/**
 * Function to Copy a String to the Clipboard
 * @param input 
 */
export function writeToClipboard(input: string){
    
    const element = document.createElement('textarea');
    const previouslyFocusedElement = document.activeElement as any;

    element.value = input;

    // Prevent keyboard from showing on mobile
    element.setAttribute('readonly', '');

    element.style.position = 'absolute';
    element.style.left = '-9999px';
    element.style.fontSize = '12pt'; // Prevent zooming on iOS

    const selection = document.getSelection();
    let originalRange: any = false;
    if (selection.rangeCount > 0) {
        originalRange = selection.getRangeAt(0);
    }

    document.body.append(element);
    element.select();

    // Explicit selection workaround for iOS
    element.selectionStart = 0;
    element.selectionEnd = input.length;

    let isSuccess = false;
    try {
        isSuccess = document.execCommand('copy');
    } catch (_) {}

    element.remove();

    if (originalRange) {
        selection.removeAllRanges();
        selection.addRange(originalRange);
    }

    // Get the focus back on the previously focused element, if any
    if (previouslyFocusedElement) {
        previouslyFocusedElement.focus();
    }

    return isSuccess;    
}

export async function readDataFromClipboard(){
    if (navigator && (navigator).clipboard) {
        const text = await (navigator).clipboard.readText();
        return text;
    } else if (navigator && (navigator).permissions) {

        const permissionStatus = await (navigator).permissions.query({
            name: 'clipboard-read'
        } as any);
        
        // Listen for changes to the permission state
        permissionStatus.onchange = () => {
            console.log('Current Permission State is ',permissionStatus.state)
        };
    }

    return null;
}

/**
 * Function to Read from Clipboard. Returns a String.
 */
export function readFromClipboard(){

    const id = 'paster'+Date.now().toString();
    const element = document.createElement('textarea');
    const previouslyFocusedElement = document.activeElement as any;

    // Prevent keyboard from showing on mobile
    // element.setAttribute('readonly', '');

    element.style.position = 'absolute';
    element.style.left = '300px';
    element.style.fontSize = '12pt'; // Prevent zooming on iOS

    element.setAttribute('id', id);

    document.body.append(element);
    document.getElementById(id).focus();
    (document.getElementById(id) as any).select();

    document.execCommand('paste', true);
    const text: string = element.textContent;
    // Get the focus back on the previously focused element, if any
    if (previouslyFocusedElement) {
        previouslyFocusedElement.focus();
    }

    // Remove the Text
    element.parentNode.removeChild(element);

    return text;    
}