#
# Copyright (c) 2024-2026, Daily
#
# SPDX-License-Identifier: BSD 2-Clause License
#

"""Fal's image generation service implementation.

This module provides integration with Fal's image generation API
for creating images from text prompts using various AI models.
"""

import asyncio
import io
import os
from typing import AsyncGenerator, Dict, Optional, Union

import aiohttp
from loguru import logger
from PIL import Image
from pydantic import BaseModel

from pipecat.frames.frames import ErrorFrame, Frame, URLImageRawFrame
from pipecat.services.image_service import ImageGenService

try:
    import fal_client
except ModuleNotFoundError as e:
    logger.error(f"Exception: {e}")
    logger.error("In order to use Fal, you need to `pip install pipecat-ai[fal]`.")
    raise Exception(f"Missing module: {e}")


class FalImageGenService(ImageGenService):
    """Fal's image generation service.

    Provides text-to-image generation using Fal.ai's API with configurable
    parameters for image quality, safety, and format options.
    """

    class InputParams(BaseModel):
        """Input parameters for Fal.ai image generation.

        Parameters:
            seed: Random seed for reproducible generation. If None, uses random seed.
            num_inference_steps: Number of inference steps for generation. Defaults to 8.
            num_images: Number of images to generate. Defaults to 1.
            image_size: Image dimensions as string preset or dict with width/height. Defaults to "square_hd".
            expand_prompt: Whether to automatically expand/enhance the prompt. Defaults to False.
            enable_safety_checker: Whether to enable content safety filtering. Defaults to True.
            format: Output image format. Defaults to "png".
        """

        seed: Optional[int] = None
        num_inference_steps: int = 8
        num_images: int = 1
        image_size: Union[str, Dict[str, int]] = "square_hd"
        expand_prompt: bool = False
        enable_safety_checker: bool = True
        format: str = "png"

    def __init__(
        self,
        *,
        params: InputParams,
        aiohttp_session: aiohttp.ClientSession,
        model: str = "fal-ai/fast-sdxl",
        key: Optional[str] = None,
        **kwargs,
    ):
        """Initialize the FalImageGenService.

        Args:
            params: Input parameters for image generation configuration.
            aiohttp_session: HTTP client session for downloading generated images.
            model: The Fal.ai model to use for generation. Defaults to "fal-ai/fast-sdxl".
            key: Optional API key for Fal.ai. If provided, sets FAL_KEY environment variable.
            **kwargs: Additional arguments passed to parent ImageGenService.
        """
        super().__init__(**kwargs)
        self.set_model_name(model)
        self._params = params
        self._aiohttp_session = aiohttp_session
        if key:
            os.environ["FAL_KEY"] = key

    async def run_image_gen(self, prompt: str) -> AsyncGenerator[Frame, None]:
        """Generate an image from a text prompt.

        Args:
            prompt: The text prompt to generate an image from.

        Yields:
            URLImageRawFrame: Frame containing the generated image data and metadata.
            ErrorFrame: If image generation fails.
        """

        def load_image_bytes(encoded_image: bytes):
            buffer = io.BytesIO(encoded_image)
            image = Image.open(buffer)
            return (image.tobytes(), image.size, image.format)

        logger.debug(f"Generating image from prompt: {prompt}")

        response = await fal_client.run_async(
            self.model_name,
            arguments={"prompt": prompt, **self._params.model_dump(exclude_none=True)},
        )

        image_url = response["images"][0]["url"] if response else None

        if not image_url:
            yield ErrorFrame("Image generation failed")
            return

        logger.debug(f"Image generated at: {image_url}")

        # Load the image from the url
        logger.debug(f"Downloading image {image_url} ...")
        async with self._aiohttp_session.get(image_url) as response:
            logger.debug(f"Downloaded image {image_url}")
            encoded_image = await response.content.read()
            (image_bytes, size, format) = await asyncio.to_thread(load_image_bytes, encoded_image)

            frame = URLImageRawFrame(url=image_url, image=image_bytes, size=size, format=format)
            yield frame
