package booking

import (
	"context"
	"strconv"
	"time"

	"dev.tandem.ws/tandem/camper/pkg/database"
	"dev.tandem.ws/tandem/camper/pkg/locale"
)

type bookingCart struct {
	Lines       []*cartLine
	Total       string
	DownPayment string
	Enabled     bool
}

type cartLine struct {
	Concept  string
	Units    int
	Subtotal string
}

func newBookingCart(ctx context.Context, conn *database.Conn, f *bookingForm, campsiteType string) (*bookingCart, error) {
	cart := &bookingCart{
		Total: "0.0",
	}
	if f.Dates == nil {
		return cart, nil
	}
	arrivalDate, err := time.Parse(database.ISODateFormat, f.Dates.ArrivalDate.Val)
	if err != nil {
		return cart, nil
	}
	departureDate, err := time.Parse(database.ISODateFormat, f.Dates.DepartureDate.Val)
	if err != nil {
		return cart, nil
	}

	if f.Guests == nil {
		return cart, nil
	}
	numAdults, err := strconv.Atoi(f.Guests.NumberAdults.Val)
	if err != nil {
		return cart, nil
	}
	numTeenagers, err := strconv.Atoi(f.Guests.NumberTeenagers.Val)
	if err != nil {
		return cart, nil
	}
	numChildren, err := strconv.Atoi(f.Guests.NumberChildren.Val)
	if err != nil {
		return cart, nil
	}
	numDogs := 0
	if f.Guests.NumberDogs != nil {
		numDogs, err = strconv.Atoi(f.Guests.NumberDogs.Val)
		if err != nil {
			return cart, nil
		}
	}
	zonePreferences := ""
	if f.Options != nil && f.Options.ZonePreferences != nil {
		zonePreferences = f.Options.ZonePreferences.Val
	}

	optionMap := make(map[int]*campsiteTypeOption)
	var typeOptions []*campsiteTypeOption
	if f.Options != nil {
		typeOptions = f.Options.Options
	}
	optionUnits := make([]*database.OptionUnits, 0, len(typeOptions))
	for _, option := range typeOptions {
		units, _ := strconv.Atoi(option.Input.Val)
		if units < 1 {
			continue
		}
		optionMap[option.ID] = option
		optionUnits = append(optionUnits, &database.OptionUnits{
			OptionID: option.ID,
			Units:    units,
		})
	}

	row := conn.QueryRow(ctx, `
		select payment.slug
		     , payment_id
		     , departure_date - arrival_date
		     , to_price(subtotal_nights, decimal_digits)
		     , to_price(subtotal_adults, decimal_digits)
		     , to_price(subtotal_teenagers, decimal_digits)
		     , to_price(subtotal_children, decimal_digits)
		     , to_price(subtotal_dogs, decimal_digits)
		     , to_price(subtotal_tourist_tax, decimal_digits)
		     , to_price(total, decimal_digits)
		     , to_price(payment.down_payment, decimal_digits)
		from draft_payment($1, $2, $3, $4, $5, $6, $7, $8, $9, $10) as payment
			join currency using (currency_code)
`,
		database.ZeroNullUUID(f.PaymentSlug.Val),
		arrivalDate,
		departureDate,
		campsiteType,
		numAdults,
		numTeenagers,
		numChildren,
		numDogs,
		zonePreferences,
		database.OptionUnitsArray(optionUnits),
	)
	var paymentID int
	var numNights int
	var nights string
	var adults string
	var teenagers string
	var children string
	var dogs string
	var touristTax string
	var total string
	var downPayment string
	if err = row.Scan(
		&f.PaymentSlug.Val,
		&paymentID,
		&numNights,
		&nights,
		&adults,
		&teenagers,
		&children,
		&dogs,
		&touristTax,
		&total,
		&downPayment,
	); err != nil {
		if database.ErrorIsNotFound(err) {
			return cart, nil
		}
		return nil, err
	}

	maybeAddLine := func(units int, subtotal string, concept string) {
		if units > 0 && subtotal != "" {
			cart.Lines = append(cart.Lines, &cartLine{
				Concept:  concept,
				Units:    units,
				Subtotal: subtotal,
			})
		}
	}
	maybeAddLine(numNights, nights, locale.PgettextNoop("Night", "cart"))
	maybeAddLine(numAdults, adults, locale.PgettextNoop("Adult", "cart"))
	maybeAddLine(numTeenagers, teenagers, locale.PgettextNoop("Teenager", "cart"))
	maybeAddLine(numChildren, children, locale.PgettextNoop("Child", "cart"))
	maybeAddLine(numDogs, dogs, locale.PgettextNoop("Dog", "cart"))

	rows, err := conn.Query(ctx, `
		select campsite_type_option_id
		     , units
		     , to_price(subtotal, decimal_digits)
		from payment_option
		   join payment using (payment_id)
		   join currency using (currency_code)
		where payment_id = $1
`, paymentID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	for rows.Next() {
		var optionID int
		var units int
		var subtotal string
		err = rows.Scan(&optionID, &units, &subtotal)
		if err != nil {
			return nil, err
		}
		option := optionMap[optionID]
		if option == nil {
			continue
		}
		maybeAddLine(units, subtotal, option.Label)
	}
	if rows.Err() != nil {
		return nil, rows.Err()
	}

	maybeAddLine(numAdults, touristTax, locale.PgettextNoop("Tourist tax", "cart"))

	if total != "0.0" {
		cart.Total = total
		cart.Enabled = f.Guests.Error == nil

		if downPayment != total {
			cart.DownPayment = downPayment
		}
	}

	return cart, nil
}