add init command

Cargo.lock

@@ -339,6 +339,7 @@ dependencies = [
  "fs-err",
  "humantime",
  "iddqd",
+ "indoc",
  "itertools",
  "libc",
  "mio",
@@ -685,6 +686,15 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "indoc"
+version = "2.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "79cf5c93f93228cf8efb3ba362535fb11199ac548a09ce117c9b1adc3030d706"
+dependencies = [
+ "rustversion",
+]
+
 [[package]]
 name = "is-terminal"
 version = "0.4.17"
@@ -1045,6 +1055,12 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
+
 [[package]]
 name = "ryu"
 version = "1.0.23"

Cargo.toml

@@ -35,6 +35,7 @@ displaydoc = "0.2.5"
 fs-err = "3.2.2"
 humantime = "2.3.0"
 iddqd = "0.3.17"
+indoc = "2.0.7"
 itertools = "0.14.0"
 libc = { version = "0.2.180", features = ["extra_traits"] }
 #macro_rules_attribute = { version = "0.2.2", features = ["better-docs", "verbose-expansions"] }

src/args.rs

@@ -32,9 +32,18 @@ pub struct DaemonCmd {
     pub bind: SocketAddr,
 }
 
+#[derive(Debug, Clone, PartialEq, clap::Parser)]
+#[command(long_about = None)]
+pub struct InitCmd {
+    /// Overwrite existing files.
+    #[arg(long)]
+    pub force: bool,
+}
+
 #[derive(Debug, Clone, PartialEq, clap::Subcommand)]
 pub enum Subcommand {
     Append(AppendCmd),
+    Init(InitCmd),
     Daemon(DaemonCmd),
     OpenApiDocs,
 }

src/lib.rs

@@ -49,7 +49,7 @@ pub mod prelude {
 use prelude::*;
 
 pub mod args;
-pub use args::{AppendCmd, Args};
+pub use args::{AppendCmd, Args, InitCmd};
 mod boxext;
 mod color;
 pub use color::{_CLI_ENABLE_COLOR, SHOULD_COLOR};
@@ -107,11 +107,6 @@ pub(crate) fn open_source_file(path: Arc<Path>) -> Result<SourceFile, IoError> {
         .tap_err(|e| error!("couldn't open source file at {}: {e}", path.display()))
 }
 
-pub(crate) fn get_line_to_insert() -> SourceLine {
-    //
-    todo!();
-}
-
 #[tracing::instrument(level = "debug")]
 pub fn do_append(args: Arc<Args>, append_args: AppendCmd) -> Result<(), BoxDynError> {
     let filepath = &args.file;
@@ -165,6 +160,70 @@ pub fn do_daemon(args: Arc<Args>, daemon_args: DaemonCmd) -> Result<(), BoxDynEr
     Ok(())
 }
 
+const DYNAMIC_NIX_INIT: &str = indoc::indoc! {"
+    /** GENERATED BY DYNIX */
+    { lib, ... }:
+
+    {
+      imports = [
+        ./configuration.nix
+      ];
+      config = lib.mkMerge [
+      ];
+    }
+"};
+
+fn open_for_init(path: &Path, init_args: &InitCmd) -> Result<File, IoError> {
+    let mut opts = File::options();
+    opts.write(true).create_new(true);
+    let file = match opts.open(path) {
+        Ok(file) => file,
+        Err(e) if e.kind() == IoErrorKind::AlreadyExists => {
+            if !init_args.force {
+                error!(
+                    "Refusing to overwrite existing file at '{}' without --force",
+                    path.display(),
+                );
+                return Err(e);
+            }
+            info!("Overwriting existing file at '{}'", path.display());
+            File::options()
+                .write(true)
+                .create(true)
+                .open(path)
+                .inspect_err(|e| {
+                    error!(
+                        "Failed to open path at '{}' for overwriting: {e}",
+                        path.display(),
+                    )
+                })?
+        },
+        Err(e) => {
+            error!(
+                "Failed to open path at '{}' for creation: {e}",
+                path.display()
+            );
+            return Err(e);
+        },
+    };
+
+    Ok(file)
+}
+
+pub fn do_init(args: Arc<Args>, init_args: InitCmd) -> Result<(), BoxDynError> {
+    let path = &*args.file;
+    let mut file = open_for_init(path, &init_args)?;
+
+    write!(&mut file, "{}", DYNAMIC_NIX_INIT)
+        .inspect_err(|e| error!("Failed to write to file at '{}': {e}", path.display()))?;
+    file.flush()
+        .inspect_err(|e| warn!("Failed to flush file at '{}': {e}", path.display()))?;
+
+    info!("Initialized Dynix file at '{}'", path.display());
+
+    Ok(())
+}
+
 #[derive(Debug, Clone, PartialEq, Hash, Serialize, Deserialize)]
 pub struct DefinitionWithLocation {
     pub file: Box<Path>,

src/main.rs

@@ -44,6 +44,7 @@ fn main_wrapped() -> Result<(), Box<dyn StdError + Send + Sync + 'static>> {
         match &args.subcommand {
             Append(append_args) => dynix::do_append(args.clone(), append_args.clone())?,
             Daemon(daemon_args) => dynix::do_daemon(args.clone(), daemon_args.clone())?,
+            Init(init_args) => dynix::do_init(args.clone(), init_args.clone())?,
             OpenApiDocs => {
                 //let api = dynix::ApiDoc::openapi();
                 //dbg!(api);