<?php

namespace Tests\Unit;

use App\Services\ProjectCosting;
use InvalidArgumentException;
use Tests\TestCase;

class ProjectCostingTest extends TestCase
{
    public function test_filament_line_converts_grams_to_kilograms_before_pricing(): void
    {
        // 250g at £20.00/kg = £5.00
        $line = ProjectCosting::lineTotal('filament', '250', 'g', '20.000000');
        $this->assertSame('5.0000', $line);
    }

    public function test_filament_line_includes_explicit_waste_without_double_counting(): void
    {
        // 250g consumed + 10g explicit purge/support waste = 260g at £20.00/kg
        $line = ProjectCosting::lineTotal('filament', '250', 'g', '20.000000', waste: '10');
        $this->assertSame('5.2000', $line);
    }

    public function test_packaging_line_is_quantity_times_unit_rate(): void
    {
        $line = ProjectCosting::lineTotal('packaging', '3', 'unit', '0.750000');
        $this->assertSame('2.2500', $line);
    }

    public function test_shipping_line_total_is_quantity_times_parcel_rate(): void
    {
        $line = ProjectCosting::lineTotal('shipping', '1', 'parcel', '4.990000');
        $this->assertSame('4.9900', $line);
    }

    public function test_shipping_unit_contribution_divides_rate_by_units_per_parcel_not_batch_yield(): void
    {
        // One £4.99 parcel covering 2 saleable units ships at £2.495 per unit,
        // independent of however many units the manufacturing batch itself yielded.
        $this->assertSame('2.4950', ProjectCosting::shippingUnitContribution('4.990000', 2));
    }

    public function test_shipping_unit_contribution_rejects_zero_or_negative_units_per_parcel(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::shippingUnitContribution('4.990000', 0);
    }

    public function test_filament_rejects_a_quantity_unit_not_in_the_category_allowlist(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::lineTotal('filament', '250', 'G', '20.000000');
    }

    public function test_filament_rejects_kilograms_as_the_quantity_unit(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::lineTotal('filament', '0.25', 'kg', '20.000000');
    }

    public function test_packaging_rejects_a_quantity_unit_not_in_the_category_allowlist(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::lineTotal('packaging', '1', 'units', '0.650000');
    }

    public function test_shipping_rejects_a_quantity_unit_not_in_the_category_allowlist(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::lineTotal('shipping', '1', 'box', '4.990000');
    }

    public function test_aggregate_rejects_a_category_total_exceeding_the_storable_decimal_precision(): void
    {
        // decimal(14,4) tops out around 9,999,999,999.9999; two large-but-individually-valid
        // lines can still sum past that bound, so the aggregate step must re-check it.
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::aggregate([
            ['category' => 'filament', 'line_total' => '9999999999.0000'],
            ['category' => 'filament', 'line_total' => '9999999999.0000'],
        ]);
    }

    public function test_aggregate_rejects_a_grand_total_exceeding_the_storable_decimal_precision(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::aggregate([
            ['category' => 'filament', 'line_total' => '9999999999.0000'],
            ['category' => 'packaging', 'line_total' => '9999999999.0000'],
        ]);
    }

    public function test_zero_quantity_is_a_valid_intentional_zero(): void
    {
        $this->assertSame('0.0000', ProjectCosting::lineTotal('packaging', '0', 'unit', '5.000000'));
    }

    public function test_negative_quantity_is_rejected(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::lineTotal('packaging', '-1', 'unit', '5.000000');
    }

    public function test_negative_rate_is_rejected(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::lineTotal('packaging', '1', 'unit', '-5.000000');
    }

    public function test_absurd_quantity_overflows_and_is_rejected(): void
    {
        $this->expectException(\Throwable::class);
        ProjectCosting::lineTotal('filament', '999999999999', 'g', '999999999999.000000');
    }

    public function test_aggregate_distinguishes_missing_category_from_intentional_zero(): void
    {
        $totals = ProjectCosting::aggregate([
            ['category' => 'filament', 'line_total' => '5.0000'],
            ['category' => 'packaging', 'line_total' => '0.0000'],
        ]);

        $this->assertSame('5.0000', $totals['filament_total']);
        $this->assertSame('0.0000', $totals['packaging_total']);
        $this->assertNull($totals['shipping_total']);
        $this->assertSame('5.0000', $totals['grand_total']);
    }

    public function test_aggregate_grand_total_is_null_when_nothing_costed(): void
    {
        $totals = ProjectCosting::aggregate([]);

        $this->assertNull($totals['filament_total']);
        $this->assertNull($totals['packaging_total']);
        $this->assertNull($totals['shipping_total']);
        $this->assertNull($totals['grand_total']);
    }

    public function test_aggregate_sums_multiple_lines_per_category(): void
    {
        $totals = ProjectCosting::aggregate([
            ['category' => 'filament', 'line_total' => '5.0000'],
            ['category' => 'filament', 'line_total' => '2.5000'],
        ]);

        $this->assertSame('7.5000', $totals['filament_total']);
    }

    public function test_per_unit_divides_grand_total_by_batch_yield_with_rounding(): void
    {
        $this->assertSame('3.3333', ProjectCosting::perUnit('10.0000', 3));
    }

    public function test_per_unit_rejects_zero_or_negative_yield(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::perUnit('10.0000', 0);
    }

    public function test_rejects_unknown_category(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::lineTotal('labour', '1', 'unit', '1.000000');
    }

    public function test_rejects_mixed_currency_summation(): void
    {
        $this->expectException(InvalidArgumentException::class);
        ProjectCosting::assertSameCurrency(['GBP', 'USD']);
    }

    public function test_allows_single_consistent_currency(): void
    {
        ProjectCosting::assertSameCurrency(['GBP', 'GBP', 'GBP']);
        $this->addToAssertionCount(1);
    }

    public function test_validates_iso_currency_allowlist(): void
    {
        $this->assertTrue(ProjectCosting::isValidCurrency('GBP'));
        $this->assertFalse(ProjectCosting::isValidCurrency('XYZ'));
    }
}