Impl into_prefstring_bytes for UserPreferencesV0

Signed-off-by: Ben Aaron Goldberg <ben@benaaron.dev>

src/user_preferences/v0.rs

@@ -119,7 +119,27 @@ impl Preference for UserPreferencesV0 {
 	}
 
 	fn into_prefstring_bytes(&self) -> Vec<u8> {
-		todo!()
+		let mut defaults_byte = 0u8;
+		if self.default_enabled {
+			defaults_byte |= 0b10000000;
+		}
+		defaults_byte |= self.default_weight & 0b01111111;
+		vec![defaults_byte]
+			.into_iter()
+			.chain(self.commands.iter().map(|cmd| cmd.into()))
+			.collect()
+	}
+}
+
+/// Default to all pronouns on with equal weight
+/// TODO make this configurable
+impl Default for UserPreferencesV0 {
+	fn default() -> Self {
+	    Self {
+			default_enabled: true,
+			default_weight: 1,
+			commands: vec![],
+		}
 	}
 }
 
@@ -166,6 +186,18 @@ impl From<u8> for Command {
 	}
 }
 
+impl From<&Command> for u8 {
+	fn from(command: &Command) -> Self {
+		match command {
+			// Some these ands shouldn't be needed if the command is valid
+			Command::SetWeight(weight) => weight & 0b01111111,
+			Command::Move { toggle_enabled, distance } => {
+				0b10000000 | ((*toggle_enabled as u8) << 6) | (distance & 0b00111111)
+			}
+		}
+	}
+}
+
 
 #[cfg(test)]
 mod tests {