<?php

namespace Tests\Unit;

use App\Models\StudentContract;
use Carbon\Carbon;
use Tests\TestCase;

class StudentContractClassQuantityTest extends TestCase
{
    public function test_it_calculates_class_quantity_correctly_for_one_weekday(): void
    {
        $contract = new StudentContract();
        $contract->signature_date = Carbon::parse('2023-01-01'); // Sunday
        $contract->end_date = Carbon::parse('2023-01-31'); // 31 days
        $contract->weekday = 1; // Monday (2023-01-02, 09, 16, 23, 30) -> 5 occurrences

        $quantity = $contract->calculateClassQuantity();

        $this->assertEquals(5, $quantity);
    }

    public function test_it_calculates_class_quantity_correctly_for_two_weekdays(): void
    {
        $contract = new StudentContract();
        $contract->signature_date = Carbon::parse('2023-01-01'); // Sunday
        $contract->end_date = Carbon::parse('2023-01-14'); // 2 weeks
        $contract->weekday = 1; // Monday (2 occurrences)
        $contract->second_weekday = 3; // Wednesday (2 occurrences)

        $quantity = $contract->calculateClassQuantity();

        $this->assertEquals(4, $quantity);
    }

    public function test_it_returns_zero_if_end_date_is_before_signature_date(): void
    {
        $contract = new StudentContract();
        $contract->signature_date = Carbon::parse('2023-01-31');
        $contract->end_date = Carbon::parse('2023-01-01');
        $contract->weekday = 1;

        $quantity = $contract->calculateClassQuantity();

        $this->assertEquals(0, $quantity);
    }

    public function test_it_returns_fallback_if_dates_are_missing(): void
    {
        $contract = new StudentContract();
        $contract->class_quantity = 10;
        
        $quantity = $contract->calculateClassQuantity();

        $this->assertEquals(10, $quantity);
    }
}