<?php

namespace App\Services;

use App\Models\Backflow;
use App\Models\Rebate;
use Carbon\Carbon;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use Throwable;

class AutomaticRewardGrantService
{
    public function run(): array
    {
        $result = [];
        foreach (RewardGrantSettingsService::TYPES as $type) {
            $result[$type] = ['granted' => 0, 'skipped' => 0, 'failed' => 0];
            $setting = DB::table('reward_grant_settings')->where('type', $type)->first();
            $scheduled = RewardGrantSettingsService::dueAt($setting, Carbon::now());
            if (!$scheduled) continue;

            $model = $type === 'rebate' ? Rebate::class : Backflow::class;
            $cutoff = $this->cutoff($type, $scheduled);
            $model::where('status', 0)->where('date', '<', $cutoff)
                ->chunkById(100, function ($rewards) use ($type, &$result) {
                    foreach ($rewards as $reward) {
                        try {
                            $outcome = DB::transaction(function () use ($type, $reward) {
                                // Configuration changes wait for the current single-row payout only.
                                $setting = DB::table('reward_grant_settings')->where('type', $type)->lockForUpdate()->first();
                                $scheduled = RewardGrantSettingsService::dueAt($setting, Carbon::now());
                                if (!$scheduled) return 'stopped';
                                return RewardGrantService::grant($type, (int) $reward->id, 'system:auto-grant', true, $this->cutoff($type, $scheduled))
                                    ? 'granted' : 'skipped';
                            }, 3);
                            if ($outcome === 'stopped') return false;
                            ++$result[$type][$outcome];
                        } catch (Throwable $e) {
                            ++$result[$type]['failed'];
                            Log::error('automatic_reward_grant_failed', ['type' => $type, 'id' => $reward->id, 'exception' => $e]);
                        }
                    }
                });
        }
        return $result;
    }

    private function cutoff(string $type, \Carbon\CarbonInterface $scheduled): string
    {
        return $type === 'rebate' ? $scheduled->copy()->setTimezone('America/New_York')->format('Y-m-d')
            : $scheduled->copy()->setTimezone('Asia/Shanghai')->format('Y-m');
    }
}