/*
 * SPDX-FileCopyrightText: 2023 jordi fita mas <jfita@peritasoft.com>
 * SPDX-License-Identifier: AGPL-3.0-only
 */

package app

import (
	"errors"
	"net/http"
	"net/mail"
	"path"
	"strings"
	"time"

	"golang.org/x/text/language"

	"dev.tandem.ws/tandem/camper/pkg/database"
	httplib "dev.tandem.ws/tandem/camper/pkg/http"
	"dev.tandem.ws/tandem/camper/pkg/locale"
	"dev.tandem.ws/tandem/camper/pkg/template"
)

const (
	sessionCookie = "camper-session"
)

func shiftPath(p string) (head, tail string) {
	p = path.Clean("/" + p)
	if i := strings.IndexByte(p[1:], '/') + 1; i <= 0 {
		return p[1:], "/"
	} else {
		return p[1:i], p[i:]
	}
}

func methodNotAllowed(w http.ResponseWriter, _ *http.Request, allowed ...string) {
	w.Header().Set("Allow", strings.Join(allowed, ", "))
	http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
}

type App struct {
	db              *database.DB
	fileHandler     http.Handler
	locales         locale.Locales
	defaultLocale   *locale.Locale
	languageMatcher language.Matcher
}

func New(db *database.DB) http.Handler {
	locales := locale.MustGetAll(db)
	app := &App{
		db:              db,
		fileHandler:     http.FileServer(http.Dir("web/static")),
		locales:         locales,
		defaultLocale:   locales[language.Catalan],
		languageMatcher: language.NewMatcher(locales.Tags()),
	}

	var handler http.Handler = app
	handler = httplib.RecoverPanic(handler)
	handler = httplib.LogRequest(handler)
	return handler
}

func (h *App) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	var head string
	head, r.URL.Path = shiftPath(r.URL.Path)
	switch head {
	case "static":
		h.fileHandler.ServeHTTP(w, r)
	case "login":
		switch r.Method {
		case http.MethodPost:
			h.handleLogin(w, r)
		default:
			methodNotAllowed(w, r, http.MethodPost)
		}
	case "":
		switch r.Method {
		case http.MethodGet:
			h.handleGet(w, r)
		default:
			methodNotAllowed(w, r, http.MethodGet)
		}
	default:
		http.NotFound(w, r)
	}
}

func (h *App) handleGet(w http.ResponseWriter, r *http.Request) {
	l := h.matchLocale(r)
	template.MustRender(w, l, "login.gohtml", nil)
}

func (h *App) matchLocale(r *http.Request) *locale.Locale {
	return locale.Match(r, h.locales, h.defaultLocale, h.languageMatcher)
}

func (h *App) handleLogin(w http.ResponseWriter, r *http.Request) {
	if err := r.ParseForm(); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	var errs []error
	l := h.matchLocale(r)
	email := strings.TrimSpace(r.FormValue("email"))
	if email == "" {
		errs = append(errs, errors.New(l.Get("Email can not be empty.")))
	} else if _, err := mail.ParseAddress(email); err != nil {
		errs = append(errs, errors.New(l.Get("This email is not valid. It should be like name@domain.com.")))
	}
	password := strings.TrimSpace(r.FormValue("password"))
	if password == "" {
		errs = append(errs, errors.New(l.Get("Password can not be empty.")))
	}
	if errs == nil {
		conn := h.db.MustAcquire(r.Context())
		cookie := conn.MustGetText(r.Context(), "select login($1, $2, $3)", email, password, httplib.RemoteAddr(r))
		if cookie != "" {
			setSessionCookie(w, cookie)
			http.Redirect(w, r, "/", http.StatusSeeOther)
			return
		}
		errs = append(errs, errors.New(l.Get("Invalid user or password.")))
		w.WriteHeader(http.StatusUnauthorized)
	} else {
		w.WriteHeader(http.StatusUnprocessableEntity)
	}
	template.MustRender(w, l, "login.gohtml", errs)
}

func setSessionCookie(w http.ResponseWriter, cookie string) {
	http.SetCookie(w, createSessionCookie(cookie, 8766*24*time.Hour))
}

func createSessionCookie(value string, duration time.Duration) *http.Cookie {
	return &http.Cookie{
		Name:     sessionCookie,
		Value:    value,
		Path:     "/",
		Expires:  time.Now().Add(duration),
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
	}
}