package httpserver

import (
	"context"
	"fmt"
	"html/template"
	"io"
	"log"
	"mime"
	"net/http"
	"time"

	"go.uber.org/zap"

	"go.c3c.cz/cv/app/server/internal/files"
)

func init() {
	err := mime.AddExtensionType(".ico", "image/x-icon")
	if err != nil {
		log.Fatal(err)
	}

	err = mime.AddExtensionType(".json", "application/json; charset=utf-8")
	if err != nil {
		log.Fatal(err)
	}
}

type Options struct {
	Logger         *zap.Logger
	BindAddr       string
	FrontendConfig string
	RequireIndex   bool
}

type server struct{ http.Server }

func New(options *Options) (*server, error) {
	handler := &handler{
		frontendConfig: options.FrontendConfig,
		logger:         options.Logger,
	}

	httpSrv := &server{
		http.Server{
			Addr:    options.BindAddr,
			Handler: handler,
		},
	}

	index, err := files.Public.Open("data/public/index.html")
	if err != nil {
		if !options.RequireIndex {
			return httpSrv, nil
		}

		return nil, fmt.Errorf("could not open index.html: %w", err)
	}

	fi, err := index.Stat()
	if err != nil || fi.IsDir() {
		if !options.RequireIndex {
			return httpSrv, nil
		}

		return nil, fmt.Errorf("invalid index.html: %w", err)
	}

	tb, err := io.ReadAll(index)
	if err != nil {
		if !options.RequireIndex {
			return httpSrv, nil
		}

		return nil, fmt.Errorf("could not read index.html: %w", err)
	}

	handler.indexTemplate, err = template.New("index").Parse(string(tb))
	if err != nil {
		if !options.RequireIndex {
			return httpSrv, nil
		}

		return nil, fmt.Errorf("could not parse index.html: index.html: %w", err)
	}

	return httpSrv, nil
}

func (s *server) ShutdownWithDelay(delay time.Duration, limit time.Duration) {
	h, ok := s.Handler.(*handler)

	var logger *zap.Logger
	if ok {
		logger = h.logger
	} else {
		logger = zap.L()
	}

	if delay > 0 {
		logger.Info(fmt.Sprintf("Waiting %s for incoming requests\n", delay))
		time.Sleep(delay)
	}

	ctx, cancel := context.WithTimeout(context.Background(), limit)
	defer cancel()

	logger.Info("Gracefully shutting down http server")
	if err := s.Shutdown(ctx); err != nil {
		logger.Error("Failed to shutdown http server", zap.Error(err))
	} else {
		logger.Info("Http server was stopped")
	}
}