import os
import shutil
import subprocess
import sys
import time
from pathlib import Path

from .config import ScreenshotCfg


class ScreenshotCapture:
    def __init__(self, cfg: ScreenshotCfg):
        self._cfg = cfg

    def capture(self) -> str:
        """截取全屏，返回保存路径。自动选择当前平台最佳方式。"""
        if self._cfg.delay_ms > 0:
            time.sleep(self._cfg.delay_ms / 1000)

        out_path = self._cfg.tmp_path
        Path(out_path).parent.mkdir(parents=True, exist_ok=True)

        if sys.platform == "darwin":
            self._capture_macos(out_path)
        else:
            self._capture_linux(out_path)

        if not Path(out_path).exists():
            raise RuntimeError(f"截图文件未生成: {out_path}")
        return out_path

    # ------------------------------------------------------------------
    # macOS
    # ------------------------------------------------------------------

    def _capture_macos(self, out_path: str) -> None:
        # screencapture -x 静默截全屏（无声音/闪烁）
        subprocess.run(["screencapture", "-x", out_path], check=True)

    # ------------------------------------------------------------------
    # Linux（按优先级尝试）
    # ------------------------------------------------------------------

    def _capture_linux(self, out_path: str) -> None:
        wayland = os.environ.get("WAYLAND_DISPLAY")

        if wayland:
            # Wayland 优先：grim（轻量）> spectacle > gnome-screenshot
            if shutil.which("grim"):
                subprocess.run(["grim", out_path], check=True)
                return
            if shutil.which("spectacle"):
                # spectacle -b 后台 -f 全屏 -n 无通知 -o 输出路径
                # 丢弃 stderr（Tesseract 未安装的无害警告）
                subprocess.run(
                    ["spectacle", "-b", "-f", "-n", "-o", out_path],
                    check=True,
                    timeout=10,
                    stderr=subprocess.DEVNULL,
                )
                return
            if shutil.which("gnome-screenshot"):
                subprocess.run(["gnome-screenshot", "-f", out_path], check=True)
                return
            # 最后尝试 mss（可能在 XWayland 下有效）
            self._capture_mss(out_path)
        else:
            # X11：mss 最快，失败则用 scrot
            try:
                self._capture_mss(out_path)
            except Exception:
                if shutil.which("scrot"):
                    subprocess.run(["scrot", out_path], check=True)
                elif shutil.which("import"):  # ImageMagick
                    subprocess.run(["import", "-window", "root", out_path], check=True)
                else:
                    raise RuntimeError("未找到可用的截图工具（scrot / import）")

    def _capture_mss(self, out_path: str) -> None:
        import mss
        import mss.tools

        with mss.mss() as sct:
            monitor = sct.monitors[0]  # 0 = 全部显示器合并
            screenshot = sct.grab(monitor)
            mss.tools.to_png(screenshot.rgb, screenshot.size, output=out_path)