"""
Edit file tool (find and replace)
"""

import os
from typing import Dict, Any
from .registry import Tool


class EditTool(Tool):
    """Tool for editing files using find and replace"""
    
    def __init__(self):
        super().__init__(
            name="edit",
            description="Edit a file by finding and replacing exact text. The old_string must match exactly (including whitespace).",
            parameters={
                "type": "object", 
                "properties": {
                    "file_path": {
                        "type": "string",
                        "description": "Path to the file to edit (relative or absolute)"
                    },
                    "old_string": {
                        "type": "string",
                        "description": "Exact text to find and replace (must match exactly)"
                    },
                    "new_string": {
                        "type": "string",
                        "description": "New text to replace the old text with"
                    }
                },
                "required": ["file_path", "old_string", "new_string"]
            }
        )
    
    async def execute(self, args: Dict[str, Any]) -> str:
        """Execute the edit tool"""
        file_path = args.get("file_path")
        old_string = args.get("old_string")
        new_string = args.get("new_string")
        
        if not file_path or old_string is None or new_string is None:
            return "Error: file_path, old_string, and new_string are required"
        
        try:
            # Convert to absolute path if relative
            if not os.path.isabs(file_path):
                file_path = os.path.abspath(file_path)
            
            if not os.path.exists(file_path):
                return f"Error: File '{file_path}' does not exist"
            
            if not os.path.isfile(file_path):
                return f"Error: '{file_path}' is not a file"
            
            # Read the current content
            with open(file_path, 'r', encoding='utf-8') as f:
                content = f.read()
            
            # Check if old_string exists in the content
            if old_string not in content:
                return f"Error: The specified text was not found in '{file_path}'"
            
            # Count occurrences
            occurrence_count = content.count(old_string)
            
            # Perform the replacement
            new_content = content.replace(old_string, new_string)
            
            # Write the modified content back
            with open(file_path, 'w', encoding='utf-8') as f:
                f.write(new_content)
            
            # Calculate changes
            old_lines = len(content.splitlines())
            new_lines = len(new_content.splitlines())
            line_diff = new_lines - old_lines
            
            result_parts = [
                f"Successfully edited '{file_path}':",
                f"- Replaced {occurrence_count} occurrence(s) of the specified text",
                f"- File now has {new_lines} lines ({line_diff:+d} lines)"
            ]
            
            return "\n".join(result_parts)
            
        except UnicodeDecodeError:
            return f"Error: Could not read file '{file_path}' - file appears to be binary"
        except Exception as e:
            return f"Error: Could not edit file '{file_path}': {e}"