FCM(Firebase Cloud Messaging) Mock with Azure Functions

FcmMock.csx

#r "Newtonsoft.Json"
using System.Net;
using System.Text;
using Newtonsoft.Json;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    var pairs = req.GetQueryNameValuePairs();
    var notRegistered = int.Parse(pairs.FirstOrDefault(q => string.Compare(q.Key, "notregistered", true) == 0)
        .Value ?? "0");
    var canonical = int.Parse( pairs.FirstOrDefault(q => string.Compare(q.Key, "canonical", true) == 0)
        .Value ?? "0");
    var failure = int.Parse(pairs.FirstOrDefault(q => string.Compare(q.Key, "failure", true) == 0)
        .Value ?? "0");

    dynamic data = await req.Content.ReadAsAsync<object>();
    var results = new List<object>();
    var i = 0;
    var successCount = 0;
    var failureCount = 0;
    var canonicalCount = 0;
    foreach (var id in data.registration_ids) {
        if (i < notRegistered) {
            results.Add(new { error = "NotRegistered" });
            failureCount++;
        }
        else if (i < (notRegistered + canonical)) {
            results.Add(new { message_id = "123:" + i.ToString(), registration_id = "canonical_" + i.ToString() });
            canonicalCount++;
            successCount++;
        }
        else if (i < (notRegistered + canonical + failure)) {
            results.Add(new { error = "Unavailable" });
            failureCount++;
        }
        else {
            results.Add(new { message_id = "123:" + i.ToString() });
            successCount++;
        }
        i++;
    }
    
    var jsonToReturn = JsonConvert.SerializeObject(new {
        multicast_id = 1234,
        success = successCount,
        failure = failureCount,
        canonical_ids = canonicalCount,
        results = results
    });

    return new HttpResponseMessage(HttpStatusCode.OK) {
        Content = new StringContent(jsonToReturn, Encoding.UTF8, "application/json")
    };
}