gcli command auto completion and arm64 build

• Extra command completion added which takes a --shell argument to generate a completions script for a specified shell.
• Adapted the Linux (amd64) build to:
  • generate the gcli-completion.bash, gcli-completion.zsh, gcli-completion.fish, gcli-completion.ps1 completion scripts
  • add the bash, zsh and fish completion scripts in the .deb package
• Added the ARM64 build generating a binary and a .deb package that also include those completion scripts.
• Includes fix for #50 (closed)

src/main.rs

@@ -12,14 +12,17 @@ mod utils;
 
 use anyhow::anyhow;
 use clap::builder::OsStr;
-use clap::Parser;
+use clap::{CommandFactory, Parser};
+use clap_complete::{generate, Shell};
 use codec::Encode;
 use colored::Colorize;
 use data::*;
 use display::DisplayEvent;
+use indoc::indoc;
 use keys::*;
 use runtime_config::*;
 use serde::{Deserialize, Serialize};
+use std::io;
 use std::str::FromStr;
 use subxt::{
 	blocks::ExtrinsicEvents,
@@ -158,6 +161,37 @@ pub enum Subcommand {
 	/// Publish a new git tag with actual version
 	#[clap(hide = true)]
 	Publish,
+	/// Generate a completions script for a specified shell (use `completion --help` for more info)
+	#[clap(long_about = indoc! {r#"Generate a completions script for a specified shell.
+
+		The base completion scripts for `bash`, `zsh` or `fish` are already registered when installing the `.deb` package.
+		If you did not/could not install the `.deb` package we can generate the script and then configure the shell to use it.
+
+		Example for `bash`:
+		  mkdir -p ~/.local/share/gcli
+		  gcli completion --shell bash > ~/.local/share/gcli/completion.bash
+		  # Direct test - gcli should have the completion after the source command
+		  source ~/.local/share/gcli/completion.bash
+
+		  # Persisting the configuration in the shell configuration file, add this at the end of your `~/.bashrc` file
+		  [[ -f $HOME/.local/share/gcli/completion.bash ]] && source $HOME/.local/share/gcli/completion.bash
+		  # Might need to reopen the shell for the configuration to be applied
+
+		Example for `zsh`:
+		  mkdir -p ~/.local/share/gcli
+		  gcli completion --shell zsh > ~/.local/share/gcli/completion.zsh
+		  # Direct test - gcli should have the completion after the source command
+		  source ~/.local/share/gcli/completion.zsh
+
+		  # Persisting the configuration in the shell configuration file, add this at the end of your `~/.zshrc` file
+		  [[ -f $HOME/.local/share/gcli/completion.zsh ]] && source $HOME/.local/share/gcli/completion.zsh
+		  # Might need to reopen the shell for the configuration to be applied
+		"#})]
+	Completion {
+		/// target shell
+		#[clap(long)]
+		shell: Shell,
+	},
 }
 
 /// main function
@@ -171,6 +205,12 @@ async fn main() -> Result<(), GcliError> {
 
 	// match subcommands
 	let result = match data.args.subcommand.clone() {
+		// handle shell completions
+		Subcommand::Completion { shell } => {
+			let mut app = Args::command();
+			generate(shell, &mut app, "gcli", &mut io::stdout());
+			return Ok(());
+		}
 		Subcommand::Nothing => Ok(()),
 		Subcommand::Account(subcommand) => {
 			commands::account::handle_command(data, subcommand).await