Add per-problem Cargo.toml and subdir structure for Rust LSP support

 • For lang='rust', generate code at code/{fid}-{slug}/src/lib.rs and tests.dat.
 • Create Cargo.toml with basic config on first edit.
 • Preserves flat structure for other languages.
 • Enables rust-analyzer integration without breaking API submissions.

Author: Antonio Bennett

src/cmds/edit.rs

@@ -62,9 +62,9 @@ impl Command for EditCommand {
     /// `edit` handler
     async fn handler(m: &ArgMatches) -> Result<()> {
         use crate::{cache::models::Question, Cache};
-        use std::fs::File;
-        use std::io::Write;
-        use std::path::Path;
+use std::fs::{self, File};
+use std::io::Write;
+use std::path::Path;
 
         let cache = Cache::new()?;
 
@@ -105,9 +105,41 @@ impl Command for EditCommand {
                 qr = Ok(cache.get_question(id).await?);
             }
 
-            let question: Question = qr?;
+let question: Question = qr?;
 
-            let mut file_code = File::create(&path)?;
+if *lang == "rust" {
+    let sanitized_slug = problem.slug.replace(|c: char| !c.is_alphanumeric(), "_");
+    let code_dir_str = format!("{}/{}-{}", conf.storage.code()?, problem.fid, sanitized_slug);
+    let code_dir = Path::new(&code_dir_str);
+    fs::create_dir_all(code_dir)?;
+
+    let src_dir_str = format!("{}/src", code_dir_str);
+    let src_dir = Path::new(&src_dir_str);
+    fs::create_dir_all(src_dir)?;
+
+    let cargo_path_str = format!("{}/Cargo.toml", code_dir_str);
+    let cargo_path = Path::new(&cargo_path_str);
+    if !cargo_path.exists() {
+        let package_name = format!("leetcode-{}-{}", problem.fid, sanitized_slug);
+        let cargo_content = format!(
+r#"[package]
+name = "{}"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+path = "src/lib.rs"
+
+[dependencies]
+"#,
+            package_name
+        );
+        let mut cargo_file = File::create(&cargo_path_str)?;
+        cargo_file.write_all(cargo_content.as_bytes())?;
+    }
+}
+
+let mut file_code = File::create(&path)?;
             let question_desc = question.desc_comment(&conf) + "\n";
 
             let test_path = crate::helper::test_cases_path(&problem)?;

src/helper.rs

@@ -194,35 +194,53 @@ mod file {
     use crate::{cache::models::Problem, Error};
 
     /// Generate test cases path by fid
-    pub fn test_cases_path(problem: &Problem) -> crate::Result<String> {
-        let conf = crate::config::Config::locate()?;
-        let mut path = format!("{}/{}.tests.dat", conf.storage.code()?, conf.code.pick);
+pub fn test_cases_path(problem: &Problem) -> crate::Result<String> {
+    let conf = crate::config::Config::locate()?;
+    let lang = conf.code.lang.clone();
+    let code_base = conf.storage.code()?;
 
+    let path = if lang == "rust" {
+        let sanitized_slug = problem.slug.replace(|c: char| !c.is_alphanumeric(), "_");
+        let subdir = format!("{}-{}/tests.dat", problem.fid, sanitized_slug);
+        format!("{}/{}", code_base, subdir)
+    } else {
+        let mut path = format!("{}/{}.tests.dat", code_base, conf.code.pick);
         path = path.replace("${fid}", &problem.fid.to_string());
         path = path.replace("${slug}", &problem.slug.to_string());
-        Ok(path)
-    }
+        path
+    };
+
+    Ok(path)
+}
 
     /// Generate code path by fid
-    pub fn code_path(problem: &Problem, l: Option<String>) -> crate::Result<String> {
-        let conf = crate::config::Config::locate()?;
-        let mut lang = conf.code.lang;
-        if l.is_some() {
-            lang = l.ok_or(Error::NoneError)?;
-        }
+pub fn code_path(problem: &Problem, l: Option<String>) -> crate::Result<String> {
+    let conf = crate::config::Config::locate()?;
+    let mut lang = conf.code.lang.clone();
+    if let Some(lang_opt) = l {
+        lang = lang_opt;
+    }
+
+    let code_base = conf.storage.code()?;
 
+    let path = if lang == "rust" {
+        let sanitized_slug = problem.slug.replace(|c: char| !c.is_alphanumeric(), "_");
+        let subdir = format!("{}-{}/src/lib.rs", problem.fid, sanitized_slug);
+        format!("{}/{}", code_base, subdir)
+    } else {
         let mut path = format!(
             "{}/{}.{}",
-            conf.storage.code()?,
+            code_base,
             conf.code.pick,
             suffix(&lang)?,
         );
-
         path = path.replace("${fid}", &problem.fid.to_string());
         path = path.replace("${slug}", &problem.slug.to_string());
+        path
+    };
 
-        Ok(path)
-    }
+    Ok(path)
+}
 
     /// Load python scripts
     pub fn load_script(module: &str) -> crate::Result<String> {