from typing import Optional, List, Tuple

from fastapi.exceptions import RequestValidationError

from backend.models.permission.models import RoleDoc, PermissionDoc, UserRoleDoc
from beanie import PydanticObjectId
from datetime import datetime


class RoleHandler:
    def __init__(self):
        pass

    async def create_role(self, role_key: str, role_name: str, role_description: Optional[str], role_level: int, custom_role_id: Optional[str] = None) -> Optional[RoleDoc]:
        """Create a new role, ensuring role_key and role_name are unique and not empty"""
        if not role_key or not role_name:
            raise RequestValidationError("role_key and role_name are required.")
        if await RoleDoc.find_one({str(RoleDoc.role_key): role_key}) or await RoleDoc.find_one(
                {str(RoleDoc.role_name): role_name}):
            raise RequestValidationError("role_key or role_name has already been created.")
        
        # Check if custom_role_id is provided and if it already exists
        if custom_role_id:
            try:
                custom_id = PydanticObjectId(custom_role_id)
                if await RoleDoc.get(custom_id):
                    raise RequestValidationError("Role with the provided custom_role_id already exists.")
            except Exception:
                raise RequestValidationError("Invalid custom_role_id format. Must be a valid ObjectId.")
        
        doc = RoleDoc(
            role_key=role_key,
            role_name=role_name,
            role_description=role_description,
            permission_ids=[],
            role_level=role_level,
            created_at=datetime.now(),
            updated_at=datetime.now()
        )
        
        # Set custom ID if provided
        if custom_role_id:
            doc.id = PydanticObjectId(custom_role_id)
        
        await doc.insert()
        return doc

    async def update_role(self, role_id: PydanticObjectId, role_key: str, role_name: str,
                          role_description: Optional[str], role_level: int, custom_role_id: Optional[str] = None) -> Optional[
        RoleDoc]:
        """Update an existing role, ensuring role_key and role_name are unique and not empty"""
        if not role_id or not role_key or not role_name:
            raise RequestValidationError("role_id, role_key and role_name are required.")
        doc = await RoleDoc.get(role_id)
        if not doc:
            raise RequestValidationError("role not found.")
        #if doc.is_default:
        #    raise RequestValidationError("Default role cannot be updated.")
        # Check for uniqueness (exclude self)
        conflict = await RoleDoc.find_one({
            "$and": [
                {"_id": {"$ne": role_id}},
                {"$or": [
                    {str(RoleDoc.role_key): role_key},
                    {str(RoleDoc.role_name): role_name}
                ]}
            ]
        })
        if conflict:
            raise RequestValidationError("role_key or role_name already exists.")
        doc.role_key = role_key
        doc.role_name = role_name
        doc.role_description = role_description
        doc.role_level = role_level
        doc.updated_at = datetime.now()
        
        # Set custom role ID if provided
        if custom_role_id:
            # Store the old ID for cleanup
            old_id = doc.id
            doc.id = PydanticObjectId(custom_role_id)
            await doc.save()
            
            # Delete the old document with the original ID
            try:
                old_doc = await RoleDoc.get(old_id)
                if old_doc:
                    await old_doc.delete()
            except Exception as e:
                # Log the error but don't fail the operation
                print(f"Warning: Failed to delete old role document {old_id}: {e}")
        else:
            await doc.save()
            
        return doc

    async def query_roles(self, role_key: Optional[str], role_name: Optional[str], skip: int = 0, limit: int = 10) -> \
    Tuple[List[RoleDoc], int]:
        """Query roles with pagination and fuzzy search by role_key and role_name"""
        query = {}
        if role_key:
            query[str(RoleDoc.role_key)] = {"$regex": role_key, "$options": "i"}
        if role_name:
            query[str(RoleDoc.role_name)] = {"$regex": role_name, "$options": "i"}
        cursor = RoleDoc.find(query)
        total = await cursor.count()
        docs = await cursor.skip(skip).limit(limit).to_list()
        return docs, total

    async def assign_permissions_to_role(self, role_id: PydanticObjectId, permission_ids: List[str]) -> Optional[RoleDoc]:
        """Assign permissions to a role by updating the permission_ids field"""
        if not role_id or not permission_ids:
            raise RequestValidationError("role_id and permission_ids are required.")
        doc = await RoleDoc.get(role_id)
        if not doc:
            raise RequestValidationError("Role not found.")
        
        # Validate that all permission_ids exist in the permission collection
        for permission_id in permission_ids:
            permission_doc = await PermissionDoc.get(PydanticObjectId(permission_id))
            if not permission_doc:
                raise RequestValidationError(f"Permission with id {permission_id} not found.")
        
        # Remove duplicates from permission_ids
        unique_permission_ids = list(dict.fromkeys(permission_ids))
        
        doc.permission_ids = unique_permission_ids
        doc.updated_at = datetime.now()
        await doc.save()
        return doc

    async def delete_role(self, role_id: PydanticObjectId) -> None:
        """Delete a role document after checking if it is referenced by any user and is not default"""
        if not role_id:
            raise RequestValidationError("role_id is required.")
        # Check if any user references this role
        user_role = await UserRoleDoc.find_one({"role_ids": str(role_id)})
        if user_role:
            raise RequestValidationError("Role is referenced by a user and cannot be deleted.")
        doc = await RoleDoc.get(role_id)
        if not doc:
            raise RequestValidationError("Role not found.")
        # Check if the role is default
        #if doc.is_default:
        #    raise RequestValidationError("Default role cannot be deleted.")
        await doc.delete()