// Copyright (C) 2022 Marius Schellenberger

package srv

import (
	"errors"
	"io"
	stdfs "io/fs"
	"net/http"
	"path"
	"strings"

	"cachefs/pkg/fs"

	"github.com/go-logr/logr"
)

type FileServer struct {
	log logr.Logger
	fs  *fs.FS
	h   http.Handler
}

func NewFileServer(fs *fs.FS, log logr.Logger) http.Handler {
	return &FileServer{log, fs, http.FileServer(fs)}
}

func skipLog(path string) bool {
	return strings.HasSuffix(path, "favicon.ico")
}

func (fs *FileServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	s := &statusInterceptor{w: w}
	w = s
	defer func() {
		if skipLog(r.RequestURI) {
			return
		}
		fs.log.Info("access",
			"uri", r.RequestURI,
			"method", r.Method,
			"status", s.Status(),
		)
	}()
	upath := r.URL.Path
	if !strings.HasPrefix(upath, "/") {
		upath = "/" + upath
		r.URL.Path = upath
	}
	p := path.Clean(upath)
	d, err := fs.fs.Stat(p)
	if err != nil {
		msg, code := toHTTPError(err)
		http.Error(w, msg, code)
		return
	}
	if r.FormValue("v") == "t" {
		err = video.Execute(w, r.URL.Path)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
		}
		return
	}

	if !d.IsDir() {
		if r.FormValue("p") == "t" {
			fs.fs.Preload(p)
			idx := strings.LastIndex(p, "/")
			if idx > 0 {
				p = p[:idx]
			} else {
				p = "/"
			}
			http.Redirect(w, r, p, http.StatusFound)
			return
		}
		if r.FormValue("n") == "t" {
			fs.fs.NoCache.ServeHTTP(w, r)
			return
		}
		fs.h.ServeHTTP(w, r)
		return
	}

	i := &responseInterceptor{w: w}
	fs.h.ServeHTTP(i, r)
	paths, err := i.GetPaths()
	if err == io.EOF {
		w.WriteHeader(i.Status())
		return
	}
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.WriteHeader(i.Status())
	err = index.Execute(w, paths)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

func toHTTPError(err error) (string, int) {
	if errors.Is(err, stdfs.ErrNotExist) {
		return "404 page not found", http.StatusNotFound
	}
	if errors.Is(err, stdfs.ErrPermission) {
		return "403 Forbidden", http.StatusForbidden
	}
	// Default:
	return "500 Internal Server Error", http.StatusInternalServerError
}