<?php

namespace app\common\service\doctor;

/**
 * 排班时段：起止时间 + 号源间隔
 */
class RosterSegmentService
{
    /**
     * 从排班记录解析 [开始 HH:mm, 结束 HH:mm]，无效返回 null
     */
    public static function resolveWindow(array $roster): ?array
    {
        $start = isset($roster['start_time']) ? trim((string) $roster['start_time']) : '';
        $end = isset($roster['end_time']) ? trim((string) $roster['end_time']) : '';

        if ($start !== '' && $end !== ''
            && preg_match('/^\d{2}:\d{2}$/', $start)
            && preg_match('/^\d{2}:\d{2}$/', $end)
            && $start < $end) {
            return [$start, $end];
        }

        $p = $roster['period'] ?? '';

        if ($p == 1 || $p === 'morning' || $p === '上午') {
            return ['09:00', '12:00'];
        }
        if ($p == 2 || $p === 'afternoon' || $p === '下午') {
            return ['14:00', '18:00'];
        }
        if ($p === 'night' || $p === '夜班' || $p === 'evening') {
            return ['18:00', '22:00'];
        }

        return null;
    }

    public static function normalizeSlotMinutes($raw): int
    {
        $n = (int) $raw;
        if ($n < 5) {
            return 15;
        }
        if ($n > 120) {
            return 120;
        }

        return $n;
    }

    /**
     * 左闭右开 [start, end) 按 slotMinutes 切分，得到每个号的开始时刻 HH:mm
     */
    public static function generateSlotTimes(string $start, string $end, int $slotMinutes): array
    {
        $slotMinutes = self::normalizeSlotMinutes($slotMinutes);
        $base = '1970-01-01 ';
        $cur = strtotime($base . $start . ':00');
        $endTs = strtotime($base . $end . ':00');
        if ($cur === false || $endTs === false || $endTs <= $cur) {
            return [];
        }

        $times = [];
        $step = $slotMinutes * 60;
        while ($cur < $endTs) {
            $times[] = date('H:i', $cur);
            $cur += $step;
        }

        return $times;
    }

    /**
     * quota>0 时限制最大可约槽位数；quota=0 表示不限制（由时段长度决定）
     */
    public static function applyQuotaCap(array $times, int $quota): array
    {
        if ($quota > 0 && count($times) > $quota) {
            return array_slice($times, 0, $quota);
        }

        return $times;
    }
}