package lib

import (
	"errors"
	"io"
	"net/http"
	"strings"
)

func Run(bind string, f *Forgejo) (*http.Server, error) {
	if f == nil {
		return nil, errors.New("forgejo is nil")
	}
	s := &http.Server{
		Addr:    bind,
		Handler: http.HandlerFunc(f.handle),
	}
	return s, nil
}

func trySet(h http.Header, key, value string) {
	if value == "" {
		h.Del(key)
		return
	}
	h.Set(key, value)
}

func (f *Forgejo) handle(w http.ResponseWriter, r *http.Request) {
	arr := strings.Split(r.URL.Path[1:], "/")
	if len(arr) < 2 {
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	user, repo := arr[0], arr[1]
	if user == "u" {
		user, repo = repo, f.Branch
	}
	file := "index.html"
	if l := len(arr); l > 2 {
		if arr[l-1] == "" {
			arr[l-1] = "index.html"
		}
		file = strings.Join(arr[2:], "/")
	}

	info, content, err := f.GetFile(r.Context(), user, repo, f.Branch, file)
	if err != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}
	defer content.Close()

	trySet(w.Header(), "Etag", info.ETag)
	trySet(w.Header(), "Last-Modified", info.LastModified)
	trySet(w.Header(), "Content-Length", info.Size)

	if r.Header.Get("If-None-Match") == info.ETag {
		w.WriteHeader(http.StatusNotModified)
		return
	}
	if r.Header.Get("If-Modified-Since") == info.LastModified {
		w.WriteHeader(http.StatusNotModified)
		return
	}

	w.WriteHeader(http.StatusOK)
	io.Copy(w, content)
}