package web

import (
	"encoding/base64"
	"errors"
	"net/http"
	"strings"
	"time"

	"gardomatic.kleiax.de/lib/client"
)

type signInForm struct {
	CSRFToken     string `form:"csrf_token"`
	Email         string `form:"email"`
	Password      string `form:"password"`
	RememberEmail bool   `form:"remember_email"`
	ReturnTo      string `form:"return_to"`
	Errors        map[string]string
	Message       string
}

type activationForm struct {
	CSRFToken       string `form:"csrf_token"`
	Token           string `form:"token"`
	Password        string `form:"password"`
	PasswordConfirm string `form:"password_confirm"`
	SetPassword     bool   `form:"set_password"`
	Errors          map[string]string
	Message         string
}

func (app *application) signIn(w http.ResponseWriter, r *http.Request) {
	returnTo := safeReturnPath(r.URL.Query().Get("return_to"))
	if app.isAuthenticated(r) {
		if returnTo != "" {
			http.Redirect(w, r, returnTo, http.StatusSeeOther)
			return
		}
		http.Redirect(w, r, app.authenticatedLandingPage(r), http.StatusSeeOther)
		return
	}
	data := app.newTemplateData(r)
	form := signInForm{ReturnTo: returnTo, Errors: make(map[string]string)}
	if cookie, err := r.Cookie("gardomatic_remembered_email"); err == nil {
		if decoded, decodeErr := base64.RawURLEncoding.DecodeString(cookie.Value); decodeErr == nil {
			form.Email, form.RememberEmail = string(decoded), true
		}
	}
	data.Form = form
	app.render(w, http.StatusOK, "signin.tmpl", data)
}

func (app *application) signInPost(w http.ResponseWriter, r *http.Request) {
	var form signInForm
	if err := app.decodePostForm(r, &form); err != nil {
		app.clientError(w, http.StatusBadRequest)
		return
	}
	form.Email = strings.TrimSpace(form.Email)
	form.ReturnTo = safeReturnPath(form.ReturnTo)
	form.Errors = make(map[string]string)
	if form.Email == "" {
		form.Errors["email"] = "E-Mail-Adresse ist erforderlich."
	}
	if form.Password == "" {
		form.Errors["password"] = "Passwort ist erforderlich."
	}
	if len(form.Errors) != 0 {
		data := app.newTemplateData(r)
		data.Form = form
		app.render(w, http.StatusUnprocessableEntity, "signin.tmpl", data)
		return
	}

	apiClient := client.FromContext(r.Context())
	user, response, err := apiClient.CreateSession(r.Context(), client.Credentials{Email: form.Email, Password: form.Password})
	if err != nil {
		var apiError *client.APIError
		if errors.As(err, &apiError) && (apiError.StatusCode == http.StatusUnauthorized || apiError.StatusCode == http.StatusUnprocessableEntity) {
			form.Message = "E-Mail-Adresse oder Passwort ist ungültig."
			data := app.newTemplateData(r)
			data.Form = form
			app.render(w, http.StatusUnprocessableEntity, "signin.tmpl", data)
			return
		}
		app.serverError(w, err)
		return
	}
	client.ForwardCookies(w, response)
	remembered := &http.Cookie{Name: "gardomatic_remembered_email", Path: webPath("login"), HttpOnly: true, Secure: app.config.CookieSecure, SameSite: http.SameSiteLaxMode}
	if form.RememberEmail {
		remembered.Value = base64.RawURLEncoding.EncodeToString([]byte(form.Email))
		remembered.Expires = time.Now().Add(365 * 24 * time.Hour)
		remembered.MaxAge = 365 * 24 * 60 * 60
	} else if _, err := r.Cookie("gardomatic_remembered_email"); err == nil {
		remembered.Expires = time.Unix(1, 0)
		remembered.MaxAge = -1
	} else {
		remembered = nil
	}
	if remembered != nil {
		http.SetCookie(w, remembered)
	}
	if !user.Activated {
		http.Redirect(w, r, webPath("activate"), http.StatusSeeOther)
		return
	}
	if form.ReturnTo != "" {
		http.Redirect(w, r, form.ReturnTo, http.StatusSeeOther)
		return
	}
	http.Redirect(w, r, pathWithQuery(webPath("gardens"), "auto", 1), http.StatusSeeOther)
}

func (app *application) activateUser(w http.ResponseWriter, r *http.Request) {
	if user, ok := userFromContext(r.Context()); ok && user.Activated {
		http.Redirect(w, r, webPath("gardens"), http.StatusSeeOther)
		return
	}

	data := app.newTemplateData(r)
	data.Form = activationForm{
		Token:       strings.TrimSpace(r.URL.Query().Get("token")),
		SetPassword: r.URL.Query().Get("set-password") == "1",
		Errors:      make(map[string]string),
	}
	app.render(w, http.StatusOK, "activate.tmpl", data)
}

func (app *application) activateUserPost(w http.ResponseWriter, r *http.Request) {
	var form activationForm
	if err := app.decodePostForm(r, &form); err != nil {
		app.clientError(w, http.StatusBadRequest)
		return
	}

	form.Token = strings.TrimSpace(form.Token)
	form.Errors = make(map[string]string)
	if form.Token == "" {
		form.Errors["token"] = "Aktivierungstoken ist erforderlich."
	}
	if form.SetPassword {
		if len(form.Password) < 8 {
			form.Errors["password"] = "Das Passwort muss mindestens 8 Zeichen lang sein."
		} else if len(form.Password) > 72 {
			form.Errors["password"] = "Das Passwort darf höchstens 72 Zeichen lang sein."
		}
		if form.Password != form.PasswordConfirm {
			form.Errors["password_confirm"] = "Die Passwörter stimmen nicht überein."
		}
	}

	if len(form.Errors) == 0 {
		apiClient := client.FromContext(r.Context())
		var err error
		if form.SetPassword {
			_, _, err = apiClient.ActivateInvitedUser(r.Context(), form.Token, form.Password)
		} else {
			_, _, err = apiClient.ActivateUser(r.Context(), form.Token)
		}
		if err == nil {
			http.Redirect(w, r, webPath("gardens"), http.StatusSeeOther)
			return
		}

		var apiError *client.APIError
		if errors.As(err, &apiError) && apiError.StatusCode == http.StatusUnprocessableEntity {
			if _, ok := apiError.Validation["token"]; ok {
				form.Errors["token"] = "Aktivierungstoken ist ungültig oder abgelaufen."
			} else {
				form.Errors = apiError.Validation
				form.Message = "Der Account konnte nicht aktiviert werden."
			}
		} else {
			app.handleAPIError(w, r, err)
			return
		}
	}

	data := app.newTemplateData(r)
	data.Form = form
	app.render(w, http.StatusUnprocessableEntity, "activate.tmpl", data)
}

func (app *application) authenticatedLandingPage(r *http.Request) string {
	if user, ok := userFromContext(r.Context()); ok && !user.Activated {
		return webPath("activate")
	}
	return webPath("gardens")
}

func (app *application) signOutPost(w http.ResponseWriter, r *http.Request) {
	apiClient := client.FromContext(r.Context())
	response, err := apiClient.DeleteSession(r.Context())
	if err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	client.ForwardCookies(w, response)
	http.Redirect(w, r, webPath("home"), http.StatusSeeOther)
}