#!/usr/bin/env python3
"""
Launch an application or focus it if already running in i3.
Usage: i3-launch-or-focus --class CLASS <command> [args...]

Examples:
  i3-launch-or-focus --class sdm-connect alacritty -e ~/.local/bin/sdm-ui.sh
  i3-launch-or-focus --class dropdown alacritty
"""

import argparse
import json
import subprocess
import sys


def find_window(tree, instance=None, title=None):
    """Recursively search the i3 tree for a window matching criteria."""
    props = tree.get("window_properties", {})

    if instance and props.get("instance", "").lower() == instance.lower():
        return tree.get("id")
    if title and tree.get("name", "") == title:
        return tree.get("id")

    for node in tree.get("nodes", []) + tree.get("floating_nodes", []):
        result = find_window(node, instance=instance, title=title)
        if result:
            return result

    return None


def focus_window(instance=None, title=None):
    """Focus a window using i3-msg criteria."""
    if instance:
        criteria = f'[instance="{instance}"]'
    elif title:
        criteria = f'[title="{title}"]'
    else:
        return
    subprocess.run(
        ["i3-msg", f"{criteria} focus"],
        stdout=subprocess.DEVNULL,
        stderr=subprocess.DEVNULL,
    )


def launch_command(command, args):
    """Launch a command, replacing this process."""
    import os

    os.execvp(command, [command] + args)


def main():
    parser = argparse.ArgumentParser(
        description="Launch an application or focus it if already running in i3"
    )
    parser.add_argument("command", help="Command to run")
    parser.add_argument("--class", dest="class_name", help="Window instance name")
    parser.add_argument("--title", help="Window title")
    parser.add_argument(
        "args", nargs=argparse.REMAINDER, help="Additional arguments for command"
    )

    args = parser.parse_args()

    try:
        result = subprocess.run(
            ["i3-msg", "-t", "get_tree"],
            capture_output=True,
            text=True,
            check=False,
        )
        tree = json.loads(result.stdout)
    except (json.JSONDecodeError, subprocess.SubprocessError):
        tree = {}

    window_id = find_window(tree, instance=args.class_name, title=args.title)

    if window_id:
        focus_window(instance=args.class_name, title=args.title)
    else:
        cmd_args = []
        if args.class_name:
            cmd_args.append(f"--class={args.class_name}")
        if args.title:
            cmd_args.append(f"--title={args.title}")
        cmd_args.extend(args.args)
        launch_command(args.command, cmd_args)


if __name__ == "__main__":
    main()