<?php

namespace App\Services\Reports;

use App\Enums\ExpenseCategory;
use App\Enums\FundingSource;
use App\Models\Department;
use App\Models\MedicationExpenseRow;
use App\Models\ReportPeriod;
use Illuminate\Support\Collection;

class MedicationExpenseService
{
    /**
     * Get all funding and category values for the given row.
     *
     * @return array<string, array<string, float>>
     */
    public function valueMatrixForRow(?MedicationExpenseRow $row): array
    {
        $matrix = [];

        foreach (FundingSource::cases() as $fundingSource) {
            foreach (ExpenseCategory::cases() as $expenseCategory) {
                $matrix[$fundingSource->value][$expenseCategory->value] = 0.0;
            }
        }

        if ($row === null) {
            return $matrix;
        }

        $row->loadMissing('values');

        foreach ($row->values as $value) {
            $matrix[$value->funding_source->value][$value->expense_category->value] = (float) $value->amount;
        }

        return $matrix;
    }

    /**
     * Calculate medication expense totals for the given matrix.
     *
     * @param  array<string, array<string, float|int|string|null>>  $matrix
     * @return array<string, mixed>
     */
    public function calculateFromMatrix(array $matrix): array
    {
        $byFundingSource = [];
        $totalWithoutDressing = 0.0;
        $totalDressing = 0.0;

        foreach (FundingSource::cases() as $fundingSource) {
            $withoutDressing = 0.0;
            $dressing = 0.0;

            foreach (ExpenseCategory::cases() as $expenseCategory) {
                $amount = (float) ($matrix[$fundingSource->value][$expenseCategory->value] ?? 0);

                if ($expenseCategory->countsTowardsWithoutDressing()) {
                    $withoutDressing += $amount;
                } else {
                    $dressing += $amount;
                }
            }

            $byFundingSource[$fundingSource->value] = [
                'label' => $fundingSource->label(),
                'without_dressing' => round($withoutDressing, 2),
                'dressing' => round($dressing, 2),
                'total' => round($withoutDressing + $dressing, 2),
            ];

            $totalWithoutDressing += $withoutDressing;
            $totalDressing += $dressing;
        }

        $budgetWithoutDressing = $byFundingSource[FundingSource::Budget->value]['without_dressing'];
        $budgetDressing = $byFundingSource[FundingSource::Budget->value]['dressing'];

        return [
            'byFundingSource' => $byFundingSource,
            'total_without_dressing' => round($totalWithoutDressing, 2),
            'total_dressing' => round($totalDressing, 2),
            'total_expense' => round($totalWithoutDressing + $totalDressing, 2),
            'without_budget_no_dressing' => round($totalWithoutDressing - $budgetWithoutDressing, 2),
            'without_budget_dressing' => round($totalDressing - $budgetDressing, 2),
            'without_budget_total' => round(($totalWithoutDressing - $budgetWithoutDressing) + ($totalDressing - $budgetDressing), 2),
        ];
    }

    /**
     * Calculate medication expense totals for a department in the given period.
     *
     * @return array<string, mixed>
     */
    public function calculateForDepartmentPeriod(ReportPeriod $period, Department $department): array
    {
        $row = MedicationExpenseRow::query()
            ->with('values')
            ->whereBelongsTo($period)
            ->whereBelongsTo($department)
            ->first();

        $matrix = $this->valueMatrixForRow($row);

        return [
            'rowId' => $row?->id,
            'matrix' => $matrix,
            'totals' => $this->calculateFromMatrix($matrix),
        ];
    }

    /**
     * Build totals for many departments in the period.
     *
     * @param  Collection<int, Department>  $departments
     * @return array<int, array<string, mixed>>
     */
    public function calculateForDepartments(ReportPeriod $period, Collection $departments): array
    {
        $rows = MedicationExpenseRow::query()
            ->with('values')
            ->whereBelongsTo($period)
            ->whereIn('department_id', $departments->pluck('id'))
            ->get()
            ->keyBy('department_id');

        return $departments->mapWithKeys(function (Department $department) use ($rows): array {
            /** @var MedicationExpenseRow|null $row */
            $row = $rows->get($department->id);
            $matrix = $this->valueMatrixForRow($row);

            return [$department->id => [
                'rowId' => $row?->id,
                'matrix' => $matrix,
                'totals' => $this->calculateFromMatrix($matrix),
            ]];
        })->all();
    }
}