package servers

import (
	"dy-admin/internal/pcmserver/config"
	"dy-admin/pkg/log"
	"dy-admin/pkg/middleware"
	"dy-admin/pkg/rescode"
	"dy-admin/pkg/version"
	"errors"
	"github.com/gin-contrib/pprof"
	"github.com/gin-gonic/gin"
	ginprometheus "github.com/zsais/go-gin-prometheus"
	"golang.org/x/sync/errgroup"
	"net"
	"net/http"
	"strconv"
)

type GenericAPIServer struct {
	middlewares         []string
	InsecureServingInfo *InsecureServingInfo
	*gin.Engine
	healthz         bool
	enableMetrics   bool
	enableProfiling bool
	insecureServer  *http.Server
}

func NewGenericApiServer(cfg *config.Config) (*GenericAPIServer, error) {

	gin.SetMode(cfg.GenericServerRunOptions.Mode)

	s := &GenericAPIServer{
		middlewares: cfg.GenericServerRunOptions.Middlewares,

		InsecureServingInfo: &InsecureServingInfo{Address: net.JoinHostPort(cfg.InsecureServing.BindAddress, strconv.Itoa(cfg.InsecureServing.BindPort))},

		Engine:          gin.New(),
		healthz:         cfg.GenericServerRunOptions.Healthz,
		enableMetrics:   cfg.FeatureOptions.EnableMetrics,
		enableProfiling: cfg.FeatureOptions.EnableProfiling,
	}
	initGenericAPIServer(s)
	return s, nil
}

func initGenericAPIServer(s *GenericAPIServer) {
	// do some setup
	// s.GET(path, ginSwagger.WrapHandler(swaggerFiles.Handler))

	s.Setup()
	s.InstallMiddlewares()
	s.InstallAPIs()
}

func (s *GenericAPIServer) Setup() {
	gin.DebugPrintRouteFunc = func(httpMethod, absolutePath, handlerName string, nuHandlers int) {
		log.Infof("%-6s %-s --> %s (%d handlers)", httpMethod, absolutePath, handlerName, nuHandlers)
	}
}

func (s *GenericAPIServer) InstallMiddlewares() {
	// necessary middlewares
	s.Use(middleware.RequestID())
	s.Use(middleware.Context())

	// install custom middlewares
	for _, m := range s.middlewares {
		mw, ok := middleware.Middlewares[m]
		if !ok {
			log.Warnf("can not find middleware: %s", m)

			continue
		}

		log.Infof("install middleware: %s", m)
		s.Use(mw)
	}
}

func (s *GenericAPIServer) InstallAPIs() {
	// install healthz handler
	if s.healthz {
		s.GET("/healthz", func(c *gin.Context) {
			rescode.WriteSuccessResponse(c, map[string]string{"status": "ok"})
		})
	}

	// install metric handler
	if s.enableMetrics {
		prometheus := ginprometheus.NewPrometheus("gin")
		prometheus.Use(s.Engine)
	}

	// install pprof handler
	if s.enableProfiling {
		pprof.Register(s.Engine)
	}

	s.GET("/version", func(c *gin.Context) {

		rescode.WriteSuccessResponse(c, version.Get())
	})
}

func (s *GenericAPIServer) Run() error {
	s.insecureServer = &http.Server{
		Addr:    s.InsecureServingInfo.Address,
		Handler: s,
	}

	var eg errgroup.Group

	eg.Go(func() error {
		log.Infof("Start to listening the incoming requests on http address: %s", s.InsecureServingInfo.Address)

		if err := s.insecureServer.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			log.Fatal(err.Error())

			return err
		}

		log.Infof("Server on %s stopped", s.InsecureServingInfo.Address)

		return nil
	})

	if err := eg.Wait(); err != nil {
		log.Fatal(err.Error())
	}

	return nil
}

type InsecureServingInfo struct {
	Address string
}