<?php

namespace app\service;

use app\model\ApprovalFlow;
use app\model\ApprovalNode;
use app\model\ApprovalOrder;
use app\model\ApprovalRecord;
use app\model\User;
use support\Db;
use Illuminate\Database\Connection;

class ApprovalService
{
    private Connection $db;

    public function __construct()
    {
        $this->db = Db::connection();
    }

    /**
     * 提交审批
     */
    public function submit(array $data): ApprovalOrder
    {
        return $this->db->transaction(function () use ($data) {
            // 1. 获取审批流程
            $flow = ApprovalFlow::active()
                ->byBusinessType($data['business_type'])
                ->with('nodes')
                ->findOrFail($data['flow_id']);

            // 2. 创建审批单
            $order = ApprovalOrder::create([
                'business_type' => $data['business_type'],
                'business_id' => $data['business_id'],
                'title' => $data['title'],
                'applicant_id' => $data['applicant_id'],
                'status' => ApprovalOrder::STATUS_PENDING,
                'current_nodes' => $this->getFirstNodeIds($flow),
                'flow_id' => $flow->id,
                'form_data' => $data['form_data'] ?? [],
                'attachments' => $data['attachments'] ?? [],
            ]);

            // 3. 记录提交操作
            ApprovalRecord::create([
                'order_id' => $order->id,
                'node_id' => $flow->nodes->first()->id ?? 0,
                'node_type' => 'submit',
                'approver_id' => $data['applicant_id'],
                'action' => ApprovalRecord::ACTION_SUBMIT,
                'comment' => $data['comment'] ?? null,
            ]);

            return $order->load(['flow', 'applicant']);
        });
    }

    /**
     * 审批通过
     */
    public function approve(int $orderId, int $approverId, ?string $comment = null): ApprovalOrder
    {
        return $this->db->transaction(function () use ($orderId, $approverId, $comment) {
            $order = ApprovalOrder::with(['flow.nodes'])->findOrFail($orderId);

            if (!$order->canApprove()) {
                throw new \Exception('当前状态无法审批');
            }

            $currentNodeIds = $order->current_nodes ?? [];
            $currentNode = ApprovalNode::whereIn('id', $currentNodeIds)->first();

            if (!$currentNode) {
                throw new \Exception('当前节点不存在');
            }

            // 记录审批操作
            ApprovalRecord::create([
                'order_id' => $order->id,
                'node_id' => $currentNode->id,
                'node_type' => $currentNode->type,
                'approver_id' => $approverId,
                'action' => ApprovalRecord::ACTION_APPROVE,
                'comment' => $comment,
            ]);

            // 判断节点是否完成
            if ($this->isNodeCompleted($order->id, $currentNode->id)) {
                // 移动到下一节点
                $nextNodes = $this->getNextNodes($order->flow, $currentNode->order);

                if (empty($nextNodes)) {
                    // 审批完成
                    $order->status = ApprovalOrder::STATUS_APPROVED;
                    $order->current_nodes = [];
                } else {
                    $order->current_nodes = collect($nextNodes)->pluck('id')->toArray();
                }

                $order->save();
            }

            return $order->fresh(['flow', 'applicant', 'records']);
        });
    }

    /**
     * 审批拒绝
     */
    public function reject(int $orderId, int $approverId, ?string $comment = null): ApprovalOrder
    {
        return $this->db->transaction(function () use ($orderId, $approverId, $comment) {
            $order = ApprovalOrder::findOrFail($orderId);

            if (!$order->canApprove()) {
                throw new \Exception('当前状态无法审批');
            }

            $currentNodeIds = $order->current_nodes ?? [];
            $currentNode = ApprovalNode::whereIn('id', $currentNodeIds)->first();

            // 记录拒绝操作
            ApprovalRecord::create([
                'order_id' => $order->id,
                'node_id' => $currentNode->id ?? 0,
                'node_type' => $currentNode->type ?? 'unknown',
                'approver_id' => $approverId,
                'action' => ApprovalRecord::ACTION_REJECT,
                'comment' => $comment,
            ]);

            // 更新状态为已拒绝
            $order->status = ApprovalOrder::STATUS_REJECTED;
            $order->current_nodes = [];
            $order->save();

            return $order->fresh(['flow', 'applicant', 'records']);
        });
    }

    /**
     * 撤销申请
     */
    public function cancel(int $orderId, int $userId): ApprovalOrder
    {
        $order = ApprovalOrder::findOrFail($orderId);

        if ($order->applicant_id !== $userId) {
            throw new \Exception('只有申请人可以撤销');
        }

        if (!$order->canEdit() && !$order->canApprove()) {
            throw new \Exception('当前状态无法撤销');
        }

        // 记录撤销操作
        ApprovalRecord::create([
            'order_id' => $order->id,
            'node_id' => 0,
            'node_type' => 'cancel',
            'approver_id' => $userId,
            'action' => ApprovalRecord::ACTION_CANCEL,
            'comment' => '申请人撤销',
        ]);

        $order->status = ApprovalOrder::STATUS_CANCELLED;
        $order->current_nodes = [];
        $order->save();

        return $order->fresh(['flow', 'applicant', 'records']);
    }

    /**
     * 获取审批列表
     */
    public function getList(int $userId, string $type = 'my', int $page = 1, int $pageSize = 20): array
    {
        $query = ApprovalOrder::with(['flow', 'applicant']);

        switch ($type) {
            case 'my':
                $query->where('applicant_id', $userId);
                break;
            case 'pending':
                // 获取用户待审批的订单
                $pendingOrderIds = $this->getPendingOrderIds($userId);
                $query->whereIn('id', $pendingOrderIds);
                break;
            case 'approved':
                // 获取用户已审批的订单
                $approvedOrderIds = ApprovalRecord::where('approver_id', $userId)
                    ->where('action', '!=', ApprovalRecord::ACTION_SUBMIT)
                    ->pluck('order_id')
                    ->unique()
                    ->toArray();
                $query->whereIn('id', $approvedOrderIds);
                break;
        }

        $total = $query->count();
        $list = $query->orderBy('created_at', 'desc')
            ->offset(($page - 1) * $pageSize)
            ->limit($pageSize)
            ->get();

        return [
            'list' => $list,
            'total' => $total,
            'page' => $page,
            'page_size' => $pageSize,
        ];
    }

    /**
     * 获取第一个节点ID列表
     */
    private function getFirstNodeIds(ApprovalFlow $flow): array
    {
        return $flow->nodes
            ->where('order', 0)
            ->pluck('id')
            ->toArray();
    }

    /**
     * 判断节点是否完成
     */
    private function isNodeCompleted(int $orderId, int $nodeId): bool
    {
        $node = ApprovalNode::findOrFail($nodeId);
        $records = ApprovalRecord::where('order_id', $orderId)
            ->where('node_id', $nodeId)
            ->where('action', 'approve')
            ->get();

        $approvers = $node->approvers ?? [];

        if ($node->type === ApprovalNode::TYPE_AND_APPROVE) {
            // 会签：需要所有人通过
            return count($records) >= count($approvers);
        } elseif ($node->type === ApprovalNode::TYPE_OR_APPROVE) {
            // 或签：任一人通过即可
            return count($records) >= 1;
        } else {
            // 单人审批：需要一人通过
            return count($records) >= 1;
        }
    }

    /**
     * 获取下一节点
     */
    private function getNextNodes(ApprovalFlow $flow, int $currentOrder): array
    {
        return $flow->nodes
            ->where('order', '>', $currentOrder)
            ->sortBy('order')
            ->values()
            ->toArray();
    }

    /**
     * 获取用户待审批的订单ID列表
     */
    private function getPendingOrderIds(int $userId): array
    {
        // 获取用户参与的待审批订单
        $pendingOrders = ApprovalOrder::where('status', ApprovalOrder::STATUS_PENDING)
            ->whereNotNull('current_nodes')
            ->get();

        $result = [];
        foreach ($pendingOrders as $order) {
            $currentNodeIds = $order->current_nodes ?? [];
            $nodes = ApprovalNode::whereIn('id', $currentNodeIds)->get();

            foreach ($nodes as $node) {
                $approvers = $node->approvers ?? [];
                if (in_array($userId, $approvers)) {
                    // 检查是否已审批
                    $hasApproved = ApprovalRecord::where('order_id', $order->id)
                        ->where('node_id', $node->id)
                        ->where('approver_id', $userId)
                        ->exists();

                    if (!$hasApproved) {
                        $result[] = $order->id;
                        break;
                    }
                }
            }
        }

        return $result;
    }
}