<?php

declare(strict_types=1);

namespace App\Service;

use App\BusProNet\Constants;
use App\BusProNet\Model\Insurance;
use App\BusProNet\Model\Service;
use App\Form\Model\BookingDto;
use App\Form\Model\ParticipantDto;

/**
 * Calculates pricing for services across all participants in a booking.
 *
 * Handles aggregation of service selections, transportation costs, and
 * insurance pricing with bulk insurance support. Groups services by
 * subtype for display with separate discount entries.
 */
class ServicePricingCalculator
{
    public function __construct(
        private readonly ParticipantEligibilityService $participantEligibilityService,
        private readonly InsuranceService $insuranceService,
        private readonly ParticipantPricingCalculator $participantPricingCalculator,
    ) {
    }

    /**
     * Calculates pricing for all selected services across all participants, grouped by subtype.
     *
     * Only includes services from eligible participants (those with available skipasses for their age).
     *
     * @param BookingDto $bookingDto The booking data containing participants and their service selections
     *
     * @return array Array of service groups with each group containing services of the same subtype
     */
    public function calculateServicePricing(BookingDto $bookingDto): array
    {
        $participants = $bookingDto->getParticipants();

        if (true === empty($participants)) {
            return [];
        }

        // Aggregate service selections across all eligible participants
        $serviceAggregation = [];

        foreach ($participants as $participantIndex => $participant) {
            // Skip ineligible participants (no skipasses available for their age)
            if (false === $this->participantEligibilityService->isParticipantEligible($bookingDto, $participantIndex)) {
                continue;
            }

            $this->aggregateParticipantServices($participant, $serviceAggregation, $bookingDto);
        }

        // Add transportation services as separate line items (Zustieg, Rabatt, Parkplatz)
        $transportationItems = $this->aggregateTransportationServices($bookingDto);
        foreach ($transportationItems as $key => $transportationItem) {
            $serviceAggregation[$key] = $transportationItem;
        }

        // Group services by subtype and convert to pricing format
        return $this->groupServicesBySubtype($serviceAggregation);
    }

    /**
     * Calculates total price for all services.
     */
    public function calculateServiceTotal(BookingDto $bookingDto): float
    {
        $servicePricing = $this->calculateServicePricing($bookingDto);

        return array_sum(array_column($servicePricing, 'groupTotal'));
    }

    /**
     * Aggregates all transportation-related services and pricing into separate line items.
     *
     * Creates separate entries for:
     * - Befoerderung: Sum of all positive pickup prices and base transportation costs
     * - Befoerderung - Rabatt: Sum of all negative transportation prices (discounts)
     * - Parkplatz: Sum of all parking service prices
     *
     * Only includes transportation costs from eligible participants.
     *
     * @param BookingDto $bookingDto The booking data containing participants
     *
     * @return array Array of transportation line items (Befoerderung, Rabatt, Parkplatz)
     */
    private function aggregateTransportationServices(BookingDto $bookingDto): array
    {
        $participants = $bookingDto->getParticipants();

        $transportationPositiveTotal = 0.0;     // Positive transportation/pickup costs
        $transportationDiscountTotal = 0.0;     // Negative transportation prices (discounts)
        $parkingTotal = 0.0;                    // Parking service costs

        $transportationParticipants = 0;
        $discountParticipants = 0;
        $parkingParticipants = 0;

        foreach ($participants as $participantIndex => $participant) {
            // Skip ineligible participants (no skipasses available for their age)
            if (false === $this->participantEligibilityService->isParticipantEligible($bookingDto, $participantIndex)) {
                continue;
            }

            $participantTransportationPositiveCost = 0.0;
            $participantTransportationDiscountCost = 0.0;
            $participantParkingCost = 0.0;

            // Transportation service pricing (outbound)
            if (null !== $participant->transportationOutbound && null !== $participant->transportationOutbound->price) {
                if ($participant->transportationOutbound->price < 0) {
                    $participantTransportationDiscountCost += $participant->transportationOutbound->price;
                } else {
                    $participantTransportationPositiveCost += $participant->transportationOutbound->price;
                }
            }

            // Transportation service pricing (inbound)
            if (null !== $participant->transportationInbound && null !== $participant->transportationInbound->price) {
                if ($participant->transportationInbound->price < 0) {
                    $participantTransportationDiscountCost += $participant->transportationInbound->price;
                } else {
                    $participantTransportationPositiveCost += $participant->transportationInbound->price;
                }
            }

            // Pickup pricing - only charged when outbound transportation is bus
            // BusProNet API ignores pickup surcharges for self-organized (PKW) outbound
            $hasOutboundBus = null !== $participant->transportationOutbound
                && 'BUS' === $participant->transportationOutbound->subType;

            if ($hasOutboundBus && null !== $participant->pickup && null !== $participant->pickup->price) {
                if ($participant->pickup->price < 0) {
                    $participantTransportationDiscountCost += $participant->pickup->price;
                } else {
                    $participantTransportationPositiveCost += $participant->pickup->price;
                }
            }

            // Parking service pricing
            if (null !== $participant->parkingService && null !== $participant->parkingService->price) {
                $participantParkingCost += $participant->parkingService->price;
            }

            // Aggregate participant totals
            if ($participantTransportationPositiveCost > 0) {
                $transportationPositiveTotal += $participantTransportationPositiveCost;
                ++$transportationParticipants;
            }
            if ($participantTransportationDiscountCost < 0) {
                $transportationDiscountTotal += $participantTransportationDiscountCost;
                ++$discountParticipants;
            }
            if ($participantParkingCost > 0) {
                $parkingTotal += $participantParkingCost;
                ++$parkingParticipants;
            }
        }

        $transportationItems = [];

        // Add transportation entry (only positive costs)
        if ($transportationPositiveTotal > 0) {
            $transportationItems['transportation_positive'] = [
                'serviceId' => 'transportation_positive',
                'label' => 'Beförderung',
                'unitPrice' => null,
                'participantCount' => $transportationParticipants,
                'totalPrice' => $transportationPositiveTotal,
                'subType' => Constants::GROUP_TRANSPORTATION,
            ];
        }

        // Add discount entry (only negative costs)
        if ($transportationDiscountTotal < 0) {
            $transportationItems['transportation_discount'] = [
                'serviceId' => 'transportation_discount',
                'label' => 'Beförderung - Rabatt',
                'unitPrice' => null,
                'participantCount' => $discountParticipants,
                'totalPrice' => $transportationDiscountTotal,
                'subType' => Constants::GROUP_TRANSPORTATION.'_discount',
            ];
        }

        // Add parking entry (only if positive costs)
        if ($parkingTotal > 0) {
            $transportationItems['transportation_parking'] = [
                'serviceId' => 'transportation_parking',
                'label' => Constants::SERVICE_LABELS[Constants::TOKEN_PARKING],
                'unitPrice' => null,
                'participantCount' => $parkingParticipants,
                'totalPrice' => $parkingTotal,
                'subType' => Constants::GROUP_TRANSPORTATION,
            ];
        }

        return $transportationItems;
    }

    /**
     * Groups services by their subtypes for display, separating positive costs and discounts.
     *
     * Creates separate entries for positive costs and negative costs (discounts) within each service group.
     * For example: "Kurse" and "Kurse - Rabatt" if there are both positive and negative priced course services.
     *
     * @param array $serviceAggregation Aggregated service data
     *
     * @return array Grouped services by subtype with separate discount entries
     */
    private function groupServicesBySubtype(array $serviceAggregation): array
    {
        $groupedServices = [];

        // First pass: separate positive and negative prices by subtype
        $servicesBySubtypeAndSign = [];

        foreach ($serviceAggregation as $serviceData) {
            $subType = $serviceData['subType'] ?? 'other';

            // Normalize rental subtypes to avoid duplicate sections
            if (true === in_array($subType, Constants::TOKEN_RENTALS, true)) {
                $subType = Constants::GROUP_RENTALS; // Normalize all rental subtypes to a single key
            }

            // Normalize insurance subtypes to avoid duplicate sections
            if (true === in_array($subType, Constants::TOKEN_INSURANCES, true)) {
                $subType = Constants::GROUP_INSURANCE; // Normalize all insurance subtypes to a single key
            }

            $isDiscount = $serviceData['totalPrice'] < 0;

            // Create separate buckets for positive costs and discounts
            $bucketKey = $subType.($isDiscount ? '_discount' : '_regular');

            if (false === isset($servicesBySubtypeAndSign[$bucketKey])) {
                $servicesBySubtypeAndSign[$bucketKey] = [
                    'subType' => $subType,
                    'isDiscount' => $isDiscount,
                    'services' => [],
                    'total' => 0.0,
                    'participantCount' => 0,
                ];
            }

            $servicesBySubtypeAndSign[$bucketKey]['services'][] = $serviceData;
            $servicesBySubtypeAndSign[$bucketKey]['total'] += $serviceData['totalPrice'];
            $servicesBySubtypeAndSign[$bucketKey]['participantCount'] += $serviceData['participantCount'];
        }

        // Second pass: create display groups
        foreach ($servicesBySubtypeAndSign as $bucketData) {
            $baseGroupName = $this->getGroupNameForSubtype($bucketData['subType']);
            $groupName = $bucketData['isDiscount'] ? $baseGroupName.' - Rabatt' : $baseGroupName;

            $groupedServices[] = [
                'groupName' => $groupName,
                'services' => $bucketData['services'],
                'groupTotal' => $bucketData['total'],
            ];
        }

        return $groupedServices;
    }

    /**
     * Maps service subtypes to user-friendly group names.
     */
    private function getGroupNameForSubtype(string $subType): string
    {
        // Handle rentals array (keep for backward compatibility with non-normalized subtypes)
        if (true === in_array($subType, Constants::TOKEN_RENTALS, true)) {
            return Constants::SERVICE_LABELS[Constants::GROUP_RENTALS];
        }

        return Constants::SERVICE_LABELS[$subType] ?? 'Sonstige Leistungen';
    }

    /**
     * Aggregates service selections from a single participant into the service aggregation array.
     */
    private function aggregateParticipantServices(
        ParticipantDto $participant,
        array &$serviceAggregation,
        BookingDto $bookingDto,
    ): void {
        // Handle single service selections (skiPass, rentalInsurance)
        if (null !== $participant->skiPass && null !== $participant->skiPass->price) {
            $this->addToServiceAggregation($serviceAggregation, $participant->skiPass, 1);
        }

        if (null !== $participant->rentalInsurance && null !== $participant->rentalInsurance->price) {
            $this->addToServiceAggregation($serviceAggregation, $participant->rentalInsurance, 1);
        }

        // Resolve insurance: use price-tier-adjusted insurance for bulk assignment
        // Skip synthetic "no insurance" option - it's a UI construct that shouldn't appear in summary
        $insuranceToAggregate = $this->resolveInsuranceForAggregation($participant, $bookingDto);

        if (null !== $insuranceToAggregate && null !== $insuranceToAggregate->price && false === $insuranceToAggregate->isNoInsurance()) {
            $this->addInsuranceToServiceAggregation($serviceAggregation, $insuranceToAggregate, 1);
        }

        // Handle multiple service selections
        $multipleServiceArrays = [
            'courses' => $participant->courses,
            'additionalServices' => $participant->additionalServices,
            'board' => $participant->board,
            'rentals' => $participant->rentals,
        ];

        foreach ($multipleServiceArrays as $serviceArray) {
            if (true === is_array($serviceArray)) {
                foreach ($serviceArray as $service) {
                    if ($service instanceof Service && null !== $service->price) {
                        $this->addToServiceAggregation($serviceAggregation, $service, 1);
                    }
                }
            }
        }
    }

    /**
     * Adds a service to the aggregation array, incrementing count and updating total price.
     */
    private function addToServiceAggregation(array &$serviceAggregation, Service $service, int $quantity): void
    {
        $serviceKey = $service->id.'_'.$service->label;

        if (false === isset($serviceAggregation[$serviceKey])) {
            $serviceAggregation[$serviceKey] = [
                'serviceId' => $service->id,
                'label' => $service->label,
                'unitPrice' => $service->price,
                'participantCount' => 0,
                'totalPrice' => 0.0,
                'subType' => $service->subType,
            ];
        }

        $serviceAggregation[$serviceKey]['participantCount'] += $quantity;
        $serviceAggregation[$serviceKey]['totalPrice'] += $service->price * $quantity;
    }

    /**
     * Adds an insurance to the service aggregation array.
     *
     * @param array     $serviceAggregation The service aggregation array to update
     * @param Insurance $insurance          The insurance to add
     * @param int       $quantity           The quantity of the insurance
     */
    private function addInsuranceToServiceAggregation(array &$serviceAggregation, Insurance $insurance, int $quantity): void
    {
        $serviceKey = $insurance->id.'_'.$insurance->label;

        if (false === isset($serviceAggregation[$serviceKey])) {
            $serviceAggregation[$serviceKey] = [
                'serviceId' => $insurance->id,
                'label' => $insurance->label,
                'unitPrice' => $insurance->price,
                'participantCount' => 0,
                'totalPrice' => 0.0,
                'subType' => $insurance->getSubType(),
            ];
        }

        $serviceAggregation[$serviceKey]['participantCount'] += $quantity;
        $serviceAggregation[$serviceKey]['totalPrice'] += $insurance->price * $quantity;
    }

    /**
     * Resolves the insurance to use for aggregation, handling bulk insurance with price tiers.
     *
     * When bulk insurance is active, dependent participants get price-tier-adjusted insurance
     * based on their individual travel price, matching the logic used in API submission.
     *
     * @param ParticipantDto $participant The participant to resolve insurance for
     * @param BookingDto     $bookingDto  The booking context
     *
     * @return Insurance|null The insurance to aggregate (null if none)
     */
    private function resolveInsuranceForAggregation(ParticipantDto $participant, BookingDto $bookingDto): ?Insurance
    {
        // If participant already has insurance assigned, use it
        if (null !== $participant->insurance) {
            return $participant->insurance;
        }

        // Check if bulk insurance is active
        $applicant = $bookingDto->getParticipant(0);
        if (null === $applicant || false === $applicant->bulkInsuranceBooking || null === $applicant->insurance) {
            return null; // No bulk insurance active
        }

        // Applicant always uses their own insurance
        if (0 === $participant->index) {
            return $participant->insurance;
        }

        // For dependent participants: calculate price-tier-adjusted insurance
        // This mirrors the logic in BookingDataProcessor::applyBulkInsuranceIfActive()
        // Get selectable (non-complementary) insurances with caching
        $selectableInsurances = $this->insuranceService->getSelectableInsurances($bookingDto->travel);

        // Get insurances of the same type as applicant's selection
        $sameTypeInsurances = $this->insuranceService->filterByType(
            $selectableInsurances,
            $applicant->insurance
        );

        // Calculate travel price for eligibility checks
        $travelPrice = $this->participantPricingCalculator->calculateIndividualParticipantPriceExcludingInsurance(
            $bookingDto,
            $participant->index
        );

        // Get eligible insurances for THIS participant (price tier adjusted)
        $eligibleInsurances = $this->insuranceService->getEligibleInsurances(
            $sameTypeInsurances,
            $participant,
            $bookingDto,
            $travelPrice
        );

        // Return first eligible insurance (sorted by price)
        return !empty($eligibleInsurances) ? array_values($eligibleInsurances)[0] : null;
    }
}