<?php

namespace App\Services;

use App\Models\BalanceLog;
use App\Models\ShareCommissionRecord;
use App\Models\User;
use Brick\Math\BigDecimal;
use Brick\Math\RoundingMode;
use Carbon\Carbon;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Facades\DB;

/** Registers rebates that have already been paid; never credits a wallet. */
class ShareCommissionRecorder
{
    public const SOURCE_TYPE = 'recharge_rebate_log';

    public function preview(BalanceLog $rebate): array
    {
        $result = $this->prepare($rebate);
        if ($result['status'] === 'skipped') return $result;
        $result['status'] = $this->recordQuery($result['attributes'])->exists() ? 'existing' : 'pending';
        return $result;
    }

    /** Context supplies the original base and percentage during a new rebate payout. */
    public function record(BalanceLog $rebate, array $context = []): array
    {
        return DB::transaction(function () use ($rebate, $context) {
            $locked = BalanceLog::where('id', $rebate->id)->lockForUpdate()->first();
            if (!$locked) return ['status' => 'skipped', 'reason' => 'missing_log'];
            $result = $this->prepare($locked, $context);
            if ($result['status'] === 'skipped') return $result;
            // Current read also protects callers whose transaction snapshot predates a backfill.
            if ($this->recordQuery($result['attributes'])->lockForUpdate()->first()) {
                $result['status'] = 'existing';
                return $result;
            }
            ShareCommissionRecord::create($result['attributes']);
            $result['status'] = 'created';
            return $result;
        });
    }

    private function recordQuery(array $attributes): Builder
    {
        return ShareCommissionRecord::where('source_type', self::SOURCE_TYPE)
            ->where('source_id', $attributes['source_id'])
            ->where('type', 'commission');
    }

    private function prepare(BalanceLog $rebate, array $context = []): array
    {
        if (!$rebate->exists || $rebate->change_type !== '充值返现' || (int)$rebate->type !== 1) {
            return ['status' => 'skipped', 'reason' => 'not_recharge_rebate'];
        }
        $amount = $this->decimal($rebate->amount);
        $before = $this->decimal($rebate->before_balance, 10);
        $after = $this->decimal($rebate->after_balance, 10);
        if ($amount === null || bccomp($amount, '0', 4) <= 0) {
            return ['status' => 'skipped', 'reason' => 'invalid_amount'];
        }
        if ($before === null || $after === null || $this->decimal(bcsub($after, $before, 10)) !== $amount) {
            return ['status' => 'skipped', 'reason' => 'unbalanced_log'];
        }
        $promoters = User::where('member_id', $rebate->member_id)->limit(2)->get(['id']);
        if ($promoters->count() !== 1) {
            return ['status' => 'skipped', 'reason' => $promoters->isEmpty() ? 'missing_promoter' : 'ambiguous_promoter'];
        }
        $rawDate = $rebate->getRawOriginal('created_at');
        if (!$rawDate) return ['status' => 'skipped', 'reason' => 'missing_date'];
        try {
            $zone = config('app.timezone', 'Asia/Shanghai');
            $date = Carbon::parse($rawDate, $zone)->setTimezone($zone)->toDateString();
        } catch (\Throwable $e) {
            return ['status' => 'skipped', 'reason' => 'invalid_date'];
        }

        $inviteeId = null;
        $base = '0.0000';
        $rate = '0.0000';
        if ($context) {
            $base = $this->decimal($context['base_amount'] ?? null);
            $rate = $this->decimal($context['rate'] ?? null);
            $inviteeId = $context['invitee_user_id'] ?? null;
            if ($base === null || bccomp($base, '0', 4) <= 0 || $rate === null
                || bccomp($rate, '0', 4) < 0 || bccomp($rate, '10000', 4) >= 0 || !$inviteeId) {
                return ['status' => 'skipped', 'reason' => 'invalid_context'];
            }
        } elseif (preg_match('/^被邀请人：([0-9]{1,64})充值金额为：(\d{1,16}(?:\.\d{1,10})?)$/u', (string)$rebate->remark, $match)) {
            // Use the historical receipt, not today's rate or the invitee's current referral link.
            $base = $this->decimal($match[2]) ?? '0.0000';
            $invitees = User::where('member_id', $match[1])->limit(2)->get(['id']);
            if ($invitees->count() === 1) $inviteeId = $invitees->first()->id;
            if (bccomp($base, '0', 4) > 0) {
                $effectiveRate = $this->decimal(bcdiv(bcmul($amount, '100', 10), $base, 10));
                if ($effectiveRate !== null && bccomp($effectiveRate, '10000', 4) < 0) $rate = $effectiveRate;
            }
        }
        return [
            'status' => 'pending',
            'incomplete_metadata' => $inviteeId === null || bccomp($base, '0', 4) <= 0,
            'attributes' => [
                'stat_date' => $date,
                'promoter_user_id' => $promoters->first()->id,
                'invitee_user_id' => $inviteeId,
                'type' => 'commission',
                'category' => 'recharge',
                'base_amount' => $base,
                'rate' => $rate,
                'amount' => $amount,
                'source_type' => self::SOURCE_TYPE,
                'source_id' => (string)$rebate->id,
                'status' => 1,
            ],
        ];
    }

    private function decimal($value, int $scale = 4): ?string
    {
        if (is_float($value) && is_finite($value)) $value = sprintf('%.10F', $value);
        if (!is_scalar($value) || !preg_match('/^-?\d{1,16}(?:\.\d+)?$/', (string)$value)) return null;
        return (string)BigDecimal::of((string)$value)->toScale($scale, RoundingMode::HALF_UP);
    }
}