"""
Access control module for Gateway interface.
Handles user access management and permission checks.
"""

from typing import Dict, Any, List, Optional

class GatewayAccess:
    """
    Access control class for Gateway interface.
    Handles user access management and permission checks.
    """
    
    def __init__(self, currentUser: Dict[str, Any], db):
        """Initialize with user context."""
        self.currentUser = currentUser
        self.mandateId = currentUser.get("mandateId")
        self.userId = currentUser.get("id")
        
        if not self.mandateId or not self.userId:
            raise ValueError("Invalid user context: mandateId and userId are required")
            
        self.db = db

    def uam(self, table: str, recordset: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
        """
        Unified user access management function that filters data based on user privileges
        and adds access control attributes.
        
        Args:
            table: Name of the table
            recordset: Recordset to filter based on access rules
            
        Returns:
            Filtered recordset with access control attributes
        """
        userPrivilege = self.currentUser.get("privilege", "user")
        filtered_records = []
        
        # Apply filtering based on privilege
        if userPrivilege == "sysadmin":
            filtered_records = recordset  # System admins see all records
        elif userPrivilege == "admin":
            # Admins see records in their mandate
            filtered_records = [r for r in recordset if r.get("mandateId","-") == self.mandateId]
        else:  # Regular users
            # Users only see records they own within their mandate
            filtered_records = [r for r in recordset 
                    if r.get("mandateId","-") == self.mandateId and r.get("_createdBy") == self.userId]
        
        # Add access control attributes to each record
        for record in filtered_records:
            record_id = record.get("id")
            
            # Set access control flags based on user permissions
            if table == "mandates":
                record["_hideView"] = False  # Everyone can view
                record["_hideEdit"] = not self.canModify("mandates", record_id)
                record["_hideDelete"] = not self.canModify("mandates", record_id)
            elif table == "users":
                record["_hideView"] = False  # Everyone can view
                record["_hideEdit"] = not self.canModify("users", record_id)
                record["_hideDelete"] = not self.canModify("users", record_id)
            else:
                # Default access control for other tables
                record["_hideView"] = False
                record["_hideEdit"] = not self.canModify(table, record_id)
                record["_hideDelete"] = not self.canModify(table, record_id)
        
        return filtered_records

    def canModify(self, table: str, recordId: Optional[int] = None) -> bool:
        """
        Checks if the current user can modify (create/update/delete) records in a table.
        
        Args:
            table: Name of the table
            recordId: Optional record ID for specific record check
            
        Returns:
            Boolean indicating permission
        """
        userPrivilege = self.currentUser.get("privilege", "user")
        
        # System admins can modify anything
        if userPrivilege == "sysadmin":
            return True
            
        # Check specific record permissions
        if recordId is not None:
            # Get the record to check ownership
            records = self.db.getRecordset(table, recordFilter={"id": recordId})
            if not records:
                return False
                
            record = records[0]
            
            # Admins can modify anything in their mandate
            if userPrivilege == "admin" and record.get("mandateId","-") == self.mandateId:
                # Exception: Can't modify Root mandate unless you are a sysadmin
                if table == "mandates" and record.get("initialid") and userPrivilege != "sysadmin":
                    return False
                return True
                
            # Users can only modify their own records
            if (record.get("mandateId","-") == self.mandateId and 
                record.get("_createdBy") == self.userId):
                return True
                
            return False
        else:
            # For general table modify permission (e.g., create)
            # Admins can create anything in their mandate
            if userPrivilege == "admin":
                return True
                
            # Regular users can create most entities
            if table == "mandates":
                return False  # Regular users can't create mandates
            return True