// Command server 启动 sundynix-gateway —— 第 2 层业务网关 / 统一接入层。
package main

import (
	"context"
	"log"
	"os"

	"github.com/sundynix/sundynix-gateway/internal/blob"
	"github.com/sundynix/sundynix-gateway/internal/nats"
	"github.com/sundynix/sundynix-gateway/internal/router"
	"github.com/sundynix/sundynix-gateway/internal/store"
	"github.com/sundynix/sundynix-shared/contract"
	"github.com/sundynix/sundynix-shared/otelx"
	"github.com/sundynix/sundynix-shared/secrets"
)

func main() {
	secrets.MustHaveKeyInProd()         // 生产须配 SUNDYNIX_SECRET_KEY 以加密落库的 api_key
	otelx.SetupSlog("sundynix-gateway") // 结构化日志 + 链路感知（日志带 trace_id）

	// 链路追踪：HTTP 入口 + 跨 NATS 传播的根。退出前 flush 残留 span。
	shutdownTrace, _ := otelx.Init(context.Background(), "sundynix-gateway")
	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")
	// 对象存储（大文档正文）：默认连 docker-compose 暴露的 MinIO；连不上则降级内联存 PG。
	blobStore := blob.Open(
		envOr("MINIO_ENDPOINT", "localhost:9000"),
		envOr("MINIO_ACCESS_KEY", "minioadmin"),
		envOr("MINIO_SECRET_KEY", "minioadmin"),
		envOr("MINIO_BUCKET", "sundynix-docs"),
	)

	db := store.OpenPostgres(pgDSN) // MainDB: Users / Billing / DSL（连不上则降级）
	defer db.Close()
	cache := store.OpenRedis(redisAddr) // CacheDB: Session / Rate Limit（连不上则降级）
	defer cache.Close()
	bus := nats.MustConnect(natsURL) // 接入 NATS 零拷贝骨干网 + 声明任务流
	defer bus.Close()

	// 配置控制面：按 kind 响应消费方（Dispatcher=chat / mcp-go=embedding）的配置请求。
	for _, kind := range []string{contract.ConfigKindChat, contract.ConfigKindEmbedding} {
		k := kind
		if _, err := bus.ServeConfig(k, func() *contract.ModelConfig {
			row, _ := db.GetActiveModel(context.Background(), k)
			if row == nil {
				return nil
			}
			return &contract.ModelConfig{Provider: row.Provider, BaseURL: row.BaseURL, APIKey: row.APIKey, Model: row.Model}
		}); err != nil {
			log.Printf("[gateway] serve %s config: %v", k, err)
		}
	}

	// 任务生命周期：订阅 dispatcher 回写的状态流转（running/done/failed/timeout），落 PG 供 UI 查询。
	if _, err := bus.SubscribeTaskStatus(func(ev *contract.TaskStatusEvent) {
		if err := db.UpdateTaskStatus(context.Background(), ev.TaskID, ev.Status, ev.Detail); err != nil {
			log.Printf("[gateway] 更新任务状态 %s=%s 失败: %v", ev.TaskID, ev.Status, err)
		}
	}); err != nil {
		log.Printf("[gateway] subscribe task status: %v", err)
	}

	r := router.New(db, cache, bus, blobStore)
	addr := envOr("GATEWAY_ADDR", ":8080")
	log.Printf("[gateway] listening on %s", addr)
	if err := r.Run(addr); err != nil {
		log.Fatalf("[gateway] exit: %v", err)
	}
}

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