"""
LinkSyncServer - Collection CRUD Endpoints with SQLAlchemy
"""

from fastapi import APIRouter, Depends, HTTPException, status, Query, Request
from sqlalchemy.orm import Session
from sqlalchemy import func, and_, or_, exists
from typing import List, Optional
import uuid
import logging

from models.base import Base, Bookmark, Collection, AuditLog, get_engine, sessionmaker
from pydantic import BaseModel, Field
import os

router = APIRouter(prefix="/api/collections", tags=["Collections"])

# Logging
logger = logging.getLogger(__name__)


class CollectionCreate(BaseModel):
    name: str = Field(..., description="Collection name")
    description: Optional[str] = Field(None, max_length=1024, description="Collection description")
    query_type: str = Field(default="static", description="Static or dynamic collection")
    query_expression: Optional[dict] = Field(None, description="Query expression for dynamic collections")
    is_public: bool = Field(default=False, description="Is collection public")
    tags: Optional[List[str]] = Field(default_factory=list, description="Collection tags")


class CollectionUpdate(BaseModel):
    name: Optional[str] = Field(None, max_length=255)
    description: Optional[str] = Field(None, max_length=1024)
    query_type: Optional[str] = Field(None)
    query_expression: Optional[dict] = Field(None)
    is_public: Optional[bool] = None
    tags: Optional[List[str]] = Field(None)


class CollectionResponse(BaseModel):
    id: str
    name: str
    description: Optional[str]
    query_type: str
    query_expression: Optional[dict]
    is_public: bool
    created_at: str
    updated_at: str
    tags: List[str]


def get_db():
    """Get database session."""
    db_session = sessionmaker(get_engine())()
    return db_session


def get_current_user(request: Request):
    """Get current authenticated user."""
    SECRET_KEY = os.environ.get("SECRET_KEY")
    
    auth_header = request.headers.get("Authorization") or request.headers.get("authorization")
    
    if auth_header and auth_header.startswith("Bearer "):
        token = auth_header[7:]
        try:
            import jwt
            payload = jwt.decode(token, SECRET_KEY, algorithms=["HS256"])
            return {"username": payload.get("sub"), "id": payload.get("sub")}
        except Exception:
            pass

    return {"username": "guest"}


class CollectionManager:
    """Collection management helper."""
    
    @staticmethod
    def get_collection(collection_id: str) -> Optional[Collection]:
        """Get collection by ID."""
        db = get_db()
        try:
            collection = db.query(Collection).filter(Collection.id == collection_id).first()
            return collection
        except Exception:
            return None
    
    @staticmethod
    def create_collection(data: CollectionCreate, request: Request) -> Collection:
        """Create new collection."""
        db = get_db()
        
        collection = Collection(
            name=data.name,
            description=data.description,
            query_type=data.query_type,
            query_expression=data.query_expression,
            is_public=data.is_public,
            tags=TagCollection(tags=data.tags or []),
        )
        
        db.add(collection)
        db.commit()
        db.refresh(collection)
        
        # Create audit log
        user = get_current_user(request)
        try:
            audit = AuditLog(
                action="create",
                entity_type="Collection",
                entity_id=collection.id,
                old_value=None,
                new_value=collection.dict(),
                user_id=user.get("id")
            )
            db.add(audit)
            db.commit()
        except Exception:
            pass
        
        return collection
    
    @staticmethod
    def update_collection(collection_id: str, data: CollectionUpdate, request: Request) -> Optional[Collection]:
        """Update collection."""
        db = get_db()
        
        collection = db.query(Collection).filter(Collection.id == collection_id).first()
        
        if not collection:
            return None
        
        # Update fields
        for field_name, value in data.dict().items():
            if value is not None:
                if hasattr(collection, field_name):
                    setattr(collection, field_name, value)
                elif field_name == "tags":
                    if isinstance(value, list):
                        collection.tags.add(*value)
                    else:
                        collection.tags.update(str(value))
        
        db.commit()
        db.refresh(collection)
        
        # Create audit log
        user = get_current_user(request)
        try:
            audit = AuditLog(
                action="update",
                entity_type="Collection",
                entity_id=collection_id,
                old_value=collection.dict(),
                new_value=collection.dict(),
                user_id=user.get("id")
            )
            db.add(audit)
            db.commit()
        except Exception:
            pass
        
        return collection
    
    @staticmethod
    def delete_collection(collection_id: str, request: Request) -> dict:
        """Delete collection."""
        db = get_db()
        
        collection = db.query(Collection).filter(Collection.id == collection_id).first()
        
        if not collection:
            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Collection not found")
        
        db.delete(collection)
        db.commit()
        
        # Create audit log
        user = get_current_user(request)
        try:
            audit = AuditLog(
                action="delete",
                entity_type="Collection",
                entity_id=collection_id,
                old_value=collection.dict(),
                new_value=None,
                user_id=user.get("id")
            )
            db.add(audit)
            db.commit()
        except Exception:
            pass
        
        return {"message": "Collection deleted successfully", "deleted_id": collection_id}
    
    @staticmethod
    def get_collection_tags(collection_id: str) -> List[str]:
        """Get collection tags."""
        db = get_db()
        
        collection = db.query(Collection).filter(Collection.id == collection_id).first()
        
        if not collection:
            return []
        
        return list(collection.tags)
    
    @staticmethod
    def get_collection_bookmarks(collection_id: str, limit: int = 50, offset: int = 0) -> List[Bookmark]:
        """
        Get bookmarks for collection (static or dynamic).
        
        For dynamic collections with query expression:
        Use query executor to parse and filter bookmarks
        """
        db = get_db()
        
        collection = db.query(Collection).filter(Collection.id == collection_id).first()
        
        if not collection:
            return []
        
        if collection.query_type == "static":
            # Static collection: get all bookmarks
            bookmarks = db.query(Bookmark).filter(Bookmark.collection_id == collection_id).limit(limit).offset(offset).all()
        else:
            # Dynamic collection: query expression
            # TODO: Use query executor to parse expression (executor module)
            bookmarks = db.query(Bookmark).limit(limit).offset(offset).all()
        
        return bookmarks