"""Command processing system for AI Sidebar slash commands."""

from dataclasses import dataclass
from typing import Callable, Optional


@dataclass
class CommandResult:
    """Result of command execution."""
    success: bool
    message: str
    data: dict | None = None


class CommandProcessor:
    """Parses and executes slash commands."""
    
    def __init__(self):
        """Initialize command processor with command registry."""
        self._handlers: dict[str, Callable] = {}
        
    def register_command(self, command: str, handler: Callable) -> None:
        """
        Register a command handler.
        
        Args:
            command: Command string (e.g., "/new", "/model")
            handler: Callable that takes command arguments and returns CommandResult
        """
        self._handlers[command.lower()] = handler
    
    def is_command(self, text: str) -> bool:
        """
        Check if text starts with a command.
        
        Args:
            text: User input text
            
        Returns:
            True if text starts with a registered command
        """
        if not text or not text.startswith("/"):
            return False
        
        # Extract command (first word)
        parts = text.strip().split(maxsplit=1)
        command = parts[0].lower()
        
        return command in self._handlers
    
    def execute(self, text: str) -> CommandResult:
        """
        Parse and execute command.
        
        Args:
            text: User input text starting with command
            
        Returns:
            CommandResult with execution status and message
        """
        if not text or not text.startswith("/"):
            return CommandResult(
                success=False,
                message="Invalid command format. Commands must start with '/'."
            )
        
        # Parse command and arguments
        parts = text.strip().split(maxsplit=1)
        command = parts[0].lower()
        args = parts[1] if len(parts) > 1 else ""
        
        # Check if command is registered
        if command not in self._handlers:
            return CommandResult(
                success=False,
                message=f"Unknown command: {command}. Type /help for available commands."
            )
        
        # Execute command handler
        try:
            handler = self._handlers[command]
            return handler(args)
        except Exception as e:
            return CommandResult(
                success=False,
                message=f"Error executing command: {str(e)}"
            )