public ActionResult CreateNewStatement(TrustLessModelLib.Statement statement)
{
using (DataContext context = new DataContext())
{
if (!PersonController.ValidateLoginSession(context,statement.Person.LoginSession.Token))
return new HttpStatusCodeResult((int)HttpStatusCode.Forbidden);
var match =
context.Statements.FirstOrDefault(x => x.MedicinOne == statement.MedicinOne && x.MedicinTwo == statement.MedicinTwo);
//Does a statement already exists with the same two medicins.
if (match != null) // && IsStatementValid(context,match)
return new HttpStatusCodeResult((int)HttpStatusCode.BadRequest);
//Security: Don't allow user to specify the person who created the statement. Set it to the current user logged in.
statement.Person =
context.Persons.FirstOrDefault(x => x.Username == statement.Person.Username);
//If the person does not exist, abort.
if (statement.Person == null)
return new HttpStatusCodeResult((int)HttpStatusCode.BadRequest);
//Rule: refuse a user with zero trust from creating statements.
if (CalculateBayesianModelTrust(statement.Person) == 0)
return new HttpStatusCodeResult((int)HttpStatusCode.BadRequest);
context.Statements.Add(statement);
//Add recommendation from user
var recommendation = new TrustLessModelLib.Recommendation(){ Person = statement.Person, Statement = statement, IsRecommended = true, Transaction = null, Description = statement.Description, CreationDate = DateTime.Now};
//This will fail if a racecondition was to add two recommendations (given that our key assignment of the table ensures only one of the same recommendation exist).
context.Recommendations.Add (recommendation);
context.SaveChanges ();
BlockChain.MakeRecommendation (context, recommendation);
return new HttpStatusCodeResult((int)HttpStatusCode.Created);
}
}
/// <summary>
/// Issues an S or F to a user for a recommendation.
/// </summary>
/// <param name="recommendation">Recommendation</param>
/// <param name="rewardUser">true for S asset and false for F</param>
public static void Issue(TrustLessModelLib.Recommendation recommendation, bool rewardUser)
{
string chainName = WebConfigurationManager.AppSettings["ChainName"];
string nodeIp = WebConfigurationManager.AppSettings["NodeIp"];
MultiChainClient client = new MultiChainClient(chainName,nodeIp);
GetTxOutResponse getTxOutResponse = client.GetTxOut(recommendation.Transaction.Tx,recommendation.Transaction.Vout);
if (getTxOutResponse == null)
return;
Dictionary<string,int> amount = new Dictionary<string, int>();
amount.Add(getTxOutResponse.assets.First(x => x.name.StartsWith(rewardUser ? "S_" : "F_")).name,1);
string multichainPublicKey = WebConfigurationManager.AppSettings["MultichainPublicKey"];
var resp = client.CreateRawTransaction (recommendation.Person.PublicKey, recommendation.Transaction.Tx,recommendation.Transaction.Vout, amount);
var respAppendRawChange = client.AppendRawChange (resp.Hex, multichainPublicKey);
var respSignTransaction = client.SignRawTransaction (respAppendRawChange.Hex);
if (respSignTransaction.complete) {
var respSendRawTransaction = client.SendRawTransaction (respSignTransaction.hex);
if (String.IsNullOrEmpty (respSendRawTransaction.TransactionId))
client.LockUnspent (true, recommendation.Transaction.Tx,recommendation.Transaction.Vout);
}
}
/// <summary>
/// Reserves/locks away one S and F asset and sets the recommendation to reference these assets.
/// </summary>
/// <param name="db">DataContext</param>
/// <param name="recommendation">Recommendation</param>
public static void MakeRecommendation(DataContext db, TrustLessModelLib.Recommendation recommendation)
{
string chainName = WebConfigurationManager.AppSettings["ChainName"];
string nodeIp = WebConfigurationManager.AppSettings["NodeIp"];
MultiChainClient client = new MultiChainClient(chainName,nodeIp);
Dictionary<string,int> dictionary = new Dictionary<string, int>();
AddressBalance[] addressBalances = client.GetTotalBalances ().Balances;
var lastFasset = addressBalances.OrderBy (x => x.name).LastOrDefault (x => x.name.StartsWith ("F_"));
var lastSasset = addressBalances.OrderBy (x => x.name).LastOrDefault (x => x.name.StartsWith ("S_"));
if (lastFasset == null || lastSasset == null) {
GenerateFunds (client);
MakeRecommendation (db, recommendation);
return;
}
string lastF = lastFasset.name;
string lastS = lastSasset.name;
dictionary.Add(lastF,1);
dictionary.Add(lastS,1);
try
{
var resp = client.PrepareLockUnspent(dictionary);
recommendation.Transaction = new ReservedTransaction()
{
Tx = resp.txid,
Vout = resp.vout
};
}
catch {
//Insurficient funds
GenerateFunds(client);
MakeRecommendation (db, recommendation);
return;
}
db.SaveChanges ();
}
/// <summary>
/// Rewards users that have made a correct recommendation with an S asset and punishes users
/// who were wrong in their recommendation.
/// </summary>
/// <param name="context">DataContext</param>
/// <param name="statement">Statement</param>
private void IssueTrustForStatement(DataContext context,TrustLessModelLib.Statement statement)
{
var recommendations =
context.Recommendations.Include("Person").Include("Transaction").Where(x => x.StatementId== statement.Id && x.Transaction != null).ToList();
int sAmount = recommendations.Count (x => x.IsRecommended) +1;
int fAmount = recommendations.Count (x => !x.IsRecommended);
foreach (Recommendation recommendation in recommendations) {
if (sAmount >= fAmount) {
if (recommendation.IsRecommended) {
BlockChain.Issue (recommendation,true);
} else {
BlockChain.Issue (recommendation,false);
}
} else {
if (recommendation.IsRecommended) {
BlockChain.Issue (recommendation,false);
} else {
BlockChain.Issue (recommendation,true);
}
}
}
}
/// <summary>
/// Returns a boolean clarifying that a statement is complete.
/// </summary>
/// <param name="context"></param>
/// <param name="statement"></param>
/// <returns></returns>
private bool IsStatementRecommendationsComplete(DataContext context,TrustLessModelLib.Statement statement)
{
var recommendationAmount =
context.Recommendations.Count(x => x.StatementId== statement.Id && x.Transaction != null);
int maxVotings = Convert.ToInt32(WebConfigurationManager.AppSettings["MaxVotings"]);
return recommendationAmount >= maxVotings;
}
