import datetime
from pathlib import Path
import base64
import io
import os
import shutil
import subprocess
from typing import Optional

import numpy as np
import pypandoc
from PIL import Image

import aiofiles


class FileHelper:

    @staticmethod
    def delete_files_older_than_one_day(directory: str):
        current_time = datetime.datetime.now()

        for entry in os.scandir(directory):
            if entry.is_file():
                file_path = Path(entry)
                file_name = file_path.name
                file_modified_time = datetime.datetime.fromtimestamp(file_path.stat().st_mtime)
                time_difference = current_time - file_modified_time
                if time_difference.days > 1 and "placeholder" not in file_name:
                    file_path.unlink()
                    print(f"Deleted file: {file_path}")

    # Supposedly pandoc covers a wide range of file extensions only tested with docx
    @staticmethod
    def convert_file_to_pdf(input_path: str, output_path: str):
        pypandoc.convert_file(input_path, 'pdf', outputfile=output_path, extra_args=[
            '-V', 'geometry:paperwidth=5.5in',
            '-V', 'geometry:paperheight=8.5in',
            '-V', 'geometry:margin=0.5in',
            '-V', 'pagestyle=empty'
        ])

    @staticmethod
    def convert_file_to_html(input_path: str, output_path: str):
        pypandoc.convert_file(input_path, 'html', outputfile=output_path)

    @staticmethod
    def pdf_to_png(path_id: str):
        to_png = f"pdftoppm -png exercises.pdf page"
        result = subprocess.run(to_png, shell=True, cwd=f'./tmp/{path_id}', capture_output=True, text=True)
        if result.returncode != 0:
            raise Exception(
                f"Couldn't convert pdf to png. Failed to run command '{to_png}' -> ```cmd {result.stderr}```")

    @staticmethod
    def is_page_blank(image_bytes: bytes, image_threshold=10) -> bool:
        with Image.open(io.BytesIO(image_bytes)) as img:
            img_gray = img.convert('L')
            img_array = np.array(img_gray)
            non_white_pixels = np.sum(img_array < 255)

        return non_white_pixels <= image_threshold

    @classmethod
    async def _encode_image(cls, image_path: str, image_threshold=10) -> Optional[str]:
        async with aiofiles.open(image_path, "rb") as image_file:
            image_bytes = await image_file.read()

        if cls.is_page_blank(image_bytes, image_threshold):
            return None

        return base64.b64encode(image_bytes).decode('utf-8')

    @classmethod
    def b64_pngs(cls, path_id: str, files: list[str]):
        png_messages = []
        for filename in files:
            b64_string = cls._encode_image(os.path.join(f'./tmp/{path_id}', filename))
            if b64_string:
                png_messages.append({
                    "type": "image_url",
                    "image_url": {
                        "url": f"data:image/png;base64,{b64_string}"
                    }
                })
        return png_messages

    @staticmethod
    def remove_directory(path):
        try:
            if os.path.exists(path):
                if os.path.isdir(path):
                    shutil.rmtree(path)
        except Exception as e:
            print(f"An error occurred while trying to remove {path}: {str(e)}")