//Make sure to implement the WKWebView delegates as needed
func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
    // Get the URL from the navigation action
    if let url = navigationAction.request.url {
        print(url)
        // Inspect the URL
        inspectURL(url)
        // Allow navigation to proceed
        decisionHandler(.allow)
    } else {
        // If there is no URL, deny the navigation
        decisionHandler(.cancel)
    }
}

private func inspectURL(_ url: URL) {
    // Parse the query parameters from the URL
    let components = URLComponents(url: url, resolvingAgainstBaseURL: false)
    let queryItems = components?.queryItems
    
    //Check for a specific query parameter of action="refill"
    if let action:String = queryItems?.first(where: { $0.name == "action" })?.value, action.lowercased() == "refill" {
        print("Query parameter 'action' has value: \(action)")
        //Check for a specific query parmater of status= one of the various callback status values
        if let status = queryItems?.first(where: { $0.name == "status" })?.value?.lowercased() {
            print("Query parameter 'status' has value: \(status)")
            switch (status)
            {
                case "back":
                    print("Open the Error View Controller, customer backed out of their refill")
                    self.dismiss(animated: true)
                    break
                case "cancel":
                    print("Open the Error View Controller, customer cancelled out of the checkout")
                    self.dismiss(animated: true)
                    break
                case "done":
                    print("Open the Success View Controller, their Rx is on its way")
                    self.dismiss(animated: true)
                    break
                case "error":
                    print("Open the Error View Controller, some error happened in the checkout")
                    self.dismiss(animated: true)
                    break
                default:
                    print("Open the Error View Controller, some unknown callback happened")
                    print(status)
                    self.dismiss(animated: true)
                    break
            }
            return
        }
    }
}

//Make sure to implement the WebView overrides as needed
override fun shouldOverrideUrlLoading(view: WebView, request: WebResourceRequest): Boolean {
    val url = request.url.toString()
    println(url)
    inspectUrl(request.url.toString())
    return false // Allow WebView to handle the URL
}

private fun inspectUrl(url: String) {
    //Parse the URI string to extract the query string
    val uri = Uri.parse(url)
    val queryParams = uri.queryParameterNames

    //Check for a specific query parameter of action="refill"
    if (queryParams.contains("action")) {
        val action = uri.getQueryParameter("action")
        if (action.equals("refill", ignoreCase = false)) {
            println("Query parameter 'action' has value: $action")
            //Check for a specific query parmater of status= one of the various callback status values
            val status = uri.getQueryParameter("status")?.toLowerCase()
            if (status != null) {
                println("Query parameter 'status' has value: $status")
                when (status) {
                    "back" -> {
                        println("Open the Error View, customer backed out of their refill")
                        finish()
                    }
                    "cancel" -> {
                        println("Open the Error View, customer cancelled out of the checkout")
                        finish()
                    }
                    "done" -> {
                        println("Open the Success View, their Rx is on its way")
                        finish()
                    }
                    "error" -> {
                        println("Open the Error View, some error happened in the checkout")
                        finish()
                    }
                    else -> {
                        println("Open the Error View, some unknown callback happened")
                        println(status)
                        finish()
                    }
                }
            }
        }
    }
}

//Route in your express router or server.js file, for the callbackURL which was passed when obtaining the checkout in your callbackURL value.
app.get('/callback', (req, res) => {
    //Parse the URI string to extract the query string
    const action = req.query.action ? req.query.action.toLowerCase() : '',
        status = req.query.status ? req.query.status.toLowerCase() : '';

    console.log(`Query parameter 'action' has value: ${action}`);
    console.log(`Query parameter 'status' has value: ${status}`);

    //Check for a specific query parameter of action="refill"
    if(action !== "refill")
    {
        console.log(`Unknown Callback Action: ${action}`)
        return res.render('pages/callback', { type: "Error", message: 'Some unknown action happened' });
    }
    //Check for a specific query parmater of status= one of the various callback status values
    switch (status) {
        case 'back':
            res.render('pages/callback', { type: 'Warning', message: 'Backed out of refill' });
            break;
        case 'cancel':
            return res.render('pages/callback', { type: 'Warning', message: 'Cancelled refill' });
            break;
        case 'done':
            return res.render('pages/callback', { type: 'Success', message: 'Success, refill is on its way!' });
            break;
        case 'error':
            return res.render('pages/callback', { type: "Error", message: 'Some error happened when refilling' });
            break;
        default:
            console.log(`Unknown Callback Status: ${status}`)
            return res.render('pages/callback', { type: "Error", message: 'Some unknown callback happened' });
            break;
    }
});

//We use then use EJS to render content for the appropriate callback message value in the callback.ejs page (you can use any view rendering engine)
<%= type %>, <%= message %>

//Make sure to implement the WKWebView delegates as needed
func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
    // Get the URL from the navigation action
    if let url = navigationAction.request.url {
        print(url)
        // Inspect the URL
        inspectURL(url)
        // Allow navigation to proceed
        decisionHandler(.allow)
    } else {
        // If there is no URL, deny the navigation
        decisionHandler(.cancel)
    }
}

private func inspectURL(_ url: URL) {
    // Parse the query parameters from the URL
    let components = URLComponents(url: url, resolvingAgainstBaseURL: false)
    let queryItems = components?.queryItems
    
    //Check for a specific query parameter of action="transfer"
    if let action:String = queryItems?.first(where: { $0.name == "action" })?.value, action.lowercased() == "transfer" {
        print("Query parameter 'action' has value: \(action)")
        //Check for a specific query parmater of status= one of the various callback status values
        if let status = queryItems?.first(where: { $0.name == "status" })?.value?.lowercased() {
            print("Query parameter 'status' has value: \(status)")
            switch (status)
            {
                case "back":
                    print("Open the Error View Controller, customer backed out of their transfer")
                    self.dismiss(animated: true)
                    break
                case "cancel":
                    print("Open the Error View Controller, customer cancelled out of the checkout")
                    self.dismiss(animated: true)
                    break
                case "done":
                    print("Open the Success View Controller, their Rx is on its way")
                    self.dismiss(animated: true)
                    break
                case "error":
                    print("Open the Error View Controller, some error happened in the checkout")
                    self.dismiss(animated: true)
                    break
                default:
                    print("Open the Error View Controller, some unknown callback happened")
                    print(status)
                    self.dismiss(animated: true)
                    break
            }
            return
        }
    }
}

//Make sure to implement the WebView overrides as needed
override fun shouldOverrideUrlLoading(view: WebView, request: WebResourceRequest): Boolean {
    val url = request.url.toString()
    println(url)
    inspectUrl(request.url.toString())
    return false // Allow WebView to handle the URL
}

private fun inspectUrl(url: String) {
    //Parse the URI string to extract the query string
    val uri = Uri.parse(url)
    val queryParams = uri.queryParameterNames

    //Check for a specific query parameter of action="transfer"
    if (queryParams.contains("action")) {
        val action = uri.getQueryParameter("action")
        if (action.equals("transfer", ignoreCase = false)) {
            println("Query parameter 'action' has value: $action")
            //Check for a specific query parmater of status= one of the various callback status values
            val status = uri.getQueryParameter("status")?.toLowerCase()
            if (status != null) {
                println("Query parameter 'status' has value: $status")
                when (status) {
                    "back" -> {
                        println("Open the Error View, customer backed out of their transfer")
                        finish()
                    }
                    "cancel" -> {
                        println("Open the Error View, customer cancelled out of the checkout")
                        finish()
                    }
                    "done" -> {
                        println("Open the Success View, their Rx is on its way")
                        finish()
                    }
                    "error" -> {
                        println("Open the Error View, some error happened in the checkout")
                        finish()
                    }
                    else -> {
                        println("Open the Error View, some unknown callback happened")
                        println(status)
                        finish()
                    }
                }
            }
        }
    }
}

//Route in your express router or server.js file, for the callbackURL which was passed when obtaining the checkout in your callbackURL value.
app.get('/callback', (req, res) => {
    //Parse the URI string to extract the query string
    const action = req.query.action ? req.query.action.toLowerCase() : '',
        status = req.query.status ? req.query.status.toLowerCase() : '';

    console.log(`Query parameter 'action' has value: ${action}`);
    console.log(`Query parameter 'status' has value: ${status}`);

    //Check for a specific query parameter of action="refill"
    if(action !== "transfer")
    {
        console.log(`Unknown Callback Action: ${action}`)
        return res.render('pages/callback', { type: "Error", message: 'Some unknown action happened' });
    }
    //Check for a specific query parmater of status= one of the various callback status values
    switch (status) {
        case 'back':
            res.render('pages/callback', { type: 'Warning', message: 'Backed out of transfer' });
            break;
        case 'cancel':
            return res.render('pages/callback', { type: 'Warning', message: 'Cancelled transfer' });
            break;
        case 'done':
            return res.render('pages/callback', { type: 'Success', message: 'Success, transfer is on its way!' });
            break;
        case 'error':
            return res.render('pages/callback', { type: "Error", message: 'Some error happened when transfering' });
            break;
        default:
            console.log(`Unknown Callback Status: ${status}`)
            return res.render('pages/callback', { type: "Error", message: 'Some unknown callback happened' });
            break;
    }
});

//We use then use EJS to render content for the appropriate callback message value in the callback.ejs page (you can use any view rendering engine)
<%= type %>, <%= message %>