package booking

import (
	"context"
	"strconv"
	"time"

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

type bookingCart struct {
	Draft              *paymentDraft
	Lines              []*cartLine
	Total              string
	DownPayment        string
	DownPaymentPercent int
	Enabled            bool
}

type cartLine struct {
	Concept  string
	Units    int
	Subtotal string
}

type paymentDraft struct {
	ArrivalDate        time.Time
	DepartureDate      time.Time
	NumAdults          int
	NumTeenagers       int
	NumChildren        int
	NumDogs            int
	ZonePreferences    string
	ACSICard           bool
	PaymentID          int
	NumNights          int
	Nights             string
	Adults             string
	Teenagers          string
	Children           string
	Dogs               string
	TouristTax         string
	Total              string
	DownPaymentPercent int
	DownPayment        string
	Options            []*paymentOption
}

type paymentOption struct {
	ID       int
	Label    string
	Units    int
	Subtotal string
}

func draftPayment(ctx context.Context, conn *database.Conn, f *bookingForm, campsiteType string) (*paymentDraft, error) {
	var err error
	if f.Dates == nil {
		return nil, nil
	}

	draft := &paymentDraft{}
	draft.ArrivalDate, err = time.Parse(database.ISODateFormat, f.Dates.ArrivalDate.Val)
	if err != nil {
		return nil, nil
	}
	draft.DepartureDate, err = time.Parse(database.ISODateFormat, f.Dates.DepartureDate.Val)
	if err != nil {
		return nil, nil
	}

	if f.Guests == nil {
		return nil, nil
	}
	draft.NumAdults, err = strconv.Atoi(f.Guests.NumberAdults.Val)
	if err != nil {
		return nil, nil
	}
	draft.NumTeenagers, err = strconv.Atoi(f.Guests.NumberTeenagers.Val)
	if err != nil {
		return nil, nil
	}
	draft.NumChildren, err = strconv.Atoi(f.Guests.NumberChildren.Val)
	if err != nil {
		return nil, nil
	}
	if f.Guests.NumberDogs != nil {
		draft.NumDogs, err = strconv.Atoi(f.Guests.NumberDogs.Val)
		if err != nil {
			return nil, nil
		}
	}

	if f.Options != nil && f.Options.ZonePreferences != nil {
		draft.ZonePreferences = f.Options.ZonePreferences.Val
	}

	if f.Guests.ACSICard != nil {
		draft.ACSICard = f.Guests.ACSICard.Checked
	}

	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)
		     , (payment.down_payment_percent * 100)::int
		from draft_payment($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11) as payment
			join currency using (currency_code)
`,
		database.ZeroNullUUID(f.PaymentSlug.Val),
		draft.ArrivalDate,
		draft.DepartureDate,
		campsiteType,
		draft.NumAdults,
		draft.NumTeenagers,
		draft.NumChildren,
		draft.NumDogs,
		draft.ZonePreferences,
		draft.ACSICard,
		database.OptionUnitsArray(optionUnits),
	)
	if err = row.Scan(
		&f.PaymentSlug.Val,
		&draft.PaymentID,
		&draft.NumNights,
		&draft.Nights,
		&draft.Adults,
		&draft.Teenagers,
		&draft.Children,
		&draft.Dogs,
		&draft.TouristTax,
		&draft.Total,
		&draft.DownPayment,
		&draft.DownPaymentPercent,
	); err != nil {
		if database.ErrorIsNotFound(err) {
			return nil, nil
		}
		return nil, err
	}

	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
		order by campsite_type_option_id
`, draft.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
		}
		draft.Options = append(draft.Options, &paymentOption{
			ID:       option.ID,
			Label:    option.Label,
			Units:    units,
			Subtotal: subtotal,
		})
	}
	if rows.Err() != nil {
		return nil, rows.Err()
	}

	return draft, nil
}

func newBookingCart(ctx context.Context, conn *database.Conn, f *bookingForm, campsiteType string) (*bookingCart, error) {
	cart := &bookingCart{
		Total: "0.0",
	}

	draft, err := draftPayment(ctx, conn, f, campsiteType)
	if err != nil {
		return nil, err
	}
	if draft == nil {
		return cart, nil
	}
	cart.Draft = draft
	cart.DownPaymentPercent = draft.DownPaymentPercent

	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(draft.NumNights, draft.Nights, locale.PgettextNoop("Night", "cart"))
	maybeAddLine(draft.NumAdults, draft.Adults, locale.PgettextNoop("Adult", "cart"))
	maybeAddLine(draft.NumTeenagers, draft.Teenagers, locale.PgettextNoop("Teenager", "cart"))
	maybeAddLine(draft.NumChildren, draft.Children, locale.PgettextNoop("Child", "cart"))
	maybeAddLine(draft.NumDogs, draft.Dogs, locale.PgettextNoop("Dog", "cart"))

	for _, option := range draft.Options {
		maybeAddLine(option.Units, option.Subtotal, option.Label)
	}

	maybeAddLine(draft.NumAdults, draft.TouristTax, locale.PgettextNoop("Tourist tax", "cart"))

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

		if draft.DownPayment != draft.Total {
			cart.DownPayment = draft.DownPayment
		}
	}

	return cart, nil
}