import io
import secrets
import uuid
import base64

from PIL import Image, ImageDraw, ImageFont

from django.core.cache import caches

default_cache = caches['default']

CAPTCHA_CHARS = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789'


def _random_color(low, high):
    return tuple(secrets.randbelow(high - low + 1) + low for _ in range(3))


def generate_captcha():
    captcha_key = str(uuid.uuid4())
    code = ''.join(secrets.choice(CAPTCHA_CHARS) for _ in range(4))

    width, height = 120, 40
    image = Image.new('RGB', (width, height), _random_color(200, 255))
    draw = ImageDraw.Draw(image)

    for _ in range(30):
        x = secrets.randbelow(width)
        y = secrets.randbelow(height)
        draw.point((x, y), fill=_random_color(0, 255))

    for _ in range(3):
        x1 = secrets.randbelow(width)
        y1 = secrets.randbelow(height)
        x2 = secrets.randbelow(width)
        y2 = secrets.randbelow(height)
        draw.line([(x1, y1), (x2, y2)], fill=_random_color(0, 255), width=1)

    font = ImageFont.load_default()

    for i, char in enumerate(code):
        font_size = secrets.randbelow(5) + 12
        try:
            char_font = ImageFont.load_default(size=font_size)
        except TypeError:
            char_font = ImageFont.load_default()

        char_image = Image.new('RGBA', (30, 30), (0, 0, 0, 0))
        char_draw = ImageDraw.Draw(char_image)
        char_color = _random_color(0, 100)
        char_draw.text((5, 5), char, font=char_font, fill=char_color)

        angle = secrets.randbelow(61) - 30
        rotated = char_image.rotate(angle, expand=True, resample=Image.BICUBIC)

        x_offset = i * 25 + secrets.randbelow(6)
        y_offset = secrets.randbelow(10)
        image.paste(rotated, (x_offset, y_offset), rotated)

    buffer = io.BytesIO()
    image.save(buffer, format='PNG')
    image_base64 = base64.b64encode(buffer.getvalue()).decode('utf-8')
    captcha_image = f'data:image/png;base64,{image_base64}'

    default_cache.set(f'captcha_{captcha_key}', code.upper(), timeout=300)

    return captcha_key, captcha_image


def verify_captcha(captcha_key, captcha_code):
    cache_key = f'captcha_{captcha_key}'
    stored_code = default_cache.get(cache_key)

    if stored_code is None:
        return 'expired'

    if stored_code == captcha_code.upper():
        default_cache.delete(cache_key)
        return 'ok'

    return 'wrong'


CAPTCHA_THRESHOLD = 3
CAPTCHA_TRIGGER_TTL = 600


def check_captcha_required(operation, identifier):
    cache_key = f'captcha_trigger_{operation}_{identifier}'
    count = default_cache.get(cache_key)
    if count is not None and count >= CAPTCHA_THRESHOLD:
        return True
    return False


def record_failure(operation, identifier):
    cache_key = f'captcha_trigger_{operation}_{identifier}'
    count = default_cache.get(cache_key)
    if count is None:
        default_cache.set(cache_key, 1, timeout=CAPTCHA_TRIGGER_TTL)
    else:
        default_cache.set(cache_key, count + 1, timeout=CAPTCHA_TRIGGER_TTL)


def reset_failures(operation, identifier):
    cache_key = f'captcha_trigger_{operation}_{identifier}'
    default_cache.delete(cache_key)