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

package booking

import (
	"context"
	"dev.tandem.ws/tandem/camper/pkg/ods"
	"errors"
	"fmt"
	"net/http"
	"strconv"
	"strings"
	"time"

	"golang.org/x/text/language"

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

type AdminHandler struct {
}

func NewAdminHandler() *AdminHandler {
	return &AdminHandler{}
}

func (h *AdminHandler) Handler(user *auth.User, company *auth.Company, conn *database.Conn) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		var head string
		head, r.URL.Path = httplib.ShiftPath(r.URL.Path)

		switch head {
		case "":
			switch r.Method {
			case http.MethodGet:
				serveBookingIndex(w, r, user, company, conn)
			case http.MethodPost:
				addBooking(w, r, user, company, conn)
			default:
				httplib.MethodNotAllowed(w, r, http.MethodGet, http.MethodPost)
			}
		case "new":
			switch r.Method {
			case http.MethodGet:
				serveAdminBookingForm(w, r, user, company, conn, 0, "/admin/bookings/new")
			default:
				httplib.MethodNotAllowed(w, r, http.MethodGet)
			}
		default:
			if !uuid.Valid(head) {
				http.NotFound(w, r)
				return
			}
			h.bookingHandler(user, company, conn, head).ServeHTTP(w, r)
		}
	})
}

func serveAdminBookingForm(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn, id int, url string) {
	f, err := newAdminBookingForm(r, conn, company, user.Locale)
	if err != nil {
		panic(err)
	}
	f.ID = id
	f.URL = url
	f.MustRender(w, r, user, company)
}

func (h *AdminHandler) bookingHandler(user *auth.User, company *auth.Company, conn *database.Conn, slug string) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		var head string
		head, r.URL.Path = httplib.ShiftPath(r.URL.Path)

		switch head {
		case "":
			switch r.Method {
			case http.MethodGet:
				if err := r.ParseForm(); err != nil {
					panic(err)
				}
				if len(r.Form) > 0 {
					// Act as if it was a new form, because everything needed to render form fields is
					// already passed as in request query.
					id, err := conn.GetInt(r.Context(), "select booking_id from booking where slug = $1", slug)
					if err != nil {
						if database.ErrorIsNotFound(err) {
							http.NotFound(w, r)
							return
						}
						panic(err)
					}
					serveAdminBookingForm(w, r, user, company, conn, id, "/admin/bookings/"+slug)
					return
				}
				f := newEmptyAdminBookingForm(r.Context(), conn, company, user.Locale)
				if err := f.FillFromDatabase(r.Context(), conn, company, slug, user.Locale); err != nil {
					if database.ErrorIsNotFound(err) {
						http.NotFound(w, r)
						return
					}
					panic(err)
				}
				f.MustRender(w, r, user, company)
			case http.MethodPut:
				updateBooking(w, r, user, company, conn, slug)
			default:
				httplib.MethodNotAllowed(w, r, http.MethodGet, http.MethodPut)
			}
		case "check-in":
			switch r.Method {
			case http.MethodGet:
				serveCheckInForm(w, r, user, company, conn, slug)
			case http.MethodPost:
				checkInBooking(w, r, user, company, conn, slug)
			default:
				httplib.MethodNotAllowed(w, r, http.MethodGet, http.MethodPost)
			}
		case "guest":
			switch r.Method {
			case http.MethodGet:
				serveGuestForm(w, r, user, company, conn, slug)
			default:
				httplib.MethodNotAllowed(w, r, http.MethodGet)
			}
		default:
			http.NotFound(w, r)
		}
	})
}

func serveBookingIndex(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn) {
	filters := newFilterForm(r.Context(), conn, company, user.Locale)
	if err := filters.Parse(r); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	bookings, err := collectBookingEntries(r.Context(), conn, user.Locale.Language, filters)
	if err != nil {
		panic(err)
	}
	page := &bookingIndex{
		Bookings: filters.buildCursor(bookings),
		Filters:  filters,
	}
	page.MustRender(w, r, user, company)
}

func collectBookingEntries(ctx context.Context, conn *database.Conn, lang language.Tag, filters *filterForm) ([]*bookingEntry, error) {
	where, args := filters.BuildQuery([]interface{}{lang.String()})
	rows, err := conn.Query(ctx, fmt.Sprintf(`
		select booking_id
		     , left(slug::text, 10)
		     , '/admin/bookings/' || slug
		     , lower(stay)
		     , upper(stay)
		     , holder_name
		, booking.booking_status
		, coalesce(i18n.name, status.name)
		from booking
		    join booking_status as status using (booking_status)
			left join booking_status_i18n as i18n on status.booking_status = i18n.booking_status and i18n.lang_tag = $1
		where (%s)
		order by lower(stay) desc
		       , booking_id desc
		LIMIT %d
	`, where, filters.perPage+1), args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var entries []*bookingEntry
	for rows.Next() {
		entry := &bookingEntry{}
		if err = rows.Scan(&entry.ID, &entry.Reference, &entry.URL, &entry.ArrivalDate, &entry.DepartureDate, &entry.HolderName, &entry.Status, &entry.StatusLabel); err != nil {
			return nil, err
		}
		entries = append(entries, entry)
	}

	return entries, nil
}

type bookingEntry struct {
	ID            int
	Reference     string
	URL           string
	ArrivalDate   time.Time
	DepartureDate time.Time
	HolderName    string
	Status        string
	StatusLabel   string
}

type bookingIndex struct {
	Bookings []*bookingEntry
	Filters  *filterForm
}

func (page bookingIndex) MustRender(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company) {
	switch r.URL.Query().Get("format") {
	case "ods":
		columns := []string{
			"Reference",
			"Arrival Date",
			"Departure Date",
			"Holder Name",
			"Status",
		}
		table, err := ods.WriteTable(page.Bookings, columns, user.Locale, func(sb *strings.Builder, entry *bookingEntry) error {
			if err := ods.WriteCellString(sb, entry.Reference); err != nil {
				return err
			}
			ods.WriteCellDate(sb, entry.ArrivalDate)
			ods.WriteCellDate(sb, entry.DepartureDate)
			if err := ods.WriteCellString(sb, entry.HolderName); err != nil {
				return err
			}
			if err := ods.WriteCellString(sb, entry.StatusLabel); err != nil {
				return err
			}
			return nil
		})
		if err != nil {
			panic(err)
		}
		ods.MustWriteResponse(w, table, user.Locale.Pgettext("bookings.ods", "filename"))
	default:
		if httplib.IsHTMxRequest(r) && page.Filters.pagination {
			template.MustRenderAdminNoLayout(w, r, user, company, "booking/results.gohtml", page)
		} else {
			template.MustRenderAdminFiles(w, r, user, company, page, "booking/index.gohtml", "booking/results.gohtml")
		}
	}
}

type adminBookingForm struct {
	*bookingForm
	ID        int
	URL       string
	Status    string
	Campsites []*CampsiteEntry
	selected  []int
	Months    []*Month
	Error     error
}

func newEmptyAdminBookingForm(ctx context.Context, conn *database.Conn, company *auth.Company, l *locale.Locale) *adminBookingForm {
	return &adminBookingForm{
		bookingForm: newEmptyBookingForm(ctx, conn, company, l),
	}
}

func newAdminBookingForm(r *http.Request, conn *database.Conn, company *auth.Company, l *locale.Locale) (*adminBookingForm, error) {
	inner, err := newBookingForm(r, company, conn, l)
	if err != nil {
		return nil, err
	}
	if inner.Options != nil {
		for _, option := range inner.Options.Options {
			option.Subtotal = findSubtotal(option.ID, inner.Cart)
		}
	}
	f := &adminBookingForm{
		bookingForm: inner,
	}
	// Dates and Campsite are valid
	if inner.Guests != nil {
		selected := r.Form["campsite"]
		if err = f.FetchCampsites(r.Context(), conn, company, selected); err != nil {
			return nil, err
		}
	}
	return f, nil
}

func (f *adminBookingForm) FetchCampsites(ctx context.Context, conn *database.Conn, company *auth.Company, selected []string) error {
	arrivalDate, _ := time.Parse(database.ISODateFormat, f.Dates.ArrivalDate.Val)
	from := arrivalDate.AddDate(0, 0, -1)
	departureDate, _ := time.Parse(database.ISODateFormat, f.Dates.DepartureDate.Val)
	to := departureDate.AddDate(0, 0, 2)
	f.Months = CollectMonths(from, to)
	var err error
	f.Campsites, err = CollectCampsiteEntries(ctx, company, conn, from, to, f.CampsiteType.String())
	if err != nil {
		return err
	}

	for _, s := range selected {
		ID, _ := strconv.Atoi(s)
		for _, c := range f.Campsites {
			if c.ID == ID {
				f.selected = append(f.selected, c.ID)
				c.Selected = true
				break
			}
		}
	}

	return nil
}

func findSubtotal(ID int, cart *bookingCart) string {
	none := "0.0"
	if cart == nil || cart.Draft == nil {
		return none
	}
	for _, option := range cart.Draft.Options {
		if option.ID == ID {
			return option.Subtotal
		}
	}
	return none
}

func (f *adminBookingForm) MustRender(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company) {
	if httplib.IsHTMxRequest(r) {
		template.MustRenderAdminNoLayoutFiles(w, r, user, company, f, "booking/fields.gohtml", "booking/grid.gohtml")
	} else {
		template.MustRenderAdminFiles(w, r, user, company, f, "booking/form.gohtml", "booking/fields.gohtml", "booking/grid.gohtml")
	}
}

func addBooking(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn) {
	processAdminBookingForm(w, r, user, company, conn, 0, func(ctx context.Context, tx *database.Tx, f *adminBookingForm) error {
		var err error
		f.ID, err = tx.AddBookingFromPayment(ctx, f.PaymentSlug.Val)
		if err != nil {
			return err
		}
		return tx.EditBooking(
			ctx,
			f.ID,
			f.Customer.FullName.Val,
			f.Customer.Address.Val,
			f.Customer.PostalCode.Val,
			f.Customer.City.Val,
			f.Customer.Country.String(),
			f.Customer.Email.Val,
			f.Customer.Phone.Val,
			language.Make("und"),
			"confirmed",
			f.selected,
		)
	})
}

func updateBooking(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn, slug string) {
	var bookingID int
	var bookingStatus string
	var langTag string
	row := conn.QueryRow(r.Context(), "select booking_id, booking_status, lang_tag from booking where slug = $1", slug)
	if err := row.Scan(&bookingID, &bookingStatus, &langTag); err != nil {
		if database.ErrorIsNotFound(err) {
			http.NotFound(w, r)
			return
		}
		panic(err)
	}
	if err := r.ParseForm(); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	if len(r.Form["cancel"]) > 0 {
		if err := conn.CancelBooking(r.Context(), bookingID); err != nil {
			panic(err)
		}
		if bookingStatus == "created" {
			httplib.Redirect(w, r, "/admin/prebookings", http.StatusSeeOther)
		} else {
			httplib.Redirect(w, r, "/admin/bookings", http.StatusSeeOther)
		}
		return
	}
	processAdminBookingForm(w, r, user, company, conn, bookingID, func(ctx context.Context, tx *database.Tx, f *adminBookingForm) error {
		var err error
		_, err = tx.EditBookingFromPayment(ctx, slug, f.PaymentSlug.Val)
		if err != nil {
			return err
		}
		if bookingStatus == "created" {
			bookingStatus = "confirmed"
		}
		return tx.EditBooking(
			ctx,
			f.ID,
			f.Customer.FullName.Val,
			f.Customer.Address.Val,
			f.Customer.PostalCode.Val,
			f.Customer.City.Val,
			f.Customer.Country.String(),
			f.Customer.Email.Val,
			f.Customer.Phone.Val,
			language.Make(langTag),
			bookingStatus,
			f.selected,
		)
	})
}

func processAdminBookingForm(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn, bookingID int, act func(ctx context.Context, tx *database.Tx, f *adminBookingForm) error) {
	f, err := newAdminBookingForm(r, conn, company, user.Locale)
	if err != nil {
		panic(err)
	}
	if err := user.VerifyCSRFToken(r); err != nil {
		http.Error(w, err.Error(), http.StatusForbidden)
		return
	}
	f.ID = bookingID
	if ok, err := f.Valid(r.Context(), conn, user.Locale); err != nil {
		panic(err)
	} else if !ok {
		if !httplib.IsHTMxRequest(r) {
			w.WriteHeader(http.StatusUnprocessableEntity)
		}
		f.MustRender(w, r, user, company)
		return
	}

	tx := conn.MustBegin(r.Context())
	defer tx.Rollback(r.Context())
	if err := act(r.Context(), tx, f); err != nil {
		panic(err)
	}
	tx.MustCommit(r.Context())
	httplib.Redirect(w, r, "/admin/bookings", http.StatusSeeOther)
}

func (f *adminBookingForm) Valid(ctx context.Context, conn *database.Conn, l *locale.Locale) (bool, error) {
	v := form.NewValidator(l)

	if f.Dates == nil {
		return false, errors.New("no booking date fields")
	}
	if f.Guests == nil {
		return false, errors.New("no guests fields")
	}
	if f.Customer == nil {
		return false, errors.New("no customer fields")
	}
	if f.Cart == nil {
		return false, errors.New("no booking cart")
	}

	v.CheckSelectedOptions(f.CampsiteType, l.GettextNoop("Selected campsite type is not valid."))
	f.Dates.Valid(v, l)
	f.Guests.Valid(v, l)
	if f.Options != nil {
		f.Options.Valid(v, l)
	}

	var country string
	if f.Customer.Country.ValidOptionsSelected() {
		country = f.Customer.Country.Selected[0]
	}

	if v.CheckRequired(f.Customer.FullName, l.GettextNoop("Full name can not be empty.")) {
		v.CheckMinLength(f.Customer.FullName, 1, l.GettextNoop("Full name must have at least one letter."))
	}

	if f.Customer.PostalCode.Val != "" {
		if country == "" {
			v.Check(f.Customer.PostalCode, false, l.GettextNoop("Country can not be empty to validate the postcode."))
		} else if _, err := v.CheckValidPostalCode(ctx, conn, f.Customer.PostalCode, country, l.GettextNoop("This postcode is not valid.")); err != nil {
			return false, err
		}
	}
	if f.Customer.Email.Val != "" {
		v.CheckValidEmail(f.Customer.Email, l.GettextNoop("This email is not valid. It should be like name@domain.com."))
	}
	if f.Customer.Phone.Val != "" {
		if country == "" {
			v.Check(f.Customer.Phone, false, l.GettextNoop("Country can not be empty to validate the phone."))
		} else if _, err := v.CheckValidPhone(ctx, conn, f.Customer.Phone, country, l.GettextNoop("This phone number is not valid.")); err != nil {
			return false, err
		}
	}

	if len(f.selected) == 0 {
		f.Error = errors.New(l.Gettext("You must select at least one accommodation."))
		v.AllOK = false
	} else if f.Dates.ArrivalDate.Error == nil && f.Dates.DepartureDate.Error == nil {
		if available, err := datesAvailable(ctx, conn, f.ID, f.Dates, f.selected); err != nil {
			return false, err
		} else if !available {
			f.Error = errors.New(l.Gettext("The selected accommodations have no available openings in the requested dates."))
			v.AllOK = false
		}
	}

	return v.AllOK, nil
}

func datesAvailable(ctx context.Context, conn *database.Conn, bookingID int, dates *DateFields, selectedCampsites []int) (bool, error) {
	return conn.GetBool(ctx, `
		select not exists (
			select 1
			from camper.booking_campsite
			where booking_id <> $1
              and campsite_id = any ($4)
		      and stay && daterange($2::date, $3::date)
		)
	`,
		bookingID,
		dates.ArrivalDate,
		dates.DepartureDate,
		selectedCampsites,
	)
}

func (f *adminBookingForm) FillFromDatabase(ctx context.Context, conn *database.Conn, company *auth.Company, slug string, l *locale.Locale) error {
	f.Cart = &bookingCart{Draft: &paymentDraft{}}
	f.Customer = newBookingCustomerFields(ctx, conn, l)
	var arrivalDate string
	var departureDate string
	var acsiCard bool
	var zonePreferences string
	var selected []string
	row := conn.QueryRow(ctx, `
		select booking_id
		     , '/admin/bookings/' || booking.slug
		     , booking_status
		     , array[campsite_type.slug::text]
		     , lower(booking.stay)::text
             , upper(booking.stay)::text
		     , upper(booking.stay) - lower(booking.stay)
		     , to_price(subtotal_nights, decimal_digits)
		     , number_adults
		     , to_price(subtotal_adults, decimal_digits)
		     , number_teenagers
		     , to_price(subtotal_teenagers, decimal_digits)
		     , number_children
		     , to_price(subtotal_children, decimal_digits)
		     , number_dogs
		     , to_price(subtotal_dogs, decimal_digits)
		     , to_price(subtotal_tourist_tax, decimal_digits)
		     , to_price(total, decimal_digits)
		     , acsi_card
             , holder_name
             , coalesce(address, '')
             , coalesce(postal_code, '')
             , coalesce(city, '')
             , array[coalesce(country_code::text, '')]
             , coalesce(email::text, '')
             , coalesce(phone::text, '')
             , zone_preferences
             , array_agg(coalesce(campsite_id::text, ''))
		from booking
		    join campsite_type using (campsite_type_id)
			left join campsite_type_pet_cost as pet using (campsite_type_id)
		    left join booking_campsite using (booking_id)
			join currency using (currency_code)
		where booking.slug = $1
		group by booking_id
		       , campsite_type.slug 
		       , booking.stay
		       , subtotal_nights
		       , number_adults
		       , subtotal_adults
		       , number_teenagers
		       , subtotal_teenagers
		       , number_children
		       , subtotal_children
		       , number_dogs
		       , subtotal_dogs
		       , subtotal_tourist_tax
		       , total
		       , acsi_card
               , holder_name
               , address
               , postal_code
               , city
               , country_code
               , email
               , phone
               , zone_preferences
		       , decimal_digits
	`, slug)
	if err := row.Scan(
		&f.ID,
		&f.URL,
		&f.Status,
		&f.CampsiteType.Selected,
		&arrivalDate,
		&departureDate,
		&f.Cart.Draft.NumNights,
		&f.Cart.Draft.Nights,
		&f.Cart.Draft.NumAdults,
		&f.Cart.Draft.Adults,
		&f.Cart.Draft.NumTeenagers,
		&f.Cart.Draft.Teenagers,
		&f.Cart.Draft.NumChildren,
		&f.Cart.Draft.Children,
		&f.Cart.Draft.NumDogs,
		&f.Cart.Draft.Dogs,
		&f.Cart.Draft.TouristTax,
		&f.Cart.Draft.Total,
		&acsiCard,
		&f.Customer.FullName.Val,
		&f.Customer.Address.Val,
		&f.Customer.PostalCode.Val,
		&f.Customer.City.Val,
		&f.Customer.Country.Selected,
		&f.Customer.Email.Val,
		&f.Customer.Phone.Val,
		&zonePreferences,
		&selected,
	); err != nil {
		return err
	}

	var err error
	f.Dates, err = NewDateFields(ctx, conn, f.CampsiteType.String())
	if err != nil {
		return err
	}
	f.Dates.ArrivalDate.Val = arrivalDate
	f.Dates.DepartureDate.Val = departureDate
	f.Dates.AdjustValues(l)

	f.Guests, err = newBookingGuestFields(ctx, conn, f.CampsiteType.String(), arrivalDate, departureDate)
	if err != nil {
		return err
	}
	f.Guests.NumberAdults.Val = strconv.Itoa(f.Cart.Draft.NumAdults)
	f.Guests.NumberTeenagers.Val = strconv.Itoa(f.Cart.Draft.NumTeenagers)
	f.Guests.NumberChildren.Val = strconv.Itoa(f.Cart.Draft.NumChildren)
	if f.Guests.NumberDogs != nil {
		f.Guests.NumberDogs.Val = strconv.Itoa(f.Cart.Draft.NumDogs)
	}
	if f.Guests.ACSICard != nil {
		f.Guests.ACSICard.Checked = acsiCard
	}
	f.Guests.AdjustValues(f.Cart.Draft.NumAdults+f.Cart.Draft.NumTeenagers+f.Cart.Draft.NumChildren, l)

	f.Options, err = newBookingOptionFields(ctx, conn, f.CampsiteType.String(), l)
	if err != nil {
		return err
	}
	if f.Options != nil {
		if f.Options.ZonePreferences != nil {
			f.Options.ZonePreferences.Val = zonePreferences
		}
		if err = f.Options.FillFromDatabase(ctx, conn, f.ID); err != nil {
			return err
		}
	}

	if err = f.FetchCampsites(ctx, conn, company, selected); err != nil {
		return err
	}

	return nil
}