package transport

import (
	"context"
	"crypto/rand"
	"database/sql"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"github.com/alexedwards/flow"
	"github.com/google/uuid"
	"log"
	"net/http"
	"whitelistmanager/auth"
	"whitelistmanager/invite"
	"whitelistmanager/minecraft"
	"whitelistmanager/store"
)

type Handler struct {
	store   store.Storer
	manager invite.InviteManager
}

type Handle interface {
	AuthMiddleware(next http.Handler) http.Handler
	Cors(next http.Handler) http.Handler
	CurrentUser(w http.ResponseWriter, r *http.Request)
	CreateInvite(w http.ResponseWriter, r *http.Request)
	GetInvite(w http.ResponseWriter, r *http.Request)
	DeleteInvite(w http.ResponseWriter, r *http.Request)
	AcceptInvite(w http.ResponseWriter, r *http.Request)
	AuthRedirect(w http.ResponseWriter, r *http.Request)
	AuthCallback(w http.ResponseWriter, r *http.Request)
	Server(w http.ResponseWriter, r *http.Request)
	Servers(w http.ResponseWriter, r *http.Request)
	CreateServer(w http.ResponseWriter, r *http.Request)
	DeleteServer(w http.ResponseWriter, r *http.Request)
	ServerInvites(w http.ResponseWriter, r *http.Request)
	InviteLog(w http.ResponseWriter, r *http.Request)
}

func New(store store.Storer) *Handler {
	im := invite.NewManager(store)
	return &Handler{
		store:   store,
		manager: im,
	}
}

func (h *Handler) Cors(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().Set("Access-Control-Allow-Headers", "Content-Type,Authorization")
		w.Header().Set("Access-Control-Allow-Methods", "*")
		next.ServeHTTP(w, r)
	})
}

func (h *Handler) SessionAuth(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		session, err := r.Cookie("session")
		if err != nil {
			log.Println(err)
			http.Error(w, err.Error(), http.StatusForbidden)
			return
		}
		user, err := h.store.SessionUser(session.Value)
		if err != nil {
			log.Println(err)
			http.Error(w, err.Error(), http.StatusForbidden)
			return
		}
		ctx := context.WithValue(r.Context(), "user", user)
		r = r.WithContext(ctx)
		next.ServeHTTP(w, r)
	})
}

type invitePayload struct {
	Server    string `json:"server"`
	Unlimited bool   `json:"unlimited"`
	Uses      int    `json:"uses"`
}

func (h *Handler) CreateInvite(w http.ResponseWriter, r *http.Request) {
	var i invitePayload
	err := json.NewDecoder(r.Body).Decode(&i)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	user := r.Context().Value("user").(store.User)
	in, err := h.manager.Create(store.Invite{
		Server:    store.Server{Id: i.Server},
		Unlimited: i.Unlimited,
		Uses:      i.Uses,
	}, user)
	if err != nil {
		if err.Error() == invite.NotOwnerofServer {
			http.Error(w, err.Error(), http.StatusForbidden)
			return
		}
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.Write([]byte(in))
}

func (h *Handler) GetInvite(w http.ResponseWriter, r *http.Request) {
	token := flow.Param(r.Context(), "id")
	in, err := h.store.GetInvite(token)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			http.Error(w, "invalid invite", http.StatusNotFound)
			return
		}
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	err = json.NewEncoder(w).Encode(in)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

func (h *Handler) AcceptInvite(w http.ResponseWriter, r *http.Request) {
	token := flow.Param(r.Context(), "id")
	in, err := h.store.GetInvite(token)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			http.Error(w, "invalid invite", http.StatusNotFound)
			return
		}
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	remainingUse, err := h.manager.RemainingUses(in)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	if remainingUse == 0 {
		http.Error(w, "no more uses remaining for invite", http.StatusForbidden)
		return
	}

	server, err := h.store.GetServer(in.Server.Id)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	user := r.Context().Value("user").(store.User)
	log.Println(user.DisplayName)
	resp, err := minecraft.Whitelist(user.DisplayName, server)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	if resp == fmt.Sprintf("Added %s to the whitelist", user.DisplayName) {
		err = h.store.LogInviteUse(user, in)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	}

	w.Write([]byte(resp))
}

func (h *Handler) AuthRedirect(w http.ResponseWriter, r *http.Request) {
	state := store.OauthState{
		Id:     uuid.New().String(),
		Origin: r.Header.Get("Referer"),
		State:  "started",
	}
	err := h.store.SaveOauthState(state)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	http.Redirect(w, r, auth.LoginUrl(state.Id), http.StatusTemporaryRedirect)
}

func (h *Handler) AuthCallback(w http.ResponseWriter, r *http.Request) {
	code := r.URL.Query()["code"][0]
	stateId := r.URL.Query()["state"][0]
	state, err := h.store.OauthState(stateId)
	if err != nil || state.State == "completed" {
		http.Error(w, err.Error(), http.StatusForbidden)
		return
	}

	user, err := auth.Authenticate(code)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	err = h.store.SaveUser(user)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	sessToken, err := generateSessionToken()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	http.SetCookie(w, &http.Cookie{
		Name:     "session",
		Value:    sessToken,
		HttpOnly: true,
		Path:     "/",
	})
	err = h.store.SaveSession(sessToken, user)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	state.State = "completed"
	err = h.store.SaveOauthState(state)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	http.Redirect(w, r, state.Origin, http.StatusTemporaryRedirect)
}

func generateSessionToken() (string, error) {
	b := make([]byte, 64)
	_, err := rand.Read(b)
	if err != nil {
		return "", err
	}

	return base64.URLEncoding.EncodeToString(b), err
}

func (h *Handler) Servers(w http.ResponseWriter, r *http.Request) {
	user := r.Context().Value("user").(store.User)
	if r.Method == http.MethodGet {
		servers, err := h.store.GetUserServers(user)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		if len(servers) == 0 {
			w.WriteHeader(http.StatusNotFound)
			w.Write([]byte("[]"))
			return
		}
		json.NewEncoder(w).Encode(servers)
		return
	}

	var server store.Server
	err := json.NewDecoder(r.Body).Decode(&server)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	server.Id = uuid.New().String()
	server.Owner.Id = user.Id

	err = h.store.SaveServer(server)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	fmt.Fprintf(w, "created server %s", server.Id)
}

func (h *Handler) Server(w http.ResponseWriter, r *http.Request) {
	user := r.Context().Value("user").(store.User)
	serverId := flow.Param(r.Context(), "id")
	if r.Method == http.MethodGet {
		server, err := h.store.GetServer(serverId)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		if server.Owner.Id != user.Id {
			http.Error(w, "not owner of server", http.StatusForbidden)
			return
		}
		server.Rcon.Password = ""

		json.NewEncoder(w).Encode(server)
		return
	}

	if r.Method == http.MethodDelete {
		serverId := flow.Param(r.Context(), "id")
		user := r.Context().Value("user").(store.User)
		server, err := h.store.GetServer(serverId)
		if err != nil {
			http.Error(w, "no such server", http.StatusNotFound)
			return
		}

		if server.Owner.Id != user.Id {
			http.Error(w, "user not server owner", http.StatusForbidden)
			return
		}

		err = h.store.DeleteServer(server, user)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		w.Write([]byte("deleted"))
	}

}

func (h *Handler) CurrentUser(w http.ResponseWriter, r *http.Request) {
	value := r.Context().Value("user")
	if value == nil {
		http.Error(w, "", http.StatusForbidden)
		return
	}
	user := value.(store.User)
	w.Write([]byte(user.DisplayName))
}

func (h *Handler) ServerInvites(w http.ResponseWriter, r *http.Request) {
	user := r.Context().Value("user").(store.User)
	serverId := flow.Param(r.Context(), "id")
	server, err := h.store.GetServer(serverId)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	if server.Owner.Id != user.Id {
		http.Error(w, "not owner of server", http.StatusForbidden)
		return
	}

	serverInvites, err := h.store.ServerInvites(server)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	if server.Owner.Id != user.Id {
		http.Error(w, "not owner of server", http.StatusForbidden)
		return
	}

	if len(serverInvites) == 0 {
		w.WriteHeader(http.StatusNotFound)
		w.Write([]byte("[]"))
		return
	}

	json.NewEncoder(w).Encode(serverInvites)
	return
}

func (h *Handler) InviteLog(w http.ResponseWriter, r *http.Request) {
	user := r.Context().Value("user").(store.User)
	inviteToken := flow.Param(r.Context(), "id")
	invite, err := h.store.GetInvite(inviteToken)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	if invite.Creator.Id != user.Id {
		http.Error(w, "not owner of invite", http.StatusForbidden)
		return
	}
	logs, err := h.store.InviteLog(invite)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	if len(logs) == 0 {
		w.WriteHeader(http.StatusNotFound)
		w.Write([]byte("[]"))
		return
	}

	json.NewEncoder(w).Encode(logs)
}

func (h *Handler) DeleteInvite(w http.ResponseWriter, r *http.Request) {
	user := r.Context().Value("user").(store.User)
	inviteToken := flow.Param(r.Context(), "id")
	invite, err := h.store.GetInvite(inviteToken)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	if invite.Creator.Id != user.Id {
		http.Error(w, "not owner of invite", http.StatusForbidden)
		return
	}

	err = h.store.DeleteInvite(invite)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.Write([]byte("deleted"))

}