import { Request, Response } from 'express';
import { logger, StructuredLogger } from '../utils/logger';
import { DocumentModel } from '../models/DocumentModel';
import { fileStorageService } from '../services/fileStorageService';
import { jobQueueService } from '../services/jobQueueService';
import { uploadProgressService } from '../services/uploadProgressService';
import { uploadMonitoringService } from '../services/uploadMonitoringService';

export const documentController = {
  async uploadDocument(req: Request, res: Response): Promise<void> {
    const startTime = Date.now();
    const structuredLogger = new StructuredLogger(req.correlationId);
    
    try {
      const userId = req.user?.uid;
      if (!userId) {
        res.status(401).json({ 
          error: 'User not authenticated',
          correlationId: req.correlationId 
        });
        return;
      }

      // Check if file was uploaded
      if (!req.file) {
        res.status(400).json({ 
          error: 'No file uploaded',
          correlationId: req.correlationId 
        });
        return;
      }

      const file = req.file;
      
      // Track upload start
      const uploadEventData: any = {
        userId,
        fileInfo: {
          originalName: file.originalname,
          size: file.size,
          mimetype: file.mimetype,
        },
        status: 'started',
        stage: 'upload_initiated',
      };

      if (req.correlationId) {
        uploadEventData.correlationId = req.correlationId;
      }

      uploadMonitoringService.trackUploadEvent(uploadEventData);

      structuredLogger.uploadStart({
        originalName: file.originalname,
        size: file.size,
        mimetype: file.mimetype,
      }, userId);
      
      // Always use optimized agentic RAG processing - no strategy selection needed
      const processingStrategy = 'optimized_agentic_rag';

      // Store file and get file path
      const storageResult = await fileStorageService.storeFile(file, userId);
      
      if (!storageResult.success || !storageResult.fileInfo) {
        const processingTime = Date.now() - startTime;
        
        // Track upload failure
        const failureEventData: any = {
          userId,
          fileInfo: {
            originalName: file.originalname,
            size: file.size,
            mimetype: file.mimetype,
          },
          status: 'failed',
          stage: 'file_storage',
          error: {
            message: storageResult.error || 'Failed to store file',
            type: 'storage_error',
            code: 'STORAGE_ERROR',
          },
          processingTime,
        };

        if (req.correlationId) {
          failureEventData.correlationId = req.correlationId;
        }

        uploadMonitoringService.trackUploadEvent(failureEventData);

        structuredLogger.uploadError(
          new Error(storageResult.error || 'Failed to store file'),
          {
            originalName: file.originalname,
            size: file.size,
            mimetype: file.mimetype,
          },
          userId,
          'file_storage'
        );

        res.status(500).json({ 
          error: 'Failed to store file',
          correlationId: req.correlationId 
        });
        return;
      }
      
      // Create document record
      const document = await DocumentModel.create({
        user_id: userId,
        original_file_name: file.originalname,
        file_path: storageResult.fileInfo.path,
        file_size: file.size,
        status: 'uploaded'
      });

      // Always auto-process with optimized agentic RAG
      try {
        const jobId = await jobQueueService.addJob(
          'document_processing',
          {
            documentId: document.id,
            userId: userId,
            options: { strategy: processingStrategy }
          },
          0 // Normal priority
        );
        logger.info('Document processing job queued with optimized agentic RAG', { 
          documentId: document.id, 
          jobId, 
          strategy: processingStrategy 
        });
        
        // Update status to indicate it's queued for processing
        await DocumentModel.updateById(document.id, { status: 'extracting_text' });
      } catch (error) {
        logger.error('Failed to queue document processing job', { error, documentId: document.id });
      }

      // Track upload success
      const processingTime = Date.now() - startTime;
      const successEventData: any = {
        userId,
        fileInfo: {
          originalName: file.originalname,
          size: file.size,
          mimetype: file.mimetype,
        },
        status: 'success',
        stage: 'upload_completed',
        processingTime,
      };

      if (req.correlationId) {
        successEventData.correlationId = req.correlationId;
      }

      uploadMonitoringService.trackUploadEvent(successEventData);

      structuredLogger.uploadSuccess({
        originalName: file.originalname,
        size: file.size,
        mimetype: file.mimetype,
      }, userId, processingTime);

      // Return document info
      res.status(201).json({
        id: document.id,
        name: document.original_file_name,
        originalName: document.original_file_name,
        status: 'extracting_text',
        uploadedAt: document.created_at,
        uploadedBy: userId,
        fileSize: document.file_size,
        processingStrategy: processingStrategy,
        correlationId: req.correlationId || undefined
      });

    } catch (error) {
      const processingTime = Date.now() - startTime;
      
      // Track upload failure
      const errorEventData: any = {
        userId: req.user?.uid || 'unknown',
        fileInfo: {
          originalName: req.file?.originalname || 'unknown',
          size: req.file?.size || 0,
          mimetype: req.file?.mimetype || 'unknown',
        },
        status: 'failed',
        stage: 'upload_error',
        error: {
          message: error instanceof Error ? error.message : 'Unknown error',
          type: 'upload_error',
        },
        processingTime,
      };

      if (req.correlationId) {
        errorEventData.correlationId = req.correlationId;
      }

      uploadMonitoringService.trackUploadEvent(errorEventData);

      structuredLogger.uploadError(
        error,
        {
          originalName: req.file?.originalname || 'unknown',
          size: req.file?.size || 0,
          mimetype: req.file?.mimetype || 'unknown',
        },
        req.user?.uid || 'unknown',
        'upload_error'
      );

      logger.error('Upload document failed', { 
        error, 
        correlationId: req.correlationId 
      });
      res.status(500).json({ 
        error: 'Upload failed',
        correlationId: req.correlationId || undefined
      });
    }
  },

  async getDocuments(req: Request, res: Response): Promise<void> {
    try {
      const userId = req.user?.uid;
      if (!userId) {
        res.status(401).json({ 
          error: 'User not authenticated',
          correlationId: req.correlationId 
        });
        return;
      }

      const documents = await DocumentModel.findByUserId(userId);
      
      const formattedDocuments = documents.map(doc => ({
        id: doc.id,
        name: doc.original_file_name,
        originalName: doc.original_file_name,
        status: doc.status,
        uploadedAt: doc.created_at,
        processedAt: doc.processing_completed_at,
        uploadedBy: userId,
        fileSize: doc.file_size,
        summary: doc.generated_summary,
        error: doc.error_message,
        extractedData: doc.analysis_data || (doc.extracted_text ? { text: doc.extracted_text } : undefined)
      }));

      res.json({
        documents: formattedDocuments,
        correlationId: req.correlationId || undefined
      });
    } catch (error) {
      logger.error('Get documents failed', { 
        error, 
        correlationId: req.correlationId 
      });
      res.status(500).json({ 
        error: 'Get documents failed',
        correlationId: req.correlationId || undefined
      });
    }
  },

  async getDocument(req: Request, res: Response): Promise<void> {
    try {
      const userId = req.user?.uid;
      if (!userId) {
        res.status(401).json({ 
          error: 'User not authenticated',
          correlationId: req.correlationId 
        });
        return;
      }

      const { id } = req.params;
      if (!id) {
        res.status(400).json({ 
          error: 'Document ID is required',
          correlationId: req.correlationId 
        });
        return;
      }

      const document = await DocumentModel.findById(id);
      
      if (!document) {
        res.status(404).json({ 
          error: 'Document not found',
          correlationId: req.correlationId 
        });
        return;
      }

      // Check if user owns the document
      if (document.user_id !== userId) {
        res.status(403).json({ 
          error: 'Access denied',
          correlationId: req.correlationId 
        });
        return;
      }

      const formattedDocument = {
        id: document.id,
        name: document.original_file_name,
        originalName: document.original_file_name,
        status: document.status,
        uploadedAt: document.created_at,
        processedAt: document.updated_at,
        uploadedBy: userId,
        fileSize: document.file_size,
        summary: document.generated_summary,
        error: document.error_message,
        extractedData: document.analysis_data || (document.extracted_text ? { text: document.extracted_text } : undefined)
      };

      res.json({
        ...formattedDocument,
        correlationId: req.correlationId || undefined
      });
    } catch (error) {
      logger.error('Get document failed', { 
        error, 
        correlationId: req.correlationId 
      });
      res.status(500).json({ 
        error: 'Get document failed',
        correlationId: req.correlationId || undefined
      });
    }
  },

  async getDocumentProgress(req: Request, res: Response): Promise<void> {
    try {
      const userId = req.user?.uid;
      if (!userId) {
        res.status(401).json({ 
          error: 'User not authenticated',
          correlationId: req.correlationId 
        });
        return;
      }

      const { id } = req.params;
      if (!id) {
        res.status(400).json({ 
          error: 'Document ID is required',
          correlationId: req.correlationId 
        });
        return;
      }

      const document = await DocumentModel.findById(id);
      
      if (!document) {
        res.status(404).json({ 
          error: 'Document not found',
          correlationId: req.correlationId 
        });
        return;
      }

      // Check if user owns the document
      if (document.user_id !== userId) {
        res.status(403).json({ 
          error: 'Access denied',
          correlationId: req.correlationId 
        });
        return;
      }

      // Get progress from upload progress service
      const progress = uploadProgressService.getProgress(id);
      
      // If no progress data from service, calculate based on document status
      let calculatedProgress = 0;
      if (document.status === 'completed') {
        calculatedProgress = 100;
      } else if (document.status === 'processing_llm' || document.status === 'generating_pdf') {
        calculatedProgress = 75;
      } else if (document.status === 'extracting_text') {
        calculatedProgress = 25;
      } else if (document.status === 'uploaded') {
        calculatedProgress = 10;
      }
      
      res.json({
        id: document.id,
        status: document.status,
        progress: progress ? progress.progress : calculatedProgress,
        uploadedAt: document.created_at,
        processedAt: document.processing_completed_at,
        correlationId: req.correlationId || undefined
      });
    } catch (error) {
      logger.error('Get document progress failed', { 
        error, 
        correlationId: req.correlationId 
      });
      res.status(500).json({ 
        error: 'Get document progress failed',
        correlationId: req.correlationId || undefined
      });
    }
  },

  async deleteDocument(req: Request, res: Response): Promise<void> {
    try {
      const userId = req.user?.uid;
      if (!userId) {
        res.status(401).json({ 
          error: 'User not authenticated',
          correlationId: req.correlationId 
        });
        return;
      }

      const { id } = req.params;
      if (!id) {
        res.status(400).json({ 
          error: 'Document ID is required',
          correlationId: req.correlationId 
        });
        return;
      }

      const document = await DocumentModel.findById(id);
      
      if (!document) {
        res.status(404).json({ 
          error: 'Document not found',
          correlationId: req.correlationId 
        });
        return;
      }

      // Check if user owns the document
      if (document.user_id !== userId) {
        res.status(403).json({ 
          error: 'Access denied',
          correlationId: req.correlationId 
        });
        return;
      }

      // Delete from database
      const deleted = await DocumentModel.delete(id);
      
      if (!deleted) {
        res.status(500).json({ 
          error: 'Failed to delete document',
          correlationId: req.correlationId 
        });
        return;
      }

      // Delete file from storage
      try {
        await fileStorageService.deleteFile(document.file_path);
      } catch (error) {
        logger.warn('Failed to delete file from storage', { 
          error, 
          filePath: document.file_path,
          correlationId: req.correlationId 
        });
      }

      res.json({ 
        message: 'Document deleted successfully',
        correlationId: req.correlationId || undefined
      });
    } catch (error) {
      logger.error('Delete document failed', { 
        error, 
        correlationId: req.correlationId 
      });
      res.status(500).json({ 
        error: 'Delete document failed',
        correlationId: req.correlationId || undefined
      });
    }
  },

  async getDocumentText(documentId: string): Promise<string> {
    try {
      // Get document from database
      const document = await DocumentModel.findById(documentId);
      if (!document) {
        throw new Error('Document not found');
      }

      // Read file from storage
      const filePath = document.file_path;
      
      // Check if file exists
      try {
        const fileBuffer = await fileStorageService.getFile(filePath);
        if (!fileBuffer) {
          throw new Error('Document file not accessible');
        }

        // For PDF files, extract text using pdf-parse
        if (filePath.toLowerCase().endsWith('.pdf')) {
          logger.info('Extracting text from PDF file', { documentId, filePath });
          
          try {
            const pdfParse = require('pdf-parse');
            const data = await pdfParse(fileBuffer);
            
            const extractedText = data.text;
            
            logger.info('PDF text extraction completed', {
              documentId,
              textLength: extractedText.length,
              pages: data.numpages,
              fileSize: fileBuffer.length
            });

            // Update document with extracted text
            await DocumentModel.updateById(documentId, {
              extracted_text: extractedText
            });

            return extractedText;
          } catch (pdfError) {
            logger.error('PDF text extraction failed', { documentId, error: pdfError });
            
            // Return a minimal error message instead of hardcoded text
            throw new Error(`PDF text extraction failed: ${pdfError instanceof Error ? pdfError.message : 'Unknown error'}`);
          }
        } else {
          // For text files, read the content directly
          const fileContent = fileBuffer.toString('utf-8');
          return fileContent;
        }
        
      } catch (fileError) {
        logger.error('Document file not accessible', { filePath, documentId, error: fileError });
        throw new Error('Document file not accessible');
      }
      
    } catch (error) {
      logger.error('Get document text failed', { error, documentId });
      throw new Error('Failed to get document text');
    }
  }
};