1 files changed, 97 insertions, 0 deletions
diff --git a/src/init.rs b/src/init.rs
new file mode 100644
index 0000000..6af3235
--- /dev/null
+++ b/src/init.rs
@@ -0,0 +1,97 @@
+use anyhow::{bail, Context, Result};
+use std::{
+    env::set_current_dir,
+    fs::{create_dir, OpenOptions},
+    io::{self, ErrorKind, Write},
+    path::Path,
+};
+
+use crate::{embedded::EMBEDDED_FILES, exercise::Exercise};
+
+fn create_cargo_toml(exercises: &[Exercise]) -> io::Result<()> {
+    let mut cargo_toml = Vec::with_capacity(1 << 13);
+    cargo_toml.extend_from_slice(b"bin = [\n");
+    for exercise in exercises {
+        cargo_toml.extend_from_slice(b"  { name = \"");
+        cargo_toml.extend_from_slice(exercise.name.as_bytes());
+        cargo_toml.extend_from_slice(b"\", path = \"");
+        cargo_toml.extend_from_slice(exercise.path.to_str().unwrap().as_bytes());
+        cargo_toml.extend_from_slice(b"\" },\n");
+    }
+
+    cargo_toml.extend_from_slice(
+        br#"]
+
+[package]
+name = "rustlings"
+edition = "2021"
+publish = false
+"#,
+    );
+    OpenOptions::new()
+        .create_new(true)
+        .write(true)
+        .open("Cargo.toml")?
+        .write_all(&cargo_toml)
+}
+
+fn create_gitignore() -> io::Result<()> {
+    let gitignore = b"/target";
+    OpenOptions::new()
+        .create_new(true)
+        .write(true)
+        .open(".gitignore")?
+        .write_all(gitignore)
+}
+
+fn create_vscode_dir() -> Result<()> {
+    create_dir(".vscode").context("Failed to create the directory `.vscode`")?;
+    let vs_code_extensions_json = br#"{"recommendations":["rust-lang.rust-analyzer"]}"#;
+    OpenOptions::new()
+        .create_new(true)
+        .write(true)
+        .open(".vscode/extensions.json")?
+        .write_all(vs_code_extensions_json)?;
+
+    Ok(())
+}
+
+pub fn init_rustlings(exercises: &[Exercise]) -> Result<()> {
+    if Path::new("exercises").is_dir() && Path::new("Cargo.toml").is_file() {
+        bail!(
+            "A directory with the name `exercises` and a file with the name `Cargo.toml` already exist
+in the current directory. It looks like Rustlings was already initialized here.
+Run `rustlings` for instructions on getting started with the exercises.
+
+If you didn't already initialize Rustlings, please initialize it in another directory."
+        );
+    }
+
+    let rustlings_path = Path::new("rustlings");
+    if let Err(e) = create_dir(rustlings_path) {
+        if e.kind() == ErrorKind::AlreadyExists {
+            bail!(
+                "A directory with the name `rustlings` already exists in the current directory.
+You probably already initialized Rustlings.
+Run `cd rustlings`
+Then run `rustlings` again"
+            );
+        }
+        return Err(e.into());
+    }
+
+    set_current_dir("rustlings")
+        .context("Failed to change the current directory to `rustlings`")?;
+
+    EMBEDDED_FILES
+        .init_exercises_dir()
+        .context("Failed to initialize the `rustlings/exercises` directory")?;
+
+    create_cargo_toml(exercises).context("Failed to create the file `rustlings/Cargo.toml`")?;
+
+    create_gitignore().context("Failed to create the file `rustlings/.gitignore`")?;
+
+    create_vscode_dir().context("Failed to create the file `rustlings/.vscode/extensions.json`")?;
+
+    Ok(())
+}