let __gradioApp = null;

function gradioApp() {
    if (__gradioApp == null) {
        const elems = document.getElementsByTagName('gradio-app');
        const elem = elems.length === 0 ? document : elems[0];
        if (elem !== document)
            elem.getElementById = (id) => { return document.getElementById(id); };
        __gradioApp = elem.shadowRoot ? elem.shadowRoot : elem;
    }

    return __gradioApp;
}

/** Get the currently selected top-level UI tab button (e.g. the button that says "Extras") */
function get_uiCurrentTab() { return gradioApp().querySelector('#tabs > .tab-nav > button.selected'); }

/** Get the first currently visible top-level UI tab content (e.g. the div hosting the "txt2img" UI) */
function get_uiCurrentTabContent() { return gradioApp().querySelector('#tabs > .tabitem[id^=tab_]:not([style*="display: none"])'); }

const uiUpdateCallbacks = [];
const uiAfterUpdateCallbacks = [];
const uiLoadedCallbacks = [];
const uiTabChangeCallbacks = [];
const optionsChangedCallbacks = [];
let uiAfterUpdateTimeout = null;
let uiCurrentTab = null;

/**
 * Register callback to be called at each UI update.
 * The callback receives an array of MutationRecords as an argument.
 */
function onUiUpdate(callback) { uiUpdateCallbacks.push(callback); }

/**
 * Register callback to be called soon after UI updates.
 * The callback receives no arguments.
 *
 * This is preferred over `onUiUpdate` if you don't need
 * access to the MutationRecords, as your function will
 * not be called quite as often.
 */
function onAfterUiUpdate(callback) { uiAfterUpdateCallbacks.push(callback); }

/**
 * Register callback to be called when the UI is loaded.
 * The callback receives no arguments.
 */
function onUiLoaded(callback) { uiLoadedCallbacks.push(callback); }

/**
 * Register callback to be called when the UI tab is changed.
 * The callback receives no arguments.
 */
function onUiTabChange(callback) { uiTabChangeCallbacks.push(callback); }

/**
 * Register callback to be called when the options are changed.
 * The callback receives no arguments.
 */
function onOptionsChanged(callback) { optionsChangedCallbacks.push(callback); }

function executeCallbacks(queue, arg) {
    for (const callback of queue) {
        try {
            callback(arg);
        } catch (e) {
            console.error(`error running callback "${callback}": ${e}`);
        }
    }
}

/**
 * Schedule the execution of the callbacks registered with onAfterUiUpdate.
 * The callbacks are executed after a short while, unless another call to this function
 * is made before that time. IOW, the callbacks are executed only once, even
 * when there are multiple mutations observed.
 */
function scheduleAfterUiUpdateCallbacks() {
    clearTimeout(uiAfterUpdateTimeout);
    uiAfterUpdateTimeout = setTimeout(() => {
        executeCallbacks(uiAfterUpdateCallbacks);
    }, 200);
}

let executedOnLoaded = false;

document.addEventListener("DOMContentLoaded", () => {
    const mutationObserver = new MutationObserver((m) => {
        if (!executedOnLoaded && gradioApp().querySelector('#txt2img_prompt')) {
            executedOnLoaded = true;
            executeCallbacks(uiLoadedCallbacks);
        }

        executeCallbacks(uiUpdateCallbacks, m);
        scheduleAfterUiUpdateCallbacks();
        const newTab = get_uiCurrentTab();
        if (newTab && (newTab !== uiCurrentTab)) {
            uiCurrentTab = newTab;
            executeCallbacks(uiTabChangeCallbacks);
        }
    });
    mutationObserver.observe(gradioApp(), { childList: true, subtree: true });
});

/**
 * Add keyboard shortcuts:
 * Ctrl+Enter to start/restart a generation
 * Alt/Option+Enter to skip a generation
 * Esc to interrupt a generation
 */
document.addEventListener('keydown', (e) => {
    const isEnter = e.key === 'Enter' || e.code === 'Enter';
    const isCtrlKey = e.metaKey || e.ctrlKey;
    const isAltKey = e.altKey;
    const isEsc = e.key === 'Escape';

    const generateButton = get_uiCurrentTabContent().querySelector('button[id$=_generate]');
    const interruptButton = get_uiCurrentTabContent().querySelector('button[id$=_interrupt]');
    const skipButton = get_uiCurrentTabContent().querySelector('button[id$=_skip]');

    if (isCtrlKey && isEnter) {
        if (interruptButton.style.display === 'block') {
            interruptButton.click();
            const callback = (mutationList) => {
                for (const mutation of mutationList) {
                    if (mutation.type === 'attributes' && mutation.attributeName === 'style') {
                        if (interruptButton.style.display === 'none') {
                            generateButton.click();
                            observer.disconnect();
                        }
                    }
                }
            };
            const observer = new MutationObserver(callback);
            observer.observe(interruptButton, { attributes: true });
        } else {
            generateButton.click();
        }
        e.preventDefault();
    }

    if (isAltKey && isEnter) {
        skipButton.click();
        e.preventDefault();
    }

    if (isEsc) {
        const globalPopup = document.querySelector('.global-popup');
        const lightboxModal = document.querySelector('#lightboxModal');
        if (!globalPopup || globalPopup.style.display === 'none') {
            if (document.activeElement === lightboxModal) return;
            if (interruptButton?.style.display === 'block') {
                interruptButton.click();
                e.preventDefault();
            }
        }
    }
});

/** checks that a UI element is not in another hidden element or tab content */
function uiElementIsVisible(el) {
    if (el === document)
        return true;

    const computedStyle = getComputedStyle(el);
    if (computedStyle.display === 'none')
        return false;

    return uiElementIsVisible(el.parentNode);
}

function uiElementInSight(el) {
    const clRect = el.getBoundingClientRect();
    const windowHeight = window.innerHeight;
    return (clRect.bottom > 0) && (clRect.top < windowHeight);
}