feat: leave a .android dotfile after project creation

This could later makes things quite easier. Instead of parsing the whole structure again to look out for certain metadata fields, the tool would just be able to read `.android` file from now.

Cargo.toml

@@ -20,3 +20,5 @@ env_logger = "0.10.0"
 dialoguer = "0.10.4"
 which = "4.4.0"
 itertools = "0.11.0"
+ron = "0.8.0"
+serde = { version = "1.0.183", features = ["derive"] }

src/commands/create.rs

@@ -83,7 +83,10 @@ fn get_vars(args: &Create) -> BTreeMap<String, String> {
 }
 
 fn post_create(args: Create) {
-    android_cli::create_local_properties_file(args.dest.unwrap().as_path(), &args.sdk_path.unwrap())
+    let dest = args.dest.clone().unwrap();
+
+    android_cli::create_local_properties_file(&dest, &args.sdk_path.unwrap());
+    android_cli::create_dot_file(&dest, args.package_id.unwrap());
 }
 
 fn ensure_valid_args(args: Create) -> Create {

src/lib.rs

@@ -1,21 +1,30 @@
 mod utils;
 
-use itertools::Itertools;
 use guidon::{GitOptions, Guidon, TryNew};
+use itertools::Itertools;
+use serde::{Deserialize, Serialize};
 
 use std::{
     collections::BTreeMap,
     path::{Path, PathBuf},
     process::{Command, ExitStatus},
 };
 
-use utils::find_gradle;
+use utils::{find_adb, find_gradle};
 
-use crate::utils::find_adb;
+const VERSION: &str = env!("CARGO_PKG_VERSION");
 
 const DEFAULT_TEMPLATE_REPO: &str = "https://github.com/SyedAhkam/android-cli-template";
 const TEMPLATE_REV: &str = "master";
 
+const DOTFILE_COMMENT: &str = "// DO NOT MODIFY; Generated by Android CLI for internal usage.\n";
+
+#[derive(Debug, Serialize, Deserialize)]
+struct DotAndroid {
+    pub package_id: String,
+    pub gen_at_version: String,
+}
+
 pub fn copy_template(dest: &Path, vars: BTreeMap<String, String>) {
     let git_options = GitOptions::builder()
         .repo(DEFAULT_TEMPLATE_REPO)
@@ -45,9 +54,7 @@ pub fn invoke_gradle_command(cmd: &str) -> Result<ExitStatus, Box<dyn std::error
     println!(
         "Invoking Gradle: {} {}",
         &run.get_program().to_string_lossy(),
-        &run.get_args()
-            .map(|arg| arg.to_string_lossy())
-            .join(" ")
+        &run.get_args().map(|arg| arg.to_string_lossy()).join(" ")
     );
 
     Ok(run.status()?)
@@ -62,10 +69,27 @@ pub fn invoke_adb_command(args: &[&str]) -> Result<ExitStatus, Box<dyn std::erro
     println!(
         "Invoking ADB: {} {}",
         &run.get_program().to_string_lossy(),
-        &run.get_args()
-            .map(|arg| arg.to_string_lossy())
-            .join(" ")
+        &run.get_args().map(|arg| arg.to_string_lossy()).join(" ")
     );
 
     Ok(run.status()?)
 }
+
+pub fn create_dot_file(dest: &Path, package_id: String) {
+    // Construct the structure
+    let dot_android = DotAndroid {
+        package_id,
+        gen_at_version: VERSION.to_owned(),
+    };
+
+    // Serialize into Ron
+    let mut ron_contents =
+        ron::ser::to_string_pretty(&dot_android, ron::ser::PrettyConfig::default()).unwrap();
+
+    // Add a comment at top
+    ron_contents.insert_str(0, DOTFILE_COMMENT);
+
+    // Write to file
+    let path = PathBuf::from(dest).join(".android");
+    std::fs::write(path, ron_contents).expect("failed to write .android file");
+}