From e7d51aee952cc68ffbe039c137763d696cdd05b3 Mon Sep 17 00:00:00 2001
From: ChanTsune <41658782+ChanTsune@users.noreply.github.com>
Date: Sun, 7 Jan 2024 22:24:19 +0900
Subject: [PATCH] :alembic: Add `--generate` option by `clap_complete`

---
 Cargo.lock                      | 10 ++++++++
 cli/Cargo.toml                  |  2 ++
 cli/src/cli.rs                  |  4 +--
 cli/src/command.rs              |  6 +----
 cli/src/command/experimental.rs | 43 ++++++++++++++++++++++++++++++---
 5 files changed, 55 insertions(+), 10 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 2574fae7..8178f330 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -247,6 +247,15 @@ dependencies = [
  "strsim",
 ]
 
+[[package]]
+name = "clap_complete"
+version = "4.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "97aeaa95557bd02f23fbb662f981670c3d20c5a26e69f7354b28f57092437fcd"
+dependencies = [
+ "clap",
+]
+
 [[package]]
 name = "clap_derive"
 version = "4.4.7"
@@ -672,6 +681,7 @@ dependencies = [
  "bytesize",
  "chrono",
  "clap",
+ "clap_complete",
  "glob",
  "indicatif",
  "nix",
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index 592b42b9..cce0706f 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -14,6 +14,7 @@ ansi_term = "0.12.1"
 bytesize = "1.3.0"
 chrono = "0.4.31"
 clap = { version = "4.4.11", features = ["derive"] }
+clap_complete = { version =  "4.4.6", optional = true }
 glob = "0.3.1"
 indicatif = { version = "0.17.7", features = ["improved_unicode"] }
 pna = { version = "0.5.0", path = "../pna" }
@@ -25,6 +26,7 @@ nix = { version = "0.27.1", features = ["user", "fs"] }
 
 [features]
 experimental = []
+generate = ["experimental", "clap_complete"]
 
 [[bin]]
 name = "pna"
diff --git a/cli/src/cli.rs b/cli/src/cli.rs
index e29d1c18..155f0615 100644
--- a/cli/src/cli.rs
+++ b/cli/src/cli.rs
@@ -4,7 +4,7 @@ use bytesize::ByteSize;
 use clap::{value_parser, ArgGroup, Parser, Subcommand, ValueEnum};
 use std::path::PathBuf;
 
-#[derive(Parser, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
+#[derive(Parser, Clone, Eq, PartialEq, Hash, Debug)]
 #[command(
     name = env!("CARGO_PKG_NAME"),
     version,
@@ -47,7 +47,7 @@ pub(crate) enum Verbosity {
     Verbose,
 }
 
-#[derive(Subcommand, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
+#[derive(Subcommand, Clone, Eq, PartialEq, Hash, Debug)]
 pub(crate) enum Commands {
     #[command(visible_alias = "c", about = "Create archive")]
     Create(CreateArgs),
diff --git a/cli/src/command.rs b/cli/src/command.rs
index b9c5d573..81334046 100644
--- a/cli/src/command.rs
+++ b/cli/src/command.rs
@@ -6,8 +6,6 @@ pub(super) mod experimental;
 pub mod extract;
 pub mod list;
 
-#[cfg(feature = "experimental")]
-use self::experimental::ExperimentalCommands;
 use crate::cli::{CipherAlgorithmArgs, Cli, Commands, PasswordArgs, Verbosity};
 use std::io;
 
@@ -18,9 +16,7 @@ pub fn entry(cli: Cli) -> io::Result<()> {
         Commands::Extract(args) => args.execute(cli.verbosity.verbosity()),
         Commands::List(args) => args.execute(cli.verbosity.verbosity()),
         #[cfg(feature = "experimental")]
-        Commands::Experimental(cmd) => match cmd.command {
-            ExperimentalCommands::Split(cmd) => cmd.execute(cli.verbosity.verbosity()),
-        },
+        Commands::Experimental(cmd) => cmd.execute(cli.verbosity.verbosity()),
     }
 }
 
diff --git a/cli/src/command/experimental.rs b/cli/src/command/experimental.rs
index ef4491b4..71f74329 100644
--- a/cli/src/command/experimental.rs
+++ b/cli/src/command/experimental.rs
@@ -1,18 +1,44 @@
+#[cfg(feature = "generate")]
+use crate::cli::Cli;
 use crate::{
     cli::Verbosity,
     command::{commons::split_to_parts, Command},
     utils::part_name,
 };
 use bytesize::ByteSize;
+#[cfg(feature = "generate")]
+use clap::CommandFactory;
 use clap::{Args, Parser, Subcommand};
+#[cfg(feature = "generate")]
+use clap_complete::{generate, Generator, Shell};
 use pna::{Archive, EntryPart, MIN_CHUNK_BYTES_SIZE, PNA_HEADER};
+#[cfg(feature = "generate")]
+use std::env;
 use std::{fs::File, io, path::PathBuf};
 
-#[derive(Args, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
-#[command(args_conflicts_with_subcommands = true)]
+#[derive(Args, Clone, Eq, PartialEq, Hash, Debug)]
+#[command(args_conflicts_with_subcommands = true, arg_required_else_help = true)]
 pub(crate) struct ExperimentalArgs {
     #[command(subcommand)]
-    pub(crate) command: ExperimentalCommands,
+    pub(crate) command: Option<ExperimentalCommands>,
+    #[cfg(feature = "generate")]
+    #[arg(long, help = "Generate shell auto complete")]
+    pub(crate) generate: Option<Shell>,
+}
+
+impl Command for ExperimentalArgs {
+    fn execute(self, verbosity: Verbosity) -> io::Result<()> {
+        #[cfg(feature = "generate")]
+        if let Some(shell) = self.generate {
+            let cmd = &mut Cli::command();
+            print_completions(shell, cmd);
+            return Ok(());
+        };
+        match self.command {
+            Some(ExperimentalCommands::Split(cmd)) => cmd.execute(verbosity),
+            None => unreachable!(),
+        }
+    }
 }
 
 #[derive(Subcommand, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
@@ -91,3 +117,14 @@ fn split_archive(args: SplitCommand, verbosity: Verbosity) -> io::Result<()> {
     writer.finalize()?;
     Ok(())
 }
+
+#[cfg(feature = "generate")]
+fn print_completions<G: Generator>(gen: G, cmd: &mut clap::Command) {
+    let name = env::args().next().map(PathBuf::from).unwrap();
+    generate(
+        gen,
+        cmd,
+        name.file_name().unwrap().to_string_lossy(),
+        &mut io::stdout(),
+    );
+}