundynix/sundynix-shared/secrets"
)

func main() {
	secrets.MustHaveKeyInProd() // 生产须配 SUNDYNIX_SECRET_KEY 以解密下发的 api_key 密文

	// 链路追踪：工具服务端 span 续上 dispatcher 的 trace（tool.call → tool.serve）。
	shutdownTrace, _ := otelx.Init(context.Background(), "sundynix-mcp-go")
	defer func() { _ = shutdownTrace(context.Background()) }()

	natsURL := envOr("NATS_URL", "nats://localhost:4222")
	pgDSN := envOr("POSTGRES_DSN", "postgres://sundynix:sundynix@localhost:5432/sundynix?sslmode=disable")
	redisAddr := envOr("REDIS_ADDR", "localhost:6379")
	milvusAddr := envOr("MILVUS_ADDR", "localhost:19530")
	embBase := envOr("EMBED_BASE_URL", "") // OpenAI 兼容 embeddings 端点（空=向量检索降级）
	embKey := envOr("EMBED_API_KEY", "")
	embModel := envOr("EMBED_MODEL", "")
	rerankBase := envOr("RERANK_BASE_URL", "") // DashScope 文本重排端点（空=不启用 rerank）
	rerankKey := envOr("RERANK_API_KEY", "")
	rerankModel := envOr("RERANK_MODEL", "")
	neo4jURI := envOr("NEO4J_URI", "neo4j://localhost:7687") // GraphRAG 图谱（连不上则降级）
	neo4jUser := envOr("NEO4J_USER", "neo4j")
	neo4jPass := envOr("NEO4J_PASS", "sundynix")

	b, err := sharedbus.Connect(natsURL)
	if err != nil {
		log.Fatalf("[mcp_go] nats connect: %v", err)
	}
	defer b.Close()
	log.Printf("[mcp_go] connected %s", natsURL)

	engine := search.NewHybrid() // LLM Wiki 混合检索：Bleve + Milvus + Neo4j
	mem := memory.Open(pgDSN)    // 偏好记忆：sundynix_user_profile（连不上则降级）
	defer mem.Close()
	hist := history.Open(redisAddr) // 会话短期历史：Redis（连不上则降级）
	defer hist.Close()

	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()

	// RAG 核心链：embedding + Milvus(向量) + Bleve(全文) + Neo4j(图谱) + 可选 rerank
	ragEngine := rag.Open(ctx, rag.Config{
		MilvusAddr: milvusAddr,
		EmbedBase:  embBase, EmbedKey: embKey, EmbedModel: embModel,
		RerankBase: rerankBase, RerankKey: rerankKey, RerankModel: rerankModel,
		Neo4jURI: neo4jURI, Neo4jUser: neo4jUser, Neo4jPass: neo4jPass,
	})
	defer ragEngine.Close()

	// 配置控制面：取激活 embedding(向量) + chat(图谱抽取) 配置并订阅热更新。
	applyEmbed := func(cfg *contract.ModelConfig) {
		if cfg != nil {
			ragEngine.SetEmbedding(cfg.BaseURL, cfg.APIKey, cfg.Model)
		}
	}
	applyChat := func(cfg *contract.ModelConfig) {
		if cfg != nil {
			ragEngine.SetChat(cfg.BaseURL, cfg.APIKey, cfg.Model)
		}
	}
	// 先订阅热更新（控制台改配置即生效）。
	if _, err := b.SubscribeConfigUpdated(contract.ConfigKindChat, applyChat); err != nil {
		log.Printf("[mcp_go] subscribe chat config: %v", err)
	}
	if _, err := b.SubscribeConfigUpdated(contract.ConfigKindEmbedding, applyEmbed); err != nil {
		log.Printf("[mcp_go] subscribe embedding config: %v", err)
	}
	// 后台重试拉初始配置：容忍 gateway 晚于本服务启动（避免一次性扑空致 RAG 长期降级）。
	go b.RequestConfigWithRetry(ctx, contract.ConfigKindEmbedding, applyEmbed)
	go b.RequestConfigWithRetry(ctx, contract.ConfigKindChat, applyChat)

	gw := mcp.NewGateway(b, engine, mem, hist, ragEngine)

	log.Println("[mcp_go] serving MCP over sundynix.tools.go.* (Ctrl-C to quit)")
	if err := gw.Serve(ctx); err != nil && err != context.Canceled {
		log.Fatalf("[mcp_go] exit: %v", err)
	}
}

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