from datetime import datetime
from langchain_core.documents import Document

def format_memories(memories: list[dict]) -> str:
    """
    Formats a list of memory dictionaries into a human-readable string.
    """
    if not memories:
        return "No memories found for this user."

    output_parts = []
    for i, memory in enumerate(memories):
        memory_text = memory.get('memory', 'N/A')
        created_at_str = memory.get('created_at')
        categories = memory.get('categories', [])

        # --- Format the timestamp for readability ---
        if created_at_str:
            try:
                dt_obj = datetime.fromisoformat(created_at_str)
                dt_obj = dt_obj.astimezone()  # Convert to system timezone
                formatted_date = dt_obj.strftime("%B %d, %Y at %I:%M %p")
            except (ValueError, TypeError):
                formatted_date = f"Invalid date format ({created_at_str})"
        else:
            formatted_date = "N/A"

        # --- Format the list of categories ---
        if categories and isinstance(categories, list):
            formatted_categories = ', '.join(cat.capitalize() for cat in categories)
        else:
            formatted_categories = "None"

        entry = (
            f"Memory #{i + 1}\n"
            f"  Created:    {formatted_date}\n"
            f"  Categories: {formatted_categories}\n"
            f"  Details:     {memory_text}"
        )
        output_parts.append(entry)

    return "\n------------\n".join(output_parts)


def format_docs(docs: list[Document]) -> str:
    """
    Converts a list of documents into XML-formatted string.
    """
    formatted_docs = "\n\n---\n\n".join(
        [
            f'<Document href="{doc.metadata["link"]}" title="{doc.metadata["title"]}">\n{doc.page_content}\n</Document>'
            for i, doc in enumerate(docs)
        ]
    )
    return formatted_docs