// Copyright (C) 2022 Marius Schellenberger

package server

import (
	"net/http"
	"time"

	"git.giftfish.de/ston1th/goacc/pkg/otp"
	"git.giftfish.de/ston1th/jwt/v3"
)

type notFoundHandler struct {
	s *Server
}

func (nf *notFoundHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	newContext(w, r, nf.s).NotFound()
}

func jwtHandler(h ctxHandler) ctxHandler {
	return func(ctx *Context) {
		if c, err := ctx.Request.Cookie(cookieName); err == nil {
			t, err := jwt.DecodeToken(c.Value)
			if err != nil {
				ctx.LogSetCookie(err, "decode failed")
				ctx.Redirect(root, http.StatusFound)
				return
			}
			if err = ctx.Srv.JWT.Verify(t); err != nil {
				ctx.LogSetCookie(err, "verify failed")
				ctx.Redirect(root, http.StatusFound)
				return
			}
			if t.Claims.GetString(totpClaim) != "" {
				path := ctx.Path()
				switch path {
				case totp, login, logout:
					ctx.Token = *t
					h(ctx)
				default:
					ctx.Redirect(totp, http.StatusFound)
				}
				return

			}
			if !ctx.Srv.DB.LockedOut(t.Claims.GetString(userClaim), t.Claims.GetString(createdClaim)) {
				ctx.Token = *t
				h(ctx)
				return
			}
			if err = ctx.Srv.JWT.Invalidate(t); err != nil {
				ctx.log.Error(err, "invalidation failed")
			}
		}
		ctx.SetCookie(nil, 0)
		h(ctx)
	}
}

func totpAuthHandler(h ctxHandler) ctxHandler {
	return func(ctx *Context) {
		if ctx.Totp() != "" {
			h(ctx)
			return
		}
		ctx.Redirect(root, http.StatusFound)
	}
}

func adminAuthHandler(h ctxHandler) ctxHandler {
	return func(ctx *Context) {
		if ctx.Admin() {
			h(ctx)
			return
		}
		ctx.Forbidden()
	}
}

func userAuthHandler(h ctxHandler) ctxHandler {
	return func(ctx *Context) {
		if ctx.Admin() {
			h(ctx)
			return
		}
		if ctx.User() == ctx.Var("user") {
			h(ctx)
			return
		}
		ctx.Forbidden()
	}
}

func authHandler(h ctxHandler) ctxHandler {
	return func(ctx *Context) {
		if ctx.LoggedOn() {
			h(ctx)
			return
		}
		ctx.Forbidden()
	}
}

func indexHandler(ctx *Context) {
	ctx.Redirect(login, http.StatusFound)
}

func sessionsHandler(ctx *Context) {
	ctx.Redirect(uroot+"sessions/"+ctx.User(), http.StatusFound)
}

func loginHandler(ctx *Context) {
	log := ctx.log.WithName("login")
	var data loginData
	data.LoginChallenge = ctx.Query("login_challenge")
	ctx.Template("loginHandler")
	ctx.Data = webData{
		Title:     "Login",
		BodyTitle: "Login",
	}
	if ctx.LoggedOn() {
		rdr := sessions
		if data.LoginChallenge != "" {
			u, err := ctx.Srv.DB.GetUserWithoutSecrets(ctx.User())
			if err != nil {
				ctx.Error(err)
				return
			}
			rdr, err = ctx.ApproveLogin(u, data.LoginChallenge)
			if err != nil {
				ctx.Error(err)
				return
			}
		}
		ctx.Redirect(rdr, http.StatusFound)
		return
	}
	switch ctx.Method() {
	case "GET":
		ctx.Data.Data = data
		ctx.Exec()
	case "POST":
		data.LoginChallenge = ctx.Form("login_challenge")
		data.User = ctx.Form("user")
		ctx.Data.Data = data
		if !ctx.CheckXsrf() {
			return
		}
		password := ctx.Form("password")
		if data.User == "" || password == "" {
			ctx.Error("empty username or password")
			return
		}
		u, err := ctx.Srv.DB.Login(data.User, password)
		if err != nil {
			log.Error(err, "login failed", "user", data.User)
			ctx.Error("bad username or password")
			return
		}

		remember := ctx.Form("remember")
		if u.Secret != "" {
			ctx.SetCookie(jwt.Claims{
				totpClaim:     data.User,
				rememberClaim: remember,
			}, time.Minute)
			rdr := totp
			if data.LoginChallenge != "" {
				rdr += "?login_challenge=" + data.LoginChallenge
			}
			ctx.Redirect(rdr, http.StatusFound)
			return
		}
		log.Info("user logged in", "user", data.User)
		ctx.Login(u, remember)
		rdr := sessions
		if data.LoginChallenge != "" {
			rdr, err = ctx.ApproveLogin(u, data.LoginChallenge)
			if err != nil {
				ctx.Error(err)
				return
			}
		}
		ctx.Redirect(rdr, http.StatusFound)
		return
	}
}

func loginTotpHandler(ctx *Context) {
	if ctx.LoggedOn() {
		ctx.Redirect(sessions, http.StatusFound)
		return
	}
	ctx.Template("loginTotpHandler")
	ctx.Data = webData{
		Title:     "TOTP Verification",
		BodyTitle: "TOTP Veriftcation",
	}
	var data loginData
	switch ctx.Method() {
	case "GET":
		data.LoginChallenge = ctx.Query("login_challenge")
		ctx.Data.Data = data
		ctx.Exec()
	case "POST":
		data.LoginChallenge = ctx.Form("login_challenge")
		ctx.Data.Data = data
		if !ctx.CheckXsrf() {
			return
		}
		pin := ctx.Form("pin")
		if pin == "" {
			ctx.Error("empty pin")
			return
		}
		user := ctx.Totp()
		log := ctx.log.WithValues("user", user)
		u, err := ctx.Srv.DB.Totp(user, pin)
		if err != nil {
			log.Error(err, "totp failed")
			ctx.Error(err)
			return
		}
		log.Info("totp successful")
		ctx.Login(u, ctx.Remember())
		rdr := sessions
		if data.LoginChallenge != "" {
			rdr, err = ctx.ApproveLogin(u, data.LoginChallenge)
			if err != nil {
				ctx.Error(err)
				ctx.log.Error(err, "error approving login")
				ctx.Error("error approving login")
				return
			}
		}
		ctx.Redirect(rdr, http.StatusFound)
	}
}

func consentHandler(ctx *Context) {
	ctx.Template("consentHandler")
	ctx.Data = webData{
		Title:     "Authorize",
		BodyTitle: "Authorize",
	}
	var data consentData
	u, err := ctx.Srv.DB.GetUserWithoutSecrets(ctx.User())
	if err != nil {
		ctx.Error(err)
		return
	}
	switch ctx.Method() {
	case "GET":
		data.ConsentChallenge = ctx.Query("consent_challenge")
		ctx.Data.Data = data
		cr, err := ctx.Consent(data.ConsentChallenge)
		if err != nil {
			ctx.log.Error(err, "error getting consent info")
			ctx.Error("error getting consent info")
			return
		}
		if cr.GetSkip() {
			rdr, err := ctx.ApproveConsent(u, data.ConsentChallenge)
			if err != nil {
				ctx.log.Error(err, "error approving consent")
				ctx.Error("error approving consent")
				return
			}
			ctx.Redirect(rdr, http.StatusFound)
		}
		data.Info = cr
		ctx.Data.Data = data
		ctx.Exec()
	case "POST":
		data.ConsentChallenge = ctx.Form("consent_challenge")
		ctx.Data.Data = data
		if !ctx.CheckXsrf() {
			return
		}
		consent := ctx.Form("consent")

		var err error
		rdr := root
		if consent == "approve" {
			rdr, err = ctx.ApproveConsent(u, data.ConsentChallenge)
			if err != nil {
				ctx.log.Error(err, "error approving consent")
				ctx.Error("error approving consent")
				return
			}
		} else {
			rdr, err = ctx.RejectConsent(data.ConsentChallenge)
			if err != nil {
				ctx.log.Error(err, "error rejecting consent")
				ctx.Error("error rejecting consent")
				return
			}
		}
		ctx.Redirect(rdr, http.StatusFound)
	}
}

func usersHandler(ctx *Context) {
	if !ctx.LoggedOn() {
		ctx.NotFound()
		return
	}
	ctx.Template("usersHandler")
	ctx.Data = webData{
		Title:     "Users",
		BodyTitle: "Users",
		User:      ctx.User(),
	}
	us, err := ctx.Srv.DB.GetUsers()
	if err != nil {
		ctx.Data.Msg = err.Error()
	}
	ctx.Data.Data = us
	ctx.Exec()
}

func userNewHandler(ctx *Context) {
	ctx.Template("userNewHandler")
	ctx.Data = webData{
		Title:     "New User",
		BodyTitle: "New User",
	}
	switch ctx.Method() {
	case "GET":
		ctx.Exec()
	case "POST":
		if !ctx.CheckXsrf() {
			return
		}
		user := ctx.Form("user")
		email := ctx.Form("email")
		password := ctx.Form("password")
		repeat := ctx.Form("repeat")
		admin := ctx.Form("admin") == "0"
		disabled := ctx.Form("disabled") == "0"

		if user == "" || email == "" || password == "" {
			ctx.Error("empty user, email or password")
			return
		}
		if password != repeat {
			ctx.Error("passwords do not match")
			return
		}
		if err := ctx.Srv.DB.CreateUser(user, email, password, admin, disabled); err != nil {
			ctx.Error(err)
			return
		}
		ctx.log.Info("user created", "user", user, "actor", ctx.User(), "admin", admin, "disabled", disabled)
		ctx.Redirect(users, http.StatusFound)
	}
}

func userEditHandler(ctx *Context) {
	ctx.Template("userEditHandler")
	ctx.Data = webData{
		Title:     "Edit User",
		BodyTitle: "Edit User",
	}
	u, err := ctx.Srv.DB.GetUserWithoutSecrets(ctx.Var("user"))
	if err != nil {
		ctx.Error(err)
		return
	}
	ctx.Data.Data = u
	switch ctx.Method() {
	case "GET":
		ctx.Exec()
	case "POST":
		if !ctx.CheckXsrf() {
			return
		}
		user := ctx.Var("user")
		self := ctx.User()
		log := ctx.log.WithValues("user", user, "actor", self)
		password := ctx.Form("password")
		repeat := ctx.Form("repeat")
		admin := ctx.Form("admin") == "0"
		disabled := ctx.Form("disabled") == "0"

		if password != repeat {
			ctx.Error("passwords do not match")
			return
		}
		if ctx.Admin() {
			if err := ctx.Srv.DB.AdminUpdateUser(user, password, admin, disabled); err != nil {
				ctx.Error(err)
				return
			}
			log.Info("user updated", "admin", admin, "disabled", disabled)
			if user == self {
				logoutHandler(ctx)
				return
			}
			ctx.Redirect(users, http.StatusFound)
			return
		}
		if err := ctx.Srv.DB.UpdateUserPassword(user, password); err != nil {
			ctx.Error(err)
			return
		}
		log.Info("user updated")
		ctx.Redirect(root, http.StatusFound)
	}
}

func userTotpHandler(ctx *Context) {
	ctx.Template("userTotpHandler")
	ctx.Data = webData{
		Title:     "TOTP",
		BodyTitle: "TOTP",
	}
	req := otp.Request{Username: ctx.Var("user")}
	u, err := ctx.Srv.DB.GetUser(req.Username)
	if err != nil {
		ctx.Error(err)
		return
	}
	if u.Secret == "" {
		switch ctx.Method() {
		case "GET":
			req, err = otp.New(req.Username, ctx.Srv.Config.Issuer)
			if err != nil {
				ctx.Error(err)
				return
			}
		case "POST":
			req.URL = ctx.Form("url")
			req.Image, req.Secret, err = otp.ImageSecretFromURL(req.URL)
			if err != nil {
				ctx.Error(err)
				return
			}
		}
	}
	switch ctx.Method() {
	case "GET":
		ctx.Data.Data = req
		ctx.Exec()
	case "POST":
		if !ctx.CheckXsrf() {
			return
		}
		pin := ctx.Form("pin")
		if pin == "" {
			ctx.Error("empty pin")
			return
		}
		ctx.Data.Data = req
		secret := req.Secret
		if u.Secret != "" {
			secret = u.Secret
		}
		valid := otp.Validate(pin, secret)
		user := ctx.User()
		if user != req.Username && ctx.Admin() {
			valid = true
		}

		if !valid {
			ctx.Error("validation failed")
			return
		}
		if err := ctx.Srv.DB.UpdateUserSecret(req.Username, req.Secret); err != nil {
			ctx.Error(err)
			return
		}
		ctx.log.Info("totp changed", "user", user, "enabled", req.Secret != "")
		ctx.Redirect(uroot+"edit/"+req.Username, http.StatusFound)
	}
}

func userSessionsHandler(ctx *Context) {
	ctx.Template("userSessionsHandler")
	ctx.Data = webData{
		Title:     "Sessions",
		BodyTitle: "Sessions",
	}
	user := ctx.Var("user")
	log := ctx.log.WithValues("user", user)
	switch ctx.Method() {
	case "GET":
		s, err := ctx.Sessions(user)
		if err != nil {
			log.Error(err, "error getting sessions")
			ctx.Error("error getting sessions")
			return
		}
		ctx.Data.Data = s
		ctx.Exec()
	case "POST":
		if !ctx.CheckXsrf() {
			return
		}
		client := ctx.Form("client")
		all := ctx.Form("all") == "all"
		err := ctx.RevokeSession(user, client, all)
		if err != nil {
			log.Error(err, "error revoking session", "client", client, "all", all)
			ctx.Error("error revoking session")
			return
		}
		sessionsHandler(ctx)
	}
}

func userUnlockHandler(ctx *Context) {
	user := ctx.Var("user")
	log := ctx.log.WithValues("user", user, "actor", ctx.User())
	err := ctx.Srv.DB.UnlockUser(user)
	if err != nil {
		log.Error(err, "user unlock failed")
	} else {
		log.Info("user unlocked")
	}
	ctx.Redirect(users, http.StatusFound)
}

func userDelHandler(ctx *Context) {
	ctx.Template("userDelHandler")
	ctx.Data = webData{
		Title:     "Delete User",
		BodyTitle: "Delete User",
	}
	switch ctx.Method() {
	case "GET":
		user, err := ctx.Srv.DB.GetUserWithoutSecrets(ctx.Var("user"))
		if err != nil {
			ctx.Error(err)
			return
		}
		ctx.Data.Data = user
		ctx.Exec()
	case "POST":
		if !ctx.CheckXsrf() {
			return
		}
		self := ctx.User()
		user := ctx.Var("user")
		err := ctx.Srv.DB.DeleteUser(user)
		log := ctx.log.WithValues("user", user, "actor", self)
		if err != nil {
			log.Error(err, "delete failed")
		} else {
			log.Info("delete successful")
		}
		if user == self {
			logoutHandler(ctx)
			return
		}
		ctx.Redirect(users, http.StatusFound)
	}
}

func logoutHandler(ctx *Context) {
	totp := false
	user := ctx.User()
	if user == "" {
		user = ctx.Totp()
		if user != "" {
			totp = true
		}
	}
	if user != "" {
		ctx.Srv.JWT.Invalidate(&ctx.Token)
	} else {
		user = empty
	}
	ctx.log.Info("logout", "user", user, "totp", totp)
	ctx.SetCookie(nil, 0)
	ctx.Redirect(root, http.StatusFound)
}

func authBasicHandler(ctx *Context) {
	if ctx.Method() != "GET" {
		ctx.PlainUnauthorized()
		return
	}
	username, password, ok := ctx.Request.BasicAuth()
	if !ok {
		ctx.PlainUnauthorized()
		return
	}
	if ctx.Srv.BasicAuth.Auth(username, password) {
		ctx.PlainOK()
		return
	}
	ctx.PlainForbidden()
}