<?php

declare(strict_types=1);

namespace App\Service;

use App\BusProNet\Model\Room;
use App\Form\Model\BookingDto;

/**
 * Calculates pricing for room allocations in bookings.
 *
 * Handles room pricing in both create mode (from room selections) and
 * edit mode (from booking entity data with individual participant prices).
 */
class RoomPricingCalculator
{
    public const PRICING_MODE_ASSIGNMENT = 'assignment';
    public const PRICING_MODE_SELECTION = 'selection';

    /**
     * Calculates pricing for all selected rooms.
     *
     * @param BookingDto $bookingDto The booking data containing room selections
     *
     * @return array<int, array<string, mixed>> Array of room pricing data with labels, quantities, and totals
     */
    public function calculateRoomPricing(
        BookingDto $bookingDto,
        string $pricingMode = self::PRICING_MODE_ASSIGNMENT,
    ): array {
        // In edit mode, use room data from the booking entity
        if (BookingDto::MODE_EDIT === $bookingDto->getMode() && null !== $bookingDto->booking) {
            return $this->calculateRoomPricingFromBooking($bookingDto);
        }

        // In create mode, use room selections from the form
        return $this->calculateRoomPricingFromSelections($bookingDto, $pricingMode);
    }

    /**
     * Calculates total price for all rooms.
     */
    public function calculateRoomTotal(
        BookingDto $bookingDto,
        string $pricingMode = self::PRICING_MODE_ASSIGNMENT,
    ): float {
        $roomPricing = $this->calculateRoomPricing($bookingDto, $pricingMode);

        return array_sum(array_column($roomPricing, 'totalPrice'));
    }

    /**
     * Retrieves a room by ID from the booking's travel data.
     */
    public function getRoomById(BookingDto $bookingDto, ?int $roomId): ?Room
    {
        if (null === $roomId) {
            return null;
        }

        foreach ($bookingDto->travel->rooms as $room) {
            if ($room->id === $roomId) {
                return $room;
            }
        }

        return null;
    }

    /**
     * Calculates room pricing from form selections (create mode).
     *
     * @param BookingDto $bookingDto The booking data containing room selections
     *
     * @return array<int, array<string, mixed>> Array of room pricing data
     */
    private function calculateRoomPricingFromSelections(BookingDto $bookingDto, string $pricingMode): array
    {
        $roomPricing = [];
        $selectedRooms = $bookingDto->getSelectedRooms();

        if (true === empty($selectedRooms)) {
            return $roomPricing;
        }

        $assignmentCounts = $bookingDto->getRoomAssignmentCounts();

        foreach ($selectedRooms as $roomSelection) {
            $room = $this->getRoomById($bookingDto, $roomSelection->id);
            if (null === $room || null === $room->price) {
                continue;
            }

            // Step 1 displays intended room pricing based on selected quantity and
            // minimum room occupancy (minPax). Subsequent steps calculate based on
            // actual participant assignments.
            $participantCount = self::PRICING_MODE_SELECTION === $pricingMode
                ? (($room->minPax ?? 1) * $roomSelection->quantity)
                : ($assignmentCounts[$room->id] ?? 0)
            ;
            $totalPrice = $participantCount * $room->price;

            $roomPricing[] = [
                'roomId' => $room->id,
                'label' => $room->label,
                'quantity' => $roomSelection->quantity,
                'participantCount' => $participantCount,
                'unitPrice' => $room->price,
                'totalPrice' => $totalPrice,
            ];
        }

        return $roomPricing;
    }

    /**
     * Calculates room pricing from booking entity data (edit mode).
     *
     * In edit mode, room prices come from the booking entity's individualPrice arrays.
     * Each participant has their room price stored in the room's individualPrice array.
     *
     * @param BookingDto $bookingDto The booking data with booking entity
     *
     * @return array<int, array<string, mixed>> Array of room pricing data with labels, quantities, and totals
     */
    private function calculateRoomPricingFromBooking(BookingDto $bookingDto): array
    {
        $roomPricing = [];
        $roomGroups = [];

        // Group participants by room and sum their individual prices
        foreach ($bookingDto->booking->rooms as $room) {
            if (false === isset($roomGroups[$room->id])) {
                $roomGroups[$room->id] = [
                    'room' => $room,
                    'participantCount' => 0,
                    'totalPrice' => 0.0,
                ];
            }

            // Sum individual prices for all participants in this room
            foreach ($room->mapping as $participantIndex) {
                $individualPrice = $room->individualPrice[$participantIndex] ?? 0.0;
                $roomGroups[$room->id]['totalPrice'] += $individualPrice;
                ++$roomGroups[$room->id]['participantCount'];
            }
        }

        // Build pricing array
        foreach ($roomGroups as $data) {
            $room = $data['room'];
            $participantCount = $data['participantCount'];
            $totalPrice = $data['totalPrice'];

            // Calculate average unit price (price per person)
            $unitPrice = $participantCount > 0 ? $totalPrice / $participantCount : 0.0;

            $roomPricing[] = [
                'roomId' => $room->id,
                'label' => $room->label,
                // Rooms, not occupants: room assignments cannot change in edit mode
                'quantity' => $room->totalCount,
                'participantCount' => $participantCount,
                'unitPrice' => $unitPrice,
                'totalPrice' => $totalPrice,
            ];
        }

        return $roomPricing;
    }
}