Extract Vue extension (#10486)

This PR extracts Vue support into an extension and removes the built-in
C# support from Zed.

Release Notes:

- Removed built-in support for Vue, in favor of making it available as
an extension. The Vue extension will be suggested for download when you
open a `.vue` file.

---------

Co-authored-by: Max <max@zed.dev>

extensions/vue/src/vue.rs

@@ -0,0 +1,135 @@
+use std::{env, fs};
+use zed::lsp::{Completion, CompletionKind};
+use zed::CodeLabelSpan;
+use zed_extension_api::{self as zed, serde_json, Result};
+
+struct VueExtension {
+    did_find_server: bool,
+}
+
+const SERVER_PATH: &str = "node_modules/@vue/language-server/bin/vue-language-server.js";
+const PACKAGE_NAME: &str = "@vue/language-server";
+
+impl VueExtension {
+    fn server_exists(&self) -> bool {
+        fs::metadata(SERVER_PATH).map_or(false, |stat| stat.is_file())
+    }
+
+    fn server_script_path(&mut self, id: &zed::LanguageServerId) -> Result<String> {
+        let server_exists = self.server_exists();
+        if self.did_find_server && server_exists {
+            return Ok(SERVER_PATH.to_string());
+        }
+
+        zed::set_language_server_installation_status(
+            id,
+            &zed::LanguageServerInstallationStatus::CheckingForUpdate,
+        );
+        // We hardcode the version to 1.8 since we do not support @vue/language-server 2.0 yet.
+        let version = "1.8".to_string();
+
+        if !server_exists
+            || zed::npm_package_installed_version(PACKAGE_NAME)?.as_ref() != Some(&version)
+        {
+            zed::set_language_server_installation_status(
+                id,
+                &zed::LanguageServerInstallationStatus::Downloading,
+            );
+            let result = zed::npm_install_package(PACKAGE_NAME, &version);
+            match result {
+                Ok(()) => {
+                    if !self.server_exists() {
+                        Err(format!(
+                            "installed package '{PACKAGE_NAME}' did not contain expected path '{SERVER_PATH}'",
+                        ))?;
+                    }
+                }
+                Err(error) => {
+                    if !self.server_exists() {
+                        Err(error)?;
+                    }
+                }
+            }
+        }
+
+        self.did_find_server = true;
+        Ok(SERVER_PATH.to_string())
+    }
+}
+
+impl zed::Extension for VueExtension {
+    fn new() -> Self {
+        Self {
+            did_find_server: false,
+        }
+    }
+
+    fn language_server_command(
+        &mut self,
+        id: &zed::LanguageServerId,
+        _: &zed::Worktree,
+    ) -> Result<zed::Command> {
+        let server_path = self.server_script_path(id)?;
+        Ok(zed::Command {
+            command: zed::node_binary_path()?,
+            args: vec![
+                env::current_dir()
+                    .unwrap()
+                    .join(&server_path)
+                    .to_string_lossy()
+                    .to_string(),
+                "--stdio".to_string(),
+            ],
+            env: Default::default(),
+        })
+    }
+
+    fn language_server_initialization_options(
+        &mut self,
+        _: &zed::LanguageServerId,
+        _: &zed::Worktree,
+    ) -> Result<Option<serde_json::Value>> {
+        Ok(Some(serde_json::json!({
+            "typescript": {
+                "tsdk": "node_modules/typescript/lib"
+            }
+        })))
+    }
+
+    fn label_for_completion(
+        &self,
+        _language_server_id: &zed::LanguageServerId,
+        completion: Completion,
+    ) -> Option<zed::CodeLabel> {
+        let highlight_name = match completion.kind? {
+            CompletionKind::Class | CompletionKind::Interface => "type",
+            CompletionKind::Constructor => "type",
+            CompletionKind::Constant => "constant",
+            CompletionKind::Function | CompletionKind::Method => "function",
+            CompletionKind::Property | CompletionKind::Field => "tag",
+            CompletionKind::Variable => "type",
+            CompletionKind::Keyword => "keyword",
+            CompletionKind::Value => "tag",
+            _ => return None,
+        };
+
+        let len = completion.label.len();
+        let name_span = CodeLabelSpan::literal(completion.label, Some(highlight_name.to_string()));
+
+        Some(zed::CodeLabel {
+            code: Default::default(),
+            spans: if let Some(detail) = completion.detail {
+                vec![
+                    name_span,
+                    CodeLabelSpan::literal(" ", None),
+                    CodeLabelSpan::literal(detail, None),
+                ]
+            } else {
+                vec![name_span]
+            },
+            filter_range: (0..len).into(),
+        })
+    }
+}
+
+zed::register_extension!(VueExtension);