package gateway

import (
	"context"
	"crypto/tls"
	"fmt"
	"io"
	"io/fs"
	"mime"
	"net/http"
	"os"
	"strings"

	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
	"github.com/osguydch/ccosproc/insecure"
	"github.com/osguydch/ccosproc/middleware"
	usersv1 "github.com/osguydch/ccosproc/proto/device/v3"
	"github.com/osguydch/ccosproc/third_party"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
	"google.golang.org/grpc/grpclog"
)


// getOpenAPIHandler serves an OpenAPI UI.
// Adapted from https://github.com/philips/grpc-gateway-example/blob/a269bcb5931ca92be0ceae6130ac27ae89582ecc/cmd/serve.go#L63
func getOpenAPIHandler() http.Handler {
	mime.AddExtensionType(".svg", "image/svg+xml")
	// Use subdirectory in embedded files
	subFS, err := fs.Sub(third_party.OpenAPI, "OpenAPI")
	if err != nil {
		panic("couldn't create sub filesystem: " + err.Error())
	}
	return http.FileServer(http.FS(subFS))
}

// Run runs the gRPC-Gateway, dialling the provided address.
func Run(dialAddr string, httpPort string, supprtSSL string) error {
	// Adds gRPC internal logs. This is quite verbose, so adjust as desired!
	log := grpclog.NewLoggerV2(os.Stdout, io.Discard, io.Discard)
	grpclog.SetLoggerV2(log)

	// Create a client connection to the gRPC Server we just started.
	// This is where the gRPC-Gateway proxies the requests.
	conn, err := grpc.DialContext(
		context.Background(),
		dialAddr,
		grpc.WithTransportCredentials(credentials.NewClientTLSFromCert(insecure.CertPool, "")),
		//grpc.WithInsecure(),
		grpc.WithBlock(),
	)
	if err != nil {
		return fmt.Errorf("failed to dial server: %w", err)
	}

	gwmux := runtime.NewServeMux()
	err = usersv1.RegisterDeviceHandler(context.Background(), gwmux, conn)
	if err != nil {
		return fmt.Errorf("failed to register gateway: %w", err)
	}

	// 预先创建CORS包装的handlers，避免每次请求重复创建
	apiHandler := middleware.Cors(gwmux)
	moduleHandler := middleware.Cors(http.StripPrefix("/module/", http.FileServer(http.Dir("./DriverDefine"))))
	dataHandler := middleware.Cors(http.StripPrefix("/Data/", http.FileServer(http.Dir("./RawData"))))
	openAPIHandler := getOpenAPIHandler()

	gatewayAddr := "0.0.0.0:" + httpPort
	gwServer := &http.Server{
		Addr: gatewayAddr,
		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if strings.HasPrefix(r.URL.Path, "/api") {
				log.Info("Serving device apis", r.URL.Path)
				apiHandler.ServeHTTP(w, r)
				return
			}
			if strings.HasPrefix(r.URL.Path, "/module") {
				log.Info("Serving module definition", r.URL.Path)
				moduleHandler.ServeHTTP(w, r)
				return
			}
			if strings.HasPrefix(r.URL.Path, "/Data") {
				log.Info("Serving data file", r.URL.Path)
				dataHandler.ServeHTTP(w, r)
				return
			}
			openAPIHandler.ServeHTTP(w, r)
		}),
	}
	if supprtSSL != "ON" {
		log.Info("Serving gRPC-Gateway and OpenAPI Documentation on http://", gatewayAddr)
		return fmt.Errorf("serving gRPC-Gateway server: %w", gwServer.ListenAndServe())
	}

	gwServer.TLSConfig = &tls.Config{
		Certificates: []tls.Certificate{insecure.Cert},
	}

	log.Info("Serving gRPC-Gateway and OpenAPI Documentation on https://", gatewayAddr)
	return fmt.Errorf("serving gRPC-Gateway server: %w", gwServer.ListenAndServeTLS("", ""))
}