#!/usr/bin/env python3
"""Open a URL, dev server, or file in the Hermes desktop GUI's preview pane.

Registration moved into the `desktop_preview` tool; this module keeps the normalizer +
open action for ``tools.preview_tool``. Emits ``preview.open`` via ``desktop_ui``: the
renderer opens the pane for the window that asked and never steals focus for a
background session. The desktop_ui toolset reaches desktop clients on any backend.
"""

import re

from tools import desktop_ui
from tools.registry import tool_error


def _normalize_target(raw: str) -> str:
    """Coax a bare host/domain into a fetchable URL; leave paths + schemes alone.

    ``www.cnn.com`` -> ``https://www.cnn.com``; ``localhost:3000`` -> ``http://localhost:3000``.
    File paths and explicit schemes pass through for the renderer's preview normalizer.
    """
    v = raw.strip().strip("`").strip()
    if not v or "://" in v or v.startswith(("/", "./", "../", "~", "file:")):
        return v
    if re.match(r"^(localhost|127\.0\.0\.1|0\.0\.0\.0|\[::1\])(:\d+)?(/|$)", v, re.I):
        return "http://" + v
    if re.match(r"^[\w.-]+\.[a-z]{2,}(:\d+)?(/.*)?$", v, re.I):
        return "https://" + v
    return v


def open_preview_tool(url: str, label: str = "") -> str:
    """Ask the desktop GUI to show ``url`` in the preview pane beside the chat."""
    target = _normalize_target(url or "")
    if not target:
        return tool_error(
            "url is required — a web URL (https://…), a localhost dev server, or a "
            "file path to show in the preview pane."
        )

    label = (label or "").strip()
    return desktop_ui.emit_or_error(
        "preview.open",
        {"url": target, "label": label},
        "Failed to open the preview pane: ",
        "The preview pane is only available in the Hermes desktop app.",
        {"success": True, "url": target, "label": label},
    )