"""Backend logic for DALL·E AI Image Generator."""

from __future__ import annotations

import base64
import logging
import os
import time
from datetime import datetime
from io import BytesIO
from pathlib import Path
from typing import List, Tuple

from dotenv import load_dotenv
from openai import OpenAI
from PIL import Image

# -------------------------------------------------------------------
# Load Environment Variables
# -------------------------------------------------------------------
load_dotenv()

# -------------------------------------------------------------------
# Directories
# -------------------------------------------------------------------
BASE_DIR = Path(__file__).parent

GENERATED_DIR = BASE_DIR / "generated_images"
LOG_DIR = BASE_DIR / "logs"

GENERATED_DIR.mkdir(exist_ok=True)
LOG_DIR.mkdir(exist_ok=True)

# -------------------------------------------------------------------
# Logging
# -------------------------------------------------------------------
logging.basicConfig(
    filename=LOG_DIR / "app.log",
    level=logging.INFO,
    format="%(asctime)s | %(levelname)s | %(message)s",
)

logger = logging.getLogger(__name__)

# -------------------------------------------------------------------
# OpenAI Client
# -------------------------------------------------------------------
client = OpenAI(
    api_key=os.getenv("OPENAI_API_KEY")
)

# -------------------------------------------------------------------
# Prompt History
# -------------------------------------------------------------------
prompt_history: List[str] = []

# -------------------------------------------------------------------
# Validation
# -------------------------------------------------------------------
def validate_prompt(prompt: str) -> None:

    if not prompt or not prompt.strip():
        raise ValueError("Prompt cannot be empty.")

    if len(prompt.strip()) < 3:
        raise ValueError("Prompt too short.")


# -------------------------------------------------------------------
# Save Image
# -------------------------------------------------------------------
def save_image(image: Image.Image) -> str:

    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")

    filename = f"generated_{timestamp}.png"

    output_path = GENERATED_DIR / filename

    image.save(output_path)

    logger.info("Image saved: %s", output_path)

    return str(output_path)


# -------------------------------------------------------------------
# Generate Image
# -------------------------------------------------------------------
def generate_image(
    prompt: str,
    size: str = "1024x1024",
    quality: str = "high",
    style: str = "vivid",
    retries: int = 3,
) -> Tuple[str, List[str], str]:

    validate_prompt(prompt)

    prompt_history.append(prompt)

    for attempt in range(retries):

        try:
            logger.info("Generating image: %s", prompt)

            response = client.images.generate(
                model="gpt-image-1",
                prompt=prompt,
                size=size,
                quality=quality,
                n=1,
            )

            image_base64 = response.data[0].b64_json

            image_bytes = base64.b64decode(image_base64)

            image = Image.open(BytesIO(image_bytes))

            image_path = save_image(image)

            return (
                image_path,
                prompt_history[-10:],
                "✅ Image generated successfully!",
            )

        except Exception as error:

            logger.error("Generation failed: %s", error)

            if attempt == retries - 1:

                return (
                    None,
                    prompt_history[-10:],
                    f"❌ Error: {error}",
                )

            time.sleep(2)

    return (
        None,
        prompt_history[-10:],
        "❌ Unknown error occurred.",
    )


# -------------------------------------------------------------------
# Clear History
# -------------------------------------------------------------------
def clear_history():

    prompt_history.clear()

    return []


"""Main launcher for Gradio app."""

from UI import build_demo
from app import clear_history, generate_image

demo = build_demo()
demo.queue()
demo.launch()