<?php

namespace App\Services\Agent;

use App\Models\Agent\Agent;
use App\Models\Agent\AgentCommissionRule;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Hash;
use Illuminate\Support\Str;

class AgentService
{
    public function create(array $data, ?int $createdBy = null, ?Agent $scopeAgent = null): Agent
    {
        return DB::transaction(function () use ($data, $createdBy, $scopeAgent): Agent {
            $parentId = isset($data['parent_id']) ? (int) $data['parent_id'] : null;
            if ($scopeAgent) {
                if ((int) $scopeAgent->level !== Agent::LEVEL_ONE) {
                    throw new \RuntimeException('二级代理不能继续新增下级代理');
                }
                if ($parentId && $parentId !== (int) $scopeAgent->id) {
                    throw new \RuntimeException('一级代理只能新增自己的直属二级代理');
                }
                $parentId = (int) $scopeAgent->id;
            } elseif ($parentId) {
                throw new \RuntimeException('总后台只能新增一级代理');
            }
            $parent = $parentId ? Agent::query()->lockForUpdate()->findOrFail($parentId) : null;
            if ($scopeAgent && $parent && (int) $parent->status !== Agent::STATUS_ENABLED) {
                throw new \RuntimeException('不能在已禁用代理下新增账号');
            }
            if ($parent) {
                $this->assertRatesWithinParent($parent, $data);
            }
            $level = $parent ? ((int) $parent->level + 1) : Agent::LEVEL_ONE;
            if ($level > Agent::MAX_LEVEL) {
                throw new \RuntimeException('代理层级最多为二级');
            }

            $agent = Agent::query()->create([
                'parent_id' => $parent?->id,
                'path' => '/',
                'level' => $level,
                'username' => trim((string) $data['username']),
                'password' => Hash::make((string) $data['password']),
                'withdraw_password' => empty($data['withdraw_password']) ? '' : Hash::make((string) $data['withdraw_password']),
                'real_name' => trim((string) ($data['real_name'] ?? '')),
                'invitation_code' => $this->invitationCode(),
                'deposit_fee_rate' => (string) ($data['deposit_fee_rate'] ?? 0),
                'withdraw_fee_rate' => (string) ($data['withdraw_fee_rate'] ?? 0),
                'flow_commission_rate' => (string) ($data['flow_commission_rate'] ?? 0),
                'profit_commission_rate' => (string) ($data['profit_commission_rate'] ?? 0),
                'status' => (int) ($data['status'] ?? Agent::STATUS_ENABLED),
                'created_by' => $createdBy,
            ]);
            $agent->path = ($parent ? rtrim((string) $parent->path, '/') . '/' : '/') . $agent->id . '/';
            $agent->save();
            AgentCommissionRule::query()->create([
                'agent_id' => $agent->id,
                'flow_rate' => $agent->flow_commission_rate,
                'profit_rate' => $agent->profit_commission_rate,
                'effective_from' => now()->toDateString(),
                'status' => 1,
                'created_by' => $createdBy,
            ]);
            return $agent->fresh();
        });
    }

    public function update(Agent $agent, array $data, ?Agent $scopeAgent = null): Agent
    {
        return DB::transaction(function () use ($agent, $data, $scopeAgent): Agent {
            $agent = Agent::query()->lockForUpdate()->findOrFail($agent->id);
            if ($scopeAgent) {
                $this->assertVisible($scopeAgent, (int) $agent->id);
                if ($agent->parent) {
                    $this->assertRatesWithinParent($agent->parent, $data);
                }
                $this->assertRatesCoverChildren($agent, $data);
            } elseif (array_key_exists('parent_id', $data)) {
                $this->move($agent, $data['parent_id'] === null ? null : (int) $data['parent_id']);
            }
            if (array_key_exists('real_name', $data)) {
                $agent->real_name = trim((string) ($data['real_name'] ?? ''));
            }
            foreach (['username', 'status', 'deposit_fee_rate', 'withdraw_fee_rate', 'flow_commission_rate', 'profit_commission_rate'] as $field) {
                if (array_key_exists($field, $data) && $data[$field] !== null) {
                    $agent->{$field} = $data[$field];
                }
            }
            if (!empty($data['password'])) {
                $agent->password = Hash::make((string) $data['password']);
            }
            if (!empty($data['withdraw_password'])) {
                $agent->withdraw_password = Hash::make((string) $data['withdraw_password']);
            }
            $agent->save();
            return $agent->fresh();
        });
    }

    public function assertVisible(Agent $root, int $targetId): void
    {
        if ((int) $root->id === $targetId) {
            return;
        }
        $visible = Agent::query()->whereKey($targetId)->where('path', 'like', rtrim((string) $root->path, '/') . '/%')->exists();
        if (!$visible) {
            throw new \RuntimeException('无权访问该代理');
        }
    }

    private function invitationCode(): string
    {
        do {
            $code = strtoupper(Str::random(10));
        } while (Agent::query()->where('invitation_code', $code)->exists());
        return $code;
    }

    private function assertRatesWithinParent(Agent $parent, array $data): void
    {
        foreach (['flow_commission_rate', 'profit_commission_rate'] as $field) {
            if (array_key_exists($field, $data) && bccomp((string) $data[$field], (string) $parent->{$field}, 4) > 0) {
                throw new \RuntimeException('下级代理佣金比例不能高于上级');
            }
        }
    }

    private function assertRatesCoverChildren(Agent $agent, array $data): void
    {
        foreach (['flow_commission_rate', 'profit_commission_rate'] as $field) {
            if (!array_key_exists($field, $data)) {
                continue;
            }
            $maxChildRate = Agent::query()->where('parent_id', $agent->id)->max($field) ?? 0;
            if (bccomp((string) $data[$field], (string) $maxChildRate, 4) < 0) {
                throw new \RuntimeException('代理佣金比例不能低于现有下级比例');
            }
        }
    }

    private function move(Agent $agent, ?int $parentId): void
    {
        if ($parentId === (int) $agent->id) {
            throw new \RuntimeException('上级代理不能是自己');
        }
        $currentParentId = $agent->parent_id === null ? null : (int) $agent->parent_id;
        if ($parentId === $currentParentId) {
            return;
        }
        $parent = $parentId ? Agent::query()->lockForUpdate()->findOrFail($parentId) : null;
        if ($parent && str_starts_with((string) $parent->path, (string) $agent->path)) {
            throw new \RuntimeException('不能把代理移动到自己的下级');
        }
        if ($parent && (int) $parent->level !== Agent::LEVEL_ONE) {
            throw new \RuntimeException('二级代理不能作为上级代理');
        }
        if ($parent) {
            $this->assertRatesWithinParent($parent, [
                'flow_commission_rate' => $agent->flow_commission_rate,
                'profit_commission_rate' => $agent->profit_commission_rate,
            ]);
        }
        $oldPath = (string) $agent->path;
        $oldLevel = (int) $agent->level;
        $newLevel = $parent ? ((int) $parent->level + 1) : 1;
        $newPath = ($parent ? rtrim((string) $parent->path, '/') . '/' : '/') . $agent->id . '/';
        $descendants = Agent::query()->where('path', 'like', rtrim($oldPath, '/') . '/%')->lockForUpdate()->get();
        $newMaxLevel = $descendants->max(fn(Agent $descendant) =>
            (int) $descendant->level + $newLevel - $oldLevel
        ) ?? $newLevel;
        if ($newLevel > Agent::MAX_LEVEL || $newMaxLevel > Agent::MAX_LEVEL) {
            throw new \RuntimeException('移动后会产生三级代理，操作已拒绝');
        }

        $agent->parent_id = $parent?->id;
        $agent->path = $newPath;
        $agent->level = $newLevel;
        foreach ($descendants as $descendant) {
            $descendant->path = $newPath . substr((string) $descendant->path, strlen($oldPath));
            $descendant->level = max(1, (int) $descendant->level + $newLevel - $oldLevel);
            $descendant->save();
        }
    }
}