feat: Add /force-encryption command and update message handling

Implement /force-encryption command to configure forced encryption
settings with on|off and policy resend-to-confirm|block options.

The changes enhance user experience by clarifying encryption requirements
and providing actionable commands. Users can now press Enter again to
confirm unencrypted messages in resend-to-confirm mode.

src/command/cmd_defs.c

@@ -2729,6 +2729,7 @@ static const struct cmd_t command_defs[] = {
               { "os on|off", "Choose whether to include the OS name if a user asks for software information (XEP-0092)." }
               )
       CMD_EXAMPLES(
+              "/privacy",
               "/privacy logging off",
               "/privacy os off")
     },
@@ -2744,6 +2745,31 @@ static const struct cmd_t command_defs[] = {
               "Redraw user interface. Can be used when some other program interrupted profanity or wrote to the same terminal and the interface looks \"broken\"." )
     },
 
+    { CMD_PREAMBLE("/force-encryption",
+                   parse_args, 1, 3, &cons_encryption_setting)
+      CMD_MAINFUNC(cmd_force_encryption)
+      CMD_TAGS(
+              CMD_TAG_CHAT)
+      CMD_SYN(
+              "/force-encryption",
+              "/force-encryption on|off",
+              "/force-encryption policy resend-to-confirm|block")
+      CMD_DESC(
+              "Configure forced encryption for outgoing messages in CProof. "
+              "When enabled, restricts sending unencrypted messages based on the specified policy. "
+              "Run without arguments to display current settings.")
+      CMD_ARGS(
+              { "on|off", "Enable or disable forced encryption. When enabled, restricts unencrypted messages per the policy. When disabled, allows sending unencrypted messages without restrictions." },
+              { "policy resend-to-confirm|block", "Set the policy for unencrypted messages when forced encryption is enabled. 'resend-to-confirm' requires pressing Enter again to confirm sending an unencrypted message (default). 'block' prevents sending unencrypted messages entirely." }
+              )
+      CMD_EXAMPLES(
+              "/force-encryption",
+              "/force-encryption on",
+              "/force-encryption off",
+              "/force-encryption policy resend-to-confirm",
+              "/force-encryption policy block")
+    },
+
     // NEXT-COMMAND (search helper)
 };
 

src/command/cmd_funcs.c

@@ -10633,3 +10633,22 @@ cmd_vcard_save(ProfWin* window, const char* const command, gchar** args)
     cons_show("User vCard uploaded");
     return TRUE;
 }
+
+gboolean
+cmd_force_encryption(ProfWin* window, const char* const command, gchar** args)
+{
+    if (g_strv_length(args) == 1 && (g_strcmp0(args[0], "on") == 0 || g_strcmp0(args[0], "off") == 0)) {
+        _cmd_set_boolean_preference(args[0], "Forces encryption", PREF_FORCE_ENCRYPTION);
+    } else if (g_strv_length(args) == 2 && g_strcmp0(args[0], "policy") == 0) {
+        if (g_strcmp0(args[1], "resend-to-confirm") != 0 && g_strcmp0(args[1], "block") != 0) {
+            cons_show_error("Invalid policy: \"%s\". See '/help force-encryption' for details.", args[1]);
+            return TRUE;
+        }
+        prefs_set_string(PREF_FORCE_ENCRYPTION_MODE, args[1]);
+        cons_show("Force encryption policy has been set to \"%s\".", args[1]);
+    } else {
+        cons_bad_cmd_usage(command);
+    }
+
+    return TRUE;
+}

src/command/cmd_funcs.h

@@ -269,5 +269,6 @@ gboolean cmd_vcard_photo(ProfWin* window, const char* const command, gchar** arg
 gboolean cmd_vcard_refresh(ProfWin* window, const char* const command, gchar** args);
 gboolean cmd_vcard_set(ProfWin* window, const char* const command, gchar** args);
 gboolean cmd_vcard_save(ProfWin* window, const char* const command, gchar** args);
+gboolean cmd_force_encryption(ProfWin* window, const char* const command, gchar** args);
 
 #endif

src/config/preferences.c

@@ -1792,6 +1792,8 @@ _get_group(preference_t pref)
     case PREF_OUTGOING_STAMP:
     case PREF_INCOMING_STAMP:
     case PREF_MOOD:
+    case PREF_FORCE_ENCRYPTION:
+    case PREF_FORCE_ENCRYPTION_MODE:
         return PREF_GROUP_UI;
     case PREF_STATES:
     case PREF_OUTTYPE:
@@ -2150,6 +2152,10 @@ _get_key(preference_t pref)
         return "strophe.sm.enabled";
     case PREF_STROPHE_SM_RESEND:
         return "strophe.sm.resend";
+    case PREF_FORCE_ENCRYPTION:
+        return "force-encryption.enabled";
+    case PREF_FORCE_ENCRYPTION_MODE:
+        return "force-encryption.policy";
     default:
         return NULL;
     }
@@ -2204,6 +2210,7 @@ _get_default_boolean(preference_t pref)
     case PREF_STROPHE_SM_RESEND:
         return TRUE;
     case PREF_PGP_PUBKEY_AUTOIMPORT:
+    case PREF_FORCE_ENCRYPTION:
     default:
         return FALSE;
     }
@@ -2310,6 +2317,8 @@ _get_default_string(preference_t pref)
         return "0";
     case PREF_DBLOG:
         return "on";
+    case PREF_FORCE_ENCRYPTION_MODE:
+        return "resend-to-confirm";
     default:
         return NULL;
     }

src/config/preferences.h

@@ -187,6 +187,8 @@ typedef enum {
     PREF_STROPHE_SM_RESEND,
     PREF_VCARD_PHOTO_CMD,
     PREF_STATUSBAR_TABMODE,
+    PREF_FORCE_ENCRYPTION,
+    PREF_FORCE_ENCRYPTION_MODE
 } preference_t;
 
 typedef struct prof_alias_t

src/event/client_events.c

@@ -45,6 +45,7 @@
 #include "config/preferences.h"
 #include "event/common.h"
 #include "plugins/plugins.h"
+#include "ui/inputwin.h"
 #include "ui/window_list.h"
 #include "xmpp/chat_session.h"
 #include "xmpp/session.h"
@@ -129,6 +130,38 @@ cl_ev_presence_send(const resource_presence_t presence_type, const int idle_secs
     presence_send(presence_type, idle_secs, signed_status);
 }
 
+// Checks if an unencrypted message can be sent based on encryption preferences.
+// Returns TRUE if allowed, FALSE if blocked.
+static gboolean
+_allow_unencrypted_message(ProfChatWin* chatwin, const char* const msg)
+{
+    if (!prefs_get_boolean(PREF_FORCE_ENCRYPTION)) {
+        return TRUE; // Encryption not enforced
+    }
+
+    auto_gchar gchar* force_enc_mode = prefs_get_string(PREF_FORCE_ENCRYPTION_MODE);
+
+    if (g_strcmp0(force_enc_mode, "block") == 0) {
+        win_println((ProfWin*)chatwin, THEME_ERROR, "-", "Message not sent: encryption required. Enable (omemo/pgp/otr) encryption or /force-encryption off.");
+        return FALSE;
+    }
+
+    if (g_strcmp0(force_enc_mode, "resend-to-confirm") == 0) {
+        // We do not use chatwin->last_message because it should be set only if it's sent.
+        guint msg_hash = g_str_hash(msg);
+        if (msg_hash != chatwin->last_attempted_msg_hash) {
+            win_println((ProfWin*)chatwin, THEME_ERROR, "-", "Message not sent: encryption required. Enable (omemo/pgp/otr) encryption or press Enter again to send without encryption. Use /force-encryption off to disable this protection.");
+            chatwin->last_attempted_msg_hash = msg_hash;
+            inp_set_line(msg); // reset message to prevent the need to retype it
+            return FALSE;
+        }
+        return TRUE;
+    }
+
+    win_println((ProfWin*)chatwin, THEME_ERROR, "-", "Message not sent: invalid encryption mode (%s). Use '/force-encryption policy resend-to-confirm'.", force_enc_mode);
+    return FALSE;
+}
+
 void
 cl_ev_send_msg_correct(ProfChatWin* chatwin, const char* const msg, const char* const oob_url, gboolean correct_last_msg)
 {
@@ -177,7 +210,7 @@ cl_ev_send_msg_correct(ProfChatWin* chatwin, const char* const msg, const char*
 #ifdef HAVE_LIBOTR
         handled = otr_on_message_send(chatwin, message, request_receipt, replace_id);
 #endif
-        if (!handled) {
+        if (!handled && _allow_unencrypted_message(chatwin, message)) {
             auto_char char* id = message_send_chat(chatwin->barejid, message, oob_url, request_receipt, replace_id);
             chat_log_msg_out(chatwin->barejid, message, NULL);
             log_database_add_outgoing_chat(id, chatwin->barejid, message, replace_id, PROF_MSG_ENC_NONE);

src/ui/console.c

@@ -2891,3 +2891,11 @@ cons_privacy_setting(void)
         }
     }
 }
+
+void
+cons_encryption_setting(void)
+{
+    cons_show("Force encryption                                           : %sabled", prefs_get_boolean(PREF_FORCE_ENCRYPTION) ? "en" : "dis");
+
+    cons_show("Force encryption mode                                      : %s", prefs_get_string(PREF_FORCE_ENCRYPTION_MODE));
+}

src/ui/inputwin.c

@@ -294,6 +294,14 @@ inp_get_line(void)
     return line;
 }
 
+void
+inp_set_line(const char* const new_line)
+{
+    rl_replace_line(new_line, 1);
+    rl_point = rl_end;
+    _inp_redisplay();
+}
+
 char*
 inp_get_password(void)
 {

src/ui/inputwin.h

@@ -46,5 +46,6 @@ void inp_win_resize(void);
 void inp_put_back(void);
 char* inp_get_password(void);
 char* inp_get_line(void);
+void inp_set_line(const char* const new_line);
 
 #endif

src/ui/ui.h

@@ -351,6 +351,7 @@ void cons_theme_properties(void);
 void cons_theme_colours(void);
 void cons_show_tlscert(const TLSCertificate* cert);
 void cons_show_tlscert_summary(const TLSCertificate* cert);
+void cons_encryption_setting(void);
 
 void cons_alert(ProfWin* alert_origin_window);
 void cons_remove_alert(ProfWin* window);

src/ui/win_types.h

@@ -188,6 +188,7 @@ typedef struct prof_chat_win_t
     char* last_message;
     char* last_msg_id;
     gboolean has_attention;
+    guint last_attempted_msg_hash;
 } ProfChatWin;
 
 typedef struct prof_muc_win_t

src/ui/window.c

@@ -164,6 +164,7 @@ win_create_chat(const char* const barejid)
     new_win->last_message = NULL;
     new_win->last_msg_id = NULL;
     new_win->has_attention = FALSE;
+    new_win->last_attempted_msg_hash = 0;
     new_win->memcheck = PROFCHATWIN_MEMCHECK;
 
     return &new_win->window;

tests/unittests/ui/stub_ui.c

@@ -675,6 +675,11 @@ inp_readline(void)
     return NULL;
 }
 
+void
+inp_set_line(const char* const new_line)
+{
+}
+
 void
 inp_nonblocking(gboolean reset)
 {
@@ -1157,6 +1162,11 @@ cons_privacy_setting(void)
 {
 }
 
+void
+cons_encryption_setting(void)
+{
+}
+
 void
 cons_show_bookmarks_ignore(gchar** list, gsize len)
 {