build rule generation and cmdline arg parsing

Cargo.toml

@@ -6,4 +6,5 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+clap = { version = "4.4.4", features = ["derive"] }
 regex = "1.9.5"

src/main.rs

@@ -2,6 +2,7 @@ use std::fs;
 use std::io::Read;
 use std::path::Path;
 use regex::Regex;
+use clap::Parser;
 
 #[derive(Debug)]
 struct CFile {
@@ -10,6 +11,16 @@ struct CFile {
     headers: Vec<String>,
 }
 
+#[derive(Parser, Debug)]
+struct Args {
+    /// Replace default make output with nice build messages
+    #[arg(short, long)]
+    pretty: bool,
+    
+    #[arg(default_value = "./build")]
+    build_dir: String,
+}
+
 fn parse_c_file(path: &Path, re: &Regex) -> CFile {
     let strpath = path.to_str().unwrap();
     let filename = path.file_stem().unwrap().to_str().unwrap();
@@ -21,7 +32,10 @@ fn parse_c_file(path: &Path, re: &Regex) -> CFile {
     let mut headers: Vec<String> = Vec::new();
     let caps = re.captures_iter(&contents);
     for (_, [include_file]) in caps.map(|c| c.extract()) {
-        headers.push(path.parent().unwrap().join(Path::new(include_file)).to_str().unwrap().to_string());
+        headers.push(path.parent().unwrap()
+                         .join(Path::new(include_file))
+                         .to_str().unwrap()
+                         .to_string());
     }
 
     return CFile { path: strpath.to_string(), filename: filename.to_string(), headers }
@@ -55,6 +69,12 @@ fn main() {
     let mut project_files: Vec<CFile> = Vec::new();
     let includes_regex = Regex::new(r#"#include\s+"(.*?)""#).unwrap();
 
+    let args = Args::parse();
+    let build_dir = Path::new(&args.build_dir);
+    let pretty = args.pretty;
+
+    let obj_dir = build_dir.join("obj");
+
     recurse_into_dir(Path::new("./"), &mut |file| {
         let path = file.path();
         match path.extension() {
@@ -72,7 +92,20 @@ fn main() {
     });
 
     for file in project_files.iter() {
-        println!("{:?}", file);
+        let mut build_rule: String = "#=mgen_rule=#\n".to_owned();
+        
+        let objname = file.filename.to_owned() + ".o";
+        let objpath = obj_dir.join(&objname);
+        let objpath = objpath.to_str().unwrap();
+
+        build_rule.push_str(&format!("{}: {}", objpath, file.path));
+        for header in file.headers.iter() {
+            build_rule.push_str(&format!(" {}", header));
+        }
+
+        build_rule.push_str(&format!("\n\t$(CC) $(CFLAGS) -o {} -c {}\n",  objpath, file.path ));
+
+        println!("'{}'", build_rule);
     }
 
 }