shortcut_parser.py

from pathlib import Path
import struct
from subprocess import Popen, PIPE
import sys


def get_selection(input_list, prompt="") -> str:
    """ Get selection from list """
    lines = str(min(len(input_list), 8))
    with Popen(
        ["fuzzel", "--dmenu", "-l", lines, "-p", prompt],
        stdin=PIPE, stdout=PIPE, stderr=PIPE
    ) as fuzzel:
        selection = fuzzel.communicate(
            input=bytes("\n".join(input_list), 'utf-8'))[0]
        if fuzzel.returncode != 0:
            sys.exit(1)
        return selection.decode().strip()


def find_shortcuts_vdf() -> Path:
    bases = [
        Path.home() / ".steam/steam/userdata",
        Path.home() / ".local/share/Steam/userdata",
    ]

    for base in bases:
        if not base.exists():
            continue

        for userdir in base.iterdir():
            path = userdir / "config/shortcuts.vdf"
            if path.exists():
                return path

    raise FileNotFoundError("shortcuts.vdf not found")


def parse_shortcuts(path: Path) -> list[dict]:
    """
    Parses the binary VDF format and extracts AppName and the
    internal Steam AppID.
    """
    with path.open("rb") as f:
        data = f.read()

    i = 0
    entries = []

    def read_cstring() -> str:
        nonlocal i
        try:
            end = data.index(b"\x00", i)
            s = data[i:end].decode("utf-8", "replace")
            i = end + 1
            return s
        except ValueError:
            return ""

    while i < len(data):
        if i >= len(data):
            break

        t = data[i]
        i += 1

        if t != 0x00:  # 0x00 indicates the start of a shortcut object
            continue

        read_cstring()  # Skip the index key (e.g., "0")
        entry = {}

        while i < len(data):
            field_type = data[i]
            i += 1

            if field_type == 0x08:  # End of current object
                break

            key = read_cstring()

            if field_type == 0x01:  # String type
                value = read_cstring()
            elif field_type == 0x02:  # Integer type (The AppID is stored here)
                value = struct.unpack_from("<I", data, i)[0]
                i += 4
            else:
                continue

            entry[key] = value

        if entry:
            entries.append(entry)

    return entries


def generate_launch_id(vdf_appid: int) -> int:
    """
    Converts the 32-bit AppID found in shortcuts.vdf into the
    64-bit ID required for the steam://rungameid/ protocol.
    """
    # Shift the 32-bit ID to the top and add the shortcut flag (0x02000000)
    return (vdf_appid << 32) | 0x02000000


def main():
    vdf_path = find_shortcuts_vdf()
    shortcuts = parse_shortcuts(vdf_path)
    games = {shortcut["AppName"]: shortcut["appid"] for shortcut in shortcuts}
    selection = get_selection(list(games))
    uri = f"steam://rungameid/{generate_launch_id(games[selection])}"
    print(uri)


if __name__ == "__main__":
    main()