// 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"
	"time"

	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"
)

func main() {
	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", "")

	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()

	ragEngine := rag.Open(ctx, milvusAddr, embBase, embKey, embModel) // RAG 核心链：embedding(env 初值) + Milvus
	defer ragEngine.Close()

	// 配置控制面：启动取激活 embedding 配置 + 订阅热更新（覆盖 env，持久化由 Gateway 管）。
	applyEmbed := func(cfg *contract.ModelConfig) {
		if cfg != nil {
			ragEngine.SetEmbedding(cfg.BaseURL, cfg.APIKey, cfg.Model)
		}
	}
	cctx, ccancel := context.WithTimeout(ctx, 3*time.Second)
	if cfg, _ := b.RequestConfig(cctx, contract.ConfigKindEmbedding); cfg != nil {
		applyEmbed(cfg)
	} else {
		log.Println("[mcp_go] 未取到 embedding 控制面配置（用 env 或降级）")
	}
	ccancel()
	if _, err := b.SubscribeConfigUpdated(contract.ConfigKindEmbedding, applyEmbed); err != nil {
		log.Printf("[mcp_go] subscribe embedding config: %v", err)
	}

	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
}