Add `uninstall` command (#98)

Adds an `uninstall` command to uninstall node versions 👏

executable/FnmApp.re

@@ -6,6 +6,7 @@ module Commands = {
   let listRemote = () => Lwt_main.run(ListRemote.run());
   let listLocal = () => Lwt_main.run(ListLocal.run());
   let install = version => Lwt_main.run(Install.run(~version));
+  let uninstall = version => Lwt_main.run(Uninstall.run(~version));
   let env =
       (
         isFishShell,
@@ -74,6 +75,25 @@ let install = {
   );
 };
 
+let uninstall = {
+  let doc = "Uninstall a node version";
+  let man = [];
+
+  let selectedVersion = {
+    let doc = "Uninstall the node version specified in $(docv).";
+    Arg.(
+      required
+      & pos(0, some(string), None)
+      & info([], ~docv="VERSION", ~doc)
+    );
+  };
+
+  (
+    Term.(const(Commands.uninstall) $ selectedVersion),
+    Term.info("uninstall", ~version, ~doc, ~exits=Term.default_exits, ~man),
+  );
+};
+
 let listLocal = {
   let doc = "List all the installed versions";
   let man = [];
@@ -248,6 +268,6 @@ let defaultCmd = {
 let _ =
   Term.eval_choice(
     defaultCmd,
-    [install, use, alias, listLocal, listRemote, env],
+    [install, uninstall, use, alias, listLocal, listRemote, env],
   )
   |> Term.exit;

executable/Uninstall.re

@@ -0,0 +1,43 @@
+open Fnm;
+open Lwt;
+
+let run = (~version) => {
+  Versions.getInstalledVersions()
+  >|= List.find_opt(x => Versions.Local.(x.name == version))
+  >>= (
+    installedVersion =>
+      switch (installedVersion) {
+      | None =>
+        Logger.log(
+          <Pastel>
+            "The version "
+            <Pastel color=Pastel.Cyan> version </Pastel>
+            " is not installed."
+          </Pastel>,
+        );
+        exit(1);
+      | Some(installedVersion) =>
+        {
+          Logger.log(
+            <Pastel>
+              "Uninstalling node "
+              <Pastel color=Pastel.Cyan>
+                Versions.Local.(installedVersion.name)
+              </Pastel>
+            </Pastel>,
+          );
+        };
+        let%lwt _ = Versions.Local.remove(installedVersion);
+        Logger.log(
+          <Pastel>
+            "Node version "
+            <Pastel color=Pastel.Cyan>
+              Versions.Local.(installedVersion.name)
+            </Pastel>
+            " has correctly been removed."
+          </Pastel>,
+        )
+        |> Lwt.return;
+      }
+  );
+};

library/Fs.re

@@ -43,6 +43,27 @@ let readlink = path =>
   | err => Lwt.return_error(err)
   };
 
+// Credit: https://github.com/fastpack/fastpack/blob/9f6aa7d5b83ffef03e73a15679200576ff9dbcb7/FastpackUtil/FS.re#L94
+let rec rmdir = dir => {
+  let%lwt files = Lwt_unix.files_of_directory(dir) |> Lwt_stream.to_list;
+  let%lwt () =
+    Lwt_list.iter_s(
+      filename =>
+        switch (filename) {
+        | "."
+        | ".." => Lwt.return_unit
+        | _ =>
+          let path = Filename.concat(dir, filename);
+          switch%lwt (Lwt_unix.stat(path)) {
+          | {st_kind: Lwt_unix.S_DIR, _} => rmdir(path)
+          | _ => Lwt_unix.unlink(path)
+          };
+        },
+      files,
+    );
+  Lwt_unix.rmdir(dir);
+};
+
 type path =
   | Exists(string)
   | Missing(string);

library/Versions.re

@@ -35,6 +35,8 @@ module Local = {
 
   let toDirectory = name => Filename.concat(Directories.nodeVersions, name);
 
+  let remove = version => Fs.rmdir(version.fullPath);
+
   let getLatestInstalledNameByPrefix = prefix => {
     open Lwt;
     let%lwt versions =