from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import status, permissions
from .rag_service import generate_chat_response
from finance.utils_mongo import get_user_db_id
import tempfile
import os
import pdfplumber

class ChatView(APIView):
    permission_classes = [permissions.IsAuthenticated]

    def post(self, request):
        query = request.data.get('message', '')
        provider = request.data.get('provider')
        is_voice = request.data.get('is_voice', False)
        attached_file = request.FILES.get('file')

        # 1. Process PDF Attachment (Text Extraction)
        if attached_file and attached_file.name.lower().endswith('.pdf'):
            try:
                with pdfplumber.open(attached_file) as pdf:
                    pdf_text = ""
                    for page in pdf.pages:
                        pdf_text += (page.extract_text() or "") + "\n"
                    if pdf_text:
                        query = f"[ATTACHED PDF CONTENT: {attached_file.name}]\n{pdf_text}\n\nUSER QUESTION: {query}"
            except Exception as e:
                print(f"PDF extraction error: {e}")

        # 2. Process Image Attachment (Temporary Save for Vision)
        image_path = None
        if attached_file and any(attached_file.name.lower().endswith(ext) for ext in ['.png', '.jpg', '.jpeg', '.webp']):
            try:
                suffix = os.path.splitext(attached_file.name)[1]
                with tempfile.NamedTemporaryFile(delete=False, suffix=suffix) as tmp:
                    for chunk in attached_file.chunks():
                        tmp.write(chunk)
                    image_path = tmp.name
            except Exception as e:
                print(f"Image save error: {e}")

        if not query and not image_path:
            return Response({"error": "Message or attachment is required"}, status=status.HTTP_400_BAD_REQUEST)
            
        mongo_user_id = get_user_db_id(request.user)
        auth_header = request.headers.get('Authorization', '')
        access_token = auth_header.replace('Bearer ', '').strip() if auth_header.startswith('Bearer ') else None
        
        if is_voice:
            from finance.ai_helper import generate_voice_response
            result = generate_voice_response(query, provider=provider)
        else:
            result = generate_chat_response(
                mongo_user_id, 
                query, 
                provider=provider, 
                access_token=access_token,
                image_path=image_path
            )
        
        # Cleanup temporary image file
        if image_path and os.path.exists(image_path):
            try:
                os.remove(image_path)
            except:
                pass
        
        # Save to MongoDB (Embedded in User)
        try:
            from expense_tracker.utils import MongoDBClient
            from datetime import datetime
            from bson import ObjectId
            
            db = MongoDBClient.get_client()
            chat_log = {
                '_id': ObjectId(),
                'query': query,
                'response': result.get('response'),
                'context_used': result.get('context_used'),
                'timestamp': datetime.now()
            }
            db.users.update_one(
                {'_id': mongo_user_id},
                {'$push': {'chat_history': chat_log}}
            )
        except Exception as e:
            pass  # Silently fail if chat log saving fails

        return Response(result)

    def get(self, request):
        """Retrieve chat history for the user"""
        try:
            from expense_tracker.utils import MongoDBClient
            from bson import ObjectId
            
            db = MongoDBClient.get_client()
            db = MongoDBClient.get_client()
            mongo_user_id = get_user_db_id(request.user)
            user = db.users.find_one({'_id': mongo_user_id}, {'chat_history': 1})
            
            history = []
            if user and 'chat_history' in user:
                # Return last 50 entries
                raw_history = user['chat_history'][-50:]
                for h in raw_history:
                    # Format for frontend with ID for deletion
                    history.append({
                        'id': str(h.get('_id', '')),
                        'sender': 'user', 
                        'text': h.get('query'),
                        'timestamp': h.get('timestamp')
                    })
                    history.append({
                        'id': str(h.get('_id', '')),
                        'sender': 'bot', 
                        'text': h.get('response'),
                        'timestamp': h.get('timestamp')
                    })
            
            return Response(history)
        except Exception as e:
            return Response({"error": str(e)}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)

    def delete(self, request, msg_id=None):
        """Delete a specific chat entry from history"""
        if not msg_id:
            return Response({"error": "Message ID required"}, status=status.HTTP_400_BAD_REQUEST)
            
        try:
            from expense_tracker.utils import MongoDBClient
            from bson import ObjectId
            
            db = MongoDBClient.get_client()
            db = MongoDBClient.get_client()
            mongo_user_id = get_user_db_id(request.user)
            if msg_id == 'all':
                result = db.users.update_one(
                    {'_id': mongo_user_id},
                    {'$set': {'chat_history': []}}
                )
                if result.modified_count > 0:
                    return Response({"message": "All chat history cleared"}, status=status.HTTP_200_OK)
                return Response({"message": "No chat history to clear"}, status=status.HTTP_200_OK)

            result = db.users.update_one(
                {'_id': mongo_user_id},
                {'$pull': {'chat_history': {'_id': ObjectId(msg_id)}}}
            )
            
            if result.modified_count > 0:
                return Response({"message": "Chat deleted successfully"}, status=status.HTTP_200_OK)
            else:
                return Response({"error": "Chat not found"}, status=status.HTTP_404_NOT_FOUND)
                
        except Exception as e:
            return Response({"error": str(e)}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)