# Copyright (c) 2025 Patrick Motsch
# All rights reserved.

"""
Email Processing helper for Outlook operations.
Handles email search query sanitization, search parameter building, and filter construction.
"""

import logging
import re
from typing import Dict, Any

logger = logging.getLogger(__name__)

class EmailProcessingHelper:
    """Helper for email search and processing operations"""
    
    def __init__(self, methodInstance):
        """
        Initialize email processing helper.
        
        Args:
            methodInstance: Instance of MethodOutlook (for access to services)
        """
        self.method = methodInstance
        self.services = methodInstance.services
    
    def sanitizeSearchQuery(self, query: str) -> str:
        """
        Sanitize and validate search query for Microsoft Graph API
        
        Microsoft Graph API has specific requirements for search queries:
        - Escape special characters properly
        - Handle search operators correctly
        - Ensure query format is valid
        """
        if not query:
            return ""
        
        # Clean the query
        clean_query = query.strip()
        
        # Handle folder specifications first
        if clean_query.lower().startswith('folder:'):
            folder_name = clean_query[7:].strip()
            if folder_name:
                # Return the folder specification as-is
                return clean_query
        
        # Remove any double quotes that might cause issues
        clean_query = clean_query.replace('"', '')
        
        # Handle common search operators
        # Recognize Graph operators including both singular and plural forms for hasAttachments
        lowered = clean_query.lower()
        if any(op in lowered for op in ['from:', 'to:', 'subject:', 'body:', 'received:', 'hasattachment:', 'hasattachments:']):
            # This is an advanced search query, return as-is
            return clean_query
        
        # Escape single quotes for OData safety (double them)
        safe_query = clean_query.replace("'", "''")
        # Remove backslashes and double quotes
        safe_query = re.sub(r'[\\"]', '', safe_query)
        
        return safe_query
    
    def buildSearchParameters(self, query: str, folder: str, limit: int) -> Dict[str, Any]:
        """
        Build search parameters for Microsoft Graph API
        
        This method handles the complexity of building search parameters
        while avoiding conflicts between $search and $filter parameters.
        """
        params = {
            "$top": limit
        }
        
        if not query or not query.strip():
            # No query specified, just get emails from folder
            if folder and folder.lower() != "all":
                # Use folder name directly for well-known folders, or get folder ID
                if folder.lower() in ["inbox", "drafts", "sentitems", "deleteditems"]:
                    params["$filter"] = f"parentFolderId eq '{folder}'"
                else:
                    # For custom folders, we need to get the folder ID first
                    # This will be handled by the calling method
                    params["$filter"] = f"parentFolderId eq '{folder}'"
            # Add orderby for basic queries
            params["$orderby"] = "receivedDateTime desc"
            return params
        
        clean_query = self.sanitizeSearchQuery(query)
        
        # Check if this is a folder specification (e.g., "folder:Drafts", "folder:Inbox")
        if clean_query.lower().startswith('folder:'):
            folder_name = clean_query[7:].strip()  # Remove "folder:" prefix
            if folder_name:
                # This is a folder specification, not a text search
                # Just filter by folder and return
                params["$filter"] = f"parentFolderId eq '{folder_name}'"
                params["$orderby"] = "receivedDateTime desc"
                return params
        
        # Check if this is a complex search query with multiple operators
        # Recognize Graph operators including both singular and plural forms for hasAttachments
        lowered = clean_query.lower()
        if any(op in lowered for op in ['from:', 'to:', 'subject:', 'body:', 'received:', 'hasattachment:', 'hasattachments:']):
            # This is an advanced search query, use $search
            # Microsoft Graph API supports complex search syntax
            params["$search"] = f'"{clean_query}"'
            
            # Note: When using $search, we cannot combine it with $orderby or $filter for folder
            # We'll need to filter results after the API call
            # Folder filtering will be done after the API call
        else:
            # Use $search (KQL) instead of $filter to avoid "InefficientFilter" - Graph rejects
            # contains(subject,x) + parentFolderId + orderby. $search handles subject:query.
            if len(clean_query) > 50:
                clean_query = clean_query[:50]
            if clean_query == "*" or clean_query == "":
                if folder and folder.lower() != "all":
                    params["$filter"] = f"parentFolderId eq '{folder}'"
                    params["$orderby"] = "receivedDateTime desc"
            else:
                # Use $search with subject: to avoid InefficientFilter
                safe = clean_query.replace('"', '')
                params["$search"] = f'"subject:{safe}"'
                # Folder filtering done post-API in searchEmails when $search is used

        return params
    
    def buildGraphFilter(self, filter_text: str) -> Dict[str, str]:
        """
        Build proper Microsoft Graph API filter parameters based on filter text
        
        Args:
            filter_text (str): The filter text to process
            
        Returns:
            Dict[str, str]: Dictionary with either $filter or $search parameter
        """
        if not filter_text:
            return {}
            
        filter_text = filter_text.strip()
        
        # Handle folder specifications (e.g., "folder:Drafts", "folder:Inbox")
        if filter_text.lower().startswith('folder:'):
            folder_name = filter_text[7:].strip()  # Remove "folder:" prefix
            if folder_name:
                # This is a folder specification, return empty to let the main method handle it
                return {}
        
        # Handle search queries (from:, to:, subject:, etc.) - check this FIRST
        # Support both singular and plural forms for hasAttachments
        lt = filter_text.lower()
        if any(lt.startswith(prefix) for prefix in ['from:', 'to:', 'subject:', 'body:', 'received:', 'hasattachment:', 'hasattachments:']):
            return {"$search": f'"{filter_text}"'}
        
        # Handle email address filters (only if it's NOT a search query)
        if '@' in filter_text and '.' in filter_text and ' ' not in filter_text and not filter_text.startswith('from:'):
            safeEmail = filter_text.replace("'", "''")
            return {"$filter": f"from/fromAddress/address eq '{safeEmail}'"}
        
        # Handle OData filter conditions (contains 'eq', 'ne', 'gt', 'lt', etc.)
        if any(op in filter_text.lower() for op in [' eq ', ' ne ', ' gt ', ' lt ', ' ge ', ' le ', ' and ', ' or ']):
            return {"$filter": filter_text}
        
        # Handle text content - search in subject (escape single quotes)
        safeText = filter_text.replace("'", "''")
        return {"$filter": f"contains(subject,'{safeText}')"}