unit PM.RateLimit;

{
  Mirrors api.php checkRateLimit / recordAttempt / clearAttempts.
  15-minute window. Caller decides the threshold (5 for register, 10 for login).
}

interface

uses
  System.SysUtils, FireDAC.Comp.Client, FireDAC.Stan.Param, IdCustomHTTPServer,
  PM.Database;

function GetClientIP(ARequest: TIdHTTPRequestInfo): string;
function CheckRateLimit(const AIP: string): Integer;
procedure RecordAttempt(const AIP: string);
procedure ClearAttempts(const AIP: string);

implementation

function GetClientIP(ARequest: TIdHTTPRequestInfo): string;
begin
  // api.php trusts X-Forwarded-For (security flaw H1 in audit). Since this
  // server is loopback-only and not behind a proxy, prefer the actual peer IP.
  Result := ARequest.RemoteIP;
  if Result = '' then Result := 'unknown';
end;

function CheckRateLimit(const AIP: string): Integer;
var
  LQ: TFDQuery;
begin
  Result := 0;
  DB.Lock;
  try
    LQ := TFDQuery.Create(nil);
    try
      LQ.Connection := DB.Connection;
      LQ.SQL.Text :=
        'SELECT COUNT(*) AS cnt FROM login_attempts ' +
        'WHERE ip = :ip ' +
        'AND attempted_at > datetime(''now'', ''-15 minutes'')';
      LQ.ParamByName('ip').AsString := AIP;
      LQ.Open;
      Result := LQ.FieldByName('cnt').AsInteger;
    finally
      LQ.Free;
    end;
  finally
    DB.Unlock;
  end;
end;

procedure RecordAttempt(const AIP: string);
var
  LQ: TFDQuery;
begin
  DB.Lock;
  try
    LQ := TFDQuery.Create(nil);
    try
      LQ.Connection := DB.Connection;
      LQ.SQL.Text := 'INSERT INTO login_attempts (ip) VALUES (:ip)';
      LQ.ParamByName('ip').AsString := AIP;
      LQ.ExecSQL;
    finally
      LQ.Free;
    end;
  finally
    DB.Unlock;
  end;
end;

procedure ClearAttempts(const AIP: string);
var
  LQ: TFDQuery;
begin
  DB.Lock;
  try
    LQ := TFDQuery.Create(nil);
    try
      LQ.Connection := DB.Connection;
      LQ.SQL.Text := 'DELETE FROM login_attempts WHERE ip = :ip';
      LQ.ParamByName('ip').AsString := AIP;
      LQ.ExecSQL;
    finally
      LQ.Free;
    end;
  finally
    DB.Unlock;
  end;
end;

end.