<?php

declare(strict_types=1);

namespace App\BusProNet\Model;

/**
 * Represents a successful API response from a booking request.
 *
 * Response structure for successful requests:
 * - <buchung>möglich</buchung> = inquiry validation successful
 * - <buchung>erfolgt</buchung> = booking creation successful
 *
 * Error responses return Notification objects instead (typ="HINWEIS").
 */
class BookingResponse
{
    /**
     * @param string                $status        Booking status (möglich|erfolgt)
     * @param int|null              $bookingNumber Booking number (BPN XML: vorgang)
     * @param array<int, PriceItem> $priceItems    Individual price items from response
     * @param float|null            $totalPrice    Total price (gesamtpreis)
     * @param PaymentTerms|null     $paymentTerms  Payment terms (anzahlung/restzahlung)
     */
    public function __construct(
        public readonly string $status,
        public readonly ?int $bookingNumber = null,
        public readonly array $priceItems = [],
        public readonly ?float $totalPrice = null,
        public readonly ?PaymentTerms $paymentTerms = null,
        public readonly ?string $message = null,
    ) {
    }

    /**
     * Returns true if the inquiry validation was successful.
     */
    public function isInquiryValid(): bool
    {
        return 'möglich' === $this->status;
    }

    /**
     * Returns true if the booking was successfully created.
     */
    public function isBookingSuccessful(): bool
    {
        return 'erfolgt' === $this->status;
    }

    /**
     * Gets voucher discounts from price items (AKTION and KULANZGUTSCHEIN types).
     *
     * Promotional vouchers appear as negative price items with art="AKTION".
     * Goodwill vouchers appear as negative price items with art="KULANZGUTSCHEIN".
     *
     * @return array<PriceItem> Price items representing voucher discounts
     */
    public function getVoucherDiscountsFromPrices(): array
    {
        return array_filter(
            $this->priceItems,
            fn (PriceItem $item) => \in_array($item->type, ['AKTION', 'KULANZGUTSCHEIN'], true)
        );
    }

    /**
     * Gets total discount from price-based vouchers (promotional and goodwill).
     *
     * Returns the absolute sum of negative price items with AKTION or KULANZGUTSCHEIN types.
     */
    public function getVoucherDiscountFromPrices(): float
    {
        $discount = 0.0;
        foreach ($this->getVoucherDiscountsFromPrices() as $item) {
            // Price items for vouchers are negative, so we take absolute value
            $discount += abs($item->totalPrice);
        }

        return round($discount, 2);
    }

    /**
     * Gets total discount from purchase vouchers in payment terms.
     */
    public function getPurchaseVoucherDiscount(): float
    {
        return $this->paymentTerms?->getPurchaseVoucherDiscount() ?? 0.0;
    }

    /**
     * Gets total voucher discount from all sources.
     *
     * Combines discounts from:
     * - Price items (art="AKTION" for promotional, art="KULANZGUTSCHEIN" for goodwill)
     * - Payment terms (kaufgutschein elements for purchase vouchers)
     */
    public function getTotalVoucherDiscount(): float
    {
        return round(
            $this->getVoucherDiscountFromPrices() + $this->getPurchaseVoucherDiscount(),
            2
        );
    }

    /**
     * Gets API-applied discounts that cannot be predicted by the local price calculator.
     *
     * The BusProNet API may apply automatic discounts based on business rules that
     * are not known to the local application, such as:
     * - ERM/GRU: Gruppenrabatt (group discount for large bookings)
     * - Other ERM subtypes: Various automatic discounts
     *
     * These discounts appear as negative price items with type "ERM" and must be
     * accounted for when comparing the API total price against the locally calculated price.
     *
     * Important: Only ERM type discounts are considered API-applied. Other negative price
     * items (like BEF transportation discounts) are already handled by the local price
     * calculator and should not be subtracted again.
     *
     * Note: Voucher discounts (AKTION, KULANZGUTSCHEIN) are handled separately via
     * getVoucherDiscountFromPrices() as they are user-initiated, not automatic.
     *
     * @return array<PriceItem> Price items representing API-applied automatic discounts
     */
    public function getApiAppliedDiscounts(): array
    {
        return array_filter(
            $this->priceItems,
            fn (PriceItem $item) => $item->totalPrice < 0 && 'ERM' === $item->type
        );
    }

    /**
     * Gets total discount from API-applied automatic discounts.
     *
     * Returns the absolute sum of negative price items that represent automatic
     * discounts applied by the API (excluding voucher discounts which are handled separately).
     */
    public function getApiAppliedDiscountTotal(): float
    {
        $discount = 0.0;
        foreach ($this->getApiAppliedDiscounts() as $item) {
            $discount += abs($item->totalPrice);
        }

        return round($discount, 2);
    }
}