<?php

if (!function_exists('vacationAbsenceTableExists')) {
    function vacationAbsenceTableExists(PDO $pdo, string $table): bool
    {
        $stmt = $pdo->prepare(
            "SELECT COUNT(*)
             FROM information_schema.TABLES
             WHERE TABLE_SCHEMA = DATABASE()
               AND TABLE_NAME = :table_name"
        );
        $stmt->execute(['table_name' => $table]);
        return (int)$stmt->fetchColumn() > 0;
    }
}

if (!function_exists('vacationAbsenceTableHasColumn')) {
    function vacationAbsenceTableHasColumn(PDO $pdo, string $table, string $column): bool
    {
        $stmt = $pdo->prepare(
            "SELECT COUNT(*)
             FROM information_schema.COLUMNS
             WHERE TABLE_SCHEMA = DATABASE()
               AND TABLE_NAME = :table_name
               AND COLUMN_NAME = :column_name"
        );
        $stmt->execute([
            'table_name' => $table,
            'column_name' => $column,
        ]);
        return (int)$stmt->fetchColumn() > 0;
    }
}

if (!function_exists('vacationAbsenceReasonOptions')) {
    function vacationAbsenceReasonOptions(): array
    {
        return [
            'urlaub' => 'Urlaub',
            'krankheit_mit_atest' => 'Krankheit mit Attest',
            'krankheit_ohne_atest' => 'Krankheit ohne Attest',
            'berufsschule' => 'Berufsschule',
            'weiterbildung' => 'Weiterbildung',
            'persoenliche_gruende' => 'Persoenliche Gründe',
            'sonstiges' => 'Sonstiges',
        ];
    }
}

if (!function_exists('vacationAbsenceDefaultReason')) {
    function vacationAbsenceDefaultReason(): string
    {
        return 'urlaub';
    }
}

if (!function_exists('vacationAbsenceNormalizeReason')) {
    function vacationAbsenceNormalizeReason($reason): string
    {
        $reason = trim((string)$reason);
        $options = vacationAbsenceReasonOptions();

        return array_key_exists($reason, $options) ? $reason : vacationAbsenceDefaultReason();
    }
}

if (!function_exists('vacationAbsenceReasonLabel')) {
    function vacationAbsenceReasonLabel($reason): string
    {
        $reason = vacationAbsenceNormalizeReason($reason);
        $options = vacationAbsenceReasonOptions();

        return $options[$reason] ?? $options[vacationAbsenceDefaultReason()];
    }
}

if (!function_exists('vacationAbsenceCountsAgainstEntitlement')) {
    function vacationAbsenceCountsAgainstEntitlement($reason): bool
    {
        return vacationAbsenceNormalizeReason($reason) === 'urlaub';
    }
}

if (!function_exists('vacationAbsenceEnsureSchema')) {
    function vacationAbsenceEnsureSchema(PDO $pdo): void
    {
        if (!vacationAbsenceTableExists($pdo, 'vacations')) {
            return;
        }

        if (!vacationAbsenceTableHasColumn($pdo, 'vacations', 'absence_reason')) {
            $pdo->exec("ALTER TABLE vacations ADD COLUMN absence_reason VARCHAR(50) NOT NULL DEFAULT 'urlaub'");
        }

        $pdo->exec("
            UPDATE vacations
            SET absence_reason = 'urlaub'
            WHERE absence_reason IS NULL OR TRIM(absence_reason) = ''
        ");
    }
}