<?php

namespace App\Http\Controllers;

use App\Http\Requests\AIChatRequest;
use App\Http\Requests\AITaskRequest;
use App\Models\AIConversation;
use App\Models\AIMessage;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;

class AIAssistantController extends Controller
{
    /**
     * AI服务
     */
    protected $aiService;

    /**
     * 构造函数
     */
    public function __construct()
    {
        $this->aiService = new \App\Services\AIService();
    }

    /**
     * AI对话
     */
    public function chat(AIChatRequest $request)
    {
        try {
            $message = $request->input('message');
            $conversationId = $request->input('conversation_id');
            $context = $request->input('context', []);
            
            // 获取或创建对话
            if ($conversationId) {
                $conversation = AIConversation::where('id', $conversationId)
                    ->where('user_id', auth()->id())
                    ->firstOrFail();
            } else {
                $conversation = AIConversation::create([
                    'user_id' => auth()->id(),
                    'title' => substr($message, 0, 50) . '...',
                    'model' => $this->config['model'],
                    'status' => 'active',
                ]);
            }

            // 添加上下文到消息
            $messages = $this->buildMessages($message, $context, $conversation);

            // 调用AI API
            $response = $this->callAIAPI($messages);

            if (!$response['success']) {
                return response()->json([
                    'code' => 500,
                    'message' => 'AI服务暂时不可用: ' . $response['error']
                ], 500);
            }

            $aiResponse = $response['data'];

            // 保存消息记录
            $userMessage = AIMessage::create([
                'conversation_id' => $conversation->id,
                'role' => 'user',
                'content' => $message,
                'tokens' => $this->estimateTokens($message),
            ]);

            $aiMessage = AIMessage::create([
                'conversation_id' => $conversation->id,
                'role' => 'assistant',
                'content' => $aiResponse,
                'tokens' => $this->estimateTokens($aiResponse),
            ]);

            // 更新对话统计
            $conversation->increment('message_count', 2);
            $conversation->increment('total_tokens', $userMessage->tokens + $aiMessage->tokens);
            $conversation->last_message_at = now();
            $conversation->save();

            return response()->json([
                'code' => 200,
                'data' => [
                    'conversation_id' => $conversation->id,
                    'response' => $aiResponse,
                    'message_id' => $aiMessage->id,
                    'tokens_used' => $userMessage->tokens + $aiMessage->tokens,
                ],
                'message' => 'success'
            ]);
        } catch (\Exception $e) {
            Log::error('AI对话失败: ' . $e->getMessage());
            
            return response()->json([
                'code' => 500,
                'message' => 'AI对话失败: ' . $e->getMessage()
            ], 500);
        }
    }

    /**
     * 构建消息数组
     */
    private function buildMessages(string $message, array $context, AIConversation $conversation): array
    {
        $messages = [];

        // 系统提示词
        $systemPrompt = $this->getSystemPrompt($context);
        $messages[] = ['role' => 'system', 'content' => $systemPrompt];

        // 添加上下文消息
        if (!empty($context)) {
            foreach ($context as $ctx) {
                if (isset($ctx['role']) && isset($ctx['content'])) {
                    $messages[] = ['role' => $ctx['role'], 'content' => $ctx['content']];
                }
            }
        }

        // 添加历史消息（最近10条）
        $historyMessages = AIMessage::where('conversation_id', $conversation->id)
            ->orderBy('created_at', 'desc')
            ->limit(10)
            ->get()
            ->reverse();

        foreach ($historyMessages as $history) {
            $messages[] = ['role' => $history->role, 'content' => $history->content];
        }

        // 添加当前消息
        $messages[] = ['role' => 'user', 'content' => $message];

        return $messages;
    }

    /**
     * 获取系统提示词
     */
    private function getSystemPrompt(array $context): string
    {
        $basePrompt = "你是一个专业的ERP系统AI助手，专门帮助用户处理企业资源管理相关的问题。";

        // 根据上下文添加特定提示
        if (isset($context['module'])) {
            switch ($context['module']) {
                case 'goods':
                    $basePrompt .= "你现在正在处理商品管理模块的问题。";
                    break;
                case 'orders':
                    $basePrompt .= "你现在正在处理订单管理模块的问题。";
                    break;
                case 'purchase':
                    $basePrompt .= "你现在正在处理采购管理模块的问题。";
                    break;
                case 'inventory':
                    $basePrompt .= "你现在正在处理库存管理模块的问题。";
                    break;
                case 'finance':
                    $basePrompt .= "你现在正在处理财务管理模块的问题。";
                    break;
            }
        }

        $basePrompt .= "\n\n请用专业、准确、简洁的语言回答用户的问题。如果涉及具体操作，请提供清晰的步骤说明。";

        return $basePrompt;
    }

    /**
     * 调用AI API
     */
    private function callAIAPI(array $messages): array
    {
        try {
            // 这里使用模拟响应，实际项目中需要配置真实的API密钥
            $apiKey = config('services.ai.api_key', '');
            
            if (empty($apiKey)) {
                // 模拟AI响应（开发环境）
                return $this->mockAIResponse($messages);
            }

            $response = Http::withHeaders([
                'Authorization' => 'Bearer ' . $apiKey,
                'Content-Type' => 'application/json',
            ])->timeout(30)->post($this->config['api_url'], [
                'model' => $this->config['model'],
                'messages' => $messages,
                'max_tokens' => $this->config['max_tokens'],
                'temperature' => $this->config['temperature'],
            ]);

            if ($response->successful()) {
                $data = $response->json();
                $content = $data['choices'][0]['message']['content'] ?? '';
                $tokens = $data['usage']['total_tokens'] ?? 0;

                return [
                    'success' => true,
                    'data' => $content,
                    'tokens' => $tokens,
                ];
            } else {
                Log::error('AI API调用失败: ' . $response->body());
                return [
                    'success' => false,
                    'error' => 'API调用失败: ' . $response->status(),
                ];
            }
        } catch (\Exception $e) {
            Log::error('AI API异常: ' . $e->getMessage());
            return [
                'success' => false,
                'error' => $e->getMessage(),
            ];
        }
    }

    /**
     * 模拟AI响应（开发环境使用）
     */
    private function mockAIResponse(array $messages): array
    {
        $lastMessage = end($messages);
        $userMessage = $lastMessage['content'] ?? '';

        // 根据用户消息生成模拟响应
        $responses = [
            '商品' => "关于商品管理，我可以帮你：\n1. 查询商品信息\n2. 添加新商品\n3. 更新商品库存\n4. 设置商品价格\n5. 管理商品分类\n\n请告诉我具体需要什么帮助？",
            '订单' => "关于订单管理，我可以帮你：\n1. 查看订单状态\n2. 处理新订单\n3. 发货操作\n4. 订单统计\n5. 退款处理\n\n请提供订单号或具体问题。",
            '采购' => "关于采购管理，我可以帮你：\n1. 创建采购单\n2. 供应商管理\n3. 采购审批流程\n4. 收货入库\n5. 采购统计\n\n请告诉我你的具体需求。",
            '库存' => "关于库存管理，我可以帮你：\n1. 库存查询\n2. 库存预警\n3. 盘点管理\n4. 出入库记录\n5. 库存调拨\n\n请提供仓库或商品信息。",
            '财务' => "关于财务管理，我可以帮你：\n1. 收支记录\n2. 财务报表\n3. 发票管理\n4. 对账处理\n5. 预算控制\n\n请告诉我具体财务问题。",
            'default' => "我是ERP系统AI助手，可以帮你处理：\n• 商品管理\n• 订单处理\n• 采购管理\n• 库存控制\n• 财务统计\n• 系统操作指导\n\n请详细描述你的问题，我会尽力提供帮助。"
        ];

        $response = $responses['default'];
        foreach ($responses as $key => $value) {
            if (strpos($userMessage, $key) !== false) {
                $response = $value;
                break;
            }
        }

        // 添加个性化问候
        if (strpos(strtolower($userMessage), '你好') !== false || 
            strpos(strtolower($userMessage), 'hi') !== false ||
            strpos(strtolower($userMessage), 'hello') !== false) {
            $response = "你好！我是ERP系统AI助手。我可以帮你处理企业资源管理的各种问题，包括商品、订单、采购、库存、财务等模块的操作和咨询。有什么可以帮你的吗？";
        }

        return [
            'success' => true,
            'data' => $response,
            'tokens' => $this->estimateTokens($response),
        ];
    }

    /**
     * 执行AI任务
     */
    public function executeTask(AITaskRequest $request)
    {
        try {
            $task = $request->input('task');
            $parameters = $request->input('parameters', []);
            
            // 根据任务类型处理
            $result = $this->processTask($task, $parameters);

            // 记录任务执行
            \App\Models\OperationLog::log([
                'module' => 'AI助手',
                'action' => '执行任务',
                'method' => 'POST',
                'path' => 'api/ai/tasks/execute',
                'request_data' => ['task' => $task, 'parameters' => $parameters],
                'response_data' => $result,
                'remark' => 'AI任务执行',
            ]);

            return response()->json([
                'code' => 200,
                'data' => $result,
                'message' => '任务执行成功'
            ]);
        } catch (\Exception $e) {
            Log::error('AI任务执行失败: ' . $e->getMessage());
            
            return response()->json([
                'code' => 500,
                'message' => '任务执行失败: ' . $e->getMessage()
            ], 500);
        }
    }

    /**
     * 处理具体任务
     */
    private function processTask(string $task, array $parameters): array
    {
        switch ($task) {
            case 'data_analysis':
                return $this->analyzeData($parameters);
            case 'report_generation':
                return $this->generateReport($parameters);
            case 'prediction':
                return $this->makePrediction($parameters);
            case 'recommendation':
                return $this->provideRecommendation($parameters);
            case 'document_summary':
                return $this->summarizeDocument($parameters);
            default:
                return [
                    'success' => false,
                    'error' => '不支持的任务类型',
                    'task' => $task,
                ];
        }
    }

    /**
     * 数据分析
     */
    private function analyzeData(array $parameters): array
    {
        $type = $parameters['type'] ?? 'sales';
        $period = $parameters['period'] ?? 'month';
        
        // 模拟数据分析结果
        $analysis = [
            'type' => $type,
            'period' => $period,
            'summary' => "根据{$period}数据，发现以下趋势：",
            'insights' => [
                '销售额增长15%',
                '最畅销商品：商品A',
                '客户复购率：45%',
                '库存周转率：2.5次',
            ],
            'recommendations' => [
                '增加商品A的库存',
                '优化营销策略提高复购率',
                '关注库存周转率提升',
            ],
        ];

        return [
            'success' => true,
            'analysis' => $analysis,
            'generated_at' => now()->toDateTimeString(),
        ];
    }

    /**
     * 生成报告
     */
    private function generateReport(array $parameters): array
    {
        $reportType = $parameters['report_type'] ?? 'sales';
        $startDate = $parameters['start_date'] ?? now()->subMonth()->toDateString();
        $endDate = $parameters['end_date'] ?? now()->toDateString();
        
        // 模拟报告生成
        $report = [
            'type' => $reportType,
            'period' => $startDate . ' 至 ' . $endDate,
            'title' => ucfirst($reportType) . '分析报告',
            'sections' => [
                'executive_summary' => '报告摘要内容...',
                'data_analysis' => '数据分析内容...',
                'key_findings' => '主要发现...',
                'recommendations' => '建议措施...',
            ],
            'metrics' => [
                'total_sales' => '¥125,000',
                'order_count' => 156,
                'average_order_value' => '¥801',
                'growth_rate' => '15%',
            ],
        ];

        return [
            'success' => true,
            'report' => $report,
            'download_url' => '/api/reports/download/' . uniqid(),
            'generated_at' => now()->toDateTimeString(),
        ];
    }

    /**
     * 预测分析
     */
    private function makePrediction(array $parameters): array
    {
        $target = $parameters['target'] ?? 'sales';
        $periods = $parameters['periods'] ?? 3;
        
        // 模拟预测结果
        $predictions = [];
        $current = 100000; // 基准值
        
        for ($i = 1; $i <= $periods; $i++) {
            $growth = rand(5, 15) / 100; // 5-15%增长
            $predicted = $current * (1 + $growth);
            
            $predictions[] = [
                'period' => "第{$i}期",
                'value' => number_format($predicted, 2),
                'growth' => number_format($growth * 100, 1) . '%',
                'confidence' => rand(70, 95) . '%',
            ];
            
            $current = $predicted;
        }

        return [
            'success' => true,
            'target' => $target,
            'predictions' => $predictions,
            'notes' => '基于历史数据的趋势预测，实际结果可能因市场变化而有所不同。',
        ];
    }

    /**
     * 提供建议
     */
    private function provideRecommendation(array $parameters): array
    {
        $area = $parameters['area'] ?? 'inventory';
        
        $recommendations = [
            'inventory' => [
                '优化库存水平，减少积压',
                '建立安全库存机制',
                '实施ABC分类管理',
                '定期盘点，确保账实相符',
            ],
            'sales' => [
                '加强客户关系管理',
                '优化产品定价策略',
                '拓展销售渠道',
                '提升客户服务质量',
            ],
            'purchase' => [
                '建立供应商评估体系',
                '优化采购审批流程',
                '实施集中采购降低成本',
                '加强采购合同管理',
            ],
            'finance' => [
                '加强现金流管理',
                '优化成本控制',
                '完善财务报告体系',
                '加强预算执行监控',
            ],
        ];

        $areaRecommendations = $recommendations[$area] ?? $recommendations['inventory'];

        return [
            'success' => true,
            'area' => $area,
            'recommendations' => $areaRecommendations,
            'priority' => '根据当前业务状况，建议优先实施前两项。',
        ];
    }

    /**
     * 文档摘要
     */
    private function summarizeDocument(array $parameters): array
    {
        $content = $parameters['content'] ?? '';
        $maxLength = $parameters['max_length'] ?? 200;
        
        if (empty($content)) {
            return [
                'success' => false,
                'error' => '文档内容不能为空',
            ];
        }

        // 简单摘要算法（实际应使用AI）
        $sentences = preg_split('/[。！？.!?]/', $content);
        $sentences = array_filter($sentences, function($sentence) {
            return strlen(trim($sentence)) > 10;
        });

        $summary = '';
        $count = 0;
        
        foreach ($sentences as $sentence) {
            if (strlen($summary) + strlen($sentence) < $maxLength) {
                $summary .= trim($sentence) . '。';
                $count++;
            }
            
            if ($count >= 3) {
                break;
            }
        }

        if (empty($summary)) {
            $summary = substr($content, 0, $maxLength) . '...';
        }

        $keywords = $this->extractKeywords($content);

        return [
            'success' => true,
            'original_length' => strlen($content),
            'summary_length' => strlen($summary),
            'summary' => $summary,
            'keywords' => $keywords,
            'compression_rate' => round((1 - strlen($summary) / strlen($content)) * 100, 1) . '%',
        ];
    }

    /**
     * 提取关键词
     */
    private function extractKeywords(string $content): array
    {
        // 简单关键词提取（实际应使用更复杂的算法）
        $words = preg_split('/\s+/', $content);
        $wordCount = array_count_values($words);
        arsort($wordCount);
        
        $keywords = array_slice(array_keys($wordCount), 0, 10);
        
        // 过滤常见词
        $commonWords = ['的', '了', '在', '是', '和', '与', '或', '等', '这个', '那个'];
        $keywords = array_diff($keywords, $commonWords);
        
        return array_values($keywords);
    }

    /**
     * 估算Token数量
     */
    private function estimateTokens(string $text): int
    {
        // 简单估算：英文约4字符=1token，中文约1.5字符=1token
        $chineseChars = preg_match_all('/[\x{4e00}-\x{9fa5}]/u', $text);
        $otherChars = strlen($text) - $chineseChars * 3; // 中文字符占3字节
        
        $tokens = ceil($chineseChars / 1.5 + $otherChars / 4);
        
        return max(1, $tokens);
    }

    /**
     * 获取对话列表
     */
    public function getConversations(Request $request)
    {
        $query = AIConversation::where('user_id', auth()->id())
            ->orderBy('last_message_at', 'desc');

        if ($request->filled('status')) {
            $query->where('status', $request->status);
        }

        if ($request->filled('keyword')) {
            $keyword = $request->keyword;
            $query->where(function ($q) use ($keyword) {
                $q->where('title', 'like', "%{$keyword}%")
                  ->orWhereHas('messages', function ($q) use ($keyword) {
                      $q->where('content', 'like', "%{$keyword}%");
                  });
            });
        }

        $perPage = $request->input('limit', 20);
        $conversations = $query->paginate($perPage);

        // 加载最后一条消息
        $conversations->load(['lastMessage']);

        return response()->json([
            'code' => 200,
            'data' => [
                'list' => $conversations->items(),
                'total' => $conversations->total(),
                'current_page' => $conversations->currentPage(),
                'last_page' => $conversations->lastPage(),
            ],
            'message' => 'success'
        ]);
    }

    /**
     * 获取对话详情
     */
    public function getConversation(string $id)
    {
        $conversation = AIConversation::with(['messages' => function ($query) {
            $query->orderBy('created_at', 'asc');
        }])->where('id', $id)
          ->where('user_id', auth()->id())
          ->firstOrFail();

        return response()->json([
            'code' => 200,
            'data' => $conversation,
            'message' => 'success'
        ]);
    }

    /**
     * 删除对话
     */
    public function deleteConversation(string $id)
    {
        $conversation = AIConversation::where('id', $id)
            ->where('user_id', auth()->id())
            ->firstOrFail();

        try {
            // 删除相关消息
            AIMessage::where('conversation_id', $id)->delete();
            
            // 删除对话
            $conversation->delete();

            return response()->json([
                'code' => 200,
                'message' => '对话删除成功'
            ]);
        } catch (\Exception $e) {
            Log::error('删除对话失败: ' . $e->getMessage());
            
            return response()->json([
                'code' => 500,
                'message' => '删除失败: ' . $e->getMessage()
            ], 500);
        }
    }

    /**
     * 清空对话消息
     */
    public function clearConversation(string $id)
    {
        $conversation = AIConversation::where('id', $id)
            ->where('user_id', auth()->id())
            ->firstOrFail();

        try {
            // 删除所有消息
            AIMessage::where('conversation_id', $id)->delete();
            
            // 重置对话统计
            $conversation->update([
                'message_count' => 0,
                'total_tokens' => 0,
                'last_message_at' => null,
            ]);

            return response()->json([
                'code' => 200,
                'message' => '对话消息已清空'
            ]);
        } catch (\Exception $e) {
            Log::error('清空对话失败: ' . $e->getMessage());
            
            return response()->json([
                'code' => 500,
                'message' => '清空失败: ' . $e->getMessage()
            ], 500);
        }
    }

    /**
     * 获取AI能力列表
     */
    public function getCapabilities()
    {
        $capabilities = [
            'chat' => [
                'name' => '智能对话',
                'description' => '回答ERP系统相关问题，提供操作指导',
                'examples' => [
                    '如何创建采购单？',
                    '查看商品库存',
                    '订单处理流程',
                ],
            ],
            'data_analysis' => [
                'name' => '数据分析',
                'description' => '分析销售、库存、财务等数据',
                'examples' => [
                    '分析本月销售趋势',
                    '库存周转率分析',
                    '客户购买行为分析',
                ],
            ],
            'report_generation' => [
                'name' => '报告生成',
                'description' => '自动生成各类业务报告',
                'examples' => [
                    '生成销售日报',
                    '制作库存月报',
                    '财务季度分析报告',
                ],
            ],
            'prediction' => [
                'name' => '趋势预测',
                'description' => '基于历史数据预测未来趋势',
                'examples' => [
                    '预测下月销售额',
                    '库存需求预测',
                    '客户增长预测',
                ],
            ],
            'recommendation' => [
                'name' => '智能建议',
                'description' => '提供业务优化建议',
                'examples' => [
                    '库存优化建议',
                    '销售策略建议',
                    '成本控制建议',
                ],
            ],
            'document_summary' => [
                'name' => '文档摘要',
                'description' => '自动提取文档关键信息',
                'examples' => [
                    '合同摘要',
                    '会议纪要整理',
                    '报告要点提取',
                ],
            ],
        ];

        return response()->json([
            'code' => 200,
            'data' => $capabilities,
            'message' => 'success'
        ]);
    }

    /**
     * 获取使用统计
     */
    public function getUsageStatistics(Request $request)
    {
        $userId = auth()->id();
        
        // 今日使用统计
        $todayStart = now()->startOfDay();
        $todayEnd = now()->endOfDay();
        
        $todayConversations = AIConversation::where('user_id', $userId)
            ->whereBetween('created_at', [$todayStart, $todayEnd])
            ->count();
        
        $todayMessages = AIMessage::whereHas('conversation', function ($query) use ($userId) {
            $query->where('user_id', $userId);
        })->whereBetween('created_at', [$todayStart, $todayEnd])
          ->count();
        
        $todayTokens = AIMessage::whereHas('conversation', function ($query) use ($userId) {
            $query->where('user_id', $userId);
        })->whereBetween('created_at', [$todayStart, $todayEnd])
          ->sum('tokens');

        // 月度统计
        $monthStart = now()->startOfMonth();
        $monthEnd = now()->endOfMonth();
        
        $monthConversations = AIConversation::where('user_id', $userId)
            ->whereBetween('created_at', [$monthStart, $monthEnd])
            ->count();
        
        $monthMessages = AIMessage::whereHas('conversation', function ($query) use ($userId) {
            $query->where('user_id', $userId);
        })->whereBetween('created_at', [$monthStart, $monthEnd])
          ->count();
        
        $monthTokens = AIMessage::whereHas('conversation', function ($query) use ($userId) {
            $query->where('user_id', $userId);
        })->whereBetween('created_at', [$monthStart, $monthEnd])
          ->sum('tokens');

        // 总体统计
        $totalConversations = AIConversation::where('user_id', $userId)->count();
        $totalMessages = AIMessage::whereHas('conversation', function ($query) use ($userId) {
            $query->where('user_id', $userId);
        })->count();
        $totalTokens = AIMessage::whereHas('conversation', function ($query) use ($userId) {
            $query->where('user_id', $userId);
        })->sum('tokens');

        $statistics = [
            'today' => [
                'conversations' => $todayConversations,
                'messages' => $todayMessages,
                'tokens' => $todayTokens,
            ],
            'month' => [
                'conversations' => $monthConversations,
                'messages' => $monthMessages,
                'tokens' => $monthTokens,
            ],
            'total' => [
                'conversations' => $totalConversations,
                'messages' => $totalMessages,
                'tokens' => $totalTokens,
            ],
        ];

        return response()->json([
            'code' => 200,
            'data' => $statistics,
            'message' => 'success'
        ]);
    }

    /**
     * 测试AI连接
     */
    public function testConnection()
    {
        try {
            $testMessage = '你好，请回复"AI服务正常"以确认连接成功。';
            $messages = [
                ['role' => 'system', 'content' => '你是一个测试助手，只需要按照要求回复。'],
                ['role' => 'user', 'content' => $testMessage],
            ];

            $response = $this->callAIAPI($messages);

            if ($response['success']) {
                return response()->json([
                    'code' => 200,
                    'data' => [
                        'status' => 'connected',
                        'response' => $response['data'],
                        'response_time' => '正常',
                    ],
                    'message' => 'AI服务连接正常'
                ]);
            } else {
                return response()->json([
                    'code' => 503,
                    'data' => [
                        'status' => 'disconnected',
                        'error' => $response['error'],
                    ],
                    'message' => 'AI服务连接失败'
                ], 503);
            }
        } catch (\Exception $e) {
            return response()->json([
                'code' => 500,
                'data' => [
                    'status' => 'error',
                    'error' => $e->getMessage(),
                ],
                'message' => '测试过程中发生错误'
            ], 500);
        }
    }
}