WIP multichannel support

src/mesh/Channels.h

@@ -0,0 +1,51 @@
+#pragma once
+
+#include "mesh-pb-constants.h"
+#include <Arduino.h>
+
+class Channels
+{
+    size_t primaryIndex = 0;
+    
+  public:
+    const ChannelSettings &getPrimary() { return getChannel(getPrimaryIndex()).settings; }
+
+    Channel &getChannel(size_t chIndex);
+
+    /** Using the index inside the channel, update the specified channel's settings and role.  If this channel is being promoted to be
+     * primary, force all other channels to be secondary.
+     */
+    void setChannel(const Channel &c);
+
+    const char *getName(size_t chIndex);
+
+    /** The index of the primary channel */
+    size_t getPrimaryIndex() const { return primaryIndex; }
+
+    /**
+ * Generate a short suffix used to disambiguate channels that might have the same "name" entered by the human but different PSKs.
+ * The ideas is that the PSK changing should be visible to the user so that they see they probably messed up and that's why they
+their nodes
+ * aren't talking to each other.
+ *
+ * This string is of the form "#name-X".
+ *
+ * Where X is either:
+ * (for custom PSKS) a letter from A to Z (base26), and formed by xoring all the bytes of the PSK together,
+ * OR (for the standard minimially secure PSKs) a number from 0 to 9.
+ *
+ * This function will also need to be implemented in GUI apps that talk to the radio.
+ *
+ * https://github.com/meshtastic/Meshtastic-device/issues/269
+ */
+    const char *getPrimaryName();
+
+    /// Called by NodeDB on initial boot when the radio config settings are unset.  Set a default single channel config.
+    void initDefaults();
+
+    /// called when the user has just changed our radio config and we might need to change channel keys
+    void onConfigChanged();
+};
+
+/// Singleton channel table
+extern Channels channels;