<?php

namespace App\Commands;

use App\Services\EnrollmentStatusService;
use CodeIgniter\CLI\BaseCommand;
use CodeIgniter\CLI\CLI;
use CodeIgniter\Database\BaseConnection;

class SyncStudentActivity extends BaseCommand
{
    protected $group = 'Enrollment';
    protected $name = 'students:sync-activity';
    protected $description = 'Synchronize students.is_active from current-year enrollment_status.';
    protected $usage = 'php spark students:sync-activity --school-year=YYYY-YYYY [--dry-run]';
    protected $options = [
        '--school-year' => 'School year to use as the controlling enrollment year.',
        '--dry-run' => 'Report changes without updating students.',
    ];

    private BaseConnection $db;
    private EnrollmentStatusService $statusService;

    public function run(array $params)
    {
        $this->db = \Config\Database::connect();
        $this->statusService = new EnrollmentStatusService($this->db);

        $schoolYear = $this->optionValue('school-year');
        if ($schoolYear === '') {
            $schoolYear = $this->statusService->currentSchoolYear();
        }

        if ($schoolYear === '') {
            CLI::error('Missing --school-year and no configured current school year was found.');
            return EXIT_ERROR;
        }

        $dryRun = CLI::getOption('dry-run') !== null;
        $duplicates = $this->duplicates($schoolYear);
        $unknownStatuses = [];
        $withoutEnrollment = [];
        $mismatches = [];
        $updated = 0;

        $students = $this->db->table('students')
            ->select('id, school_id, firstname, lastname, is_active')
            ->orderBy('id', 'ASC')
            ->get()
            ->getResultArray();

        foreach ($students as $student) {
            $studentId = (int) $student['id'];
            $enrollment = $this->statusService->controllingEnrollment($studentId, $schoolYear);
            if ($enrollment === null) {
                $expected = 0;
                $withoutEnrollment[] = $this->studentLabel($student);
            } else {
                try {
                    $status = $this->statusService->normalizeStatus((string) ($enrollment['enrollment_status'] ?? ''));
                    $expected = $this->statusService->activeFlagForStatus($status);
                } catch (\InvalidArgumentException $e) {
                    $unknownStatuses[] = [
                        'student' => $this->studentLabel($student),
                        'enrollment_id' => (int) ($enrollment['id'] ?? 0),
                        'status' => (string) ($enrollment['enrollment_status'] ?? ''),
                    ];
                    continue;
                }
            }

            $actual = (int) ($student['is_active'] ?? 1);
            if ($actual !== $expected) {
                $mismatches[] = [
                    'student' => $this->studentLabel($student),
                    'current' => $actual,
                    'expected' => $expected,
                    'status' => (string) ($enrollment['enrollment_status'] ?? 'no enrollment'),
                ];

                if (! $dryRun) {
                    $this->db->table('students')->where('id', $studentId)->update(['is_active' => $expected]);
                    $updated++;
                }
            }
        }

        CLI::write('School year: ' . $schoolYear);
        CLI::write('Dry run: ' . ($dryRun ? 'yes' : 'no'));
        CLI::write('Duplicate enrollment groups: ' . count($duplicates));
        foreach ($duplicates as $row) {
            CLI::write(sprintf(
                '  student_id=%d school_year=%s semester=%s count=%d',
                (int) $row['student_id'],
                (string) $row['school_year'],
                (string) ($row['semester'] ?? ''),
                (int) $row['row_count']
            ));
        }

        CLI::write('Unknown statuses: ' . count($unknownStatuses));
        foreach ($unknownStatuses as $row) {
            CLI::write(sprintf('  %s enrollment_id=%d status=%s', $row['student'], $row['enrollment_id'], $row['status']));
        }

        CLI::write('Students without current enrollment: ' . count($withoutEnrollment));
        foreach (array_slice($withoutEnrollment, 0, 50) as $label) {
            CLI::write('  ' . $label);
        }
        if (count($withoutEnrollment) > 50) {
            CLI::write('  ... ' . (count($withoutEnrollment) - 50) . ' more');
        }

        CLI::write('Mismatches: ' . count($mismatches));
        foreach ($mismatches as $row) {
            CLI::write(sprintf(
                '  %s current=%d expected=%d status=%s',
                $row['student'],
                $row['current'],
                $row['expected'],
                $row['status']
            ));
        }

        if (! $dryRun) {
            CLI::write('Updated students: ' . $updated);
        }

        return EXIT_SUCCESS;
    }

    private function duplicates(string $schoolYear): array
    {
        return $this->db->table('enrollments')
            ->select('student_id, school_year, semester, COUNT(*) AS row_count')
            ->where('school_year', $schoolYear)
            ->groupBy('student_id, school_year, semester')
            ->having('COUNT(*) >', 1)
            ->orderBy('student_id', 'ASC')
            ->get()
            ->getResultArray();
    }

    private function studentLabel(array $student): string
    {
        $name = trim((string) ($student['firstname'] ?? '') . ' ' . (string) ($student['lastname'] ?? ''));
        return '#' . (int) ($student['id'] ?? 0) . ($name !== '' ? ' ' . $name : '');
    }

    private function optionValue(string $name): string
    {
        $value = CLI::getOption($name);
        if (is_string($value) && trim($value) !== '') {
            return trim($value);
        }

        $argv = $_SERVER['argv'] ?? [];
        $prefix = '--' . $name . '=';
        foreach ($argv as $index => $arg) {
            if (is_string($arg) && str_starts_with($arg, $prefix)) {
                return trim(substr($arg, strlen($prefix)));
            }

            if ($arg === '--' . $name && isset($argv[$index + 1])) {
                return trim((string) $argv[$index + 1]);
            }
        }

        return '';
    }
}