"""
Screenshot capture functionality
"""

import subprocess
import tempfile
import shutil
from pathlib import Path
from typing import Optional

from . import config


class ScreenshotError(Exception):
    """Raised when screenshot capture fails"""
    pass


def find_screenshot_tool() -> Optional[str]:
    """Find available screenshot tool on the system"""
    for tool in config.SCREENSHOT_TOOLS:
        if shutil.which(tool):
            return tool
    return None


def take_screenshot() -> Optional[str]:
    """
    Take screenshot of full screen

    Returns:
        Path to screenshot file, or None if capture failed
    """
    import os
    import time

    tool = find_screenshot_tool()

    if not tool:
        if config.DEBUG:
            print(f"[DEBUG] No screenshot tool found. Tried: {', '.join(config.SCREENSHOT_TOOLS)}")
        return None

    # Create temporary file
    cache_dir = config.get_cache_dir()
    screenshot_path = cache_dir / f"screenshot_{int(time.time())}.png"

    # Preserve DISPLAY environment variable
    env = os.environ.copy()
    if 'DISPLAY' not in env:
        env['DISPLAY'] = ':0'  # Default X display

    try:
        if tool == "scrot":
            # Capture full screen (more reliable than -u for active window)
            result = subprocess.run(
                ["scrot", str(screenshot_path)],
                check=True,
                capture_output=True,
                timeout=config.SCREENSHOT_TIMEOUT,
                env=env
            )
        elif tool == "gnome-screenshot":
            # Capture full screen
            result = subprocess.run(
                ["gnome-screenshot", "-f", str(screenshot_path)],
                check=True,
                capture_output=True,
                timeout=config.SCREENSHOT_TIMEOUT,
                env=env
            )
        elif tool == "import":
            # ImageMagick - capture root window
            result = subprocess.run(
                ["import", "-window", "root", str(screenshot_path)],
                check=True,
                capture_output=True,
                timeout=config.SCREENSHOT_TIMEOUT,
                env=env
            )
        elif tool == "maim":
            # Capture full screen
            result = subprocess.run(
                ["maim", str(screenshot_path)],
                check=True,
                capture_output=True,
                timeout=config.SCREENSHOT_TIMEOUT,
                env=env
            )
        else:
            return None

        if screenshot_path.exists():
            if config.DEBUG:
                print(f"[DEBUG] Screenshot saved to {screenshot_path}")
            return str(screenshot_path)
        else:
            return None

    except subprocess.TimeoutExpired as e:
        if config.DEBUG:
            print(f"[DEBUG] Screenshot timeout with tool: {tool}")
        return None
    except subprocess.CalledProcessError as e:
        if config.DEBUG:
            print(f"[DEBUG] Screenshot failed with {tool}: {e}")
            if e.stderr:
                print(f"[DEBUG] Error output: {e.stderr.decode('utf-8', errors='ignore')}")
        return None
    except Exception as e:
        if config.DEBUG:
            print(f"[DEBUG] Unexpected screenshot error: {type(e).__name__}: {e}")
        return None


def cleanup_old_screenshots(max_age_seconds: int = None):
    """
    Clean up old screenshots from cache directory

    Args:
        max_age_seconds: Maximum age of screenshots to keep (default from config)
    """
    import time

    if max_age_seconds is None:
        max_age_seconds = config.SCREENSHOT_CACHE_CLEANUP

    cache_dir = config.get_cache_dir()
    current_time = time.time()

    for screenshot in cache_dir.glob("screenshot_*.png"):
        if current_time - screenshot.stat().st_mtime > max_age_seconds:
            try:
                screenshot.unlink()
                if config.DEBUG:
                    print(f"[DEBUG] Cleaned up old screenshot: {screenshot}")
            except Exception as e:
                if config.DEBUG:
                    print(f"[DEBUG] Failed to cleanup {screenshot}: {e}")