package api

import (
	"encoding/json"
	"io"
	"mime/multipart"
	"net/http"
	"path"
	"strings"
	"time"

	"chfs-ng/internal/auth"
	"chfs-ng/internal/storage"
)

type Server struct {
	Store    storage.Storage
	Auth     *auth.Manager
	Sessions map[string]*auth.Account
}
type fileInfo struct {
	Name      string `json:"name"`
	Path      string `json:"path"`
	Size      int64  `json:"size"`
	Modified  string `json:"modified"`
	Dir       bool   `json:"dir"`
	Mask      string `json:"mask"`
	GuestMask string `json:"guestMask"`
	HasSubDir bool   `json:"hasSubDir"`
}

func (s *Server) Handler() http.Handler {
	mux := http.NewServeMux()
	mux.HandleFunc("/chfs/files", s.files)
	mux.HandleFunc("/chfs/newdir", s.newdir)
	mux.HandleFunc("/chfs/rename", s.rename)
	mux.HandleFunc("/chfs/rmfiles", s.remove)
	mux.HandleFunc("/chfs/exist", s.exist)
	mux.HandleFunc("/chfs/session", s.session)
	mux.HandleFunc("/chfs/newtext", s.newtext)
	mux.HandleFunc("/chfs/updatetext", s.updatetext)
	mux.HandleFunc("/chfs/upload", s.upload)
	mux.HandleFunc("/chfs/upload2", s.upload)
	return mux
}
func account(r *http.Request, s *Server) *auth.Account {
	if c, e := r.Cookie("chfs_token"); e == nil {
		if a := s.Sessions[c.Value]; a != nil {
			return a
		}
	}
	return s.Auth.Guest
}
func writeJSON(w http.ResponseWriter, v any) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	json.NewEncoder(w).Encode(v)
}
func qpath(r *http.Request) string {
	return strings.Trim(strings.ReplaceAll(r.URL.Query().Get("filepath"), "\\", "/"), "/")
}
func permString(p auth.PermMask) string {
	if p.HasDelete() {
		return "d"
	}
	if p.HasWrite() {
		return "w"
	}
	if p.HasRead() {
		return "r"
	}
	return ""
}
func (s *Server) files(w http.ResponseWriter, r *http.Request) {
	a := account(r, s)
	p := qpath(r)
	m := a.MaskFor(p)
	if !m.HasRead() {
		http.Error(w, "forbidden", 403)
		return
	}
	list, e := s.Store.List(p)
	if e != nil {
		http.Error(w, e.Error(), 404)
		return
	}
	out := make([]fileInfo, 0, len(list))
	for _, fi := range list {
		fp := path.Join(p, fi.Name())
		sub := false
		if fi.IsDir() {
			if xs, e := s.Store.List(fp); e == nil {
				sub = len(xs) > 0
			}
		}
		out = append(out, fileInfo{Name: fi.Name(), Path: fp, Size: fi.Size(), Modified: fi.ModTime().Format(time.RFC3339), Dir: fi.IsDir(), Mask: permString(a.MaskFor(fp)), HasSubDir: sub})
	}
	writeJSON(w, map[string]any{"files": out, "currentMask": permString(m), "virtualRoot": false})
}
func (s *Server) newdir(w http.ResponseWriter, r *http.Request) {
	a := account(r, s)
	p := qpath(r)
	if !a.MaskFor(p).HasWrite() {
		http.Error(w, "forbidden", 403)
		return
	}
	name := r.FormValue("name")
	if name == "" {
		name = r.FormValue("new")
	}
	if name == "" {
		http.Error(w, "name required", 400)
		return
	}
	if e := s.Store.MkdirAll(path.Join(p, name)); e != nil {
		http.Error(w, e.Error(), 500)
		return
	}
	writeJSON(w, map[string]any{"ok": true})
}
func (s *Server) rename(w http.ResponseWriter, r *http.Request) {
	a := account(r, s)
	old := strings.Trim(r.FormValue("old"), "/")
	neu := strings.Trim(r.FormValue("new"), "/")
	if !a.MaskFor(old).HasWrite() {
		http.Error(w, "forbidden", 403)
		return
	}
	if e := s.Store.Rename(old, neu); e != nil {
		http.Error(w, e.Error(), 500)
		return
	}
	writeJSON(w, map[string]any{"ok": true})
}
func (s *Server) remove(w http.ResponseWriter, r *http.Request) {
	a := account(r, s)
	_ = r.ParseForm()
	items := r.Form["filepath"]
	if len(items) == 0 {
		items = r.Form["path"]
	}
	for _, p := range items {
		if !a.MaskFor(p).HasDelete() {
			http.Error(w, "forbidden", 403)
			return
		}
		if e := s.Store.Remove(p); e != nil {
			http.Error(w, e.Error(), 500)
			return
		}
	}
	writeJSON(w, map[string]any{"ok": true})
}
func (s *Server) exist(w http.ResponseWriter, r *http.Request) {
	p := strings.Trim(strings.ReplaceAll(r.URL.Query().Get("file"), "\\", "/"), "/")
	_, e := s.Store.Stat(p)
	writeJSON(w, map[string]any{"exist": e == nil})
}
func (s *Server) session(w http.ResponseWriter, r *http.Request) {
	if r.Method == "DELETE" {
		http.SetCookie(w, &http.Cookie{Name: "chfs_token", Value: "", Path: "/", MaxAge: -1, HttpOnly: true})
		writeJSON(w, map[string]any{"ok": true})
		return
	}
	if r.Method == "GET" {
		a := account(r, s)
		writeJSON(w, map[string]any{"login": a != nil, "user": a.Username})
		return
	}
	user, pwd := r.FormValue("user"), r.FormValue("pwd")
	a := s.Auth.Authenticate(user, pwd)
	if a == nil {
		http.Error(w, "invalid account", 401)
		return
	}
	token := auth.NewToken()
	s.Sessions[token] = a
	http.SetCookie(w, &http.Cookie{Name: "chfs_token", Value: token, Path: "/", HttpOnly: true, SameSite: http.SameSiteLaxMode})
	writeJSON(w, map[string]any{"ok": true, "user": a.Username})
}
func (s *Server) newtext(w http.ResponseWriter, r *http.Request) {
	a := account(r, s)
	p := strings.Trim(r.FormValue("filepath"), "/")
	if filename := strings.Trim(r.FormValue("filename"), "/"); filename != "" {
		p = path.Join(p, filename)
	}
	if !a.MaskFor(p).HasWrite() {
		http.Error(w, "forbidden", 403)
		return
	}
	f, e := s.Store.Create(p)
	if e != nil {
		http.Error(w, e.Error(), 500)
		return
	}
	defer f.Close()
	io.WriteString(f, r.FormValue("text"))
	writeJSON(w, map[string]any{"ok": true})
}
func (s *Server) updatetext(w http.ResponseWriter, r *http.Request) { s.newtext(w, r) }
func (s *Server) upload(w http.ResponseWriter, r *http.Request) {
	a := account(r, s)
	dir := strings.Trim(r.FormValue("folder"), "/")
	if !a.MaskFor(dir).HasWrite() {
		http.Error(w, "forbidden", 403)
		return
	}
	if e := r.ParseMultipartForm(64 << 20); e != nil {
		http.Error(w, e.Error(), 400)
		return
	}
	var saved []string
	for _, hs := range r.MultipartForm.File {
		for _, h := range hs {
			if e := savePart(s.Store, dir, h); e != nil {
				http.Error(w, e.Error(), 500)
				return
			}
			saved = append(saved, h.Filename)
		}
	}
	w.WriteHeader(http.StatusCreated)
	writeJSON(w, map[string]any{"ok": true, "files": saved})
}
func savePart(st storage.Storage, dir string, h *multipart.FileHeader) error {
	in, e := h.Open()
	if e != nil {
		return e
	}
	defer in.Close()
	f, e := st.Create(path.Join(dir, h.Filename))
	if e != nil {
		return e
	}
	defer f.Close()
	_, e = io.Copy(f, in)
	return e
}