import gradio as gr
import spaces
import torch
from diffusers import AutoencoderKL, TCDScheduler
from diffusers.models.model_loading_utils import load_state_dict
# Remove ImageSlider import
# from gradio_imageslider import ImageSlider
from huggingface_hub import hf_hub_download

from controlnet_union import ControlNetModel_Union
from pipeline_fill_sd_xl import StableDiffusionXLFillPipeline

from PIL import Image, ImageDraw
import numpy as np

# --- Model Loading (Unchanged) ---
config_file = hf_hub_download(
    "xinsir/controlnet-union-sdxl-1.0",
    filename="config_promax.json",
)

config = ControlNetModel_Union.load_config(config_file)
controlnet_model = ControlNetModel_Union.from_config(config)
model_file = hf_hub_download(
    "xinsir/controlnet-union-sdxl-1.0",
    filename="diffusion_pytorch_model_promax.safetensors",
)

sstate_dict = load_state_dict(model_file)
model, _, _, _, _ = ControlNetModel_Union._load_pretrained_model(
    controlnet_model, sstate_dict, model_file, "xinsir/controlnet-union-sdxl-1.0"
)
model.to(device="cuda", dtype=torch.float16)
#----------------------

vae = AutoencoderKL.from_pretrained(
    "madebyollin/sdxl-vae-fp16-fix", torch_dtype=torch.float16
).to("cuda")

pipe = StableDiffusionXLFillPipeline.from_pretrained(
    "SG161222/RealVisXL_V5.0_Lightning",
    torch_dtype=torch.float16,
    vae=vae,
    controlnet=model,
    variant="fp16",
).to("cuda")

pipe.scheduler = TCDScheduler.from_config(pipe.scheduler.config)

# --- Helper Functions (Mostly Unchanged) ---
def can_expand(source_width, source_height, target_width, target_height, alignment):
    """Checks if the image can be expanded based on the alignment."""
    if alignment in ("Left", "Right") and source_width >= target_width:
        return False
    if alignment in ("Top", "Bottom") and source_height >= target_height:
        return False
    return True

def prepare_image_and_mask(image, width, height, overlap_percentage, resize_option, custom_resize_percentage, alignment, overlap_left, overlap_right, overlap_top, overlap_bottom):
    target_size = (width, height)

    # Calculate the scaling factor to fit the image within the target size
    scale_factor = min(target_size[0] / image.width, target_size[1] / image.height)
    new_width = int(image.width * scale_factor)
    new_height = int(image.height * scale_factor)

    # Resize the source image to fit within target size
    source = image.resize((new_width, new_height), Image.LANCZOS)

    # Apply resize option using percentages
    if resize_option == "Full":
        resize_percentage = 100
    elif resize_option == "50%":
        resize_percentage = 50
    elif resize_option == "33%":
        resize_percentage = 33
    elif resize_option == "25%":
        resize_percentage = 25
    else:  # Custom
        resize_percentage = custom_resize_percentage

    # Calculate new dimensions based on percentage
    resize_factor = resize_percentage / 100
    new_width = int(source.width * resize_factor)
    new_height = int(source.height * resize_factor)

    # Ensure minimum size of 64 pixels
    new_width = max(new_width, 64)
    new_height = max(new_height, 64)

    # Resize the image
    source = source.resize((new_width, new_height), Image.LANCZOS)

    # Calculate the overlap in pixels based on the percentage
    overlap_x = int(new_width * (overlap_percentage / 100))
    overlap_y = int(new_height * (overlap_percentage / 100))

    # Ensure minimum overlap of 1 pixel
    overlap_x = max(overlap_x, 1)
    overlap_y = max(overlap_y, 1)

    # Calculate margins based on alignment
    if alignment == "Middle":
        margin_x = (target_size[0] - new_width) // 2
        margin_y = (target_size[1] - new_height) // 2
    elif alignment == "Left":
        margin_x = 0
        margin_y = (target_size[1] - new_height) // 2
    elif alignment == "Right":
        margin_x = target_size[0] - new_width
        margin_y = (target_size[1] - new_height) // 2
    elif alignment == "Top":
        margin_x = (target_size[0] - new_width) // 2
        margin_y = 0
    elif alignment == "Bottom":
        margin_x = (target_size[0] - new_width) // 2
        margin_y = target_size[1] - new_height

    # Adjust margins to eliminate gaps
    margin_x = max(0, min(margin_x, target_size[0] - new_width))
    margin_y = max(0, min(margin_y, target_size[1] - new_height))

    # Create a new background image and paste the resized source image
    background = Image.new('RGB', target_size, (255, 255, 255))
    background.paste(source, (margin_x, margin_y))

    # Create the mask
    mask = Image.new('L', target_size, 255)
    mask_draw = ImageDraw.Draw(mask)

    # Calculate overlap areas
    white_gaps_patch = 2 # Pixels to leave unmasked at edges if overlap is disabled for that edge

    left_overlap = margin_x + overlap_x if overlap_left else margin_x + white_gaps_patch
    right_overlap = margin_x + new_width - overlap_x if overlap_right else margin_x + new_width - white_gaps_patch
    top_overlap = margin_y + overlap_y if overlap_top else margin_y + white_gaps_patch
    bottom_overlap = margin_y + new_height - overlap_y if overlap_bottom else margin_y + new_height - white_gaps_patch

    # Adjust overlap boundaries based on alignment when specific overlap directions are *disabled*
    # This prevents unmasking the absolute edge of the canvas in alignment modes
    if alignment == "Left":
        left_overlap = margin_x + overlap_x if overlap_left else margin_x # Keep edge masked if alignment is left
    elif alignment == "Right":
        right_overlap = margin_x + new_width - overlap_x if overlap_right else margin_x + new_width # Keep edge masked
    elif alignment == "Top":
        top_overlap = margin_y + overlap_y if overlap_top else margin_y # Keep edge masked
    elif alignment == "Bottom":
        bottom_overlap = margin_y + new_height - overlap_y if overlap_bottom else margin_y + new_height # Keep edge masked

    # Ensure coordinates are within bounds
    left_overlap = max(0, left_overlap)
    top_overlap = max(0, top_overlap)
    right_overlap = min(target_size[0], right_overlap)
    bottom_overlap = min(target_size[1], bottom_overlap)

    # Draw the mask (black rectangle for the area to keep)
    if right_overlap > left_overlap and bottom_overlap > top_overlap:
        mask_draw.rectangle([
            (left_overlap, top_overlap),
            (right_overlap, bottom_overlap)
        ], fill=0) # 0 means keep this area (not masked for inpainting)

    # Invert the mask: White areas (255) will be inpainted. Black (0) is kept.
    mask = Image.fromarray(255 - np.array(mask))

    return background, mask

def preview_image_and_mask(image, width, height, overlap_percentage, resize_option, custom_resize_percentage, alignment, overlap_left, overlap_right, overlap_top, overlap_bottom):
    background, mask = prepare_image_and_mask(image, width, height, overlap_percentage, resize_option, custom_resize_percentage, alignment, overlap_left, overlap_right, overlap_top, overlap_bottom)

    # Create a preview image showing the mask
    preview = background.copy().convert('RGBA')

    # Create a semi-transparent red overlay for the masked (inpainting) area
    red_overlay = Image.new('RGBA', background.size, (255, 0, 0, 100)) # 100 alpha (~40% opacity)

    # The mask is now white (255) where inpainting happens. Use this directly.
    preview.paste(red_overlay, (0, 0), mask)

    return preview

@spaces.GPU(duration=24)
def infer(image, width, height, overlap_percentage, num_inference_steps, resize_option, custom_resize_percentage, prompt_input, alignment, overlap_left, overlap_right, overlap_top, overlap_bottom):
    background, mask = prepare_image_and_mask(image, width, height, overlap_percentage, resize_option, custom_resize_percentage, alignment, overlap_left, overlap_right, overlap_top, overlap_bottom)

    # Ensure alignment allows expansion, default to Middle if not
    source_w, source_h = background.size # Use background size after initial resize/placement
    target_w, target_h = width, height
    if alignment in ("Left", "Right") and source_w >= target_w:
        print(f"Warning: Source width ({source_w}) >= target width ({target_w}) with {alignment} alignment. Forcing Middle alignment.")
        alignment = "Middle"
        # Re-prepare mask/background with corrected alignment if needed (optional, depends if prepare func uses alignment early)
        # background, mask = prepare_image_and_mask(...) # If needed
    if alignment in ("Top", "Bottom") and source_h >= target_h:
        print(f"Warning: Source height ({source_h}) >= target height ({target_h}) with {alignment} alignment. Forcing Middle alignment.")
        alignment = "Middle"
        # Re-prepare mask/background with corrected alignment if needed
        # background, mask = prepare_image_and_mask(...) # If needed

    # Image for ControlNet input (masked original content)
    # The pipeline expects the original image content in the non-masked area
    cnet_image = background.copy()
    # The pipeline's `image` argument is the *initial* content for the *masked* area (often noise, but here we provide the background)
    # The `mask_image` tells the pipeline *where* to perform the inpainting/outpainting.
    # The controlnet `image` needs the original content visible in the non-masked area.
    # ControlNet Union seems to work well by just passing the background with the source image pasted.

    final_prompt = f"{prompt_input} , high quality, 4k" if prompt_input else "high quality, 4k"

    (
        prompt_embeds,
        negative_prompt_embeds,
        pooled_prompt_embeds,
        negative_pooled_prompt_embeds,
    ) = pipe.encode_prompt(final_prompt, "cuda", True)

    # The pipeline call
    # Note: The pipeline expects `image` (initial state for masked area) and `mask_image`
    # The `control_image` is implicitly handled by the ControlNet attached to the pipeline
    output_image = pipe(
        prompt_embeds=prompt_embeds,
        negative_prompt_embeds=negative_prompt_embeds,
        pooled_prompt_embeds=pooled_prompt_embeds,
        negative_pooled_prompt_embeds=negative_pooled_prompt_embeds,
        image=background, # Provide the initial canvas state
        mask_image=mask,   # Provide the mask (white is area to change)
        control_image=cnet_image, # Pass the control image explicitly if needed by pipeline logic
        num_inference_steps=num_inference_steps,
        output_type="pil" # Ensure PIL output
    ).images[0]

    # The pipeline should have already handled the compositing based on the mask
    # If not, uncomment the paste operation below:
    # final_image = background.copy().convert("RGBA") # Start with original background
    # output_image = output_image.convert("RGBA")
    # mask_rgba = mask.convert('L').point(lambda p: 255 if p > 128 else 0) # Ensure mask is binary 0/255
    # final_image.paste(output_image, (0, 0), mask_rgba) # Paste generated content using the mask

    # Return the single final image
    return output_image


def clear_result():
    """Clears the result Image component."""
    return gr.update(value=None)

# --- UI Helper Functions (Unchanged) ---
def preload_presets(target_ratio, ui_width, ui_height):
    """Updates the width and height sliders based on the selected aspect ratio."""
    if target_ratio == "9:16":
        changed_width = 720
        changed_height = 1280
        return changed_width, changed_height, gr.update() # Close accordion
    elif target_ratio == "16:9":
        changed_width = 1280
        changed_height = 720
        return changed_width, changed_height, gr.update() # Close accordion
    elif target_ratio == "1:1":
        changed_width = 1024
        changed_height = 1024
        return changed_width, changed_height, gr.update() # Close accordion
    elif target_ratio == "Custom":
        # Don't change sliders, just open accordion
        return ui_width, ui_height, gr.update(open=True)

def select_the_right_preset(user_width, user_height):
    """Updates the radio button based on the current slider values."""
    if user_width == 720 and user_height == 1280:
        return "9:16"
    elif user_width == 1280 and user_height == 720:
        return "16:9"
    elif user_width == 1024 and user_height == 1024:
        return "1:1"
    else:
        return "Custom"

def toggle_custom_resize_slider(resize_option):
    """Shows/hides the custom resize slider."""
    return gr.update(visible=(resize_option == "Custom"))

def update_history(new_image, history):
    """Updates the history gallery with the new image."""
    if history is None:
        history = []
    # Ensure new_image is a PIL Image before adding
    if isinstance(new_image, Image.Image):
        history.insert(0, new_image)
    return history

# --- Gradio UI Definition ---
css = """
.gradio-container {
    width: 1200px !important;
    margin: auto !important; /* Center the container */
}
h1 { text-align: center; }
footer { visibility: hidden; }
/* Ensure result image takes reasonable space */
#result-image img {
    max-height: 768px; /* Adjust max height as needed */
    object-fit: contain;
    width: auto;
    height: auto;
}
#history-gallery .thumbnail-item { /* Style history items */
    height: 100px !important;
}
#history-gallery .gallery {
    grid-template-rows: repeat(auto-fill, 100px) !important;
}

"""

title = """<h1 align="center">Diffusers Image Outpaint Lightning</h1>"""

with gr.Blocks(css=css) as demo:
    with gr.Column():
        gr.HTML(title)

        with gr.Row():
            with gr.Column(scale=1): # Left column for inputs
                input_image = gr.Image(
                    type="pil",
                    label="Input Image",
                    height=400 # Give input image reasonable height
                )

                with gr.Row():
                    with gr.Column(scale=2):
                        prompt_input = gr.Textbox(label="Prompt (Optional)", placeholder="Describe the scene to expand...")
                    with gr.Column(scale=1):
                        run_button = gr.Button("Generate", variant="primary") # Make primary

                with gr.Row():
                    target_ratio = gr.Radio(
                        label="Target Ratio",
                        choices=["9:16", "16:9", "1:1", "Custom"],
                        value="9:16",
                        scale=2
                    )

                    alignment_dropdown = gr.Dropdown(
                        choices=["Middle", "Left", "Right", "Top", "Bottom"],
                        value="Middle",
                        label="Align Source Image"
                    )

                with gr.Accordion(label="Advanced settings", open=False) as settings_panel:
                    with gr.Row():
                         width_slider = gr.Slider(
                             label="Target Width",
                             minimum=512, # Lowered minimum slightly
                             maximum=2048, # Increased maximum slightly
                             step=64, # Use steps of 64 common for SD
                             value=720,
                         )
                         height_slider = gr.Slider(
                             label="Target Height",
                             minimum=512,
                             maximum=2048,
                             step=64,
                             value=1280,
                         )
                    num_inference_steps = gr.Slider(label="Steps", minimum=1, maximum=12, step=1, value=4) # TCD/Lightning allows few steps

                    with gr.Group():
                        overlap_percentage = gr.Slider(
                            label="Mask overlap (%)",
                            minimum=1,
                            maximum=50,
                            value=12, # Default overlap
                            step=1
                        )
                        with gr.Row():
                            overlap_top = gr.Checkbox(label="Top", value=True)
                            overlap_right = gr.Checkbox(label="Right", value=True)
                            overlap_bottom = gr.Checkbox(label="Bottom", value=True)
                            overlap_left = gr.Checkbox(label="Left", value=True)


                    with gr.Row():
                        resize_option = gr.Radio(
                            label="Resize input within target",
                            choices=["Full", "50%", "33%", "25%", "Custom"],
                            value="Full"
                        )
                        custom_resize_percentage = gr.Slider(
                            label="Custom resize (%)",
                            minimum=1,
                            maximum=100,
                            step=1,
                            value=50,
                            visible=False # Initially hidden
                        )

                    preview_button = gr.Button("Preview Mask & Alignment")
                    preview_image = gr.Image(label="Mask Preview (Red = Outpaint Area)", type="pil", interactive=False)


                gr.Examples(
                    examples=[
                        ["./examples/example_1.webp", "A wide landscape view of the mountains", 1280, 720, "Middle"],
                        ["./examples/example_2.jpg", "Full body shot of the astronaut on the moon", 720, 1280, "Middle"],
                        ["./examples/example_3.jpg", "Expanding the sky and ground around the subject", 1024, 1024, "Middle"],
                         ["./examples/example_3.jpg", "Expanding downwards from the subject", 1024, 1024, "Top"], # Align subject Top
                         ["./examples/example_3.jpg", "Expanding upwards from the subject", 1024, 1024, "Bottom"], # Align subject Bottom
                    ],
                    inputs=[input_image, prompt_input, width_slider, height_slider, alignment_dropdown],
                    label="Examples (Click to load)"
                )


            with gr.Column(scale=1): # Right column for output
                # Replace ImageSlider with gr.Image
                result = gr.Image(label="Generated Image", type="pil", interactive=False, elem_id="result-image")
                use_as_input_button = gr.Button("Use Result as Input Image", visible=False) # Initially hidden

                history_gallery = gr.Gallery(
                    label="History",
                    columns=6,
                    object_fit="contain",
                    interactive=False,
                    height=110, # Fixed height for the row
                    elem_id="history-gallery"
                )


    # --- Event Handling ---

    def use_output_as_input(output_image):
        """Sets the generated output as the new input image."""
        # output_image is now the single final image from gr.Image
        return gr.update(value=output_image)

    use_as_input_button.click(
        fn=use_output_as_input,
        inputs=[result], # Input is the result image component
        outputs=[input_image] # Output updates the input image component
    )

    target_ratio.change(
        fn=preload_presets,
        inputs=[target_ratio, width_slider, height_slider],
        outputs=[width_slider, height_slider, settings_panel], # Also control accordion state
        queue=False
    )

    # Link sliders back to the ratio selector
    width_slider.change(
        fn=select_the_right_preset,
        inputs=[width_slider, height_slider],
        outputs=[target_ratio],
        queue=False
    )
    height_slider.change(
        fn=select_the_right_preset,
        inputs=[width_slider, height_slider],
        outputs=[target_ratio],
        queue=False
    )

    resize_option.change(
        fn=toggle_custom_resize_slider,
        inputs=[resize_option],
        outputs=[custom_resize_percentage],
        queue=False
    )

    # Consolidate common inputs for generation
    gen_inputs = [
        input_image, width_slider, height_slider, overlap_percentage, num_inference_steps,
        resize_option, custom_resize_percentage, prompt_input, alignment_dropdown,
        overlap_left, overlap_right, overlap_top, overlap_bottom
    ]

    # Chain generation logic
    run_button.click(
        fn=clear_result,
        inputs=None,
        outputs=[result], # Clear the single image output
        queue=False # Run clearing immediately
    ).then(
        fn=infer,
        inputs=gen_inputs,
        outputs=[result], # Output the single image to the result component
    ).then(
        # Update history with the single result image
        fn=lambda res_img, hist: update_history(res_img, hist),
        inputs=[result, history_gallery],
        outputs=[history_gallery],
        queue=False # Update history immediately after generation
    ).then(
        # Show the 'Use as Input' button
        fn=lambda: gr.update(visible=True),
        inputs=None,
        outputs=[use_as_input_button],
        queue=False # Show button immediately
    )

    prompt_input.submit(
         fn=clear_result,
        inputs=None,
        outputs=[result],
        queue=False
    ).then(
        fn=infer,
        inputs=gen_inputs,
        outputs=[result],
    ).then(
        fn=lambda res_img, hist: update_history(res_img, hist),
        inputs=[result, history_gallery],
        outputs=[history_gallery],
         queue=False
    ).then(
        fn=lambda: gr.update(visible=True),
        inputs=None,
        outputs=[use_as_input_button],
        queue=False
    )

    preview_button.click(
        fn=preview_image_and_mask,
        inputs=[input_image, width_slider, height_slider, overlap_percentage, resize_option, custom_resize_percentage, alignment_dropdown,
                overlap_left, overlap_right, overlap_top, overlap_bottom],
        outputs=preview_image,
        queue=False # Preview should be fast
    )

demo.queue(max_size=10).launch(ssr_mode=False, show_error=True) # Removed share=False for potential Hugging Face Spaces use