package server

import (
	"context"
	"fmt"
	"html/template"
	"net"
	"net/http"
	"strconv"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/cors"
	"github.com/pkg/errors"
	"gitlab.com/wpetit/goweb/api"
	"gitlab.com/wpetit/goweb/logger"

	_ "embed"
)

var (
	//go:embed templates/idle.html.gotmpl
	rawIdleTemplate []byte
	idleTemplate    *template.Template
)

func init() {
	tmpl, err := template.New("").Parse(string(rawIdleTemplate))
	if err != nil {
		panic(errors.Wrap(err, "could not parse idle template"))
	}

	idleTemplate = tmpl
}

func (s *Server) startHTTPServer(ctx context.Context) error {
	router := chi.NewRouter()

	if s.webApps {
		ips, err := getLANIPv4Addrs()
		if err != nil {
			return errors.WithStack(err)
		}

		allowedOrigins := make([]string, len(ips))
		for idx, ip := range ips {
			allowedOrigins[idx] = fmt.Sprintf("http://%s:%d", ip, s.port)
		}

		router.Use(cors.Handler(cors.Options{
			AllowedOrigins:   allowedOrigins,
			AllowedMethods:   []string{"GET", "POST", "PUT", "DELETE", "OPTIONS"},
			AllowedHeaders:   []string{"Accept", "Authorization", "Content-Type"},
			AllowCredentials: false,
		}))
	}

	router.Get("/", s.handleHome)
	router.Post("/api/v1/cast", s.handleCast)
	router.Delete("/api/v1/cast", s.handleReset)
	router.Get("/api/v1/status", s.handleStatus)

	if s.webApps {
		router.Get("/apps", s.handleDefaultApp)
		router.Get("/api/v1/apps", s.handleApps)
		router.Handle("/apps/*", http.FileServer(http.FS(appsFS)))
	}

	server := http.Server{
		Addr:    s.address,
		Handler: router,
	}

	listener, err := net.Listen("tcp", s.address)
	if err != nil {
		return errors.WithStack(err)
	}

	host, rawPort, err := net.SplitHostPort(listener.Addr().String())
	if err != nil {
		return errors.WithStack(err)
	}

	port, err := strconv.ParseInt(rawPort, 10, 32)
	if err != nil {
		return errors.Wrapf(err, "could not parse listening port '%v'", rawPort)
	}

	logger.Debug(ctx, "listening for tcp connections", logger.F("port", port), logger.F("host", host))

	s.port = int(port)

	go func() {
		logger.Debug(ctx, "starting http server")
		if err := server.Serve(listener); err != nil && !errors.Is(err, http.ErrServerClosed) {
			logger.Error(ctx, "could not listen", logger.CapturedE(errors.WithStack(err)))
		}
	}()

	go func() {
		<-ctx.Done()
		logger.Debug(ctx, "closing http server")
		if err := server.Close(); err != nil {
			logger.Error(ctx, "could not close http server", logger.CapturedE(errors.WithStack(err)))
		}
	}()

	if err := s.resetBrowser(); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

type CastRequest struct {
	URL string `json:"url" validate:"required"`
}

func (s *Server) handleCast(w http.ResponseWriter, r *http.Request) {
	req := &CastRequest{}
	if ok := api.Bind(w, r, req); !ok {
		return
	}

	if err := s.browser.Load(req.URL); err != nil {
		logger.Error(r.Context(), "could not load url", logger.CapturedE(errors.WithStack(err)))
		api.ErrorResponse(w, http.StatusInternalServerError, api.ErrCodeUnknownError, nil)

		return
	}

	http.Redirect(w, r, "/api/v1/status", http.StatusSeeOther)
}

func (s *Server) handleReset(w http.ResponseWriter, r *http.Request) {
	if err := s.resetBrowser(); err != nil {
		logger.Error(r.Context(), "could not unload url", logger.CapturedE(errors.WithStack(err)))
		api.ErrorResponse(w, http.StatusInternalServerError, api.ErrCodeUnknownError, nil)

		return
	}

	http.Redirect(w, r, "/api/v1/status", http.StatusSeeOther)
}

func (s *Server) resetBrowser() error {
	idleURL := fmt.Sprintf("http://localhost:%d", s.port)
	if err := s.browser.Reset(idleURL); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

type StatusResponse struct {
	ID     string `json:"id"`
	URL    string `json:"url"`
	Status string `json:"status"`
	Title  string `json:"title"`
}

func (s *Server) handleStatus(w http.ResponseWriter, r *http.Request) {
	url, err := s.browser.URL()
	if err != nil {
		logger.Error(r.Context(), "could not retrieve browser url", logger.CapturedE(errors.WithStack(err)))
		api.ErrorResponse(w, http.StatusInternalServerError, api.ErrCodeUnknownError, nil)

		return
	}

	status, err := s.browser.Status()
	if err != nil {
		logger.Error(r.Context(), "could not retrieve browser status", logger.CapturedE(errors.WithStack(err)))
		api.ErrorResponse(w, http.StatusInternalServerError, api.ErrCodeUnknownError, nil)

		return
	}

	title, err := s.browser.Title()
	if err != nil {
		logger.Error(r.Context(), "could not retrieve browser page title", logger.CapturedE(errors.WithStack(err)))
		api.ErrorResponse(w, http.StatusInternalServerError, api.ErrCodeUnknownError, nil)

		return
	}

	api.DataResponse(w, http.StatusOK, &StatusResponse{
		ID:     s.instanceID,
		URL:    url,
		Status: status.String(),
		Title:  title,
	})
}

func (s *Server) handleHome(w http.ResponseWriter, r *http.Request) {
	type templateData struct {
		IPs     []string
		Port    int
		ID      string
		WebApps bool
	}

	ips, err := getLANIPv4Addrs()
	if err != nil {
		logger.Error(r.Context(), "could not retrieve lan ip addresses", logger.CapturedE(errors.WithStack(err)))
		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		return
	}

	d := templateData{
		ID:      s.instanceID,
		IPs:     ips,
		Port:    s.port,
		WebApps: s.webApps,
	}

	if err := idleTemplate.Execute(w, d); err != nil {
		logger.Error(r.Context(), "could not render idle page", logger.CapturedE(errors.WithStack(err)))
	}
}