package handlers

import (
	stderrors "errors"
	"net/http"

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

	"git.haelnorr.com/h/oslstats/internal/config"
	"git.haelnorr.com/h/oslstats/internal/db"
	"git.haelnorr.com/h/oslstats/internal/discord"
	"git.haelnorr.com/h/oslstats/internal/notify"
	"git.haelnorr.com/h/oslstats/internal/respond"
	"git.haelnorr.com/h/oslstats/internal/store"
	"git.haelnorr.com/h/oslstats/internal/throw"
	"git.haelnorr.com/h/oslstats/pkg/oauth"
)

func Login(
	s *hws.Server,
	conn *db.DB,
	cfg *config.Config,
	st *store.Store,
	discordAPI *discord.APIClient,
) http.Handler {
	return http.HandlerFunc(
		func(w http.ResponseWriter, r *http.Request) {
			errDB := conn.Ping()
			_, errDisc := discordAPI.Ping()
			err := stderrors.Join(errors.Wrap(errDB, "conn.Ping"), errors.Wrap(errDisc, "discordAPI.Ping"))
			err = errors.Wrap(err, "login error")

			if r.Method == "POST" {
				if err != nil {
					notify.ServiceUnavailable(s, w, r, "Login currently unavailable", err)
					respond.OK(w)
					return
				}
				respond.HXRedirect(w, "/login")
				return
			}

			if err != nil {
				throw.ServiceUnavailable(s, w, r, "Login currently unavailable", err)
				return
			}
			cookies.SetPageFrom(w, r, cfg.HWSAuth.TrustedHost)
			attempts, exceeded, track := st.TrackRedirect(r, "/login", 5)

			if exceeded {
				err = track.Error(attempts)
				st.ClearRedirectTrack(r, "/login")
				throw.BadRequest(s, w, r, "Too many redirects. Please clear your browser cookies and try again", err)
				return
			}

			state, uak, err := oauth.GenerateState(cfg.OAuth, "login")
			if err != nil {
				throw.InternalServiceError(s, w, r, "Failed to generate state token", err)
				return
			}
			oauth.SetStateCookie(w, uak, cfg.HWSAuth.SSL)

			link, err := discordAPI.GetOAuthLink(state)
			if err != nil {
				throw.InternalServiceError(s, w, r, "An error occurred trying to generate the login link", err)
				return
			}
			st.ClearRedirectTrack(r, "/login")

			http.Redirect(w, r, link, http.StatusSeeOther)
		},
	)
}