feat(gradle): add gradle module (#4423)

* docs: document gradle module

* implement gradle module

* gradle-module: add test for wrapper properties case

* docs: improve gradle module documentation

* fix: fix gradle module wrapper properties test

* drop gradle executable strategy

* apply suggested stuff

* Fix config schema

12 files changed, 394 insertions, 0 deletions

diff --git a/.github/config-schema.json b/.github/config-schema.json
index 2cb9bb5f1..404cdd6aa 100644
--- a/.github/config-schema.json
+++ b/.github/config-schema.json
@@ -621,6 +621,29 @@
         }
       ]
     },
+    "gradle": {
+      "default": {
+        "detect_extensions": [
+          "gradle",
+          "gradle.kts"
+        ],
+        "detect_files": [],
+        "detect_folders": [
+          "gradle"
+        ],
+        "disabled": false,
+        "format": "via [$symbol($version )]($style)",
+        "recursive": false,
+        "style": "bold bright-cyan",
+        "symbol": "🅶 ",
+        "version_format": "v${raw}"
+      },
+      "allOf": [
+        {
+          "$ref": "#/definitions/GradleConfig"
+        }
+      ]
+    },
     "guix_shell": {
       "default": {
         "disabled": false,
@@ -3189,6 +3212,62 @@
       },
       "additionalProperties": false
     },
+    "GradleConfig": {
+      "type": "object",
+      "properties": {
+        "format": {
+          "default": "via [$symbol($version )]($style)",
+          "type": "string"
+        },
+        "version_format": {
+          "default": "v${raw}",
+          "type": "string"
+        },
+        "symbol": {
+          "default": "🅶 ",
+          "type": "string"
+        },
+        "style": {
+          "default": "bold bright-cyan",
+          "type": "string"
+        },
+        "disabled": {
+          "default": false,
+          "type": "boolean"
+        },
+        "recursive": {
+          "default": false,
+          "type": "boolean"
+        },
+        "detect_extensions": {
+          "default": [
+            "gradle",
+            "gradle.kts"
+          ],
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "detect_files": {
+          "default": [],
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "detect_folders": {
+          "default": [
+            "gradle"
+          ],
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        }
+      },
+      "additionalProperties": false
+    },
     "GuixShellConfig": {
       "type": "object",
       "properties": {
diff --git a/docs/.vuepress/public/presets/toml/bracketed-segments.toml b/docs/.vuepress/public/presets/toml/bracketed-segments.toml
index f871774dd..c86ed0479 100644
--- a/docs/.vuepress/public/presets/toml/bracketed-segments.toml
+++ b/docs/.vuepress/public/presets/toml/bracketed-segments.toml
@@ -58,6 +58,9 @@ format = '([\[$all_status$ahead_behind\]]($style))'
 [golang]
 format = '\[[$symbol($version)]($style)\]'
 
+[gradle]
+format = '\[[$symbol($version)]($style)\]'
+
 [guix_shell]
 format = '\[[$symbol]($style)\]'
 
diff --git a/docs/.vuepress/public/presets/toml/no-runtime-versions.toml b/docs/.vuepress/public/presets/toml/no-runtime-versions.toml
index 28ffb7fca..97b6a3ed7 100644
--- a/docs/.vuepress/public/presets/toml/no-runtime-versions.toml
+++ b/docs/.vuepress/public/presets/toml/no-runtime-versions.toml
@@ -37,6 +37,9 @@ format = 'via [$symbol]($style)'
 [golang]
 format = 'via [$symbol]($style)'
 
+[gradle]
+format = 'via [$symbol]($style)'
+
 [haxe]
 format = 'via [$symbol]($style)'
 
diff --git a/docs/.vuepress/public/presets/toml/pastel-powerline.toml b/docs/.vuepress/public/presets/toml/pastel-powerline.toml
index 6c240d063..f5cee6ecc 100644
--- a/docs/.vuepress/public/presets/toml/pastel-powerline.toml
+++ b/docs/.vuepress/public/presets/toml/pastel-powerline.toml
@@ -12,6 +12,7 @@ $c\
 $elixir\
 $elm\
 $golang\
+$gradle\
 $haskell\
 $java\
 $julia\
@@ -97,6 +98,10 @@ symbol = " "
 style = "bg:#86BBD8"
 format = '[ $symbol ($version) ]($style)'
 
+[gradle]
+style = "bg:#86BBD8"
+format = '[ $symbol ($version) ]($style)'
+
 [haskell]
 symbol = " "
 style = "bg:#86BBD8"
diff --git a/docs/.vuepress/public/presets/toml/plain-text-symbols.toml b/docs/.vuepress/public/presets/toml/plain-text-symbols.toml
index bf6591980..1efccd243 100644
--- a/docs/.vuepress/public/presets/toml/plain-text-symbols.toml
+++ b/docs/.vuepress/public/presets/toml/plain-text-symbols.toml
@@ -64,6 +64,9 @@ symbol = "git "
 [golang]
 symbol = "go "
 
+[gradle]
+symbol = "gradle "
+
 [guix_shell]
 symbol = "guix "
 
diff --git a/docs/config/README.md b/docs/config/README.md
index 0d4d13ac8..4d1a7161f 100644
--- a/docs/config/README.md
+++ b/docs/config/README.md
@@ -291,6 +291,7 @@ $helm\
 $java\
 $julia\
 $kotlin\
+$gradle\
 $lua\
 $nim\
 $nodejs\
@@ -1927,6 +1928,42 @@ disabled = true
 format = 'via [🐂](yellow bold) '
 ```
 
+## Gradle
+
+The `gradle` module shows the version of the [Gradle Wrapper](https://docs.gradle.org/current/userguide/gradle_wrapper.html)
+currently used in the project directory.
+
+By default the module will be shown if any of the following conditions are met:
+
+- The current directory contains a `gradle/wrapper/gradle-wrapper.properties` directory.
+- The current directory contains a file ending with `.gradle` or `.gradle.kts`.
+
+The `gradle` module is only able to read your Gradle Wrapper version from your config file, we don't execute your wrapper, because of the security concerns.
+
+### Options
+
+| Option              | Default                              | Description                                                               |
+| ------------------- | ------------------------------------ | ------------------------------------------------------------------------- |
+| `format`            | `"via [$symbol($version )]($style)"` | The format for the module.                                                |
+| `version_format`    | `"v${raw}"`                          | The version format. Available vars are `raw`, `major`, `minor`, & `patch` |
+| `symbol`            | `"🅶 "`                               | A format string representing the symbol of Gradle.                        |
+| `detect_extensions` | `["gradle", "gradle.kts"]`           | Which extensions should trigger this module.                              |
+| `detect_files`      | `[]`                                 | Which filenames should trigger this module.                               |
+| `detect_folders`    | `["gradle"]`                         | Which folders should trigger this module.                                 |
+| `style`             | `"bold bright-cyan"`                 | The style for the module.                                                 |
+| `disabled`          | `false`                              | Disables the `gradle` module.                                             |
+| `recursive`         | `false`                              | Enables recursive finding for the `gradle` directory.                     |
+
+### Variables
+
+| Variable | Example  | Description                          |
+| -------- | -------- | ------------------------------------ |
+| version  | `v7.5.1` | The version of `gradle`              |
+| symbol   |          | Mirrors the value of option `symbol` |
+| style*   |          | Mirrors the value of option `style`  |
+
+*: This variable can only be used as a part of a style string
+
 ## Haskell
 
 The `haskell` module finds the current selected GHC version and/or the selected Stack snapshot.
diff --git a/src/configs/gradle.rs b/src/configs/gradle.rs
new file mode 100644
index 000000000..5026f83e5
--- /dev/null
+++ b/src/configs/gradle.rs
@@ -0,0 +1,36 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Deserialize, Serialize)]
+#[cfg_attr(
+    feature = "config-schema",
+    derive(schemars::JsonSchema),
+    schemars(deny_unknown_fields)
+)]
+#[serde(default)]
+pub struct GradleConfig<'a> {
+    pub format: &'a str,
+    pub version_format: &'a str,
+    pub symbol: &'a str,
+    pub style: &'a str,
+    pub disabled: bool,
+    pub recursive: bool,
+    pub detect_extensions: Vec<&'a str>,
+    pub detect_files: Vec<&'a str>,
+    pub detect_folders: Vec<&'a str>,
+}
+
+impl<'a> Default for GradleConfig<'a> {
+    fn default() -> Self {
+        GradleConfig {
+            format: "via [$symbol($version )]($style)",
+            version_format: "v${raw}",
+            symbol: "🅶 ",
+            style: "bold bright-cyan",
+            disabled: false,
+            recursive: false,
+            detect_extensions: vec!["gradle", "gradle.kts"],
+            detect_files: vec![],
+            detect_folders: vec!["gradle"],
+        }
+    }
+}
diff --git a/src/configs/mod.rs b/src/configs/mod.rs
index a7717c3ac..88d1d8d97 100644
--- a/src/configs/mod.rs
+++ b/src/configs/mod.rs
@@ -33,6 +33,7 @@ pub mod git_metrics;
 pub mod git_state;
 pub mod git_status;
 pub mod go;
+pub mod gradle;
 pub mod guix_shell;
 pub mod haskell;
 pub mod haxe;
@@ -164,6 +165,8 @@ pub struct FullConfig<'a> {
     #[serde(borrow)]
     golang: go::GoConfig<'a>,
     #[serde(borrow)]
+    gradle: gradle::GradleConfig<'a>,
+    #[serde(borrow)]
     guix_shell: guix_shell::GuixShellConfig<'a>,
     #[serde(borrow)]
     haskell: haskell::HaskellConfig<'a>,
diff --git a/src/configs/starship_root.rs b/src/configs/starship_root.rs
index fd67bc65c..3fdd06f68 100644
--- a/src/configs/starship_root.rs
+++ b/src/configs/starship_root.rs
@@ -58,6 +58,7 @@ pub const PROMPT_ORDER: &[&str] = &[
     "elm",
     "erlang",
     "golang",
+    "gradle",
     "haskell",
     "haxe",
     "helm",
diff --git a/src/module.rs b/src/module.rs
index f0d1a0e0d..64518afd6 100644
--- a/src/module.rs
+++ b/src/module.rs
@@ -41,6 +41,7 @@ pub const ALL_MODULES: &[&str] = &[
     "git_state",
     "git_status",
     "golang",
+    "gradle",
     "guix_shell",
     "haskell",
     "haxe",
diff --git a/src/modules/gradle.rs b/src/modules/gradle.rs
new file mode 100644
index 000000000..e19c9a4c9
--- /dev/null
+++ b/src/modules/gradle.rs
@@ -0,0 +1,220 @@
+use crate::{
+    config::ModuleConfig,
+    configs::gradle::GradleConfig,
+    context::Context,
+    formatter::{StringFormatter, VersionFormatter},
+    module::Module,
+    utils,
+};
+
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
+    let mut module = context.new_module("gradle");
+    let config = GradleConfig::try_load(module.config);
+    let is_gradle_project = context
+        .try_begin_scan()?
+        .set_files(&config.detect_files)
+        .set_extensions(&config.detect_extensions)
+        .set_folders(&config.detect_folders)
+        .is_match();
+
+    if !is_gradle_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" => {
+                    let gradle_version = {
+                        let properties = get_wrapper_properties_file(context, config.recursive)?;
+                        parse_gradle_version_from_properties(&properties)?
+                    };
+                    VersionFormatter::format_module_version(
+                        module.get_name(),
+                        &gradle_version,
+                        config.version_format,
+                    )
+                    .map(Ok)
+                }
+                _ => None,
+            })
+            .parse(None, Some(context))
+    });
+
+    module.set_segments(match parsed {
+        Ok(segments) => segments,
+        Err(error) => {
+            log::warn!("Error in module `gradle`:\n{}", error);
+            return None;
+        }
+    });
+
+    Some(module)
+}
+
+fn parse_gradle_version_from_properties(wrapper_properties: &str) -> Option<String> {
+    // example gradle.properties content
+    /*
+        distributionBase=GRADLE_USER_HOME
+        distributionPath=wrapper/dists
+        distributionUrl=https\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+        zipStoreBase=GRADLE_USER_HOME
+        zipStorePath=wrapper/dists
+    */
+    let version = wrapper_properties
+        .lines()
+        .find(|line| line.starts_with("distributionUrl="))?
+        .rsplit_once('/')?
+        .1
+        .strip_prefix("gradle-")?
+        .split_once('-')?
+        .0;
+    Some(version.to_string())
+}
+
+/// Tries to find the gradle-wrapper.properties file.
+fn get_wrapper_properties_file(context: &Context, recursive: bool) -> Option<String> {
+    let mut properties = None;
+    if context
+        .try_begin_scan()?
+        .set_folders(&["gradle"])
+        .is_match()
+    {
+        properties = utils::read_file(
+            &context
+                .current_dir
+                .join("gradle/wrapper/gradle-wrapper.properties"),
+        )
+        .ok();
+    };
+    if recursive && properties.is_none() {
+        for dir in context.current_dir.ancestors().skip(1) {
+            properties =
+                utils::read_file(&dir.join("gradle/wrapper/gradle-wrapper.properties")).ok();
+            if properties.is_some() {
+                break;
+            }
+        }
+    }
+    properties
+}
+
+#[cfg(test)]
+mod tests {
+    use nu_ansi_term::Color;
+
+    use super::*;
+    use crate::test::ModuleRenderer;
+    use std::fs::{self, File};
+    use std::io::{self, Write};
+
+    #[test]
+    fn folder_without_gradle_files() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+
+        let actual = ModuleRenderer::new("gradle").path(dir.path()).collect();
+
+        let expected = None;
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
+    #[test]
+    fn folder_with_gradle_wrapper_properties() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let properties = dir
+            .path()
+            .join("gradle")
+            .join("wrapper")
+            .join("gradle-wrapper.properties");
+        // create gradle/wrapper/ directories
+        fs::create_dir_all(properties.parent().unwrap())?;
+        // create build.gradle file to mark it as a gradle project
+        File::create(dir.path().join("build.gradle"))?.sync_all()?;
+        let mut file = File::create(properties)?;
+        file.write_all(
+            b"\
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists",
+        )?;
+        file.sync_all()?;
+
+        let actual = ModuleRenderer::new("gradle").path(dir.path()).collect();
+
+        let expected = Some(format!(
+            "via {}",
+            Color::LightCyan.bold().paint("🅶 v7.5.1 ")
+        ));
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
+    #[test]
+    fn gradle_wrapper_recursive() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let properties = dir
+            .path()
+            .join("gradle")
+            .join("wrapper")
+            .join("gradle-wrapper.properties");
+        // create gradle/wrapper/ directories
+        fs::create_dir_all(properties.parent().unwrap())?;
+        // create build.gradle file to mark it as a gradle project
+        File::create(dir.path().join("build.gradle"))?.sync_all()?;
+        let mut file = File::create(properties)?;
+        file.write_all(
+            b"\
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists",
+        )?;
+        file.sync_all()?;
+
+        let target_dir = dir.path().join("working_dir");
+        fs::create_dir(&target_dir)?;
+        File::create(target_dir.join("build.gradle.kts"))?.sync_all()?;
+
+        let actual = ModuleRenderer::new("gradle")
+            .config(toml::toml! {
+                [gradle]
+                recursive = true
+            })
+            .path(target_dir)
+            .collect();
+
+        let expected = Some(format!(
+            "via {}",
+            Color::LightCyan.bold().paint("🅶 v7.5.1 ")
+        ));
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
+    #[test]
+    fn test_format_wrapper_properties() {
+        let input = "\
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+        ";
+        assert_eq!(
+            parse_gradle_version_from_properties(input),
+            Some("7.5.1".to_string())
+        );
+    }
+}
diff --git a/src/modules/mod.rs b/src/modules/mod.rs
index 12b7f8ddc..8e463aa55 100644
--- a/src/modules/mod.rs
+++ b/src/modules/mod.rs
@@ -30,6 +30,7 @@ mod git_metrics;
 mod git_state;
 mod git_status;
 mod golang;
+mod gradle;
 mod guix_shell;
 mod haskell;
 mod haxe;
@@ -129,6 +130,7 @@ pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
             "git_state" => git_state::module(context),
             "git_status" => git_status::module(context),
             "golang" => golang::module(context),
+            "gradle" => gradle::module(context),
             "guix_shell" => guix_shell::module(context),
             "haskell" => haskell::module(context),
             "haxe" => haxe::module(context),
@@ -239,6 +241,7 @@ pub fn description(module: &str) -> &'static str {
         "git_state" => "The current git operation, and it's progress",
         "git_status" => "Symbol representing the state of the repo",
         "golang" => "The currently installed version of Golang",
+        "gradle" => "The currently installed version of Gradle",
         "guix_shell" => "The guix-shell environment",
         "haskell" => "The selected version of the Haskell toolchain",
         "haxe" => "The currently installed version of Haxe",