"""
Document organization service for managing hierarchical folder structures, 
tagging, categorization, and metadata with multi-tenant support.
"""

import asyncio
import logging
from typing import Dict, List, Optional, Any, Set
from datetime import datetime
import uuid
from pathlib import Path
import json

from sqlalchemy.orm import Session
from sqlalchemy import and_, or_, func

from app.models.document import Document, DocumentTag, DocumentType
from app.models.tenant import Tenant
from app.core.database import get_db

logger = logging.getLogger(__name__)


class DocumentOrganizationService:
    """Service for organizing documents with hierarchical structures and metadata."""
    
    def __init__(self, tenant: Tenant):
        self.tenant = tenant
        self.default_categories = {
            DocumentType.BOARD_PACK: ["Board Meetings", "Strategic Planning", "Governance"],
            DocumentType.MINUTES: ["Board Meetings", "Committee Meetings", "Executive Meetings"],
            DocumentType.STRATEGIC_PLAN: ["Strategic Planning", "Business Planning", "Long-term Planning"],
            DocumentType.FINANCIAL_REPORT: ["Financial", "Reports", "Performance"],
            DocumentType.COMPLIANCE_REPORT: ["Compliance", "Regulatory", "Audit"],
            DocumentType.POLICY_DOCUMENT: ["Policies", "Procedures", "Governance"],
            DocumentType.CONTRACT: ["Legal", "Contracts", "Agreements"],
            DocumentType.PRESENTATION: ["Presentations", "Communications", "Training"],
            DocumentType.SPREADSHEET: ["Data", "Analysis", "Reports"],
            DocumentType.OTHER: ["General", "Miscellaneous"]
        }
    
    async def create_folder_structure(self, db: Session, folder_path: str, description: str = None) -> Dict[str, Any]:
        """
        Create a hierarchical folder structure.
        """
        try:
            # Parse folder path (e.g., "Board Meetings/2024/Q1")
            folders = folder_path.strip("/").split("/")
            
            # Create folder metadata
            folder_metadata = {
                "type": "folder",
                "path": folder_path,
                "name": folders[-1],
                "parent_path": "/".join(folders[:-1]) if len(folders) > 1 else "",
                "description": description,
                "created_at": datetime.utcnow().isoformat(),
                "tenant_id": str(self.tenant.id)
            }
            
            # Store folder metadata in document table with special type
            folder_document = Document(
                id=uuid.uuid4(),
                title=folder_path,
                description=description or f"Folder: {folder_path}",
                document_type=DocumentType.OTHER,
                filename="",  # Folders don't have files
                file_path="",
                file_size=0,
                mime_type="application/x-folder",
                uploaded_by=None,  # System-created
                organization_id=self.tenant.id,
                processing_status="completed",
                document_metadata=folder_metadata
            )
            
            db.add(folder_document)
            db.commit()
            db.refresh(folder_document)
            
            return {
                "id": str(folder_document.id),
                "path": folder_path,
                "name": folders[-1],
                "parent_path": folder_metadata["parent_path"],
                "description": description,
                "created_at": folder_document.created_at.isoformat()
            }
            
        except Exception as e:
            logger.error(f"Error creating folder structure {folder_path}: {str(e)}")
            raise
    
    async def move_document_to_folder(self, db: Session, document_id: str, folder_path: str) -> bool:
        """
        Move a document to a specific folder.
        """
        try:
            document = db.query(Document).filter(
                and_(
                    Document.id == document_id,
                    Document.organization_id == self.tenant.id
                )
            ).first()
            
            if not document:
                raise ValueError("Document not found")
            
            # Update document metadata with folder information
            if not document.document_metadata:
                document.document_metadata = {}
            
            document.document_metadata["folder_path"] = folder_path
            document.document_metadata["folder_name"] = folder_path.split("/")[-1]
            document.document_metadata["moved_at"] = datetime.utcnow().isoformat()
            
            db.commit()
            
            return True
            
        except Exception as e:
            logger.error(f"Error moving document {document_id} to folder {folder_path}: {str(e)}")
            return False
    
    async def get_documents_in_folder(self, db: Session, folder_path: str, 
                                    skip: int = 0, limit: int = 100) -> Dict[str, Any]:
        """
        Get all documents in a specific folder.
        """
        try:
            # Query documents with folder metadata
            query = db.query(Document).filter(
                and_(
                    Document.organization_id == self.tenant.id,
                    Document.document_metadata.contains({"folder_path": folder_path})
                )
            )
            
            total = query.count()
            documents = query.offset(skip).limit(limit).all()
            
            return {
                "folder_path": folder_path,
                "documents": [
                    {
                        "id": str(doc.id),
                        "title": doc.title,
                        "description": doc.description,
                        "document_type": doc.document_type,
                        "filename": doc.filename,
                        "file_size": doc.file_size,
                        "processing_status": doc.processing_status,
                        "created_at": doc.created_at.isoformat(),
                        "tags": [{"id": str(tag.id), "name": tag.name} for tag in doc.tags]
                    }
                    for doc in documents
                ],
                "total": total,
                "skip": skip,
                "limit": limit
            }
            
        except Exception as e:
            logger.error(f"Error getting documents in folder {folder_path}: {str(e)}")
            return {"folder_path": folder_path, "documents": [], "total": 0, "skip": skip, "limit": limit}
    
    async def get_folder_structure(self, db: Session, root_path: str = "") -> Dict[str, Any]:
        """
        Get the complete folder structure.
        """
        try:
            # Get all folder documents
            folder_query = db.query(Document).filter(
                and_(
                    Document.organization_id == self.tenant.id,
                    Document.mime_type == "application/x-folder"
                )
            )
            
            folders = folder_query.all()
            
            # Build hierarchical structure
            folder_tree = self._build_folder_tree(folders, root_path)
            
            return {
                "root_path": root_path,
                "folders": folder_tree,
                "total_folders": len(folders)
            }
            
        except Exception as e:
            logger.error(f"Error getting folder structure: {str(e)}")
            return {"root_path": root_path, "folders": [], "total_folders": 0}
    
    async def auto_categorize_document(self, db: Session, document: Document) -> List[str]:
        """
        Automatically categorize a document based on its type and content.
        """
        try:
            categories = []
            
            # Add default categories based on document type
            if document.document_type in self.default_categories:
                categories.extend(self.default_categories[document.document_type])
            
            # Add categories based on extracted text content
            if document.extracted_text:
                text_categories = await self._extract_categories_from_text(document.extracted_text)
                categories.extend(text_categories)
            
            # Add categories based on metadata
            if document.document_metadata:
                metadata_categories = await self._extract_categories_from_metadata(document.document_metadata)
                categories.extend(metadata_categories)
            
            # Remove duplicates and limit to top categories
            unique_categories = list(set(categories))[:10]
            
            return unique_categories
            
        except Exception as e:
            logger.error(f"Error auto-categorizing document {document.id}: {str(e)}")
            return []
    
    async def create_or_get_tag(self, db: Session, tag_name: str, description: str = None, 
                               color: str = None) -> DocumentTag:
        """
        Create a new tag or get existing one.
        """
        try:
            # Check if tag already exists
            tag = db.query(DocumentTag).filter(
                and_(
                    DocumentTag.name == tag_name,
                    # In a real implementation, you'd have tenant_id in DocumentTag
                )
            ).first()
            
            if not tag:
                tag = DocumentTag(
                    id=uuid.uuid4(),
                    name=tag_name,
                    description=description or f"Tag: {tag_name}",
                    color=color or "#3B82F6"  # Default blue color
                )
                db.add(tag)
                db.commit()
                db.refresh(tag)
            
            return tag
            
        except Exception as e:
            logger.error(f"Error creating/getting tag {tag_name}: {str(e)}")
            raise
    
    async def add_tags_to_document(self, db: Session, document_id: str, tag_names: List[str]) -> bool:
        """
        Add multiple tags to a document.
        """
        try:
            document = db.query(Document).filter(
                and_(
                    Document.id == document_id,
                    Document.organization_id == self.tenant.id
                )
            ).first()
            
            if not document:
                raise ValueError("Document not found")
            
            for tag_name in tag_names:
                tag = await self.create_or_get_tag(db, tag_name.strip())
                if tag not in document.tags:
                    document.tags.append(tag)
            
            db.commit()
            return True
            
        except Exception as e:
            logger.error(f"Error adding tags to document {document_id}: {str(e)}")
            return False
    
    async def remove_tags_from_document(self, db: Session, document_id: str, tag_names: List[str]) -> bool:
        """
        Remove tags from a document.
        """
        try:
            document = db.query(Document).filter(
                and_(
                    Document.id == document_id,
                    Document.organization_id == self.tenant.id
                )
            ).first()
            
            if not document:
                raise ValueError("Document not found")
            
            for tag_name in tag_names:
                tag = db.query(DocumentTag).filter(DocumentTag.name == tag_name).first()
                if tag and tag in document.tags:
                    document.tags.remove(tag)
            
            db.commit()
            return True
            
        except Exception as e:
            logger.error(f"Error removing tags from document {document_id}: {str(e)}")
            return False
    
    async def get_documents_by_tags(self, db: Session, tag_names: List[str], 
                                  skip: int = 0, limit: int = 100) -> Dict[str, Any]:
        """
        Get documents that have specific tags.
        """
        try:
            query = db.query(Document).filter(Document.organization_id == self.tenant.id)
            
            # Add tag filters
            for tag_name in tag_names:
                query = query.join(Document.tags).filter(DocumentTag.name == tag_name)
            
            total = query.count()
            documents = query.offset(skip).limit(limit).all()
            
            return {
                "tag_names": tag_names,
                "documents": [
                    {
                        "id": str(doc.id),
                        "title": doc.title,
                        "description": doc.description,
                        "document_type": doc.document_type,
                        "filename": doc.filename,
                        "file_size": doc.file_size,
                        "processing_status": doc.processing_status,
                        "created_at": doc.created_at.isoformat(),
                        "tags": [{"id": str(tag.id), "name": tag.name} for tag in doc.tags]
                    }
                    for doc in documents
                ],
                "total": total,
                "skip": skip,
                "limit": limit
            }
            
        except Exception as e:
            logger.error(f"Error getting documents by tags {tag_names}: {str(e)}")
            return {"tag_names": tag_names, "documents": [], "total": 0, "skip": skip, "limit": limit}
    
    async def get_popular_tags(self, db: Session, limit: int = 20) -> List[Dict[str, Any]]:
        """
        Get the most popular tags.
        """
        try:
            # Count tag usage
            tag_counts = db.query(
                DocumentTag.name,
                func.count(DocumentTag.documents).label('count')
            ).join(DocumentTag.documents).filter(
                Document.organization_id == self.tenant.id
            ).group_by(DocumentTag.name).order_by(
                func.count(DocumentTag.documents).desc()
            ).limit(limit).all()
            
            return [
                {
                    "name": tag_name,
                    "count": count,
                    "percentage": round((count / sum(t[1] for t in tag_counts)) * 100, 2)
                }
                for tag_name, count in tag_counts
            ]
            
        except Exception as e:
            logger.error(f"Error getting popular tags: {str(e)}")
            return []
    
    async def extract_metadata(self, document: Document) -> Dict[str, Any]:
        """
        Extract metadata from document content and structure.
        """
        try:
            metadata = {
                "extraction_timestamp": datetime.utcnow().isoformat(),
                "tenant_id": str(self.tenant.id)
            }
            
            # Extract basic metadata
            if document.filename:
                metadata["original_filename"] = document.filename
                metadata["file_extension"] = Path(document.filename).suffix.lower()
            
            # Extract metadata from content
            if document.extracted_text:
                text_metadata = await self._extract_text_metadata(document.extracted_text)
                metadata.update(text_metadata)
            
            # Extract metadata from document structure
            if document.document_metadata:
                structure_metadata = await self._extract_structure_metadata(document.document_metadata)
                metadata.update(structure_metadata)
            
            return metadata
            
        except Exception as e:
            logger.error(f"Error extracting metadata for document {document.id}: {str(e)}")
            return {}
    
    def _build_folder_tree(self, folders: List[Document], root_path: str) -> List[Dict[str, Any]]:
        """
        Build hierarchical folder tree structure.
        """
        tree = []
        
        for folder in folders:
            folder_metadata = folder.document_metadata or {}
            folder_path = folder_metadata.get("path", "")
            
            if folder_path.startswith(root_path):
                relative_path = folder_path[len(root_path):].strip("/")
                if "/" not in relative_path:  # Direct child
                    tree.append({
                        "id": str(folder.id),
                        "name": folder_metadata.get("name", folder.title),
                        "path": folder_path,
                        "description": folder_metadata.get("description"),
                        "created_at": folder.created_at.isoformat(),
                        "children": self._build_folder_tree(folders, folder_path + "/")
                    })
        
        return tree
    
    async def _extract_categories_from_text(self, text: str) -> List[str]:
        """
        Extract categories from document text content.
        """
        categories = []
        
        # Simple keyword-based categorization
        text_lower = text.lower()
        
        # Financial categories
        if any(word in text_lower for word in ["revenue", "profit", "loss", "financial", "budget", "cost"]):
            categories.append("Financial")
        
        # Risk categories
        if any(word in text_lower for word in ["risk", "threat", "vulnerability", "compliance", "audit"]):
            categories.append("Risk & Compliance")
        
        # Strategic categories
        if any(word in text_lower for word in ["strategy", "planning", "objective", "goal", "initiative"]):
            categories.append("Strategic Planning")
        
        # Operational categories
        if any(word in text_lower for word in ["operation", "process", "procedure", "workflow"]):
            categories.append("Operations")
        
        # Technology categories
        if any(word in text_lower for word in ["technology", "digital", "system", "platform", "software"]):
            categories.append("Technology")
        
        return categories
    
    async def _extract_categories_from_metadata(self, metadata: Dict[str, Any]) -> List[str]:
        """
        Extract categories from document metadata.
        """
        categories = []
        
        # Extract from tables
        if "tables" in metadata:
            categories.append("Data & Analytics")
        
        # Extract from charts
        if "charts" in metadata:
            categories.append("Visualizations")
        
        # Extract from images
        if "images" in metadata:
            categories.append("Media Content")
        
        return categories
    
    async def _extract_text_metadata(self, text: str) -> Dict[str, Any]:
        """
        Extract metadata from text content.
        """
        metadata = {}
        
        # Word count
        metadata["word_count"] = len(text.split())
        
        # Character count
        metadata["character_count"] = len(text)
        
        # Line count
        metadata["line_count"] = len(text.splitlines())
        
        # Language detection (simplified)
        metadata["language"] = "en"  # Default to English
        
        # Content type detection
        text_lower = text.lower()
        if any(word in text_lower for word in ["board", "director", "governance"]):
            metadata["content_type"] = "governance"
        elif any(word in text_lower for word in ["financial", "revenue", "profit"]):
            metadata["content_type"] = "financial"
        elif any(word in text_lower for word in ["strategy", "planning", "objective"]):
            metadata["content_type"] = "strategic"
        else:
            metadata["content_type"] = "general"
        
        return metadata
    
    async def _extract_structure_metadata(self, structure_metadata: Dict[str, Any]) -> Dict[str, Any]:
        """
        Extract metadata from document structure.
        """
        metadata = {}
        
        # Page count
        if "pages" in structure_metadata:
            metadata["page_count"] = structure_metadata["pages"]
        
        # Table count
        if "tables" in structure_metadata:
            metadata["table_count"] = len(structure_metadata["tables"])
        
        # Chart count
        if "charts" in structure_metadata:
            metadata["chart_count"] = len(structure_metadata["charts"])
        
        # Image count
        if "images" in structure_metadata:
            metadata["image_count"] = len(structure_metadata["images"])
        
        return metadata