/** Shim for the keyboard API because it won't hit in FF57. */

// {{{ Helper functions

function pick (o, ...props) {
    return Object.assign({}, ...props.map(prop => ({[prop]: o[prop]})))
}

// Shallow copy of keyevent.
function shallowKeyboardEvent (ke): Event {
    let shallow = pick(
        ke,
        'shiftKey', 'metaKey', 'altKey', 'ctrlKey', 'repeat', 'key',
        'bubbles', 'composed', 'defaultPrevented', 'eventPhase',
        'timeStamp', 'type', 'isTrusted'
    )
    shallow.target = pick(
        ke.target,
        'type', 'nodeName', 'role', 'contentEditable',
        'tagName', 
    )
    shallow.target.ownerDocument = pick(ke.target.ownerDocument, 'URL')
    return shallow
} // }}}

function keyeventHandler(ke: KeyboardEvent) {
    // Suppress events, if requested
    if (preventDefault) {
        ke.preventDefault()
    }
    if (stopPropagation) {
        ke.stopPropagation()
    }
    browser.runtime.sendMessage({type: "keydown", event: shallowKeyboardEvent(ke)})
}

// Listen for suppression messages from bg script.
function backgroundListener(message) {
    if (message.type === "keydown-suppress") {
        if ('preventDefault' in message.data) {
            preventDefault = message.data.preventDefault
        }
        if ('stopPropagation' in message.data) {
            stopPropagation = message.data.stopPropagation
        }
    }
}

// State
let preventDefault = false
let stopPropagation = false

// Add listeners
window.addEventListener("keydown", keyeventHandler)
browser.runtime.onMessage.addListener(backgroundListener) 

// Dummy export so that TS treats this as a module.
export {}