<?php

/**
 * Attendance helper functions - shared between user and admin handlers
 */

declare(strict_types=1);

/**
 * Vraci aktualni cas a datum z MySQL (jednotny zdroj casu)
 * @return array{now: string, today: string, year: int, month: int}
 */
function getDbNow(PDO $pdo): array
{
    $row = $pdo->query("SELECT NOW() AS now, CURDATE() AS today, YEAR(NOW()) AS y, MONTH(NOW()) AS m")->fetch();
    return [
        'now' => $row['now'],
        'today' => $row['today'],
        'year' => (int)$row['y'],
        'month' => (int)$row['m'],
    ];
}

function roundUpTo15Minutes(string $datetime): string
{
    $timestamp = strtotime($datetime);
    $minutes = (int)date('i', $timestamp);

    $remainder = $minutes % 15;

    if ($remainder === 0) {
        $roundedMinutes = $minutes;
    } else {
        $roundedMinutes = $minutes + (15 - $remainder);
    }

    $baseTime = strtotime(date('Y-m-d H:00:00', $timestamp));
    return date('Y-m-d H:i:s', $baseTime + ($roundedMinutes * 60));
}

function roundDownTo15Minutes(string $datetime): string
{
    $timestamp = strtotime($datetime);
    $minutes = (int)date('i', $timestamp);

    $remainder = $minutes % 15;
    $roundedMinutes = $minutes - $remainder;

    $baseTime = strtotime(date('Y-m-d H:00:00', $timestamp));
    return date('Y-m-d H:i:s', $baseTime + ($roundedMinutes * 60));
}

function roundToNearest10Minutes(string $datetime): string
{
    $timestamp = strtotime($datetime);
    $minutes = (int)date('i', $timestamp);

    $remainder = $minutes % 10;

    if ($remainder < 5) {
        $roundedMinutes = $minutes - $remainder;
    } else {
        $roundedMinutes = $minutes + (10 - $remainder);
    }

    $baseTime = strtotime(date('Y-m-d H:00:00', $timestamp));
    return date('Y-m-d H:i:s', $baseTime + ($roundedMinutes * 60));
}

/**
 * @param array<string, mixed> $record
 */
function calculateWorkMinutes(array $record): int
{
    if (!$record['arrival_time'] || !$record['departure_time']) {
        return 0;
    }

    $arrival = strtotime($record['arrival_time']);
    $departure = strtotime($record['departure_time']);
    $totalMinutes = ($departure - $arrival) / 60;

    if ($record['break_start'] && $record['break_end']) {
        $breakStart = strtotime($record['break_start']);
        $breakEnd = strtotime($record['break_end']);
        $breakMinutes = ($breakEnd - $breakStart) / 60;
        $totalMinutes -= $breakMinutes;
    }

    return max(0, (int)$totalMinutes);
}

/**
 * @return array{vacation_total: float, vacation_used: float, vacation_remaining: float, sick_used: float}
 */
function getLeaveBalance(PDO $pdo, int $userId, ?int $year = null): array
{
    $year = $year ?: (int)date('Y');

    $stmt = $pdo->prepare(
        'SELECT vacation_total, vacation_used, sick_used FROM leave_balances WHERE user_id = ? AND year = ?'
    );
    $stmt->execute([$userId, $year]);
    $balance = $stmt->fetch();

    if (!$balance) {
        return [
            'vacation_total' => 160,
            'vacation_used' => 0,
            'vacation_remaining' => 160,
            'sick_used' => 0,
        ];
    }

    return [
        'vacation_total' => (float)$balance['vacation_total'],
        'vacation_used' => (float)$balance['vacation_used'],
        'vacation_remaining' => (float)$balance['vacation_total'] - (float)$balance['vacation_used'],
        'sick_used' => (float)$balance['sick_used'],
    ];
}

/**
 * Batch get leave balances for multiple users (eliminates N+1 queries)
 *
 * @param array<int, int> $userIds
 * @return array<int, array{vacation_total: float, vacation_used: float, vacation_remaining: float, sick_used: float}>
 */
function getLeaveBalancesBatch(PDO $pdo, array $userIds, ?int $year = null): array
{
    $year = $year ?: (int)date('Y');
    $result = [];

    $default = [
        'vacation_total' => 160,
        'vacation_used' => 0,
        'vacation_remaining' => 160,
        'sick_used' => 0,
    ];

    if (empty($userIds)) {
        return $result;
    }

    $placeholders = implode(',', array_fill(0, count($userIds), '?'));
    $stmt = $pdo->prepare("
        SELECT user_id, vacation_total, vacation_used, sick_used
        FROM leave_balances
        WHERE user_id IN ($placeholders) AND year = ?
    ");
    $params = array_values($userIds);
    $params[] = $year;
    $stmt->execute($params);
    $rows = $stmt->fetchAll();

    $balanceMap = [];
    foreach ($rows as $row) {
        $balanceMap[$row['user_id']] = [
            'vacation_total' => (float)$row['vacation_total'],
            'vacation_used' => (float)$row['vacation_used'],
            'vacation_remaining' => (float)$row['vacation_total'] - (float)$row['vacation_used'],
            'sick_used' => (float)$row['sick_used'],
        ];
    }

    foreach ($userIds as $uid) {
        $result[$uid] = $balanceMap[$uid] ?? $default;
    }

    return $result;
}

function updateLeaveBalance(PDO $pdo, int $userId, string $date, string $leaveType, float $hours): void
{
    if ($leaveType === 'work' || $leaveType === 'holiday' || $leaveType === 'unpaid') {
        return;
    }

    $year = (int)date('Y', strtotime($date));

    $stmt = $pdo->prepare('SELECT id FROM leave_balances WHERE user_id = ? AND year = ?');
    $stmt->execute([$userId, $year]);
    $balance = $stmt->fetch();

    if (!$balance) {
        $stmt = $pdo->prepare(
            'INSERT INTO leave_balances (user_id, year, vacation_total, vacation_used, sick_used)
            VALUES (?, ?, 160, 0, 0)'
        );
        $stmt->execute([$userId, $year]);
    }

    if ($leaveType === 'vacation') {
        $stmt = $pdo->prepare(
            'UPDATE leave_balances SET vacation_used = vacation_used + ? WHERE user_id = ? AND year = ?'
        );
        $stmt->execute([$hours, $userId, $year]);
    } elseif ($leaveType === 'sick') {
        $stmt = $pdo->prepare('UPDATE leave_balances SET sick_used = sick_used + ? WHERE user_id = ? AND year = ?');
        $stmt->execute([$hours, $userId, $year]);
    }
}

function getCzechMonthName(int $month): string
{
    $months = [
        1 => 'Leden', 2 => 'Únor', 3 => 'Březen', 4 => 'Duben',
        5 => 'Květen', 6 => 'Červen', 7 => 'Červenec', 8 => 'Srpen',
        9 => 'Září', 10 => 'Říjen', 11 => 'Listopad', 12 => 'Prosinec',
    ];
    return $months[$month] ?? '';
}

function getCzechDayName(int $dayOfWeek): string
{
    $days = [
        0 => 'neděle', 1 => 'pondělí', 2 => 'úterý', 3 => 'středa',
        4 => 'čtvrtek', 5 => 'pátek', 6 => 'sobota',
    ];
    return $days[$dayOfWeek] ?? '';
}

/**
 * Enrich attendance records with project logs and project names (in-place)
 *
 * @param array<int, array<string, mixed>> $records
 */
function enrichRecordsWithProjectLogs(PDO $pdo, array &$records): void
{
    $recordIds = array_column($records, 'id');
    $recordProjectLogs = [];
    if (!empty($recordIds)) {
        $placeholders = implode(',', array_fill(0, count($recordIds), '?'));
        $stmt = $pdo->prepare(
            "SELECT id, attendance_id, project_id, started_at, ended_at, hours, minutes
            FROM attendance_project_logs
            WHERE attendance_id IN ($placeholders) ORDER BY started_at ASC"
        );
        $stmt->execute($recordIds);
        foreach ($stmt->fetchAll() as $log) {
            $recordProjectLogs[$log['attendance_id']][] = $log;
        }
    }

    $projectIds = [];
    foreach ($records as $rec) {
        if ($rec['project_id']) {
            $projectIds[$rec['project_id']] = $rec['project_id'];
        }
    }
    foreach ($recordProjectLogs as $logs) {
        foreach ($logs as $l) {
            $projectIds[$l['project_id']] = $l['project_id'];
        }
    }
    $projectNameMap = fetchProjectNames($projectIds);

    foreach ($records as &$rec) {
        $rec['project_name'] = $rec['project_id'] ? ($projectNameMap[$rec['project_id']] ?? null) : null;
        $logs = $recordProjectLogs[$rec['id']] ?? [];
        foreach ($logs as &$l) {
            $l['project_name'] = $projectNameMap[$l['project_id']] ?? null;
        }
        unset($l);
        $rec['project_logs'] = $logs;
    }
    unset($rec);
}

/**
 * Calculate per-user totals from records array
 *
 * @param list<array<string, mixed>> $records
 * @return array<int, array<string, mixed>>
 */
function calculateUserTotals(array $records, bool $includeRecords = false): array
{
    $userTotals = [];
    foreach ($records as $record) {
        $uid = $record['user_id'];
        if (!isset($userTotals[$uid])) {
            $userTotals[$uid] = [
                'name' => $record['user_name'],
                'minutes' => 0,
                'working' => false,
                'vacation_hours' => 0,
                'sick_hours' => 0,
                'holiday_hours' => 0,
                'unpaid_hours' => 0,
            ];
            if ($includeRecords) {
                $userTotals[$uid]['records'] = [];
            }
        }

        $leaveType = $record['leave_type'] ?? 'work';
        $leaveHours = (float)($record['leave_hours'] ?? 0);

        if ($leaveType === 'vacation') {
            $userTotals[$uid]['vacation_hours'] += $leaveHours;
        } elseif ($leaveType === 'sick') {
            $userTotals[$uid]['sick_hours'] += $leaveHours;
        } elseif ($leaveType === 'holiday') {
            $userTotals[$uid]['holiday_hours'] += $leaveHours;
        } elseif ($leaveType === 'unpaid') {
            $userTotals[$uid]['unpaid_hours'] += $leaveHours;
        } else {
            $userTotals[$uid]['minutes'] += calculateWorkMinutes($record);
        }

        if ($includeRecords) {
            $userTotals[$uid]['records'][] = $record;
        }

        if ($record['arrival_time'] && !$record['departure_time']) {
            $userTotals[$uid]['working'] = true;
        }
    }
    return $userTotals;
}

/**
 * Add monthly fund data and "working now" status to user totals
 *
 * @param array<array<string, mixed>> $userTotals
 */
function addFundDataToUserTotals(PDO $pdo, array &$userTotals, int $year, int $monthNum): void
{
    $fund = CzechHolidays::getMonthlyWorkFund($year, $monthNum);
    $businessDays = CzechHolidays::getBusinessDaysInMonth($year, $monthNum);

    foreach ($userTotals as $uid => &$ut) {
        $workedHours = round($ut['minutes'] / 60, 1);
        $leaveHours = $ut['vacation_hours'] + $ut['sick_hours'];
        $covered = $workedHours + $leaveHours;
        $ut['fund'] = $fund;
        $ut['business_days'] = $businessDays;
        $ut['worked_hours'] = $workedHours;
        $ut['covered'] = $covered;
        $ut['missing'] = max(0, round($fund - $covered, 1));
        $ut['overtime'] = max(0, round($covered - $fund, 1));
    }
    unset($ut);

    $stmt = $pdo->prepare("
        SELECT DISTINCT user_id FROM attendance
        WHERE shift_date = CURDATE()
        AND arrival_time IS NOT NULL
        AND departure_time IS NULL
        AND (leave_type IS NULL OR leave_type = 'work')
    ");
    $stmt->execute();
    $workingNow = $stmt->fetchAll(PDO::FETCH_COLUMN);
    foreach ($workingNow as $uid) {
        if (isset($userTotals[$uid])) {
            $userTotals[$uid]['working'] = true;
        }
    }
}

/**
 * Fetch project names from offers DB
 *
 * @param array<int, int> $projectIds
 * @return array<int, string>
 */
function fetchProjectNames(array $projectIds): array
{
    if (empty($projectIds)) {
        return [];
    }
    try {
        $pdo = db();
        $placeholders = implode(',', array_fill(0, count($projectIds), '?'));
        $stmt = $pdo->prepare("SELECT id, project_number, name FROM projects WHERE id IN ($placeholders)");
        $stmt->execute(array_values($projectIds));
        $map = [];
        foreach ($stmt->fetchAll() as $p) {
            $map[$p['id']] = $p['project_number'] . ' – ' . $p['name'];
        }
        return $map;
    } catch (\Exception $e) {
        error_log('Failed to fetch project names: ' . $e->getMessage());
        return [];
    }
}