package internal

import (
	"fmt"
	"image/png"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"

	"git.mills.io/prologic/useragent"
	securejoin "github.com/cyphar/filepath-securejoin"
	"github.com/julienschmidt/httprouter"
	log "github.com/sirupsen/logrus"
)

func (s *Server) NotFoundHandler(w http.ResponseWriter, r *http.Request) {
	if r.Header.Get("Accept") == "application/json" {
		w.Header().Set("Content-Type", "application/json")
		http.Error(w, "Endpoint Not Found", http.StatusNotFound)
		return
	}

	w.WriteHeader(http.StatusNotFound)
	w.Write([]byte("404 Not Found"))
}

// ConfigHandler ...
func (s *Server) ConfigHandler() httprouter.Handle {
	configDir := filepath.Join(s.config.Data, wellknownPath)
	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
		w.Header().Set("Accept-Encoding", "br, gzip, deflate")
		w.Header().Set("X-Salty-Accept-Encoding", "br, gzip, deflate")
		http.ServeFile(w, r, filepath.Join(configDir, p.ByName("config")))
	}
}

// IndexHandler ...
func (s *Server) IndexHandler() httprouter.Handle {
	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
		ua := useragent.Parse(r.UserAgent())
		if ua != nil && ua.Type == useragent.Browser {
			http.Redirect(w, r, "/app/", http.StatusFound)
		}
	}
}

// AvatarHandler ...
func (s *Server) AvatarHandler() httprouter.Handle {
	avatarsDir := filepath.Join(s.config.Data, avatarsPath)
	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
		w.Header().Set("Cache-Control", "public, no-cache, must-revalidate")
		hash := p.ByName("hash")
		if hash == "" {
			http.Error(w, "Bad Request", http.StatusBadRequest)
			return
		}

		fn, err := securejoin.SecureJoin(avatarsDir, fmt.Sprintf("%s.png", hash))
		if err != nil {
			http.Error(w, "Bad Request", http.StatusBadRequest)
			return
		}
		if fileInfo, err := os.Stat(fn); err == nil {
			w.Header().Set("Etag", fmt.Sprintf("W/\"%s-%s\"", r.RequestURI, fileInfo.ModTime().Format(time.RFC3339)))
			w.Header().Set("Last-Modified", fileInfo.ModTime().Format(http.TimeFormat))
			http.ServeFile(w, r, fn)
			return
		}
		etag := fmt.Sprintf("W/\"%s\"", r.RequestURI)
		if match := r.Header.Get("If-None-Match"); match != "" {
			if strings.Contains(match, etag) {
				w.WriteHeader(http.StatusNotModified)
				return
			}
		}
		w.Header().Set("Etag", etag)
		if r.Method == http.MethodHead {
			return
		}
		img, err := GenerateAvatar(s.config, hash)
		if err != nil {
			log.WithError(err).Errorf("error generating avatar for %s", hash)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}
		if r.Method == http.MethodHead {
			return
		}
		w.Header().Set("Content-Type", "image/png")
		if err := png.Encode(w, img); err != nil {
			log.WithError(err).Error("error encoding auto generated avatar")
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}
	}
}