package handlers

import (
	"context"
	"net/http"

	"git.haelnorr.com/h/golib/cookies"
	"git.haelnorr.com/h/golib/hws"
	"git.haelnorr.com/h/golib/hwsauth"
	"github.com/pkg/errors"
	"github.com/uptrace/bun"

	"git.haelnorr.com/h/oslstats/internal/config"
	"git.haelnorr.com/h/oslstats/internal/db"
	"git.haelnorr.com/h/oslstats/internal/store"
	"git.haelnorr.com/h/oslstats/internal/throw"
	authview "git.haelnorr.com/h/oslstats/internal/view/authview"
)

func Register(
	s *hws.Server,
	auth *hwsauth.Authenticator[*db.User, bun.Tx],
	conn *db.DB,
	cfg *config.Config,
	store *store.Store,
) http.Handler {
	return http.HandlerFunc(
		func(w http.ResponseWriter, r *http.Request) {
			attempts, exceeded, track := store.TrackRedirect(r, "/register", 3)

			if exceeded {
				err := track.Error(attempts)
				store.ClearRedirectTrack(r, "/register")
				throw.BadRequest(s, w, r, "Cookies appear to be blocked or disabled. Please enable cookies in your browser and try again", err)
				return
			}

			sessionCookie, err := r.Cookie("registration_session")
			if err != nil {
				http.Redirect(w, r, "/login", http.StatusSeeOther)
				return
			}
			details, ok := store.GetRegistrationSession(sessionCookie.Value)
			if !ok {
				http.Redirect(w, r, "/login", http.StatusSeeOther)
				return
			}

			store.ClearRedirectTrack(r, "/register")

			if r.Method == "GET" {
				renderSafely(authview.RegisterPage(details.DiscordUser.Username), s, r, w)
				return
			}
			username := r.FormValue("username")
			unique := false
			var user *db.User
			if ok := conn.WithNotifyTx(s, w, r, func(ctx context.Context, tx bun.Tx) (bool, error) {
				unique, err = db.IsUnique(ctx, tx, (*db.User)(nil), "username", username)
				if err != nil {
					return false, errors.Wrap(err, "db.IsUsernameUnique")
				}
				if !unique {
					return true, nil
				}
				user, err = db.CreateUser(ctx, tx, username, details.DiscordUser, db.NewAudit(r, nil))
				if err != nil {
					return false, errors.Wrap(err, "db.CreateUser")
				}
				err = user.UpdateDiscordToken(ctx, tx, details.Token)
				if err != nil {
					return false, errors.Wrap(err, "db.UpdateDiscordToken")
				}
				if shouldGrantAdmin(user, cfg.RBAC) {
					err := ensureUserHasAdminRole(ctx, tx, user)
					if err != nil {
						return false, errors.Wrap(err, "ensureUserHasAdminRole")
					}
				}
				return true, nil
			}); !ok {
				return
			}
			if !unique {
				w.WriteHeader(http.StatusConflict)
			} else {
				err = auth.Login(w, r, user, true)
				if err != nil {
					throw.InternalServiceError(s, w, r, "Login failed", err)
					return
				}
				pageFrom := cookies.CheckPageFrom(w, r)
				w.Header().Set("HX-Redirect", pageFrom)
			}
		},
	)
}