// allows drag-and-drop files into prompt fields, and also pasting images from clipboard

function isValidImageList(files) {
    return files != null && files.length === 1 && files[0].type.startsWith("image");
}

function dropReplaceImage(imgWrap, files) {
    if (!isValidImageList(files)) return;

    const tmpFile = files[0];

    imgWrap.querySelector(".modify-upload button + button, .touch-none + div button + button")?.click();

    const callback = () => {
        const fileInput = imgWrap.querySelector('input[type="file"]');
        if (fileInput) {
            if (files.length === 0) {
                files = new DataTransfer();
                files.items.add(tmpFile);
                fileInput.files = files.files;
            } else {
                fileInput.files = files;
            }
            fileInput.dispatchEvent(new Event("change"));
        }
    };

    window.requestAnimationFrame(() => callback());
}

function eventHasFiles(e) {
    if (!e.dataTransfer || !e.dataTransfer.files) return false;
    if (e.dataTransfer.files.length > 0) return true;
    if (e.dataTransfer.items.length > 0 && e.dataTransfer.items[0].kind == "file") return true;

    return false;
}

function isURL(url) {
    try {
        const _ = new URL(url);
        return true;
    } catch {
        return false;
    }
}

function dragDropTargetIsPrompt(target) {
    if (target?.placeholder && target?.placeholder.indexOf("Prompt") >= 0) return true;
    if (target?.parentNode?.parentNode?.className?.indexOf("prompt") > 0) return true;
    return false;
}

window.document.addEventListener("dragover", (e) => {
    const target = e.composedPath()[0];
    if (!eventHasFiles(e)) return;

    const targetImage = target.closest('[data-testid="image"]');
    if (!dragDropTargetIsPrompt(target) && !targetImage) return;

    e.stopPropagation();
    e.preventDefault();
    e.dataTransfer.dropEffect = "copy";
});

window.document.addEventListener("drop", async (e) => {
    const target = e.composedPath()[0];
    const url = e.dataTransfer.getData("text/uri-list") || e.dataTransfer.getData("text/plain");
    if (!eventHasFiles(e) && !isURL(url)) return;

    if (dragDropTargetIsPrompt(target)) {
        e.stopPropagation();
        e.preventDefault();

        const isImg2img = get_tab_index("tabs") == 1;
        const prompt_image_target = isImg2img ? "img2img_prompt_image" : "txt2img_prompt_image";

        const imgParent = gradioApp().getElementById(prompt_image_target);
        const files = e.dataTransfer.files;
        const fileInput = imgParent.querySelector('input[type="file"]');
        if (eventHasFiles(e) && fileInput) {
            fileInput.files = files;
            fileInput.dispatchEvent(new Event("change"));
        } else if (url) {
            try {
                const request = await fetch(url);
                if (!request.ok) {
                    console.error("Error fetching URL:", url, request.status);
                    return;
                }
                const data = new DataTransfer();
                data.items.add(new File([await request.blob()], "image.png"));
                fileInput.files = data.files;
                fileInput.dispatchEvent(new Event("change"));
            } catch (error) {
                console.error("Error fetching URL:", url, error);
                return;
            }
        }
    }

    const targetImage = target.closest('[data-testid="image"]');
    if (targetImage) {
        e.stopPropagation();
        e.preventDefault();
        const files = e.dataTransfer.files;
        dropReplaceImage(targetImage, files);
        return;
    }
});

window.addEventListener("paste", (e) => {
    const files = e.clipboardData.files;
    if (!isValidImageList(files)) return;

    const visibleImageFields = [...gradioApp().querySelectorAll('[data-testid="image"]')]
        .filter((el) => uiElementIsVisible(el))
        .sort((a, b) => uiElementInSight(b) - uiElementInSight(a));

    if (!visibleImageFields.length) return;

    const firstFreeImageField = visibleImageFields.filter((el) => !el.querySelector("img"))?.[0];

    dropReplaceImage(
        firstFreeImageField ? firstFreeImageField : visibleImageFields[visibleImageFields.length - 1],
        files,
    );
});