feat: Implement `starship configure` command (#751)

src/configure.rs

@@ -0,0 +1,37 @@
+use std::env;
+use std::process::Command;
+
+const UNKNOWN_CONFIG: &str = "<unknown config>";
+const STD_EDITOR: &str = "vi";
+
+pub fn edit_configuration() {
+    let editor = get_editor();
+    let config_path = get_config_path();
+
+    Command::new(editor)
+        .arg(config_path)
+        .status()
+        .expect("failed to open file");
+}
+
+fn get_editor() -> String {
+    match env::var("EDITOR") {
+        Ok(val) => val,
+        Err(_) => STD_EDITOR.to_string(),
+    }
+}
+
+fn get_config_path() -> String {
+    let home_dir = dirs::home_dir();
+
+    if home_dir.is_none() {
+        return UNKNOWN_CONFIG.to_string();
+    }
+
+    let path = home_dir.unwrap().join(".config/starship.toml");
+
+    match path.to_str() {
+        Some(p) => String::from(p),
+        None => UNKNOWN_CONFIG.to_string(),
+    }
+}

src/main.rs

@@ -4,6 +4,7 @@ extern crate clap;
 mod bug_report;
 mod config;
 mod configs;
+mod configure;
 mod context;
 mod init;
 mod module;
@@ -110,6 +111,7 @@ fn main() {
                     .arg(&keymap_arg)
                     .arg(&jobs_arg),
             )
+            .subcommand(SubCommand::with_name("configure").about("Edit the starship configuration"))
             .subcommand(SubCommand::with_name("bug-report").about(
                 "Create a pre-populated GitHub issue with information about your configuration",
             ))
@@ -137,6 +139,7 @@ fn main() {
                 print::module(module_name, sub_m.clone());
             }
         }
+        ("configure", Some(_)) => configure::edit_configuration(),
         ("bug-report", Some(_)) => bug_report::create(),
         _ => {}
     }