<?php
namespace app\common\utils\approval\service;

use support\exception\BusinessException;
use support\Db;

class ApprovalFlowService 
{
    // --- 公共方法 ---

    /**
     * 启动审批流程
     */
    public function start(string $flowType, string $bizType, string $bizId, array $formData, int $initiatorId): array
    {
        // 1. 获取流程定义
        $flow = Db::table('approval_flows')
            ->where('type', $flowType)
            ->where('is_active', 1)
            ->first();

        if (!$flow) {
            throw new BusinessException("审批流程未找到或已停用: {$flowType}");
        }

        $steps = json_decode($flow->steps, true);
        if (!is_array($steps) || empty($steps)) {
            throw new BusinessException("流程步骤配置错误");
        }

        // 2. 查找第一个有效步骤（考虑 condition）
        $firstStep = $this->getNextValidStep($steps, $formData);
        if (!$firstStep) {
            throw new BusinessException("未找到可执行的审批步骤");
        }

        // 3. 计算截止时间
        $deadlineAt = null;
        if ($flow->timeout_hours > 0) {
            $deadlineAt = date('Y-m-d H:i:s', time() + $flow->timeout_hours * 3600);
        }

        // 4. 创建审批实例
        $instanceId = Db::table('approval_instances')->insertGetId([
            'flow_type' => $flowType,
            'biz_type' => $bizType,
            'biz_id' => $bizId,
            'form_data' => json_encode($formData, JSON_UNESCAPED_UNICODE),
            'initiator_id' => $initiatorId,
            'status' => 'processing', // processing 表示正在进行中
            'current_step' => 0,
            'deadline_at' => $deadlineAt,
            'created_at' => date('Y-m-d H:i:s'),
            'updated_at' => date('Y-m-d H:i:s'),
        ]);

        // 5. 创建审批记录（待办）
        $approverIds = $this->resolveApprovers($firstStep, (object)[
            'initiator_id' => $initiatorId,
            'form_data' => json_encode($formData)
        ]);
        
        foreach ($approverIds as $approverId) {
            Db::table('approval_records')->insert([
                'instance_id' => $instanceId,
                'approver_id' => $approverId,
                'step_index' => 0,
                'action' => '', // 未操作时为空
                'status' => 'pending',
                'approved_at' => date('Y-m-d H:i:s', 0), // 未审批时设置为初始时间
                'created_at' => date('Y-m-d H:i:s'),
                'updated_at' => date('Y-m-d H:i:s'),
            ]);
        }

        // 6. 通知审批人
        $instance = (object)[
            'id' => $instanceId,
            'flow_type' => $flowType,
            'form_data' => json_encode($formData),
            'initiator_id' => $initiatorId
        ];
        $this->sendNotification($approverIds, $instance, 'pending', false);

        // 7. 通知抄送人（当前步骤）
        $this->notifyCCs($firstStep, $instance, 'pending');

        return ['instance_id' => $instanceId];
    }

    /**
     * 执行审批
     */
    public function approve(int $instanceId, int $approverId, string $action, string $comment = '')
    {
        // 验证操作是否有效
        if (!in_array($action, ['approve', 'reject'])) {
            throw new BusinessException("无效的审批操作");
        }

        $instance = Db::table('approval_instances')->where('id', $instanceId)->first();
        if (!$instance) {
            throw new BusinessException("审批实例未找到");
        }

        // 获取流程定义
        $flow = Db::table('approval_flows')
            ->where('type', $instance->flow_type)
            ->first();
            
        if (!$flow) {
            throw new BusinessException("审批流程定义未找到");
        }

        $steps = json_decode($flow->steps, true);
        $currentStepIndex = $instance->current_step;
        $currentStep = $steps[$currentStepIndex] ?? null;

        if (!$currentStep) {
            throw new BusinessException("当前步骤配置错误");
        }

        // 检查用户是否有权限审批
        if (!$this->canUserApproveStep($currentStep, $approverId, $instance)) {
            throw new BusinessException("您无权审批此步骤");
        }

        // 检查用户是否已经审批过
        $existingRecord = Db::table('approval_records')
            ->where('instance_id', $instanceId)
            ->where('approver_id', $approverId)
            ->where('step_index', $currentStepIndex)
            ->first();
            
        if ($existingRecord && $existingRecord->status !== 'pending') {
            throw new BusinessException("您已经审批过此步骤");
        }

        // 更新审批记录
        Db::table('approval_records')
            ->where('instance_id', $instanceId)
            ->where('approver_id', $approverId)
            ->where('step_index', $currentStepIndex)
            ->where('status', 'pending')
            ->update([
                'action' => $action,
                'status' => $action, // 状态与操作一致
                'comment' => $comment,
                'approved_at' => date('Y-m-d H:i:s'),
                'updated_at' => date('Y-m-d H:i:s'),
            ]);

        // 检查当前步骤是否完成（根据 type: any, all）
        $stepCompleted = $this->isStepCompleted($instanceId, $currentStepIndex, $currentStep['type']);

        if (!$stepCompleted) {
            // 步骤未完成，不进入下一步
            return ['status' => 'step_pending'];
        }

        // 步骤已完成，进入下一步或结束
        $nextStepIndex = $this->getNextStepIndex($steps, json_decode($instance->form_data, true), $currentStepIndex);

        if ($nextStepIndex === null) {
            // 流程结束
            Db::table('approval_instances')->where('id', $instanceId)->update([
                'status' => $action, // 最终状态与最后一次操作一致
                'finished_at' => date('Y-m-d H:i:s'),
                'updated_at' => date('Y-m-d H:i:s'),
            ]);

            // 通知发起人结果
            $this->sendNotification([$instance->initiator_id], $instance, $action, false);

            return ['status' => 'completed', 'result' => $action];
        }

        // 进入下一步
        Db::table('approval_instances')->where('id', $instanceId)->update([
            'current_step' => $nextStepIndex,
            'updated_at' => date('Y-m-d H:i:s'),
        ]);

        // 获取下一步信息
        $nextStep = $steps[$nextStepIndex];

        // 创建下一步的审批记录
        $nextApprovers = $this->resolveApprovers($nextStep, $instance);
        foreach ($nextApprovers as $approverId) {
            Db::table('approval_records')->insert([
                'instance_id' => $instanceId,
                'approver_id' => $approverId,
                'step_index' => $nextStepIndex,
                'action' => '',
                'status' => 'pending',
                'approved_at' => date('Y-m-d H:i:s', 0),
                'created_at' => date('Y-m-d H:i:s'),
                'updated_at' => date('Y-m-d H:i:s'),
            ]);
        }

        // 通知下一步审批人
        $this->sendNotification($nextApprovers, $instance, 'pending', false);

        // 通知下一步抄送人
        $this->notifyCCs($nextStep, $instance, 'pending');

        return ['status' => 'next_step', 'step_name' => $nextStep['name']];
    }

    /**
     * 解析审批人
     */
    private function resolveApprovers(array $step, object $instance): array
    {
        $resolved = [];
        $formData = json_decode($instance->form_data ?? '{}', true);

        foreach ($step['approvers'] as $approverConfig) {
            $approverIds = [];

            switch ($approverConfig['type']) {
                case 'role':
                    $approverIds = $this->getUserIdsByRole($approverConfig['value']);
                    break;
                case 'user':
                    $approverIds = [(int)$approverConfig['value']];
                    break;
                case 'initiator_leader':
                    $leaderId = $this->getLeaderIdByUserId($instance->initiator_id);
                    if ($leaderId) $approverIds = [$leaderId];
                    break;
                case 'field_user':
                    if (isset($formData[$approverConfig['value']])) {
                        $approverIds = [(int)$formData[$approverConfig['value']]];
                    }
                    break;
                case 'dept_head':
                    $approverIds = $this->getDeptHeadId($approverConfig['value']);
                    if ($approverIds) $approverIds = [$approverIds];
                    break;
                default:
                    throw new BusinessException("不支持的审批人类型: {$approverConfig['type']}");
            }

            $resolved = array_merge($resolved, $approverIds);
        }

        return array_unique(array_filter($resolved));
    }

    /**
     * 通知抄送人
     */
    private function notifyCCs(array $step, object $instance, string $action = 'pending')
    {
        $ccConfig = $step['cc'] ?? [];
        $ccUserIds = [];
        $formData = json_decode($instance->form_data ?? '{}', true);

        foreach ($ccConfig as $cc) {
            switch ($cc['type']) {
                case 'role':
                    $ccUserIds = array_merge($ccUserIds, $this->getUserIdsByRole($cc['value']));
                    break;
                case 'user':
                    $ccUserIds[] = (int)$cc['value'];
                    break;
                case 'initiator_leader':
                    $leaderId = $this->getLeaderIdByUserId($instance->initiator_id);
                    if ($leaderId) $ccUserIds[] = $leaderId;
                    break;
                case 'field_user':
                    if (isset($formData[$cc['value']])) {
                        $ccUserIds[] = (int)$formData[$cc['value']];
                    }
                    break;
                case 'dept_head':
                    $deptHeadId = $this->getDeptHeadId($cc['value']);
                    if ($deptHeadId) $ccUserIds[] = $deptHeadId;
                    break;
                default:
                    break;
            }
        }

        $ccUserIds = array_unique(array_filter($ccUserIds));

        if (!empty($ccUserIds)) {
            // 记录抄送信息到数据库
            foreach ($ccUserIds as $userId) {
                // 检查是否已存在抄送记录
                $exists = Db::table('approval_ccs')
                    ->where('instance_id', $instance->id)
                    ->where('user_id', $userId)
                    ->exists();
                
                if (!$exists) {
                    Db::table('approval_ccs')->insert([
                        'instance_id' => $instance->id,
                        'user_id' => $userId,
                        'notified_at' => date('Y-m-d H:i:s'),
                        'created_at' => date('Y-m-d H:i:s'),
                        'updated_at' => date('Y-m-d H:i:s'),
                    ]);
                }
            }
            
            // 发送通知
            $this->sendNotification($ccUserIds, $instance, $action, true);
        }
    }

    /**
     * 评估条件
     */
    private function evaluateCondition(?string $condition, array $formData): bool
    {
        if (!$condition) return true;

        $pattern = '/^(\w+)\s*(==|!=|>|<|>=|<=)\s*(.+)$/';
        if (!preg_match($pattern, $condition, $matches)) {
            throw new BusinessException("条件格式错误: {$condition}");
        }

        $field = $matches[1];
        $op = $matches[2];
        $value = trim($matches[3], "\"'");

        $actualValue = $formData[$field] ?? null;

        if (is_numeric($value) && is_numeric($actualValue)) {
            $value = (float)$value;
            $actualValue = (float)$actualValue;
        }

        switch ($op) {
            case '==': return $actualValue == $value;
            case '!=': return $actualValue != $value;
            case '>':  return $actualValue > $value;
            case '<':  return $actualValue < $value;
            case '>=': return $actualValue >= $value;
            case '<=': return $actualValue <= $value;
            default: throw new BusinessException("不支持的操作符: {$op}");
        }
    }

    /**
     * 获取下一个有效步骤索引（考虑 condition）
     */
    private function getNextStepIndex(array $steps, array $formData, int $currentStepIndex): ?int
    {
        for ($i = $currentStepIndex + 1; $i < count($steps); $i++) {
            $step = $steps[$i];
            if (!isset($step['condition']) || $this->evaluateCondition($step['condition'], $formData)) {
                return $i;
            }
        }
        return null;
    }

    /**
     * 检查用户是否有权限审批
     */
    private function canUserApproveStep(array $step, int $userId, object $instance): bool
    {
        $approvers = $this->resolveApprovers($step, $instance);
        return in_array($userId, $approvers);
    }

    /**
     * 检查当前步骤是否完成
     */
    private function isStepCompleted(int $instanceId, int $stepIndex, string $type): bool
    {
        // 获取当前步骤的所有审批记录
        $records = Db::table('approval_records')
            ->where('instance_id', $instanceId)
            ->where('step_index', $stepIndex)
            ->get();

        if ($records->isEmpty()) {
            return false;
        }

        switch ($type) {
            case 'any':
                // 任意一人审批即可（approve或reject都算完成）
                foreach ($records as $record) {
                    if ($record->status !== 'pending') {
                        return true;
                    }
                }
                return false;
                
            case 'all':
                // 所有人都必须审批
                foreach ($records as $record) {
                    if ($record->status === 'pending') {
                        return false;
                    }
                }
                return true;
                
            default:
                return false;
        }
    }

    /**
     * 发送通知（你可以替换为你的通知系统）
     */
    private function sendNotification(array $userIds, object $instance, string $action, bool $isCC)
    {
        $actionText = [
            'pending' => '待审批',
            'approve' => '已通过',
            'reject' => '已拒绝'
        ][$action] ?? $action;

        $prefix = $isCC ? '[抄送]' : '';
        $message = "{$prefix}您有一条审批 {$actionText}：流程ID {$instance->id}，类型 {$instance->flow_type}";

        // TODO: 调用你的消息系统，如邮件、站内信、企业微信等
        // 示例：MessageService::send($userIds, $message);
        echo "通知用户 " . implode(',', $userIds) . "：$message\n";
    }

    /**
     * 获取用户待审批列表
     * @param int $userId 用户ID
     * @return array
     */
    public function getPendingApprovals(int $userId): array
    {
        return Db::table('approval_records as ar')
            ->join('approval_instances as ai', 'ar.instance_id', '=', 'ai.id')
            ->where('ar.approver_id', $userId)
            ->where('ar.status', 'pending')
            ->where('ai.status', 'processing')
            ->select('ai.*')
            ->get()
            ->toArray();
    }

    /**
     * 获取审批历史记录
     * @param int $instanceId
     * @return array
     */
    public function getApprovalHistory(int $instanceId): array
    {
        return Db::table('approval_records')
            ->where('instance_id', $instanceId)
            ->orderBy('step_index')
            ->orderBy('approved_at')
            ->get()
            ->toArray();
    }

    /**
     * 获取审批流程图数据 (简化版)
     * @param int $instanceId
     * @return array
     */
    public function getFlowDiagramData(int $instanceId): array
    {
        $instance = Db::table('approval_instances')->find($instanceId);
        if (!$instance) return [];

        $flow = Db::table('approval_flows')->where('type', $instance->flow_type)->first();
        if (!$flow) return [];

        $steps = json_decode($flow->steps, true);
        $records = Db::table('approval_records')
            ->where('instance_id', $instanceId)
            ->orderBy('step_index')
            ->orderBy('approved_at')
            ->get()
            ->groupBy('step_index');

        $diagramData = [];
        foreach ($steps as $index => $step) {
            $status = 'pending';
            $actions = $records->get($index, collect())->toArray();

            if (!empty($actions)) {
                $hasReject = collect($actions)->contains('action', 'reject');
                if ($hasReject) {
                    $status = 'rejected';
                } else {
                    $status = 'approved';
                }
            } elseif ($index < $instance->current_step) {
                $status = 'approved';
            } elseif ($index == $instance->current_step) {
                $status = 'processing';
            }

            $diagramData[] = [
                'index' => $index,
                'name' => $step['name'],
                'type' => $step['type'],
                'status' => $status,
                'actions' => $actions
            ];
        }
        return $diagramData;
    }

    /**
     * 处理超时的审批实例 (定时任务调用)
     */
    public function handleTimeouts()
    {
        $now = date('Y-m-d H:i:s');
        $expiredInstances = Db::table('approval_instances')
            ->where('status', 'processing')
            ->where('deadline_at', '<=', $now)
            ->get();

        foreach ($expiredInstances as $instance) {
            $flow = Db::table('approval_flows')->where('type', $instance->flow_type)->first();
            if ($flow && $flow->timeout_action) {
                $updateData = [
                    'finished_at' => $now,
                    'updated_at' => $now
                ];
                if ($flow->timeout_action === 'auto_reject') {
                    $updateData['status'] = 'reject';
                } elseif ($flow->timeout_action === 'auto_approve') {
                    $updateData['status'] = 'approve';
                }
                
                Db::table('approval_instances')->where('id', $instance->id)->update($updateData);
                $this->notifyInitiator($instance, $flow->timeout_action);
            }
        }
    }

    // --- 辅助方法 ---

    private function getUserIdsByRole(string $roleCode): array
    {
        return Db::table('user_roles as ur')
            ->join('roles as r', 'ur.role_id', '=', 'r.id')
            ->where('r.code', $roleCode)
            ->pluck('ur.user_id')
            ->toArray();
    }

    private function getLeaderIdByUserId(int $userId): ?int
    {
        return Db::table('user')->where('id', $userId)->value('report_to');
    }

    private function getDeptHeadId(int $deptId): ?int
    {
        return Db::table('departments')->where('id', $deptId)->value('head_user_id');
    }

    private function notifyInitiator(object $instance, string $result)
    {
        echo "通知发起人 {$instance->initiator_id} 审批结果: {$result}\n";
    }
}