import argparse

import requests
from image_api_utils import (
    IMAGE_API_BASE_URL,
    API_KEY,
    encode_json_request,
    get_auth_headers,
    poll_and_download_result,
    prepare_reference_images,
)

MODEL_NAME = "gemini-3-pro-image-preview"


def generate_image(images=None, prompt="", aspect_ratio="1:1", image_size="2K", notify_url=None):
    """
    Triggers the image generation task using the Nano Banana Pro (gemini-3-pro-image-preview) model.
    
    :param images: Up to 14 local image paths, HTTP(S) URLs, or base64 data URLs.
    :param prompt: Text prompt describing the desired image content.
    :param aspect_ratio: Image aspect ratio. Allowed: "1:1", "2:3", "3:2", "3:4", "4:3", "4:5", "5:4", "9:16", "16:9", "21:9"
    :param image_size: Image resolution/quality. Allowed: "1K", "2K", "4K"
    :param notify_url: Optional webhook URL for async callback.
    :return: task_id string/int
    """
    url = f"{IMAGE_API_BASE_URL}/v1/media/generate"
    
    params = {
        "aspectRatio": aspect_ratio,
        "imageSize": image_size
    }
    
    reference_images = prepare_reference_images(images)
    if reference_images:
        params["images"] = reference_images

    payload = {
        "model": MODEL_NAME,
        "params": params,
        "prompt": prompt
    }
    
    if notify_url:
        payload["notify_url"] = notify_url

    payload_body = encode_json_request(payload)
    
    headers = get_auth_headers(api_key=API_KEY)
    print(f"[*] Sending Banana Pro ({MODEL_NAME}) generation request to: {url}")
    response = requests.post(url, data=payload_body, headers=headers)
    response.raise_for_status()
    res_json = response.json()
    
    # Try parsing task_id from root or nested "data" dictionary
    task_id = res_json.get("task_id")
    if not task_id and "data" in res_json and isinstance(res_json["data"], dict):
        task_id = res_json["data"].get("task_id")
        
    if not task_id:
        raise ValueError(f"Failed to obtain task_id from response: {res_json}")
    print(f"[+] Task created successfully. Task ID: {task_id}")
    return task_id


def generate_txt2img(prompt, output_path=None, aspect_ratio="1:1", image_size="2K", notify_url=None):
    """
    Text-to-image API for Nano Banana Pro (gemini-3-pro-image-preview).
    """
    task_id = generate_image(
        images=None,
        prompt=prompt,
        aspect_ratio=aspect_ratio,
        image_size=image_size,
        notify_url=notify_url,
    )
    return poll_and_download_result(
        task_id=task_id,
        output_path=output_path,
        default_prefix="banana_pro_result",
    )


def generate_img2img(local_image_paths, prompt, output_path=None, aspect_ratio="1:1", image_size="2K", notify_url=None):
    """
    Image-to-image API accepting local paths, HTTP(S) URLs, or base64 data URLs.
    """
    task_id = generate_image(
        images=local_image_paths,
        prompt=prompt,
        aspect_ratio=aspect_ratio,
        image_size=image_size,
        notify_url=notify_url,
    )
    return poll_and_download_result(
        task_id=task_id,
        output_path=output_path,
        default_prefix="banana_pro_result",
    )


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description="Generate image using Gemini 3 Pro (Nano Banana Pro) model.")
    parser.add_argument("prompt", help="Text prompt for image generation.")
    parser.add_argument(
        "-i",
        "--images",
        nargs="+",
        help="Reference image path(s), HTTP(S) URL(s), or base64 data URL(s), up to 14.",
    )
    parser.add_argument("-o", "--output", help="Output path for the generated image.")
    parser.add_argument("-a", "--aspect-ratio", default="1:1", 
                        choices=["1:1", "2:3", "3:2", "3:4", "4:3", "4:5", "5:4", "9:16", "16:9", "21:9"], 
                        help="Aspect ratio (default: 1:1).")
    parser.add_argument("-s", "--image-size", default="2K", choices=["1K", "2K", "4K"], help="Resolution size (default: 2K).")
    args = parser.parse_args()

    if args.images:
        generate_img2img(
            local_image_paths=args.images,
            prompt=args.prompt,
            output_path=args.output,
            aspect_ratio=args.aspect_ratio,
            image_size=args.image_size
        )
    else:
        generate_txt2img(
            prompt=args.prompt,
            output_path=args.output,
            aspect_ratio=args.aspect_ratio,
            image_size=args.image_size
        )