<?php

declare(strict_types=1);

namespace App\Scolarite\Application\Query\GetStudentProgression;

use App\Scolarite\Application\Port\TeacherStatisticsReader;
use App\Scolarite\Domain\Service\TeacherStatisticsCalculator;

use function array_map;
use function array_values;

use DateTimeImmutable;

use function sprintf;

use Symfony\Component\Messenger\Attribute\AsMessageHandler;

#[AsMessageHandler(bus: 'query.bus')]
final readonly class GetStudentProgressionHandler
{
    public function __construct(
        private TeacherStatisticsReader $reader,
        private TeacherStatisticsCalculator $calculator,
    ) {
    }

    public function __invoke(GetStudentProgressionQuery $query): StudentProgressionDto
    {
        $now = new DateTimeImmutable();
        $month = (int) $now->format('n');
        $yearStart = $month >= 9 ? (int) $now->format('Y') : (int) $now->format('Y') - 1;
        $academicYearStart = sprintf('%d-09-01', $yearStart);
        $academicYearEnd = sprintf('%d-08-31', $yearStart + 1);

        $history = $this->reader->studentGradeHistory(
            $query->studentId,
            $query->subjectId,
            $query->classId,
            $query->teacherId,
            $query->tenantId,
            $academicYearStart,
            $academicYearEnd,
        );

        $grades = array_map(
            static fn (array $row) => new GradePointDto(
                date: $row['date'],
                value: $row['value'],
                evaluationTitle: $row['evaluationTitle'],
            ),
            $history,
        );

        $points = array_values(array_map(
            static fn (int $i, GradePointDto $g) => [$i + 1, $g->value],
            array_keys($grades),
            $grades,
        ));

        $trendLine = $this->calculator->calculateTrendLine($points);

        return new StudentProgressionDto(
            grades: $grades,
            trendLine: $trendLine,
        );
    }
}