from textual.widgets import Static
import subprocess

def action_previous(app) -> None:
    """Show the previous email message by finding the next lower ID from the list of envelope IDs."""
    try:
        result = subprocess.run(
            ["himalaya", "envelope", "list", "-o", "json"],
            capture_output=True,
            text=True
        )
        if result.returncode == 0:
            import json
            envelopes = json.loads(result.stdout)
            ids = sorted((int(envelope['id']) for envelope in envelopes), reverse=True)
            for envelope_id in ids:
                if envelope_id < int(app.current_message_id):
                    app.current_message_id = envelope_id
                    app.show_message(app.current_message_id)
                    return
            app.show_status("No older messages found.", severity="warning")
        else:
            app.show_status("Failed to fetch envelope list.", severity="error")
    except Exception as e:
        app.show_status(f"Error: {e}", severity="error")