1 files changed, 90 insertions, 0 deletions
diff --git a/src/project.rs b/src/project.rs
new file mode 100644
index 0000000..0df00b9
--- /dev/null
+++ b/src/project.rs
@@ -0,0 +1,90 @@
+use glob::glob;
+use serde::{Deserialize, Serialize};
+use std::error::Error;
+use std::process::Command;
+
+/// Contains the structure of resulting rust-project.json file
+/// and functions to build the data required to create the file
+#[derive(Serialize, Deserialize)]
+pub struct RustAnalyzerProject {
+    sysroot_src: String,
+    pub crates: Vec<Crate>,
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct Crate {
+    root_module: String,
+    edition: String,
+    deps: Vec<String>,
+    cfg: Vec<String>,
+}
+
+impl RustAnalyzerProject {
+    pub fn new() -> RustAnalyzerProject {
+        RustAnalyzerProject {
+            sysroot_src: String::new(),
+            crates: Vec::new(),
+        }
+    }
+
+    /// Write rust-project.json to disk
+    pub fn write_to_disk(&self) -> Result<(), std::io::Error> {
+        std::fs::write(
+            "./rust-project.json",
+            serde_json::to_vec(&self).expect("Failed to serialize to JSON"),
+        )?;
+        Ok(())
+    }
+
+    /// If path contains .rs extension, add a crate to `rust-project.json`
+    fn path_to_json(&mut self, path: String) {
+        if let Some((_, ext)) = path.split_once('.') {
+            if ext == "rs" {
+                self.crates.push(Crate {
+                    root_module: path,
+                    edition: "2021".to_string(),
+                    deps: Vec::new(),
+                    // This allows rust_analyzer to work inside #[test] blocks
+                    cfg: vec!["test".to_string()],
+                })
+            }
+        }
+    }
+
+    /// Parse the exercises folder for .rs files, any matches will create
+    /// a new `crate` in rust-project.json which allows rust-analyzer to
+    /// treat it like a normal binary
+    pub fn exercies_to_json(&mut self) -> Result<(), Box<dyn Error>> {
+        for e in glob("./exercises/**/*")? {
+            let path = e?.to_string_lossy().to_string();
+            self.path_to_json(path);
+        }
+        Ok(())
+    }
+
+    /// Use `rustc` to determine the default toolchain
+    pub fn get_sysroot_src(&mut self) -> Result<(), Box<dyn Error>> {
+        let toolchain = Command::new("rustc")
+            .arg("--print")
+            .arg("sysroot")
+            .output()?
+            .stdout;
+
+        let toolchain = String::from_utf8_lossy(&toolchain);
+        let mut whitespace_iter = toolchain.split_whitespace();
+
+        let toolchain = whitespace_iter.next().unwrap_or(&toolchain);
+
+        println!("Determined toolchain: {}\n", &toolchain);
+
+        self.sysroot_src = (std::path::Path::new(&*toolchain)
+            .join("lib")
+            .join("rustlib")
+            .join("src")
+            .join("rust")
+            .join("library")
+            .to_string_lossy())
+        .to_string();
+        Ok(())
+    }
+}