import base64
import io
import os
import shutil
import subprocess
import uuid
from typing import Optional, Tuple

import numpy as np
import pypandoc
from PIL import Image


class FileHelper:

    # 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
    def _encode_image(cls, image_path: str, image_threshold=10) -> Optional[str]:
        with open(image_path, "rb") as image_file:
            image_bytes = 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)}")

    @staticmethod
    def remove_file(file_path):
        try:
            if os.path.exists(file_path):
                if os.path.isfile(file_path):
                    os.remove(file_path)
        except Exception as e:
            print(f"An error occurred while trying to remove the file {file_path}: {str(e)}")

    @staticmethod
    def save_upload(file) -> Tuple[str, str]:
        ext = file.filename.split('.')[-1]
        path_id = str(uuid.uuid4())
        os.makedirs(f'./tmp/{path_id}', exist_ok=True)

        tmp_filename = f'./tmp/{path_id}/uploaded.{ext}'
        file.save(tmp_filename)
        return ext, path_id