// A full size 'lightbox' preview modal shown when left clicking on gallery previews
function closeModal() {
    gradioApp().getElementById("lightboxModal").style.display = "none";
}

function showModal(event) {
    const source = event.target || event.srcElement;
    const modalImage = gradioApp().getElementById("modalImage");
    const modalToggleLivePreviewBtn = gradioApp().getElementById(
        "modal_toggle_live_preview",
    );
    modalToggleLivePreviewBtn.innerHTML = opts.js_live_preview_in_modal_lightbox
        ? "🗇"
        : "🗆";
    const lb = gradioApp().getElementById("lightboxModal");
    modalImage.src = source.src;
    if (modalImage.style.display === "none") {
        lb.style.setProperty("background-image", "url(" + source.src + ")");
    }
    lb.style.display = "flex";
    lb.focus();

    const tabTxt2Img = gradioApp().getElementById("tab_txt2img");
    const tabImg2Img = gradioApp().getElementById("tab_img2img");
    // show the save button in modal only on txt2img or img2img tabs
    if (
        tabTxt2Img.style.display != "none" ||
        tabImg2Img.style.display != "none"
    ) {
        gradioApp().getElementById("modal_save").style.display = "inline";
    } else {
        gradioApp().getElementById("modal_save").style.display = "none";
    }
    event.stopPropagation();
}

function negmod(n, m) {
    return ((n % m) + m) % m;
}

function updateOnBackgroundChange() {
    const modalImage = gradioApp().getElementById("modalImage");
    if (modalImage && modalImage.offsetParent) {
        let currentButton = selected_gallery_button();
        let preview = gradioApp().querySelectorAll(".livePreview > img");
        if (opts.js_live_preview_in_modal_lightbox && preview.length > 0) {
            // show preview image if available
            modalImage.src = preview[preview.length - 1].src;
        } else if (
            currentButton?.children?.length > 0 &&
            modalImage.src != currentButton.children[0].src
        ) {
            modalImage.src = currentButton.children[0].src;
            if (modalImage.style.display === "none") {
                const modal = gradioApp().getElementById("lightboxModal");
                modal.style.setProperty("background-image", `url(${modalImage.src})`);
            }
        }
    }
}

function modalImageSwitch(offset) {
    let galleryButtons = all_gallery_buttons();

    if (galleryButtons.length > 1) {
        let result = selected_gallery_index();

        if (result != -1) {
            let nextButton =
                galleryButtons[negmod(result + offset, galleryButtons.length)];
            nextButton.click();
            const modalImage = gradioApp().getElementById("modalImage");
            const modal = gradioApp().getElementById("lightboxModal");
            modalImage.src = nextButton.children[0].src;
            if (modalImage.style.display === "none") {
                modal.style.setProperty("background-image", `url(${modalImage.src})`);
            }
            setTimeout(function () {
                modal.focus();
            }, 10);
        }
    }
}

function saveImage() {
    const tabTxt2Img = gradioApp().getElementById("tab_txt2img");
    const tabImg2Img = gradioApp().getElementById("tab_img2img");
    const saveTxt2Img = "save_txt2img";
    const saveImg2Img = "save_img2img";
    if (tabTxt2Img.style.display != "none") {
        gradioApp().getElementById(saveTxt2Img).click();
    } else if (tabImg2Img.style.display != "none") {
        gradioApp().getElementById(saveImg2Img).click();
    } else {
        console.error("missing implementation for saving modal of this type");
    }
}

function modalSaveImage(event) {
    saveImage();
    event.stopPropagation();
}

function modalNextImage(event) {
    modalImageSwitch(1);
    event.stopPropagation();
}

function modalPrevImage(event) {
    modalImageSwitch(-1);
    event.stopPropagation();
}

function modalKeyHandler(event) {
    switch (event.key) {
        case "s":
            saveImage();
            break;
        case "ArrowLeft":
            modalPrevImage(event);
            break;
        case "ArrowRight":
            modalNextImage(event);
            break;
        case "Escape":
            closeModal();
            break;
    }
}

function setupImageForLightbox(e) {
    if (e.dataset.modded) {
        return;
    }

    e.dataset.modded = true;
    e.style.cursor = "pointer";
    e.style.userSelect = "none";

    e.addEventListener(
        "mousedown",
        function (evt) {
            if (evt.button == 1) {
                open(evt.target.src);
                evt.preventDefault();
                return;
            }
        },
        true,
    );

    e.addEventListener(
        "click",
        function (evt) {
            if (!opts.js_modal_lightbox || evt.button != 0) return;

            modalZoomSet(
                gradioApp().getElementById("modalImage"),
                opts.js_modal_lightbox_initially_zoomed,
            );
            evt.preventDefault();
            showModal(evt);
        },
        true,
    );
}

function modalZoomSet(modalImage, enable) {
    if (modalImage) modalImage.classList.toggle("modalImageFullscreen", !!enable);
}

function modalZoomToggle(event) {
    let modalImage = gradioApp().getElementById("modalImage");
    modalZoomSet(
        modalImage,
        !modalImage.classList.contains("modalImageFullscreen"),
    );
    event.stopPropagation();
}

function modalLivePreviewToggle(event) {
    const modalToggleLivePreview = gradioApp().getElementById(
        "modal_toggle_live_preview",
    );
    opts.js_live_preview_in_modal_lightbox =
        !opts.js_live_preview_in_modal_lightbox;
    modalToggleLivePreview.innerHTML = opts.js_live_preview_in_modal_lightbox
        ? "🗇"
        : "🗆";
    event.stopPropagation();
}

function modalTileImageToggle(event) {
    const modalImage = gradioApp().getElementById("modalImage");
    const modal = gradioApp().getElementById("lightboxModal");
    const isTiling = modalImage.style.display === "none";
    if (isTiling) {
        modalImage.style.display = "block";
        modal.style.setProperty("background-image", "none");
    } else {
        modalImage.style.display = "none";
        modal.style.setProperty("background-image", `url(${modalImage.src})`);
    }

    event.stopPropagation();
}

onAfterUiUpdate(function () {
    let fullImg_preview = gradioApp().querySelectorAll(
        ".gradio-gallery > button > button > img, .gradio-gallery > .livePreview",
    );
    if (fullImg_preview != null) {
        fullImg_preview.forEach(setupImageForLightbox);
    }
    updateOnBackgroundChange();
});

document.addEventListener("DOMContentLoaded", function () {
    //const modalFragment = document.createDocumentFragment();
    const modal = document.createElement("div");
    modal.onclick = closeModal;
    modal.id = "lightboxModal";
    modal.tabIndex = 0;
    modal.addEventListener("keydown", modalKeyHandler, true);

    const modalControls = document.createElement("div");
    modalControls.className = "modalControls gradio-container";
    modal.append(modalControls);

    const modalZoom = document.createElement("span");
    modalZoom.className = "modalZoom cursor";
    modalZoom.innerHTML = "⤡";
    modalZoom.addEventListener("click", modalZoomToggle, true);
    modalZoom.title = "Toggle zoomed view";
    modalControls.appendChild(modalZoom);

    const modalTileImage = document.createElement("span");
    modalTileImage.className = "modalTileImage cursor";
    modalTileImage.innerHTML = "⊞";
    modalTileImage.addEventListener("click", modalTileImageToggle, true);
    modalTileImage.title = "Preview tiling";
    modalControls.appendChild(modalTileImage);

    const modalSave = document.createElement("span");
    modalSave.className = "modalSave cursor";
    modalSave.id = "modal_save";
    modalSave.innerHTML = "🖫";
    modalSave.addEventListener("click", modalSaveImage, true);
    modalSave.title = "Save Image(s)";
    modalControls.appendChild(modalSave);

    const modalToggleLivePreview = document.createElement("span");
    modalToggleLivePreview.className = "modalToggleLivePreview cursor";
    modalToggleLivePreview.id = "modal_toggle_live_preview";
    modalToggleLivePreview.innerHTML = "🗆";
    modalToggleLivePreview.onclick = modalLivePreviewToggle;
    modalToggleLivePreview.title = "Toggle live preview";
    modalControls.appendChild(modalToggleLivePreview);

    const modalClose = document.createElement("span");
    modalClose.className = "modalClose cursor";
    modalClose.innerHTML = "×";
    modalClose.onclick = closeModal;
    modalClose.title = "Close image viewer";
    modalControls.appendChild(modalClose);

    const modalImage = document.createElement("img");
    modalImage.id = "modalImage";
    modalImage.onclick = closeModal;
    modalImage.tabIndex = 0;
    modalImage.addEventListener("keydown", modalKeyHandler, true);
    modal.appendChild(modalImage);

    const modalPrev = document.createElement("a");
    modalPrev.className = "modalPrev";
    modalPrev.innerHTML = "❮";
    modalPrev.tabIndex = 0;
    modalPrev.addEventListener("click", modalPrevImage, true);
    modalPrev.addEventListener("keydown", modalKeyHandler, true);
    modal.appendChild(modalPrev);

    const modalNext = document.createElement("a");
    modalNext.className = "modalNext";
    modalNext.innerHTML = "❯";
    modalNext.tabIndex = 0;
    modalNext.addEventListener("click", modalNextImage, true);
    modalNext.addEventListener("keydown", modalKeyHandler, true);

    modal.appendChild(modalNext);

    try {
        gradioApp().appendChild(modal);
    } catch (e) {
        gradioApp().body.appendChild(modal);
    }

    document.body.appendChild(modal);
});