import os
from PIL import Image
from html2image import Html2Image
import numpy as np
from djagitit.mailing import html
import uuid
from config import emailParams
from contextlib import contextmanager


@contextmanager
def silence_stderr_fd():
    """
    Silence C-level stderr (fd 2), so subprocesses like Chrome
    can't write their DBus / GL / GPU spam.
    """
    # Duplicate current stderr fd
    saved_stderr_fd = os.dup(2)
    devnull_fd = None
    try:
        # Open /dev/null and dup it over fd 2
        devnull_fd = os.open(os.devnull, os.O_WRONLY)
        os.dup2(devnull_fd, 2)
        os.close(devnull_fd)
        devnull_fd = None  # Mark as closed
        yield
    finally:
        # Ensure devnull_fd is closed if dup2 failed
        if devnull_fd is not None:
            try:
                os.close(devnull_fd)
            except OSError:
                pass
        # Restore original stderr
        os.dup2(saved_stderr_fd, 2)
        os.close(saved_stderr_fd)


def generate_img64_from_html(
    html_str, 
    tmp_path=os.path.join(os.path.dirname(__file__), '..', 'tmp'),
    width=600
    ):
    random_id = str(uuid.uuid4())
    raw_path = os.path.join(tmp_path, f'{random_id}_raw.png')
    cropped_path = os.path.join(tmp_path, f'{random_id}_cropped.png')
    
    try:
        hti = Html2Image(output_path=tmp_path)
        with silence_stderr_fd():
            hti.screenshot(html_str=html_str, save_as=f'{random_id}_raw.png')
        img = np.array(Image.open(raw_path))  # img is 1080 rows by 1920 cols and 4 color channels, the 4'th channel is alpha.
        idx = np.where(img[:, :, 3] > 0) # Find indices of non-transparent pixels (indices where alpha channel value is above zero).
        x0, y0, x1, y1 = idx[1].min(), idx[0].min(), idx[1].max(), idx[0].max() # Get minimum and maximum index in both axes (top left corner and bottom right corner)
        img = Image.fromarray(img[y0:y1+1, x0:x1+1, :]) # Crop rectangle and convert to Image
        img.save(cropped_path) # save cropped image
        img64 = html.image_to_base64(cropped_path, width=width)
        return img64
    finally:
        # Ensure temporary files are always cleaned up, even if an exception occurs
        for file_path in [raw_path, cropped_path]:
            try:
                if os.path.exists(file_path):
                    os.remove(file_path)
            except OSError:
                # Ignore errors during cleanup (e.g., file already deleted)
                pass


def get_subject(mode):
    return emailParams.subjects.get(mode, emailParams.subjects['daily'])