feat: add auto install and update mechanism

src/helm.rs

@@ -1,35 +1,168 @@
-use zed_extension_api::{self as zed, serde_json, settings::LspSettings, LanguageServerId, Result};
+use std::fs;
+use zed::LanguageServerId;
+use zed_extension_api::{self as zed, serde_json, settings::LspSettings, Result};
 
-struct HelmExtension;
+struct HelmExtension {
+    cached_binary_path: Option<String>,
+}
 
 impl HelmExtension {
     const HELM_LS: &'static str = "helm_ls";
     const HELM_LS_HYPHENATED: &'static str = "helm-ls";
+
+    fn language_server_binary_path(
+        &mut self,
+        language_server_id: &LanguageServerId,
+        worktree: &zed::Worktree,
+    ) -> Result<String> {
+        // 1. In-memory cache: fastest path, valid within a single Zed session.
+        if let Some(path) = &self.cached_binary_path {
+            if fs::metadata(path).map_or(false, |stat| stat.is_file()) {
+                return Ok(path.clone());
+            }
+        }
+
+        // 2. System-wide installation: respect an existing helm_ls or helm-ls on PATH.
+        if let Some(path) = worktree
+            .which(Self::HELM_LS)
+            .or_else(|| worktree.which(Self::HELM_LS_HYPHENATED))
+        {
+            self.cached_binary_path = Some(path.clone());
+            return Ok(path);
+        }
+
+        // Resolve platform strings once — used for both the disk scan and the
+        // asset/binary name construction below.
+        let (platform, arch) = zed::current_platform();
+        let binary_prefix = format!("{}_", Self::HELM_LS);
+
+        let os = match platform {
+            zed::Os::Mac => "darwin",
+            zed::Os::Linux => "linux",
+            zed::Os::Windows => "windows",
+        };
+        let arch = match arch {
+            zed::Architecture::Aarch64 => "arm64",
+            zed::Architecture::X86 => "x86",
+            zed::Architecture::X8664 => "amd64",
+        };
+        let extension = match platform {
+            zed::Os::Mac | zed::Os::Linux => "",
+            zed::Os::Windows => ".exe",
+        };
+
+        // The asset filename used by helm-ls releases, e.g. "helm_ls_linux_amd64".
+        let binary_name = format!("{binary_prefix}{os}_{arch}{extension}");
+
+        // 3. Disk scan: look for a binary from a previous download.
+        //    This is the offline fallback — if the network call below fails we
+        //    can still return a working binary that was installed earlier.
+        let installed_binary_path = fs::read_dir(".").ok().and_then(|entries| {
+            entries
+                .filter_map(|e| e.ok())
+                .filter(|e| {
+                    e.file_name()
+                        .to_str()
+                        .map_or(false, |n| n.starts_with(&binary_prefix))
+                })
+                .filter_map(|dir| {
+                    let dir_name = dir.file_name();
+                    let path = format!("{}/{binary_name}", dir_name.to_str()?);
+                    if fs::metadata(&path).map_or(false, |s| s.is_file()) {
+                        Some(path)
+                    } else {
+                        None
+                    }
+                })
+                .next()
+        });
+
+        // 4. Try to reach GitHub for the latest release.
+        //    If offline, fall back to whatever is already on disk (step 3).
+        zed::set_language_server_installation_status(
+            language_server_id,
+            &zed::LanguageServerInstallationStatus::CheckingForUpdate,
+        );
+        let release = match zed::latest_github_release(
+            "mrjosh/helm-ls",
+            zed::GithubReleaseOptions {
+                require_assets: true,
+                pre_release: false,
+            },
+        ) {
+            Ok(release) => release,
+            Err(_) => {
+                if let Some(path) = installed_binary_path {
+                    self.cached_binary_path = Some(path.clone());
+                    return Ok(path);
+                }
+                return Err(format!(
+                    "{} is not installed and cannot be downloaded without an internet connection",
+                    Self::HELM_LS
+                )
+                .into());
+            }
+        };
+
+        // 5. Already on the latest version — nothing to download.
+        let version_dir = format!("{binary_prefix}{}", release.version);
+        let binary_path = format!("{version_dir}/{binary_name}");
+
+        if !fs::metadata(&binary_path).map_or(false, |stat| stat.is_file()) {
+            // 6. Download the new release.
+            let asset = release
+                .assets
+                .iter()
+                .find(|asset| asset.name == binary_name)
+                .ok_or_else(|| format!("no asset found matching {:?}", binary_name))?;
+
+            fs::create_dir_all(&version_dir)
+                .map_err(|err| format!("failed to create directory '{version_dir}': {err}"))?;
+
+            zed::set_language_server_installation_status(
+                language_server_id,
+                &zed::LanguageServerInstallationStatus::Downloading,
+            );
+
+            zed::download_file(
+                &asset.download_url,
+                &binary_path,
+                zed::DownloadedFileType::Uncompressed,
+            )
+            .map_err(|e| format!("failed to download file: {e}"))?;
+
+            zed::make_file_executable(&binary_path)?;
+
+            // 7. Remove older version directories to keep the extension directory clean.
+            let entries =
+                fs::read_dir(".").map_err(|e| format!("failed to list working directory: {e}"))?;
+            for entry in entries {
+                let entry = entry.map_err(|e| format!("failed to read directory entry: {e}"))?;
+                if entry.file_name().to_str() != Some(&version_dir) {
+                    fs::remove_dir_all(entry.path()).ok();
+                }
+            }
+        }
+
+        self.cached_binary_path = Some(binary_path.clone());
+        Ok(binary_path)
+    }
 }
 
 impl zed::Extension for HelmExtension {
     fn new() -> Self {
-        Self
+        Self {
+            cached_binary_path: None,
+        }
     }
 
     fn language_server_command(
         &mut self,
-        _language_server_id: &LanguageServerId,
+        language_server_id: &LanguageServerId,
         worktree: &zed::Worktree,
     ) -> Result<zed::Command> {
-        let path = worktree
-            .which(Self::HELM_LS)
-            .or_else(|| worktree.which(Self::HELM_LS_HYPHENATED))
-            .ok_or_else(|| {
-                format!(
-                    "The LSP for helm is not installed. Neither '{}' nor '{}' found on PATH",
-                    Self::HELM_LS,
-                    Self::HELM_LS_HYPHENATED
-                )
-            })?;
-
         Ok(zed::Command {
-            command: path,
+            command: self.language_server_binary_path(language_server_id, worktree)?,
             args: vec!["serve".to_string()],
             env: Default::default(),
         })
@@ -48,4 +181,4 @@ impl zed::Extension for HelmExtension {
     }
 }
 
-zed::register_extension!(HelmExtension);
+zed_extension_api::register_extension!(HelmExtension);