unit DatabaseTestExecutor;

interface
  uses
    System.SysUtils,
    System.Diagnostics,
    ZConnection,
    ZDataset,
    ZExceptions,
    DataGenerator;


    type
      TDatabaseManager = class

      private
        FConnection: TZConnection;
        FDataGenerator: TDataGenerator;
        FSeed: Integer;
        FStopwatch: TStopwatch;

        function PerformSingleInsert(APrimaryKey: Integer): Double;
        function PerformSingleRead(APrimaryKey: Integer): Double;

      public
        constructor Create(AConnection:TZConnection; ASeed:Integer);
        destructor Destroy; override;

        function SetupDatabase: Boolean;
        function TestInserts(ACount:Integer): TArray<Double>;
        function TestReads(ACount:Integer): TArray<Double>;
    end;
implementation
  constructor TDatabaseManager.Create(AConnection:TZConnection; ASeed:Integer);
  begin
    FSeed := ASeed;
    FConnection := AConnection;
    FDataGenerator := TDataGenerator.Create(FSeed);
    FStopwatch := TStopwatch.Create;
  end;

  destructor TDatabaseManager.Destroy;
  begin
    FreeAndNil(FDataGenerator);
  end;

  function TDatabaseManager.SetupDatabase: Boolean;
  begin
    var Query: TZQuery;
    Query := TZQuery.Create(nil);
    Query.Connection := FConnection;

    Query.Sql.Add('DROP TABLE IF EXISTS users');
    try
      Query.ExecSQL;
    except
    on E: EZSQLException do
    	begin
        Exit(False);
      end;
    end;

    Query.SQL.Clear;
    Query.SQL.Add('CREATE TABLE IF NOT EXISTS users (id INT PRIMARY KEY, email VARCHAR(255), social_security_number VARCHAR(255), age INT);');
    try
      try
        Query.ExecSQL;
      except
      on E: EZSQLException do
        begin
          Exit(False);
        end
      end;
    finally
      FreeAndNil(Query);
    end;

    Result := True;
  end;


  function TDatabaseManager.PerformSingleInsert(APrimaryKey: Integer): Double;
  begin
    var LEmail: string;
    LEmail := FDataGenerator.GenerateRandomEmail;

    var LSocial: string;
    LSocial := FDataGenerator.GenerateRandomSocial;

    var LAge: Integer;
    LAge := FDataGenerator.GenerateRandomAge;

    var LQuery: TZQuery;

    try
      LQuery := TZQuery.Create(nil);
      LQuery.Connection := FConnection;

      LQuery.SQL.Add('INSERT INTO users (id, email, social_security_number, age) ' +
                    'VALUES (:id, :email, :ssn, :age)');

      LQuery.ParamByName('id').AsInteger := APrimaryKey;
      LQuery.ParamByName('email').AsString := LEmail;
      LQuery.ParamByName('ssn').AsString := LSocial;
      LQuery.ParamByName('age').AsInteger := LAge;

      FStopwatch := TStopwatch.StartNew;
      try
        LQuery.ExecSQL;
      except
      on E: EZSQLException do
        begin
          Exit(-1.0);
        end

    end;
    finally
      FreeAndNil(LQuery);

    end;

  	FStopwatch.Stop;

    Result := FStopwatch.ElapsedMilliseconds;
  end;

  function TDatabaseManager.PerformSingleRead(APrimaryKey: Integer): Double;
    begin
      var LQuery: TZQuery;

      try
        LQuery := TZQuery.Create(nil);
        LQuery.Connection := FConnection;

        LQuery.SQL.Add('SELECT id, email, social_security_number, age FROM users WHERE id = :id');

        LQuery.ParamByName('id').AsInteger := APrimaryKey;

        FStopwatch := TStopwatch.StartNew;
        try
          LQuery.Open;
        except
        on E: EZSQLException do
          begin
            Exit(-1.0);
          end
        end;
      finally
        FreeAndNil(LQuery);
      end;

      FStopwatch.Stop;

      Result := FStopwatch.ElapsedMilliseconds;
    end;

  function TDatabaseManager.TestReads(ACount: Integer):Tarray<Double>;
  begin
    Result := TArray<Double>.Create();
    var LIndex: Integer;
    for LIndex := 1 to ACount do
    begin
      var LRunResult := PerformSingleRead(LIndex);
      if LRunResult <> -1.0 then
        Result := Result + [LRunResult];
    end;
  end;

  function TDatabaseManager.TestInserts(ACount: Integer): TArray<Double>;
  begin
    Result := TArray<Double>.Create();
    var Index: Integer;
    for Index := 1 to ACount do
    begin

      var RunResult := PerformSingleInsert(Index);

      if RunResult <> -1.0 then
        Result := Result + [RunResult];

    end;
end;
end.