<?php

declare(strict_types=1);

namespace app\common\service;

use support\think\Db;

/**
 * 代理管理员树形分红：子代理从上级分红中按 commission_share_rate 抽取，上级保留剩余部分
 */
class AdminCommissionDistributionService
{
    /**
     * @return int[]
     */
    public static function getDescendantAdminIds(int $adminId): array
    {
        if ($adminId <= 0) {
            return [];
        }
        $childIds = Db::name('admin')
            ->where('parent_admin_id', $adminId)
            ->where('status', 'enable')
            ->column('id');
        $all = [];
        foreach ($childIds as $cid) {
            $cid = intval($cid);
            if ($cid <= 0) {
                continue;
            }
            $all[] = $cid;
            foreach (self::getDescendantAdminIds($cid) as $descId) {
                $all[] = $descId;
            }
        }
        return $all;
    }

    /**
     * 非超管可见管理员 ID；超管返回空数组表示不限制
     *
     * @return int[]
     */
    public static function getVisibleAdminIdsForOperator(int $operatorAdminId, bool $isSuperAdmin): array
    {
        if ($isSuperAdmin || $operatorAdminId <= 0) {
            return [];
        }
        $ids = self::getDescendantAdminIds($operatorAdminId);
        $ids[] = $operatorAdminId;
        return array_values(array_unique($ids));
    }

    /**
     * @return array{used_rate:string,remaining_rate:string}
     */
    public static function getShareRemainder(int $parentAdminId, ?int $excludeAdminId = null): array
    {
        $used = '0.00';
        if ($parentAdminId <= 0) {
            return ['used_rate' => $used, 'remaining_rate' => '100.00'];
        }
        $query = Db::name('admin')
            ->where('parent_admin_id', $parentAdminId)
            ->where('status', 'enable');
        if ($excludeAdminId !== null && $excludeAdminId > 0) {
            $query->where('id', '<>', $excludeAdminId);
        }
        $rows = $query->column('commission_share_rate');
        foreach ($rows as $rate) {
            if ($rate === null || $rate === '') {
                continue;
            }
            $used = bcadd($used, bcadd(strval($rate), '0', 2), 2);
        }
        $remaining = bcsub('100.00', $used, 2);
        if (bccomp($remaining, '0', 2) < 0) {
            $remaining = '0.00';
        }
        return ['used_rate' => $used, 'remaining_rate' => $remaining];
    }

    public static function validateCommissionShareRate(?int $parentAdminId, mixed $rateRaw, ?int $excludeAdminId = null): ?string
    {
        if ($parentAdminId === null || $parentAdminId <= 0) {
            return null;
        }
        if ($rateRaw === null || $rateRaw === '') {
            return (string) __('Sub-agent commission share rate is required');
        }
        $rate = bcadd(strval($rateRaw), '0', 2);
        if (bccomp($rate, '0', 2) < 0 || bccomp($rate, '100', 2) > 0) {
            return (string) __('Commission share rate must be between 0 and 100');
        }
        $remainder = self::getShareRemainder($parentAdminId, $excludeAdminId);
        if (bccomp(bcadd($remainder['used_rate'], $rate, 2), '100.00', 2) > 0) {
            return (string) __('Sum of sibling commission share rates cannot exceed 100%');
        }
        return null;
    }

    /**
     * 将渠道本期总佣金按管理员树分配，返回各管理员实得金额
     *
     * @return array<int, array{admin_id:int,commission_amount:string,commission_rate:string,calc_base_amount:string}>
     */
    public static function distributeChannelCommission(int $channelId, string $totalCommission, string $calcBaseAmount): array
    {
        if ($channelId <= 0 || bccomp($totalCommission, '0', 2) <= 0) {
            return [];
        }
        $roots = Db::name('admin')
            ->where('channel_id', $channelId)
            ->where('status', 'enable')
            ->whereRaw('(parent_admin_id IS NULL OR parent_admin_id = 0)')
            ->order('id', 'asc')
            ->column('id');
        if ($roots === []) {
            return [];
        }
        $rootCount = count($roots);
        $perRoot = bcdiv($totalCommission, strval($rootCount), 2);
        $assigned = '0.00';
        $merged = [];
        foreach ($roots as $index => $rootId) {
            $rootId = intval($rootId);
            if ($rootId <= 0) {
                continue;
            }
            $isLast = $index === $rootCount - 1;
            $rootAmount = $isLast ? bcsub($totalCommission, $assigned, 2) : $perRoot;
            if (!$isLast) {
                $assigned = bcadd($assigned, $rootAmount, 2);
            }
            $parts = self::distributeFromAdmin($rootId, $rootAmount, $calcBaseAmount);
            foreach ($parts as $adminId => $amount) {
                if (!isset($merged[$adminId])) {
                    $merged[$adminId] = '0.00';
                }
                $merged[$adminId] = bcadd($merged[$adminId], $amount, 2);
            }
        }
        $out = [];
        foreach ($merged as $adminId => $amount) {
            if (bccomp($amount, '0', 2) <= 0) {
                continue;
            }
            $effectiveRate = bccomp($calcBaseAmount, '0', 2) <= 0
                ? '0.0000'
                : bcdiv($amount, $calcBaseAmount, 6);
            $out[] = [
                'admin_id' => intval($adminId),
                'commission_amount' => $amount,
                'commission_rate' => $effectiveRate,
                'calc_base_amount' => $calcBaseAmount,
            ];
        }
        return $out;
    }

    /**
     * @return array<int, string> admin_id => amount
     */
    private static function distributeFromAdmin(int $adminId, string $amount, string $calcBaseAmount): array
    {
        if ($adminId <= 0 || bccomp($amount, '0', 2) <= 0) {
            return [];
        }
        $children = Db::name('admin')
            ->where('parent_admin_id', $adminId)
            ->where('status', 'enable')
            ->order('id', 'asc')
            ->field(['id', 'commission_share_rate'])
            ->select()
            ->toArray();
        $givenToChildren = '0.00';
        $result = [];
        foreach ($children as $child) {
            $childId = intval($child['id'] ?? 0);
            if ($childId <= 0) {
                continue;
            }
            $rate = bcadd(strval($child['commission_share_rate'] ?? '0'), '0', 2);
            if (bccomp($rate, '0', 2) <= 0) {
                continue;
            }
            $childAmount = bcmul($amount, bcdiv($rate, '100', 4), 2);
            if (bccomp($childAmount, '0', 2) <= 0) {
                continue;
            }
            $givenToChildren = bcadd($givenToChildren, $childAmount, 2);
            $childParts = self::distributeFromAdmin($childId, $childAmount, $calcBaseAmount);
            foreach ($childParts as $aid => $part) {
                if (!isset($result[$aid])) {
                    $result[$aid] = '0.00';
                }
                $result[$aid] = bcadd($result[$aid], $part, 2);
            }
        }
        $selfKeep = bcsub($amount, $givenToChildren, 2);
        if (bccomp($selfKeep, '0', 2) > 0) {
            if (!isset($result[$adminId])) {
                $result[$adminId] = '0.00';
            }
            $result[$adminId] = bcadd($result[$adminId], $selfKeep, 2);
        }
        return $result;
    }

    /**
     * @return array<int, array{admin_id:int,admin_username:string,share_rate:string,commission_amount:string}>
     */
    public static function buildSplitPreview(int $channelId, string $commissionTotal, string $calcBaseAmount): array
    {
        $rows = self::distributeChannelCommission($channelId, $commissionTotal, $calcBaseAmount);
        if ($rows === []) {
            return [];
        }
        $adminIds = array_map(static fn(array $r): int => intval($r['admin_id']), $rows);
        $adminNames = Db::name('admin')->where('id', 'in', $adminIds)->column('username', 'id');
        $parentMap = Db::name('admin')->where('id', 'in', $adminIds)->column('parent_admin_id', 'id');
        $shareRates = Db::name('admin')->where('id', 'in', $adminIds)->column('commission_share_rate', 'id');
        $out = [];
        foreach ($rows as $row) {
            $aid = intval($row['admin_id']);
            $parentId = intval($parentMap[$aid] ?? 0);
            $shareRate = $parentId > 0 ? bcadd(strval($shareRates[$aid] ?? '0'), '0', 2) : '100.00';
            $out[] = [
                'admin_id' => $aid,
                'admin_username' => strval($adminNames[$aid] ?? ('#' . $aid)),
                'share_rate' => $shareRate,
                'commission_amount' => strval($row['commission_amount']),
            ];
        }
        return $out;
    }
}