<?php

namespace App\Services;

use App\Models\SystemSetting;
use App\Models\WechatUser;
use App\Models\WechatUserHomeVisit;
use Illuminate\Support\Carbon;

class WechatHomeVisitService
{
    public const KEY_TOTAL_OFFSET = 'home_visit_total_offset';

    public const KEY_TODAY_OFFSET = 'home_visit_today_offset';

    public const KEY_TODAY_OFFSET_DATE = 'home_visit_today_offset_date';

    public function record(WechatUser $user): void
    {
        WechatUserHomeVisit::query()->create([
            'wechat_user_id' => $user->id,
            'visited_at' => now(),
        ]);
    }

    public function actualTotalVisits(): int
    {
        return (int) WechatUserHomeVisit::query()->count();
    }

    public function actualTodayVisits(): int
    {
        $tz = (string) config('app.timezone');
        $start = Carbon::now($tz)->startOfDay();
        $end = Carbon::now($tz)->endOfDay();

        return (int) WechatUserHomeVisit::query()
            ->whereBetween('visited_at', [$start, $end])
            ->count();
    }

    public function totalVisits(): int
    {
        return max(0, $this->actualTotalVisits() + $this->totalOffset());
    }

    public function todayVisits(): int
    {
        return max(0, $this->actualTodayVisits() + $this->todayOffset());
    }

    public function totalOffset(): int
    {
        return SystemSetting::getInt(self::KEY_TOTAL_OFFSET, 0);
    }

    public function todayOffset(): int
    {
        $today = Carbon::now((string) config('app.timezone'))->toDateString();
        $offsetDate = SystemSetting::getString(self::KEY_TODAY_OFFSET_DATE);

        if ($offsetDate !== $today) {
            return 0;
        }

        return SystemSetting::getInt(self::KEY_TODAY_OFFSET, 0);
    }

    /**
     * @return array{
     *     actual_total: int,
     *     actual_today: int,
     *     display_total: int,
     *     display_today: int,
     *     total_offset: int,
     *     today_offset: int
     * }
     */
    public function visitStatsPayload(): array
    {
        return [
            'actual_total' => $this->actualTotalVisits(),
            'actual_today' => $this->actualTodayVisits(),
            'display_total' => $this->totalVisits(),
            'display_today' => $this->todayVisits(),
            'total_offset' => $this->totalOffset(),
            'today_offset' => $this->todayOffset(),
        ];
    }

    public function updateDisplayValues(int $displayTotal, int $displayToday): void
    {
        SystemSetting::setInt(
            self::KEY_TOTAL_OFFSET,
            $displayTotal - $this->actualTotalVisits(),
        );

        $today = Carbon::now((string) config('app.timezone'))->toDateString();
        SystemSetting::setInt(
            self::KEY_TODAY_OFFSET,
            $displayToday - $this->actualTodayVisits(),
        );
        SystemSetting::setString(self::KEY_TODAY_OFFSET_DATE, $today);
    }

    public function totalWechatUsers(): int
    {
        return (int) WechatUser::query()->count();
    }
}