implement watch command

Cargo.toml

@@ -17,9 +17,10 @@ name = "shulkerscript"
 path = "src/main.rs"
 
 [features]
-default = ["zip", "lua"]
+default = ["zip", "lua", "watch"]
 lang-debug = []
 lua = ["shulkerscript/lua"]
+watch = ["dep:notify-debouncer-mini", "dep:ctrlc"]
 zip = ["shulkerbox/zip"]
 
 [dependencies]
@@ -34,4 +35,5 @@ git2 = { version = "0.18.3", default-features = false }
 path-absolutize = "3.1.1"
 color-eyre = "0.6.3"
 dotenvy = "0.15.7"
-
+notify-debouncer-mini = { version = "0.4.1", default-features = false, optional = true }
+ctrlc = { version = "3.4.4", optional = true }

README.md

@@ -57,6 +57,16 @@ Options:
 Environment variables:
 - `DATAPACK_DIR`       The output directory [default: `./dist`]
 
+### Watch for changes
+```bash
+shulkerscript watch [OPTIONS] [SUBCOMMAND]
+```
+Where [SUBCOMMAND] is either `build` or `package` [default: `build`]
+
+Options:
+- `--no-initial`                     Do not run the command initially
+- `--debounce-time <DEBOUNCE_TIME>`  The time to wait in ms after the last change before running the command [default: `2000`]
+
 ## Contributing
 
 Pull requests are welcome. For major changes, please open an issue first

src/cli.rs

@@ -24,6 +24,9 @@ pub enum Command {
     #[cfg(feature = "zip")]
     /// Build and package the project.
     Package(subcommands::PackageArgs),
+    #[cfg(feature = "watch")]
+    /// Watch for changes and execute command.
+    Watch(subcommands::WatchArgs),
     #[cfg(feature = "lang-debug")]
     /// Build the project and dump the intermediate state.
     LangDebug(subcommands::LangDebugArgs),
@@ -31,12 +34,20 @@ pub enum Command {
 
 impl Args {
     pub fn run(&self) -> Result<()> {
-        match &self.cmd {
-            Command::Init(args) => subcommands::init(self.verbose, args)?,
-            Command::Build(args) => subcommands::build(self.verbose, args)?,
-            Command::Clean(args) => subcommands::clean(self.verbose, args)?,
+        self.cmd.run(self.verbose)
+    }
+}
+
+impl Command {
+    pub fn run(&self, verbose: bool) -> Result<()> {
+        match self {
+            Command::Init(args) => subcommands::init(verbose, args)?,
+            Command::Build(args) => subcommands::build(verbose, args)?,
+            Command::Clean(args) => subcommands::clean(verbose, args)?,
             #[cfg(feature = "zip")]
-            Command::Package(args) => subcommands::package(self.verbose, args)?,
+            Command::Package(args) => subcommands::package(verbose, args)?,
+            #[cfg(feature = "watch")]
+            Command::Watch(args) => subcommands::watch(verbose, args)?,
             #[cfg(feature = "lang-debug")]
             Command::LangDebug(args) => subcommands::lang_debug(args)?,
         }

src/subcommands/init.rs

@@ -20,26 +20,26 @@ use crate::{
 pub struct InitArgs {
     /// The path of the folder to initialize in.
     #[clap(default_value = ".")]
-    path: PathBuf,
+    pub path: PathBuf,
     /// The name of the project.
     #[clap(short, long)]
-    name: Option<String>,
+    pub name: Option<String>,
     /// The description of the project.
     #[clap(short, long)]
-    description: Option<String>,
+    pub description: Option<String>,
     /// The pack format version.
     #[clap(short, long)]
-    pack_format: Option<u8>,
+    pub pack_format: Option<u8>,
     /// Force initialization even if the directory is not empty.
     #[clap(short, long)]
-    force: bool,
+    pub force: bool,
     /// The version control system to initialize.
     #[clap(long, default_value = "git")]
-    vcs: VersionControlSystem,
+    pub vcs: VersionControlSystem,
 }
 
 #[derive(Debug, Clone, Copy, Default, ValueEnum)]
-enum VersionControlSystem {
+pub enum VersionControlSystem {
     #[default]
     Git,
     None,

src/subcommands/lang_debug.rs

@@ -7,13 +7,13 @@ use std::path::PathBuf;
 pub struct LangDebugArgs {
     /// The path of the project to compile.
     #[clap(default_value = ".")]
-    path: PathBuf,
+    pub path: PathBuf,
     /// The state to dump.
     #[clap(short, long, default_value = "ast")]
-    dump: DumpState,
+    pub dump: DumpState,
     /// Pretty-print the output.
     #[clap(short, long)]
-    pretty: bool,
+    pub pretty: bool,
 }
 
 #[derive(ValueEnum, Debug, Clone, Copy, Default)]

src/subcommands/mod.rs

@@ -12,6 +12,11 @@ mod package;
 #[cfg(feature = "zip")]
 pub use package::{package, PackageArgs};
 
+#[cfg(feature = "watch")]
+mod watch;
+#[cfg(feature = "watch")]
+pub use watch::{watch, WatchArgs};
+
 #[cfg(feature = "lang-debug")]
 mod lang_debug;
 #[cfg(feature = "lang-debug")]

src/subcommands/package.rs

@@ -14,7 +14,7 @@ use super::BuildArgs;
 #[derive(Debug, clap::Args, Clone)]
 pub struct PackageArgs {
     #[clap(flatten)]
-    build_args: BuildArgs,
+    pub build_args: BuildArgs,
 }
 
 pub fn package(_verbose: bool, args: &PackageArgs) -> Result<()> {

src/subcommands/watch.rs

@@ -0,0 +1,112 @@
+use std::{
+    path::{Path, PathBuf},
+    thread,
+    time::Duration,
+};
+
+use clap::Subcommand;
+use notify_debouncer_mini::{new_debouncer, notify::*, DebounceEventResult};
+
+use super::BuildArgs;
+use crate::{
+    cli::Command,
+    error::Result,
+    terminal_output::{print_error, print_info},
+};
+
+#[derive(Debug, clap::Args, Clone)]
+pub struct WatchArgs {
+    /// Do not run the command when starting, only after changes are detected.
+    #[clap(short, long)]
+    no_inital: bool,
+    /// The time to wait in ms before running the command after changes are detected.
+    #[clap(short, long, default_value = "2000")]
+    debounce_time: u64,
+    /// The command to run when changes are detected.
+    #[command(subcommand)]
+    cmd: Option<WatchSubcommand>,
+}
+
+#[derive(Debug, Clone, Subcommand)]
+pub enum WatchSubcommand {
+    /// Build the project.
+    Build(BuildArgs),
+    #[cfg(feature = "zip")]
+    /// Build and package the project.
+    Package(super::PackageArgs),
+}
+
+impl From<WatchSubcommand> for Command {
+    fn from(value: WatchSubcommand) -> Self {
+        match value {
+            WatchSubcommand::Build(args) => Command::Build(args),
+            #[cfg(feature = "zip")]
+            WatchSubcommand::Package(args) => Command::Package(args),
+        }
+    }
+}
+
+pub fn watch(verbose: bool, args: &WatchArgs) -> Result<()> {
+    let cmd = Command::from(args.cmd.to_owned().unwrap_or_else(|| {
+        WatchSubcommand::Build(BuildArgs {
+            path: PathBuf::from("."),
+            output: None,
+            assets: None,
+        })
+    }));
+
+    let project_path = match &args.cmd {
+        Some(WatchSubcommand::Build(args)) => args.path.as_path(),
+        #[cfg(feature = "zip")]
+        Some(WatchSubcommand::Package(args)) => args.build_args.path.as_path(),
+        None => Path::new("."),
+    };
+
+    #[allow(clippy::collapsible_if)]
+    if !args.no_inital {
+        if cmd.run(verbose).is_err() {
+            print_error("Command failed to run initially");
+        }
+    }
+
+    ctrlc::set_handler(move || {
+        print_info("Stopping watcher...");
+        std::process::exit(0);
+    })
+    .expect("Error setting Ctrl-C handler");
+
+    let mut debouncer = new_debouncer(
+        Duration::from_millis(args.debounce_time),
+        move |res: DebounceEventResult| {
+            if res.is_ok() {
+                if cmd.run(verbose).is_err() {
+                    print_error("Command failed to run");
+                }
+            } else {
+                std::process::exit(1);
+            }
+        },
+    )
+    .expect("Failed to initialize watcher");
+
+    let watcher = debouncer.watcher();
+    watcher
+        .watch(project_path.join("src").as_path(), RecursiveMode::Recursive)
+        .expect("Failed to watch project src");
+    watcher
+        .watch(
+            project_path.join("pack.png").as_path(),
+            RecursiveMode::NonRecursive,
+        )
+        .expect("Failed to watch project pack.png");
+    watcher
+        .watch(
+            project_path.join("pack.toml").as_path(),
+            RecursiveMode::NonRecursive,
+        )
+        .expect("Failed to watch project pack.toml");
+
+    loop {
+        thread::sleep(Duration::from_secs(60));
+    }
+}