import { Request, Response } from 'express';
import { AppDataSource } from '../config/database';
import { Agent, AgentStatus } from '../entities/Agent';
import { Subscription, SubscriptionStatus } from '../entities/Subscription';
import { Transaction, TransactionType, TransactionStatus } from '../entities/Transaction';
import { ChatProtocolService } from '../services/chatProtocol';
import { WalletService } from '../services/walletService';

const agentRepository = AppDataSource.getRepository(Agent);
const subscriptionRepository = AppDataSource.getRepository(Subscription);
const chatService = new ChatProtocolService();
const walletService = new WalletService();

export class ChatController {
  /**
   * Send chat message to agent (with optional file uploads)
   */
  async sendMessage(req: Request, res: Response) {
    try {
      const { id: agentId } = req.params;
      const { message, conversationId, metadata } = req.body;
      const userId = (req as any).user?.id;
      // Extract files from multer - support both 'file' (singular) and 'files' (plural)
      interface MulterFile {
        fieldname: string;
        originalname: string;
        encoding: string;
        mimetype: string;
        size: number;
        buffer: Buffer;
      }
      const multerFiles = (req as any).files;
      const files = Array.isArray(multerFiles) 
        ? multerFiles as Array<MulterFile>
        : multerFiles 
          ? [multerFiles as MulterFile]
          : undefined;

      // Message is optional if files are provided
      if (!message && (!files || files.length === 0)) {
        return res.status(400).json({ 
          error: 'Message or files are required' 
        });
      }

      const user = (req as any).user;
      const isAdmin = user?.isAdmin || false;

      // Get agent - admins can test pending/rejected agents, regular users only approved
      const agent = await agentRepository.findOne({
        where: { 
          id: agentId,
          ...(isAdmin ? {} : { status: AgentStatus.APPROVED })
        },
      });

      if (!agent) {
        return res.status(404).json({ error: 'Agent not found' });
      }

      // Admins don't pay for unapproved agents (pending/rejected) - they're testing quality
      const isAdminTestingUnapproved = isAdmin && agent.status !== AgentStatus.APPROVED;
      const shouldCharge = userId && !isAdminTestingUnapproved;

      // Check wallet balance and charge points (first 2 tasks free)
      if (shouldCharge) {
        const chargeResult = await walletService.chargeForTask(userId, agentId, agent);
        
        if (!chargeResult.success) {
          const balance = await walletService.getBalance(userId);
          const pointsRequired = Number(agent.pointsPerTask) || 0;
          const freeTasksRemaining = await walletService.getFreeTasksRemaining(userId);

          return res.status(402).json({
            error: 'Insufficient wallet balance',
            details: {
              balance,
              required: pointsRequired,
              freeTasksRemaining,
              message: freeTasksRemaining > 0
                ? `You have ${freeTasksRemaining} free task(s) remaining. After that, you need ${pointsRequired} points ($${(pointsRequired * 0.05).toFixed(2)}) per task.`
                : `You need ${pointsRequired} points ($${(pointsRequired * 0.05).toFixed(2)}) to use this agent. Please fund your wallet.`,
            },
          });
        }
      } else if (isAdminTestingUnapproved) {
        // Create a free transaction for admin testing (for tracking purposes)
        const wallet = await walletService.getOrCreateWallet(userId);
        const transactionRepository = AppDataSource.getRepository(Transaction);
        const transaction = transactionRepository.create({
          walletId: wallet.id,
          userId,
          agentId,
          type: TransactionType.ADMIN_TEST,
          status: TransactionStatus.COMPLETED,
          amount: 0,
          balanceAfter: Number(wallet.balance),
          description: `Admin test of ${agent.name} (${agent.status}) - no charge`,
          metadata: { 
            agentId, 
            agentName: agent.name,
            agentStatus: agent.status,
            isAdminTest: true 
          },
        });
        await transactionRepository.save(transaction);
      }

      // Convert multer files to chat protocol format
      const chatFiles = files?.map(file => ({
        fieldname: file.fieldname,
        originalname: file.originalname,
        mimetype: file.mimetype,
        size: file.size,
        buffer: file.buffer,
      }));

      // Send message via chat protocol
      const response = await chatService.sendMessage(agent, {
        message: message || '',
        conversationId,
        userId,
        metadata: metadata ? (typeof metadata === 'string' ? JSON.parse(metadata) : metadata) : undefined,
        files: chatFiles,
      });

      res.json(response);
    } catch (error: any) {
      console.error('Chat error:', error);
      res.status(500).json({
        error: error.message || 'Failed to send message to agent',
      });
    }
  }

  /**
   * Get conversation history
   */
  async getHistory(req: Request, res: Response) {
    try {
      const { id: agentId } = req.params;
      const { conversationId, limit } = req.query;
      const user = (req as any).user;
      const userId = user?.id;
      const isAdmin = user?.isAdmin || false;

      if (!userId) {
        return res.status(401).json({ error: 'Authentication required' });
      }

      // Admins can view history for any agent, regular users only approved agents
      const agent = await agentRepository.findOne({
        where: { 
          id: agentId,
          ...(isAdmin ? {} : { status: AgentStatus.APPROVED })
        },
      });

      if (!agent) {
        return res.status(404).json({ error: 'Agent not found' });
      }

      const messages = await chatService.getConversationHistory(
        agentId,
        userId,
        conversationId as string,
        limit ? Number(limit) : 50
      );

      res.json({ messages });
    } catch (error) {
      console.error('Get history error:', error);
      res.status(500).json({ error: 'Failed to get conversation history' });
    }
  }

  /**
   * Check if user has access to agent
   */
  private async checkUserAccess(
    userId: string,
    agentId: string
  ): Promise<boolean> {
    // Check for active subscription
    const subscription = await subscriptionRepository.findOne({
      where: {
        userId,
        agentId,
        status: SubscriptionStatus.ACTIVE,
        isPaymentVerified: true,
      },
    });

    if (!subscription) {
      return false;
    }

    // Check if subscription is expired
    if (subscription.expiresAt && subscription.expiresAt < new Date()) {
      subscription.status = SubscriptionStatus.EXPIRED;
      await subscriptionRepository.save(subscription);
      return false;
    }

    return true;
  }
}