function gradioApp() {
    const elems = document.getElementsByTagName('gradio-app')
    const elem = elems.length == 0 ? document : elems[0]

    if (elem !== document) {
        elem.getElementById = function (id) {
            return document.getElementById(id)
        }
    }
    return elem.shadowRoot ? elem.shadowRoot : elem
}

/**
 * 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"])'
    )
}

var uiUpdateCallbacks = []
var uiAfterUpdateCallbacks = []
var uiLoadedCallbacks = []
var uiTabChangeCallbacks = []
var optionsChangedCallbacks = []
var uiAfterUpdateTimeout = null
var 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.
 * @param callback
 */
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(function () {
        executeCallbacks(uiAfterUpdateCallbacks)
    }, 200)
}

var executedOnLoaded = false

document.addEventListener('DOMContentLoaded', function () {
    var mutationObserver = new MutationObserver(function (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 a ctrl+enter as a shortcut to start a generation
 */
document.addEventListener('keydown', function (e) {
    const isEnter = e.key === 'Enter' || e.keyCode === 13
    const isModifierKey = e.metaKey || e.ctrlKey || e.altKey

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

    if (isEnter && isModifierKey) {
        if (interruptButton.style.display === 'block') {
            interruptButton.click()
            setTimeout(function () {
                generateButton.click()
            }, 500)
        } else {
            generateButton.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)
    const isVisible = computedStyle.display !== 'none'

    if (!isVisible) return false
    return uiElementIsVisible(el.parentNode)
}

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

    return isOnScreen
}