import os
from pathlib import Path
from google.genai import types


def read_file(filepath: str) -> str:
    """Read and return file contents."""
    try:
        p = Path(filepath)
        if not p.exists():
            return f"File not found: {filepath}"
        if p.stat().st_size > 5 * 1024 * 1024:  # 5MB limit
            return "File too large (max 5MB)."
        return p.read_text(encoding="utf-8", errors="replace")
    except Exception as e:
        return f"Error reading file: {e}"


def save_upload(filepath_or_obj, upload_dir="/app/data/uploads") -> str:
    """Save uploaded file and return path. Gradio provides filepath as string."""
    os.makedirs(upload_dir, exist_ok=True)

    # Gradio with type="filepath" passes a string path
    if isinstance(filepath_or_obj, str) and filepath_or_obj:
        src = Path(filepath_or_obj)
        if src.exists():
            dest = Path(upload_dir) / src.name
            import shutil
            shutil.copy2(str(src), str(dest))
            return str(dest)
        return filepath_or_obj

    return str(filepath_or_obj) if filepath_or_obj else ""


def get_file_info(filepath: str) -> dict:
    """Get file information."""
    p = Path(filepath)
    if not p.exists():
        return {"exists": False}
    stat = p.stat()
    return {
        "exists": True,
        "name": p.name,
        "extension": p.suffix.lower(),
        "size": stat.st_size,
        "size_human": f"{stat.st_size / 1024:.1f} KB" if stat.st_size < 1024 * 1024 else f"{stat.st_size / (1024*1024):.1f} MB",
    }


# Tool declarations for google-genai function calling
file_tool_declarations = [
    types.FunctionDeclaration(
        name="read_uploaded_file",
        description="Read the contents of a file that the user uploaded. Use to analyze uploaded documents, code, or text files.",
        parameters=types.Schema(
            type="OBJECT",
            properties={
                "filepath": types.Schema(type="STRING", description="Path to the uploaded file"),
            },
            required=["filepath"],
        ),
    )
]


def handle_file_read(args: dict) -> str:
    """Handle file read tool call."""
    filepath = args.get("filepath", "")
    return read_file(filepath)