import axios, { AxiosError } from 'axios';
import FormData from 'form-data';
import { Agent } from '../entities/Agent';
import { ChatMessage, MessageRole } from '../entities/ChatMessage';
import { AppDataSource } from '../config/database';

export interface ChatRequest {
  message: string;
  conversationId?: string;
  userId?: string;
  metadata?: Record<string, any>;
  files?: Array<{
    fieldname: string;
    originalname: string;
    mimetype: string;
    size: number;
    buffer: Buffer;
    ipfsHash?: string; // CID if uploaded to IPFS
    url?: string; // Direct URL if agent provides
  }>;
}

export interface ChatResponse {
  response: string;
  conversationId: string;
  metadata?: Record<string, any>;
  error?: string;
}

/**
 * Chat Protocol Service
 * Handles communication with agents via standardized chat interface
 */
export class ChatProtocolService {
  private timeout: number;
  private maxFileSize: number;

  constructor() {
    this.timeout = parseInt(process.env.AGENT_CHAT_TIMEOUT || '30000');
    this.maxFileSize = parseInt(process.env.MAX_FILE_SIZE || '10485760'); // 10MB default
  }

  /**
   * Validate files (no IPFS upload - files stored temporarily in memory)
   * Files are kept in memory during request processing and sent directly to agent endpoints
   */
  private validateFiles(files: ChatRequest['files']): void {
    if (!files || files.length === 0) {
      return;
    }

    for (const file of files) {
      // Validate file size
      if (file.size > this.maxFileSize) {
        throw new Error(
          `File ${file.originalname} exceeds maximum size of ${this.maxFileSize} bytes`
        );
      }
    }
  }

  /**
   * Send a chat message to an agent
   */
  async sendMessage(
    agent: Agent,
    request: ChatRequest
  ): Promise<ChatResponse> {
    try {
      // Validate message length
      const maxLength = parseInt(process.env.MAX_MESSAGE_LENGTH || '10000');
      if (request.message && request.message.length > maxLength) {
        throw new Error(`Message exceeds maximum length of ${maxLength} characters`);
      }

      // Store files temporarily (don't upload to IPFS)
      // Files will be available for 1 hour before cleanup
      let uploadedFiles: Array<{
        fieldname: string;
        originalname: string;
        mimetype: string;
        size: number;
        buffer: Buffer;
        tempUrl?: string; // Temporary URL for chat viewing
        expiresAt: Date; // Cleanup after 1 hour
      }> = [];

      if (request.files && request.files.length > 0) {
        // Validate files first
        this.validateFiles(request.files);
        
        // Store files temporarily without IPFS upload
        // Files are kept in memory during request processing
        // Metadata stored in DB with 1-hour expiration timestamp
        const oneHourFromNow = new Date(Date.now() + 60 * 60 * 1000);
        uploadedFiles = request.files.map(file => ({
          fieldname: file.fieldname,
          originalname: file.originalname,
          mimetype: file.mimetype,
          size: file.size,
          buffer: file.buffer,
          expiresAt: oneHourFromNow,
        }));
      }

      const conversationId = request.conversationId || this.generateConversationId();

        // Build metadata with file information (temporary storage, no IPFS)
      const metadata = {
        ...request.metadata,
        agentId: agent.id,
        timestamp: new Date().toISOString(),
        ...(uploadedFiles.length > 0 && {
          files: uploadedFiles.map(f => ({
            fieldname: f.fieldname,
            originalname: f.originalname,
            mimetype: f.mimetype,
            size: f.size,
            expiresAt: f.expiresAt.toISOString(),
            // Note: Files are stored temporarily, not on IPFS
          })),
        }),
      };

      // Determine if we need to send as multipart/form-data or JSON
      const hasFiles = uploadedFiles.length > 0;
      
      // Detect file-only requests (single file, no message, endpoint suggests file-only)
      const isFileOnly = hasFiles && 
                        uploadedFiles.length === 1 && 
                        (!request.message || request.message.trim() === '') &&
                        (agent.endpoint?.toLowerCase().includes('/remove-background') ||
                         agent.endpoint?.toLowerCase().includes('/transcribe') ||
                         agent.endpoint?.toLowerCase().includes('/edit'));
      
      let response;
      
      if (hasFiles) {
        // Send as multipart/form-data with files
        const formData = new FormData();
        
        // For file-only requests, only send the file (no message, conversationId, metadata, systemPrompt)
        if (isFileOnly) {
          const file = request.files![0];
          const audioFiles = request.files!.filter(f => f.mimetype.startsWith('audio/'));
          
          // If single audio file, use 'audio_file' (common for transcription agents)
          if (audioFiles.length === 1) {
            formData.append('audio_file', file.buffer, {
              filename: file.originalname,
              contentType: file.mimetype,
            });
          } else {
            // For other single files, use 'file'
            formData.append('file', file.buffer, {
              filename: file.originalname,
              contentType: file.mimetype,
            });
          }
        } else {
          // Regular requests with files - include message, conversationId, metadata
          // Add message
          if (request.message) {
            formData.append('message', request.message);
          }
          
          formData.append('conversationId', conversationId);
          formData.append('metadata', JSON.stringify(metadata));
          
          if (agent.promptTemplate) {
            formData.append('systemPrompt', agent.promptTemplate);
          }

          // Send actual files directly to agent endpoint (no IPFS upload)
          // Use smart field naming based on file type and count
          if (request.files && request.files.length > 0) {
            const audioFiles = request.files.filter(f => f.mimetype.startsWith('audio/'));
            
            // If single audio file, use 'audio_file' (common for transcription agents)
            if (audioFiles.length === 1 && request.files.length === 1) {
              const audioFile = request.files.find(f => f.mimetype.startsWith('audio/'));
              if (audioFile) {
                formData.append('audio_file', audioFile.buffer, {
                  filename: audioFile.originalname,
                  contentType: audioFile.mimetype,
                });
              }
            }
            // If single file of any type, use 'file'
            else if (request.files.length === 1) {
              const file = request.files[0];
              formData.append('file', file.buffer, {
                filename: file.originalname,
                contentType: file.mimetype,
              });
            }
            // Multiple files - use 'files' array or indexed fields
            else {
              request.files.forEach((file, index) => {
                // Try common field names first
                if (file.mimetype.startsWith('audio/')) {
                  formData.append(`audio_file${index > 0 ? `_${index}` : ''}`, file.buffer, {
                    filename: file.originalname,
                    contentType: file.mimetype,
                  });
                } else if (file.mimetype.startsWith('image/')) {
                  formData.append(`image_file${index > 0 ? `_${index}` : ''}`, file.buffer, {
                    filename: file.originalname,
                    contentType: file.mimetype,
                  });
                } else {
                  formData.append(`file${index > 0 ? `_${index}` : ''}`, file.buffer, {
                    filename: file.originalname,
                    contentType: file.mimetype,
                  });
                }
              });
            }
          }
        }

        response = await axios.post(agent.endpoint, formData, {
          timeout: this.timeout,
          headers: {
            ...formData.getHeaders(),
            ...(agent.metadata?.headers && agent.metadata.headers),
          },
          responseType: 'arraybuffer',
        });
      } else {
        // Send as JSON (no files)
        const payload = {
          message: request.message || '',
          conversationId,
          metadata,
          ...(agent.promptTemplate && { systemPrompt: agent.promptTemplate }),
        };

        response = await axios.post(agent.endpoint, payload, {
          timeout: this.timeout,
          headers: {
            'Content-Type': 'application/json',
            ...(agent.metadata?.headers && agent.metadata.headers),
          },
          responseType: 'arraybuffer',
        });
      }

      // Check if response is a binary image
      const contentType = response.headers['content-type'] || response.headers['Content-Type'] || '';
      let agentResponse: any;
      let imageBase64: string | null = null;

      if (contentType.startsWith('image/')) {
        // Response is a binary image - convert to base64
        const buffer = Buffer.isBuffer(response.data) ? response.data : Buffer.from(response.data);
        imageBase64 = buffer.toString('base64');
        const mimeType = contentType.split(';')[0].trim();
        agentResponse = {
          response: `data:${mimeType};base64,${imageBase64}`,
        };
      } else {
        // Try to parse as JSON or text
        try {
          const buffer = Buffer.isBuffer(response.data) ? response.data : Buffer.from(response.data);
          const textResponse = buffer.toString('utf-8');
          try {
            agentResponse = JSON.parse(textResponse);
          } catch {
            // Not JSON, treat as plain text
            agentResponse = {
              response: textResponse,
            };
          }
        } catch {
          // Fallback: treat as text
          const buffer = Buffer.isBuffer(response.data) ? response.data : Buffer.from(response.data);
          const textResponse = buffer.toString('utf-8');
          agentResponse = {
            response: textResponse,
          };
        }
      }

      const finalConversationId = agentResponse.conversationId || conversationId;

      // Build content with file references
      const userContent = request.message || '';
      const filesInfo = uploadedFiles.length > 0 
        ? `\n[Files: ${uploadedFiles.map(f => f.originalname).join(', ')}]`
        : '';

      // Save message to database with file metadata (files stored temporarily, not on IPFS)
      await this.saveMessage({
        agentId: agent.id,
        userId: request.userId,
        role: MessageRole.USER,
        content: userContent + filesInfo,
        metadata: {
          ...metadata,
          files: uploadedFiles.map(f => ({
            fieldname: f.fieldname,
            originalname: f.originalname,
            mimetype: f.mimetype,
            size: f.size,
            expiresAt: f.expiresAt.toISOString(),
            // Note: File buffers are not stored in DB, only metadata
            // Files are available temporarily in memory for 1 hour
          })),
        },
      });

      const assistantContent = agentResponse.response || agentResponse.message || (typeof agentResponse === 'string' ? agentResponse : JSON.stringify(agentResponse));
      
      await this.saveMessage({
        agentId: agent.id,
        userId: request.userId,
        role: MessageRole.ASSISTANT,
        content: assistantContent,
        metadata: {
          ...agentResponse.metadata,
          files: agentResponse.files || [],
        },
      });

      // Update agent usage count
      agent.usageCount += 1;
      await AppDataSource.getRepository(Agent).save(agent);

      return {
        response: assistantContent,
        conversationId: finalConversationId,
        metadata: {
          ...agentResponse.metadata,
          files: uploadedFiles,
        },
      };
    } catch (error) {
      const axiosError = error as AxiosError;
      if (axios.isAxiosError(axiosError)) {
        if (axiosError.code === 'ECONNABORTED') {
          throw new Error('Agent request timeout');
        }
        if (axiosError.response) {
          throw new Error(
            `Agent returned error: ${axiosError.response.status} - ${JSON.stringify(axiosError.response.data)}`
          );
        }
        if (axiosError.request) {
          throw new Error('Agent endpoint unreachable');
        }
      }
      throw error;
    }
  }

  /**
   * Save chat message to database
   */
  private async saveMessage(data: {
    agentId: string;
    userId?: string;
    role: MessageRole;
    content: string;
    metadata?: Record<string, any>;
  }): Promise<ChatMessage> {
    const messageRepository = AppDataSource.getRepository(ChatMessage);
    const message = messageRepository.create(data);
    return await messageRepository.save(message);
  }

  /**
   * Generate a unique conversation ID
   */
  private generateConversationId(): string {
    return `conv_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
  }

  /**
   * Get conversation history
   */
  async getConversationHistory(
    agentId: string,
    userId: string,
    conversationId?: string,
    limit: number = 50
  ): Promise<ChatMessage[]> {
    const messageRepository = AppDataSource.getRepository(ChatMessage);
    const query = messageRepository
      .createQueryBuilder('message')
      .where('message.agentId = :agentId', { agentId })
      .andWhere('message.userId = :userId', { userId })
      .orderBy('message.createdAt', 'ASC')
      .limit(limit);

    if (conversationId) {
      query.andWhere('message.metadata->>conversationId = :conversationId', {
        conversationId,
      });
    }

    return await query.getMany();
  }
}