package handlers

import (
	"database/sql"
	"html/template"
	"log"
	"net/http"
	"path/filepath"

	"github.com/google/uuid"
	"github.com/gorilla/mux"

	"github.com/orohi/vpn-panel/internal/auth"
	"github.com/orohi/vpn-panel/internal/db"
	"github.com/orohi/vpn-panel/internal/secretbox"
)

type Server struct {
	DB        *sql.DB
	Auth      *auth.Manager
	Templates *template.Template
	SecretKey []byte
}

type pageData map[string]any

func New(database *sql.DB, authMgr *auth.Manager, appSecret, templatesDir string) (*Server, error) {
	pattern := filepath.Join(templatesDir, "*.html")
	tmpl, err := template.New("").Funcs(template.FuncMap{
		"statusClass": func(s string) string {
			switch s {
			case "online":
				return "on"
			case "installing":
				return "warn"
			case "error":
				return "err"
			case "offline":
				return "off"
			default:
				return "off"
			}
		},
	}).ParseGlob(pattern)
	if err != nil {
		return nil, err
	}
	return &Server{
		DB:        database,
		Auth:      authMgr,
		Templates: tmpl,
		SecretKey: secretbox.DeriveKey(appSecret),
	}, nil
}

func (s *Server) Routes() http.Handler {
	r := mux.NewRouter()
	r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir("web/static"))))

	r.HandleFunc("/", s.home).Methods(http.MethodGet)
	r.HandleFunc("/login", s.loginGet).Methods(http.MethodGet)
	r.HandleFunc("/login", s.loginPost).Methods(http.MethodPost)
	r.HandleFunc("/logout", s.logout).Methods(http.MethodPost, http.MethodGet)

	r.HandleFunc("/admin", s.Auth.RequireAuth(s.dashboard)).Methods(http.MethodGet)
	r.HandleFunc("/admin/protocols", s.Auth.RequireAuth(s.protocols)).Methods(http.MethodGet)
	r.HandleFunc("/admin/protocols/{id}/toggle", s.Auth.RequireAuth(s.toggleProtocol)).Methods(http.MethodPost)

	r.HandleFunc("/admin/nodes", s.Auth.RequireAuth(s.nodesList)).Methods(http.MethodGet)
	r.HandleFunc("/admin/nodes/new", s.Auth.RequireAuth(s.nodesNewGet)).Methods(http.MethodGet)
	r.HandleFunc("/admin/nodes/new", s.Auth.RequireAuth(s.nodesCreate)).Methods(http.MethodPost)
	r.HandleFunc("/admin/nodes/{id}", s.Auth.RequireAuth(s.nodeView)).Methods(http.MethodGet)
	r.HandleFunc("/admin/nodes/{id}/install", s.Auth.RequireAuth(s.nodeInstall)).Methods(http.MethodPost)
	r.HandleFunc("/admin/nodes/{id}/check", s.Auth.RequireAuth(s.nodeCheck)).Methods(http.MethodPost)
	r.HandleFunc("/admin/nodes/{id}/delete", s.Auth.RequireAuth(s.nodeDelete)).Methods(http.MethodPost)

	r.HandleFunc("/health", func(w http.ResponseWriter, _ *http.Request) {
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte("ok"))
	}).Methods(http.MethodGet)

	return r
}

func (s *Server) render(w http.ResponseWriter, name string, data pageData) {
	if data == nil {
		data = pageData{}
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	if err := s.Templates.ExecuteTemplate(w, name, data); err != nil {
		log.Printf("template %s: %v", name, err)
		http.Error(w, "template error", http.StatusInternalServerError)
	}
}

func (s *Server) home(w http.ResponseWriter, r *http.Request) {
	if s.Auth.IsAuthenticated(r) {
		http.Redirect(w, r, "/admin", http.StatusSeeOther)
		return
	}
	s.render(w, "home.html", pageData{
		"Title": "VPN Panel",
	})
}

func (s *Server) loginGet(w http.ResponseWriter, r *http.Request) {
	if s.Auth.IsAuthenticated(r) {
		http.Redirect(w, r, "/admin", http.StatusSeeOther)
		return
	}
	s.render(w, "login.html", pageData{
		"Title": "Вход",
		"Error": "",
	})
}

func (s *Server) loginPost(w http.ResponseWriter, r *http.Request) {
	if err := r.ParseForm(); err != nil {
		http.Error(w, "bad request", http.StatusBadRequest)
		return
	}
	email := r.FormValue("email")
	password := r.FormValue("password")

	user, err := db.GetUserByEmail(s.DB, email)
	if err != nil || user == nil || !auth.CheckPassword(user.PasswordHash, password) {
		s.render(w, "login.html", pageData{
			"Title": "Вход",
			"Error": "Неверный email или пароль",
			"Email": email,
		})
		return
	}

	if err := s.Auth.Login(w, r, user.ID.String(), user.Email, user.Name); err != nil {
		http.Error(w, "session error", http.StatusInternalServerError)
		return
	}
	http.Redirect(w, r, "/admin", http.StatusSeeOther)
}

func (s *Server) logout(w http.ResponseWriter, r *http.Request) {
	_ = s.Auth.Logout(w, r)
	http.Redirect(w, r, "/login", http.StatusSeeOther)
}

func (s *Server) dashboard(w http.ResponseWriter, r *http.Request) {
	stats, err := db.GetStats(s.DB)
	if err != nil {
		http.Error(w, "db error", http.StatusInternalServerError)
		return
	}
	protocols, err := db.ListProtocols(s.DB)
	if err != nil {
		http.Error(w, "db error", http.StatusInternalServerError)
		return
	}
	nodes, _ := db.ListNodes(s.DB)
	s.render(w, "dashboard.html", pageData{
		"Title":     "Админка",
		"UserName":  s.Auth.CurrentName(r),
		"Stats":     stats,
		"Protocols": protocols,
		"Nodes":     nodes,
		"Active":    "dashboard",
	})
}

func (s *Server) protocols(w http.ResponseWriter, r *http.Request) {
	protocols, err := db.ListProtocols(s.DB)
	if err != nil {
		http.Error(w, "db error", http.StatusInternalServerError)
		return
	}
	s.render(w, "protocols.html", pageData{
		"Title":     "Протоколы",
		"UserName":  s.Auth.CurrentName(r),
		"Protocols": protocols,
		"Active":    "protocols",
	})
}

func (s *Server) toggleProtocol(w http.ResponseWriter, r *http.Request) {
	idStr := mux.Vars(r)["id"]
	id, err := uuid.Parse(idStr)
	if err != nil {
		http.Error(w, "invalid id", http.StatusBadRequest)
		return
	}
	if err := db.ToggleProtocol(s.DB, id); err != nil {
		http.Error(w, "db error", http.StatusInternalServerError)
		return
	}
	http.Redirect(w, r, "/admin/protocols", http.StatusSeeOther)
}