package server

import (
	"context"
	"encoding/json"
	"fmt"
	"net"
	"net/http"
	"strings"
	"time"

	"github.com/google/uuid"
	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	"github.com/pkg/errors"
	echoSwagger "github.com/swaggo/echo-swagger"
	"go.uber.org/zap"

	apiv1 "github.com/usememos/memos/api/v1"
	apiv2 "github.com/usememos/memos/api/v2"
	"github.com/usememos/memos/common/log"
	"github.com/usememos/memos/plugin/telegram"
	"github.com/usememos/memos/server/profile"
	"github.com/usememos/memos/server/service"
	"github.com/usememos/memos/store"
)

type Server struct {
	e *echo.Echo

	ID      string
	Secret  string
	Profile *profile.Profile
	Store   *store.Store

	// API services.
	apiV2Service *apiv2.APIV2Service

	// Asynchronous runners.
	backupRunner *service.BackupRunner
	telegramBot  *telegram.Bot
}

func NewServer(ctx context.Context, profile *profile.Profile, store *store.Store) (*Server, error) {
	e := echo.New()
	e.Debug = true
	e.HideBanner = true
	e.HidePort = true

	telegramBot := telegram.NewBotWithHandler(newTelegramHandler(store))
	s := &Server{
		e:       e,
		Store:   store,
		Profile: profile,

		// Asynchronous runners.
		backupRunner: service.NewBackupRunner(store),
		telegramBot:  telegramBot,
	}

	e.Use(middleware.LoggerWithConfig(middleware.LoggerConfig{
		Format: `{"time":"${time_rfc3339}",` +
			`"method":"${method}","uri":"${uri}",` +
			`"status":${status},"error":"${error}"}` + "\n",
	}))

	e.Use(middleware.Gzip())

	e.Use(middleware.CORSWithConfig(middleware.CORSConfig{
		Skipper:      grpcRequestSkipper,
		AllowOrigins: []string{"*"},
		AllowMethods: []string{http.MethodGet, http.MethodHead, http.MethodPut, http.MethodPatch, http.MethodPost, http.MethodDelete},
	}))

	e.Use(middleware.TimeoutWithConfig(middleware.TimeoutConfig{
		Skipper: grpcRequestSkipper,
		Timeout: 30 * time.Second,
	}))

	e.Use(middleware.RateLimiterWithConfig(middleware.RateLimiterConfig{
		Skipper: grpcRequestSkipper,
		Store: middleware.NewRateLimiterMemoryStoreWithConfig(
			middleware.RateLimiterMemoryStoreConfig{Rate: 30, Burst: 60, ExpiresIn: 3 * time.Minute},
		),
		IdentifierExtractor: func(ctx echo.Context) (string, error) {
			id := ctx.RealIP()
			return id, nil
		},
		ErrorHandler: func(context echo.Context, err error) error {
			return context.JSON(http.StatusForbidden, nil)
		},
		DenyHandler: func(context echo.Context, identifier string, err error) error {
			return context.JSON(http.StatusTooManyRequests, nil)
		},
	}))

	serverID, err := s.getSystemServerID(ctx)
	if err != nil {
		return nil, errors.Wrap(err, "failed to retrieve system server ID")
	}
	s.ID = serverID

	// Serve frontend.
	embedFrontend(e)

	// Serve swagger in dev/demo mode.
	if profile.Mode == "dev" || profile.Mode == "demo" {
		e.GET("/api/*", echoSwagger.WrapHandler)
	}

	secret := "usememos"
	if profile.Mode == "prod" {
		secret, err = s.getSystemSecretSessionName(ctx)
		if err != nil {
			return nil, errors.Wrap(err, "failed to retrieve system secret session name")
		}
	}
	s.Secret = secret

	rootGroup := e.Group("")
	apiV1Service := apiv1.NewAPIV1Service(s.Secret, profile, store, telegramBot)
	apiV1Service.Register(rootGroup)

	s.apiV2Service = apiv2.NewAPIV2Service(s.Secret, profile, store, s.Profile.Port+1)
	// Register gRPC gateway as api v2.
	if err := s.apiV2Service.RegisterGateway(ctx, e); err != nil {
		return nil, errors.Wrap(err, "failed to register gRPC gateway")
	}

	return s, nil
}

func (s *Server) Start(ctx context.Context) error {
	if err := s.createServerStartActivity(ctx); err != nil {
		return errors.Wrap(err, "failed to create activity")
	}

	go s.telegramBot.Start(ctx)
	go s.backupRunner.Run(ctx)

	// Start gRPC server.
	listen, err := net.Listen("tcp", fmt.Sprintf("%s:%d", s.Profile.Addr, s.Profile.Port+1))
	if err != nil {
		return err
	}
	go func() {
		if err := s.apiV2Service.GetGRPCServer().Serve(listen); err != nil {
			log.Error("grpc server listen error", zap.Error(err))
		}
	}()

	return s.e.Start(fmt.Sprintf("%s:%d", s.Profile.Addr, s.Profile.Port))
}

func (s *Server) Shutdown(ctx context.Context) {
	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
	defer cancel()

	// Shutdown echo server
	if err := s.e.Shutdown(ctx); err != nil {
		fmt.Printf("failed to shutdown server, error: %v\n", err)
	}

	// Close database connection
	if err := s.Store.GetDB().Close(); err != nil {
		fmt.Printf("failed to close database, error: %v\n", err)
	}

	fmt.Printf("memos stopped properly\n")
}

func (s *Server) GetEcho() *echo.Echo {
	return s.e
}

func (s *Server) getSystemServerID(ctx context.Context) (string, error) {
	serverIDSetting, err := s.Store.GetSystemSetting(ctx, &store.FindSystemSetting{
		Name: apiv1.SystemSettingServerIDName.String(),
	})
	if err != nil {
		return "", err
	}
	if serverIDSetting == nil || serverIDSetting.Value == "" {
		serverIDSetting, err = s.Store.UpsertSystemSetting(ctx, &store.SystemSetting{
			Name:  apiv1.SystemSettingServerIDName.String(),
			Value: uuid.NewString(),
		})
		if err != nil {
			return "", err
		}
	}
	return serverIDSetting.Value, nil
}

func (s *Server) getSystemSecretSessionName(ctx context.Context) (string, error) {
	secretSessionNameValue, err := s.Store.GetSystemSetting(ctx, &store.FindSystemSetting{
		Name: apiv1.SystemSettingSecretSessionName.String(),
	})
	if err != nil {
		return "", err
	}
	if secretSessionNameValue == nil || secretSessionNameValue.Value == "" {
		secretSessionNameValue, err = s.Store.UpsertSystemSetting(ctx, &store.SystemSetting{
			Name:  apiv1.SystemSettingSecretSessionName.String(),
			Value: uuid.NewString(),
		})
		if err != nil {
			return "", err
		}
	}
	return secretSessionNameValue.Value, nil
}

func (s *Server) createServerStartActivity(ctx context.Context) error {
	payload := apiv1.ActivityServerStartPayload{
		ServerID: s.ID,
		Profile:  s.Profile,
	}
	payloadBytes, err := json.Marshal(payload)
	if err != nil {
		return errors.Wrap(err, "failed to marshal activity payload")
	}
	activity, err := s.Store.CreateActivity(ctx, &store.Activity{
		CreatorID: apiv1.UnknownID,
		Type:      apiv1.ActivityServerStart.String(),
		Level:     apiv1.ActivityInfo.String(),
		Payload:   string(payloadBytes),
	})
	if err != nil || activity == nil {
		return errors.Wrap(err, "failed to create activity")
	}
	return err
}

func grpcRequestSkipper(c echo.Context) bool {
	return strings.HasPrefix(c.Request().URL.Path, "/memos.api.v2.")
}