Add authentication dialog

Introduce start_auth_flow, a function invoked by typing `/auth username`
in OOC. It sends an public-key authentication request to the server,
starting the entire flow.

The flow invoves two dialogs: to select the key, and to enter the
passphrase to unlock the key. For convenience, each successful unlock
also remembers the key for that username on the server, storing this
in `saved_auth.json` (I chose JSON because I wanted it to stay
human-editable; INI would be better, but it suffers from bad platform
quirks in Qt).

1 files changed, 66 insertions, 0 deletions

diff --git a/src/auth_flow.h b/src/auth_flow.h
new file mode 100644
index 0000000..942e1aa
--- /dev/null
+++ b/src/auth_flow.h
@@ -0,0 +1,66 @@
+#pragma once
+
+#include <QString>
+
+#include "aoapplication.h"
+#include "ext_packet.h"
+#include "keyring.h"
+
+class KeySelectDialog : public QDialog
+{
+  Q_OBJECT
+
+public:
+  explicit KeySelectDialog(KeyringModel *model, QStringView username, QWidget *parent = nullptr);
+
+private:
+  KeyringModel *m_model;
+
+signals:
+  void key_selected(QByteArrayView key_id, QStringView key_name);
+};
+
+class KeyPassphraseDialog : public QDialog
+{
+  Q_OBJECT
+
+public:
+  explicit KeyPassphraseDialog(QStringView key_name, QWidget *parent = nullptr);
+  void display_error(ResponseResult error) const;
+
+private:
+  QLabel *m_err_lbl;
+  QLineEdit *m_pw_line;
+
+signals:
+  void passphrase_submitted(QByteArrayView passphrase);
+};
+
+// The only reason this inherits QObject is so I can call deleteLater()
+// when the authentication finishes. Auth flow involves coordinating two
+// asynchronous dialogs emitting signals, so I'd rather let Qt's event loop
+// clean everything up to be safe.
+class AuthFlow : public QObject
+{
+  Q_OBJECT
+
+public:
+  explicit AuthFlow(AOApplication *ao_app, const AuthChallenge &challenge, QWidget *parent = nullptr);
+
+private:
+  enum class FlowMode
+  {
+    Default,
+    Saved
+  };
+
+  FlowMode m_mode;
+  AOApplication *m_ao_app;
+  AuthChallenge m_challenge;
+  KeySelectDialog *m_key_dlg;
+  KeyPassphraseDialog *m_pwd_dlg;
+
+  void on_key_selected(QByteArrayView key_id, QStringView key_name);
+};
+
+void start_auth_flow(AOApplication *ao_app, QString username);