"""
ActionExecutor — translate action name strings into OS input events.

Backends:
  xdotool   — Linux X11; requires xdotool package installed
  pyautogui — cross-platform fallback
  auto      — detects xdotool at init, falls back to pyautogui
"""

from __future__ import annotations

import logging
import os
import shutil
import subprocess
from typing import Literal

# Suppress pyautogui DISPLAY errors on headless systems
if not os.environ.get("DISPLAY"):
    os.environ["DISPLAY"] = ":0"

import pyautogui

logger = logging.getLogger(__name__)

Backend = Literal["xdotool", "pyautogui", "auto"]

_XDOTOOL_CLICK: dict[str, list[str]] = {
    "left_click": ["xdotool", "click", "1"],
    "right_click": ["xdotool", "click", "3"],
    "double_click": ["xdotool", "click", "--repeat", "2", "1"],
    "middle_click": ["xdotool", "click", "2"],
    "scroll_up": ["xdotool", "click", "4"],
    "scroll_down": ["xdotool", "click", "5"],
}

_XDOTOOL_KEY: dict[str, str] = {
    "key_enter": "Return",
    "key_escape": "Escape",
    "key_space": "space",
    "key_tab": "Tab",
}


class ActionExecutor:
    def __init__(self, backend: Backend = "auto") -> None:
        if backend == "auto":
            self._backend: Backend = (
                "xdotool" if shutil.which("xdotool") else "pyautogui"
            )
        else:
            self._backend = backend

    def execute(self, action: str) -> None:
        """Execute a named action. Silently ignores unknown action names."""
        try:
            if self._backend == "xdotool":
                self._xdotool(action)
            else:
                self._pyautogui(action)
        except Exception as exc:
            logger.warning("ActionExecutor error for action=%r: %s", action, exc)

    def _xdotool(self, action: str) -> None:
        if action in _XDOTOOL_CLICK:
            subprocess.run(_XDOTOOL_CLICK[action], capture_output=True)
        elif action in _XDOTOOL_KEY:
            subprocess.run(
                ["xdotool", "key", _XDOTOOL_KEY[action]], capture_output=True
            )
        elif action.startswith("drag_start"):
            subprocess.run(["xdotool", "mousedown", "1"], capture_output=True)
        elif action.startswith("drag_end"):
            subprocess.run(["xdotool", "mouseup", "1"], capture_output=True)
        else:
            logger.warning("xdotool: unknown action %r", action)

    def _pyautogui(self, action: str) -> None:
        if action == "left_click":
            pyautogui.click()
        elif action == "right_click":
            pyautogui.rightClick()
        elif action == "double_click":
            pyautogui.doubleClick()
        elif action == "scroll_up":
            pyautogui.scroll(3)
        elif action == "scroll_down":
            pyautogui.scroll(-3)
        elif action == "key_enter":
            pyautogui.press("enter")
        elif action == "key_escape":
            pyautogui.press("escape")
        elif action == "key_space":
            pyautogui.press("space")
        else:
            logger.warning("pyautogui: unknown action %r", action)