from io import BytesIO
from math import ceil

import requests
from PIL import Image


def fetch_contributors(owner, repo):
    contributors = []
    page = 1
    
    while True:
        url = f"https://api.github.com/repos/{owner}/{repo}/contributors"
        params = {"page": page, "per_page": 100}
        
        headers = {
            "User-Agent": "github-contributors-graph",
            "Accept": "application/vnd.github.v3+json"
        }
        
        response = requests.get(url, headers=headers, params=params)
        
        if not response.ok:
            return []
        
        data = response.json()
        
        if not data:
            break
        
        contributors.extend(data)
        page += 1
        
        if response.headers.get('X-RateLimit-Remaining') == '0':
            break
    
    return contributors


def download_avatar(avatar_url, size):
    try:
        if "avatars.githubusercontent.com" in avatar_url:
            avatar_url = f"{avatar_url}?s={size}"
        
        response = requests.get(avatar_url, timeout=10)
        
        if not response.ok:
            return None
        
        img = Image.open(BytesIO(response.content))
        
        if img.size != (size, size):
            img = img.resize((size, size), Image.Resampling.LANCZOS)
        
        return img
    
    except Exception:
        return None


def generate_contributors_image(owner="neoarz", repo="syntrel", size=64, images_per_row=20):
    contributors = fetch_contributors(owner, repo)
    
    if not contributors:
        return None
    
    images = []
    
    for contributor in contributors:
        avatar_url = contributor.get("avatar_url")
        
        if not avatar_url:
            continue
        
        img = download_avatar(avatar_url, size)
        
        if img is None:
            continue
        
        images.append(img)
    
    if not images:
        return None
    
    actual_images_per_row = min(len(images), images_per_row)
    width = size * actual_images_per_row
    row_count = ceil(len(images) / images_per_row)
    height = size * row_count
    
    canvas = Image.new("RGB", (width, height), color="black")
    
    for idx, img in enumerate(images):
        col = idx % images_per_row
        row = idx // images_per_row
        x = col * size
        y = row * size
        
        canvas.paste(img, (x, y))
    
    buffer = BytesIO()
    canvas.save(buffer, "PNG")
    buffer.seek(0)
    
    return buffer