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/discord"
	"git.haelnorr.com/h/oslstats/internal/rbac"
	"git.haelnorr.com/h/oslstats/internal/respond"
	"git.haelnorr.com/h/oslstats/internal/store"
	"git.haelnorr.com/h/oslstats/internal/throw"
	authview "git.haelnorr.com/h/oslstats/internal/view/authview"
	"git.haelnorr.com/h/oslstats/pkg/slapshotapi"
)

func Register(
	s *hws.Server,
	auth *hwsauth.Authenticator[*db.User, bun.Tx],
	conn *db.DB,
	slapAPI *slapshotapi.SlapAPI,
	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(""), s, r, w)
				return
			}
			username := r.FormValue("username")
			unique := false
			var user *db.User
			audit := db.NewAudit(r.RemoteAddr, r.UserAgent(), user)
			if ok := conn.WithWriteTx(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 = registerUser(ctx, tx, username, details, cfg.RBAC, audit)
				if err != nil {
					return false, errors.Wrap(err, "registerUser")
				}
				err = ConnectSlapID(ctx, tx, user, details.Token, slapAPI, audit)
				if err != nil {
					return false, errors.Wrap(err, "connectSlapID")
				}
				return true, nil
			}); !ok {
				throw.InternalServiceError(s, w, r, "Registration failed", err)
				return
			}
			if !unique {
				respond.Conflict(w, errors.New("username is taken"))
			} 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)
				respond.HXRedirect(w, "%s", pageFrom)
			}
		},
	)
}

func registerUser(ctx context.Context, tx bun.Tx,
	username string, details *store.RegistrationSession,
	rbac *rbac.Config, audit *db.AuditMeta,
) (*db.User, error) {
	// Register the user
	user, err := db.CreateUser(ctx, tx, username, details.DiscordUser, audit)
	if err != nil {
		return nil, errors.Wrap(err, "db.CreateUser")
	}
	err = user.UpdateDiscordToken(ctx, tx, details.Token)
	if err != nil {
		return nil, errors.Wrap(err, "db.UpdateDiscordToken")
	}
	err = user.ConnectPlayer(ctx, tx, audit)
	if err != nil {
		return nil, errors.Wrap(err, "db.ConnectPlayer")
	}
	// Check if they should be an admin
	if shouldGrantAdmin(user, rbac) {
		err := ensureUserHasAdminRole(ctx, tx, user)
		if err != nil {
			return nil, errors.Wrap(err, "ensureUserHasAdminRole")
		}
	}
	return user, nil
}

// ConnectSlapID attempts to link a player's Slapshot ID via their Discord Steam connection.
// If fails due to no steam connection or no slapID, fails silently and returns nil.
func ConnectSlapID(ctx context.Context, tx bun.Tx, user *db.User,
	token *discord.Token, slapAPI *slapshotapi.SlapAPI, audit *db.AuditMeta,
) error {
	session, err := discord.NewOAuthSession(token)
	if err != nil {
		return errors.Wrap(err, "discord.NewOAuthSession")
	}
	steamID, err := session.GetSteamID()
	if err != nil {
		if err == discord.ErrNoSteam {
			return nil
		}
		return errors.Wrap(err, "session.GetSteamID")
	}
	slapID, err := slapAPI.GetSlapID(ctx, steamID)
	if err != nil {
		if err == slapshotapi.ErrNoSlapID {
			return nil
		}
		return errors.Wrap(err, "slapAPI.GetSlapID")
	}
	// slapID exists, we can update their player connection
	err = db.UpdatePlayerSlapID(ctx, tx, user.Player.ID, slapID, audit)
	if err != nil {
		return errors.Wrap(err, "db.UpdatePlayerSlapID")
	}

	return nil
}