feat(vlang): create module (#2577)

* Add V module

* Format

* Fix tests

* fix typo

* Update src/configs/v.rs

Co-authored-by: Dario Vladović <d.vladimyr@gmail.com>

* Update docs/config/README.md

Co-authored-by: Dario Vladović <d.vladimyr@gmail.com>

* Update docs/config/README.md

Co-authored-by: Dario Vladović <d.vladimyr@gmail.com>

* Update docs/config/README.md

Co-authored-by: Dario Vladović <d.vladimyr@gmail.com>

* Use blue bold

* v -> vlang

* change docs

* More vlang fixes

* add package support for v

* Update docs/config/README.md

Co-authored-by: Dario Vladović <d.vladimyr@gmail.com>

* use regex

* Update src/configs/mod.rs

Co-authored-by: David Knaack <davidkna@users.noreply.github.com>

* apply patch

* fix

Co-authored-by: Dario Vladović <d.vladimyr@gmail.com>
Co-authored-by: David Knaack <davidkna@users.noreply.github.com>

9 files changed, 194 insertions, 0 deletions

diff --git a/docs/config/README.md b/docs/config/README.md
index b6ff32819..86e206160 100644
--- a/docs/config/README.md
+++ b/docs/config/README.md
@@ -223,6 +223,7 @@ $rust\
 $scala\
 $swift\
 $terraform\
+$vlang\
 $vagrant\
 $zig\
 $nix_shell\
@@ -2022,6 +2023,7 @@ package, and shows its current version. The module currently supports `npm`, `ca
 - [**helm**](https://helm.sh/docs/helm/helm_package/) - The `helm` chart version is extracted from the `Chart.yaml` present
 - [**maven**](https://maven.apache.org/) - The `maven` package version is extracted from the `pom.xml` present
 - [**meson**](https://mesonbuild.com/) - The `meson` package version is extracted from the `meson.build` present
+- [**vlang**](https://vlang.io) - The `vlang` package version is extracted from the `v.mod` present
 
 > ⚠️ The version being shown is that of the package whose source code is in your
 > current directory, not your package manager.
@@ -2839,6 +2841,41 @@ By default the module will be shown if any of the following conditions are met:
 format = "via [⍱ $version](bold white) "
 ```
 
+## VLang
+
+The `vlang` module shows you your currently installed version of V.
+By default the module will be shown if any of the following conditions are met:
+- The current directory contains a file with `.v` extension
+- The current directory contains a `v.mod` file
+
+### Options
+
+| Option              | Default                                           | Description                                     |
+| ------------------- | ------------------------------------------------- | ----------------------------------------------- |
+| `format`            | `"via [$symbol($version )]($style)"`              | The format for the module.                      |
+| `symbol`            | `"V "`                                           | A format string representing the symbol of V |
+| `detect_extensions` | `["v"]`                                        | Which extensions should trigger this module.    |
+| `detect_files`      | `["v.mod"]` | Which filenames should trigger this module. |
+| `detect_folders`    | `[]`                                  | Which folders should trigger this module.       |
+| `style`             | `"blue bold"`                                     | The style for the module.                       |
+| `disabled`          | `false`                                           | Disables the `vlang` module.                    |
+
+### Variables
+
+| Variable | Example  | Description                          |
+| -------- | -------- | ------------------------------------ |
+| version  | `v0.2` | The version of `v`                |
+| symbol   |          | Mirrors the value of option `symbol` |
+| style\*  |          | Mirrors the value of option `style`  |
+
+### Example
+
+```toml
+# ~/.config/starship.toml
+[v]
+format = "via [V $version](blue bold) "
+```
+
 ## VCSH
 
 The `vcsh` module displays the current active [VCSH](https://github.com/RichiH/vcsh) repository.
diff --git a/src/configs/mod.rs b/src/configs/mod.rs
index a7663fac1..08fbbfa07 100644
--- a/src/configs/mod.rs
+++ b/src/configs/mod.rs
@@ -59,6 +59,7 @@ pub mod swift;
 pub mod terraform;
 pub mod time;
 pub mod username;
+pub mod v;
 pub mod vagrant;
 pub mod vcsh;
 pub mod zig;
@@ -128,6 +129,7 @@ pub struct FullConfig<'a> {
     terraform: terraform::TerraformConfig<'a>,
     time: time::TimeConfig<'a>,
     username: username::UsernameConfig<'a>,
+    vlang: v::VLangConfig<'a>,
     vagrant: vagrant::VagrantConfig<'a>,
     zig: zig::ZigConfig<'a>,
     custom: IndexMap<String, custom::CustomConfig<'a>>,
@@ -196,6 +198,7 @@ impl<'a> Default for FullConfig<'a> {
             time: Default::default(),
             username: Default::default(),
             vagrant: Default::default(),
+            vlang: Default::default(),
             zig: Default::default(),
             custom: Default::default(),
         }
diff --git a/src/configs/starship_root.rs b/src/configs/starship_root.rs
index 50c206c06..f8cc2c62d 100644
--- a/src/configs/starship_root.rs
+++ b/src/configs/starship_root.rs
@@ -58,6 +58,7 @@ pub const PROMPT_ORDER: &[&str] = &[
     "scala",
     "swift",
     "terraform",
+    "vlang",
     "vagrant",
     "zig",
     // ↑ Toolchain version modules ↑
diff --git a/src/configs/v.rs b/src/configs/v.rs
new file mode 100644
index 000000000..dc8624c69
--- /dev/null
+++ b/src/configs/v.rs
@@ -0,0 +1,29 @@
+use crate::config::ModuleConfig;
+
+use serde::Serialize;
+use starship_module_config_derive::ModuleConfig;
+
+#[derive(Clone, ModuleConfig, Serialize)]
+pub struct VLangConfig<'a> {
+    pub format: &'a str,
+    pub symbol: &'a str,
+    pub style: &'a str,
+    pub disabled: bool,
+    pub detect_extensions: Vec<&'a str>,
+    pub detect_files: Vec<&'a str>,
+    pub detect_folders: Vec<&'a str>,
+}
+
+impl<'a> Default for VLangConfig<'a> {
+    fn default() -> Self {
+        VLangConfig {
+            format: "via [$symbol($version )]($style)",
+            symbol: "V ",
+            style: "blue bold",
+            disabled: false,
+            detect_extensions: vec!["v"],
+            detect_files: vec!["v.mod"],
+            detect_folders: vec![],
+        }
+    }
+}
diff --git a/src/module.rs b/src/module.rs
index cee9f357f..860ca04c9 100644
--- a/src/module.rs
+++ b/src/module.rs
@@ -67,6 +67,7 @@ pub const ALL_MODULES: &[&str] = &[
     "username",
     "vcsh",
     "vagrant",
+    "vlang",
     "zig",
 ];
 
diff --git a/src/modules/mod.rs b/src/modules/mod.rs
index 1d5eac0e5..b255a7f2a 100644
--- a/src/modules/mod.rs
+++ b/src/modules/mod.rs
@@ -57,6 +57,7 @@ mod username;
 mod utils;
 mod vagrant;
 mod vcsh;
+mod vlang;
 mod zig;
 
 #[cfg(feature = "battery")]
@@ -130,6 +131,7 @@ pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
             "time" => time::module(context),
             "crystal" => crystal::module(context),
             "username" => username::module(context),
+            "vlang" => vlang::module(context),
             "vagrant" => vagrant::module(context),
             "vcsh" => vcsh::module(context),
             "zig" => zig::module(context),
@@ -210,6 +212,7 @@ pub fn description(module: &str) -> &'static str {
         "terraform" => "The currently selected terraform workspace and version",
         "time" => "The current local time",
         "username" => "The active user's username",
+        "vlang" => "The currently installed version of V",
         "vagrant" => "The currently installed version of Vagrant",
         "vcsh" => "The currently active VCSH repository",
         "zig" => "The currently installed version of Zig",
diff --git a/src/modules/package.rs b/src/modules/package.rs
index bd7372ca6..1f95a7e0a 100644
--- a/src/modules/package.rs
+++ b/src/modules/package.rs
@@ -54,6 +54,13 @@ fn extract_cargo_version(file_contents: &str) -> Option<String> {
     Some(formatted_version)
 }
 
+fn extract_vlang_version(file_contents: &str) -> Option<String> {
+    let re = Regex::new(r"(?m)^\s*version\s*:\s*'(?P<version>[^']+)'").unwrap();
+    let caps = re.captures(file_contents)?;
+    let formatted_version = format_version(&caps["version"]);
+    Some(formatted_version)
+}
+
 fn extract_package_version(file_contents: &str, display_private: bool) -> Option<String> {
     let package_json: json::Value = json::from_str(file_contents).ok()?;
 
@@ -198,6 +205,8 @@ fn get_package_version(base_dir: &Path, config: &PackageConfig) -> Option<String
         extract_maven_version(&pom_file)
     } else if let Ok(meson_build) = utils::read_file(base_dir.join("meson.build")) {
         extract_meson_version(&meson_build)
+    } else if let Ok(vlang_mod) = utils::read_file(base_dir.join("v.mod")) {
+        extract_vlang_version(&vlang_mod)
     } else {
         None
     }
@@ -818,6 +827,21 @@ end";
         project_dir.close()
     }
 
+    #[test]
+    fn test_extract_vlang_version() -> io::Result<()> {
+        let config_name = "v.mod";
+        let config_content = "
+        Module {
+            name: 'starship',
+            author: 'matchai',
+            version: '1.2.3'
+        }";
+        let project_dir = create_project_dir()?;
+        fill_config(&project_dir, config_name, Some(&config_content))?;
+        expect_output(&project_dir, Some("v1.2.3"), None);
+        project_dir.close()
+    }
+
     fn create_project_dir() -> io::Result<TempDir> {
         tempfile::tempdir()
     }
diff --git a/src/modules/vlang.rs b/src/modules/vlang.rs
new file mode 100644
index 000000000..0d7d0e7b0
--- /dev/null
+++ b/src/modules/vlang.rs
@@ -0,0 +1,92 @@
+use super::{Context, Module, RootModuleConfig};
+
+use crate::configs::v::VLangConfig;
+use crate::formatter::StringFormatter;
+
+/// Creates a module with the current V version
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
+    let mut module = context.new_module("vlang");
+    let config = VLangConfig::try_load(module.config);
+    let is_v_project = context
+        .try_begin_scan()?
+        .set_extensions(&config.detect_extensions)
+        .is_match();
+
+    if !is_v_project {
+        return None;
+    }
+
+    let parsed = StringFormatter::new(config.format).and_then(|formatter| {
+        formatter
+            .map_meta(|var, _| match var {
+                "symbol" => Some(config.symbol),
+                _ => None,
+            })
+            .map_style(|variable| match variable {
+                "style" => Some(Ok(config.style)),
+                _ => None,
+            })
+            .map(|variable| match variable {
+                "version" => context
+                    .exec_cmd("v", &["version"])
+                    .and_then(|output| parse_v_version(output.stdout.trim()))
+                    .map(Ok),
+                _ => None,
+            })
+            .parse(None)
+    });
+
+    module.set_segments(match parsed {
+        Ok(segments) => segments,
+        Err(error) => {
+            log::warn!("Error in module `vlang`:\n{}", error);
+            return None;
+        }
+    });
+
+    Some(module)
+}
+
+fn parse_v_version(v_version: &str) -> Option<String> {
+    let version = v_version
+        // split into ["V", "0.2", "30c0659"]
+        .split_whitespace()
+        // return "0.2"
+        .nth(1)?;
+
+    Some(format!("v{}", version))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::parse_v_version;
+    use crate::test::ModuleRenderer;
+    use ansi_term::Color;
+    use std::fs::File;
+    use std::io;
+
+    #[test]
+    fn test_parse_v_version() {
+        const OUTPUT: &str = "V 0.2 30c0659\n";
+        assert_eq!(parse_v_version(OUTPUT.trim()), Some("v0.2".to_string()))
+    }
+
+    #[test]
+    fn folder_without_v_files() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let actual = ModuleRenderer::new("vlang").path(dir.path()).collect();
+        let expected = None;
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
+    #[test]
+    fn folder_with_v_files() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        File::create(dir.path().join("hello.v"))?.sync_all()?;
+        let actual = ModuleRenderer::new("vlang").path(dir.path()).collect();
+        let expected = Some(format!("via {}", Color::Blue.bold().paint("V v0.2 ")));
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+}
diff --git a/src/utils.rs b/src/utils.rs
index 32fd342f5..7ef829a31 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -188,6 +188,10 @@ Target: x86_64-apple-darwin19.4.0\n",
             stdout: String::from("Vagrant 2.2.10\n"),
             stderr: String::default(),
         }),
+        "v version" => Some(CommandOutput {
+            stdout: String::from("V 0.2 30c0659"),
+            stderr: String::default()
+        }),
         "zig version" => Some(CommandOutput {
             stdout: String::from("0.6.0\n"),
             stderr: String::default(),