add initial autocomplete for installed templatetags (#46)

Author: joshuadavidthomas

Cargo.toml

@@ -4,6 +4,7 @@ resolver = "2"
 
 [workspace.dependencies]
 djls = { path = "crates/djls" }
+djls-project = { path = "crates/djls-project" }
 djls-server = { path = "crates/djls-server" }
 djls-template-ast = { path = "crates/djls-template-ast" }
 djls-worker = { path = "crates/djls-worker" }
@@ -16,6 +17,7 @@ serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 thiserror = "2.0"
 tokio = { version = "1.42", features = ["full"] }
+tower-lsp = { version = "0.20", features = ["proposed"] }
 
 [profile.dev.package]
 insta.opt-level = 3

crates/djls-project/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "djls-project"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+pyo3 = { workspace = true }
+tower-lsp = { workspace = true }

crates/djls-project/src/lib.rs

@@ -0,0 +1,62 @@
+mod templatetags;
+
+pub use templatetags::TemplateTags;
+
+use pyo3::prelude::*;
+use std::path::{Path, PathBuf};
+use tower_lsp::lsp_types::*;
+
+#[derive(Debug)]
+pub struct DjangoProject {
+    path: PathBuf,
+    template_tags: Option<TemplateTags>,
+}
+
+impl DjangoProject {
+    pub fn new(path: PathBuf) -> Self {
+        Self {
+            path,
+            template_tags: None,
+        }
+    }
+
+    pub fn from_initialize_params(params: &InitializeParams) -> Option<Self> {
+        // Try current directory first
+        let path = std::env::current_dir()
+            .ok()
+            // Fall back to workspace root if provided
+            .or_else(|| {
+                params
+                    .root_uri
+                    .as_ref()
+                    .and_then(|uri| uri.to_file_path().ok())
+            });
+
+        path.map(Self::new)
+    }
+
+    pub fn initialize(&mut self) -> PyResult<()> {
+        Python::with_gil(|py| {
+            // Add project to Python path
+            let sys = py.import("sys")?;
+            let py_path = sys.getattr("path")?;
+            py_path.call_method1("append", (self.path.to_str().unwrap(),))?;
+
+            // Setup Django
+            let django = py.import("django")?;
+            django.call_method0("setup")?;
+
+            self.template_tags = Some(TemplateTags::from_python(py)?);
+
+            Ok(())
+        })
+    }
+
+    pub fn template_tags(&self) -> Option<&TemplateTags> {
+        self.template_tags.as_ref()
+    }
+
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+}

crates/djls-project/src/templatetags.rs

@@ -0,0 +1,94 @@
+use pyo3::prelude::*;
+use pyo3::types::{PyDict, PyList};
+use std::ops::Deref;
+
+#[derive(Debug, Default, Clone)]
+pub struct TemplateTags(Vec<TemplateTag>);
+
+impl Deref for TemplateTags {
+    type Target = Vec<TemplateTag>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl TemplateTags {
+    fn new() -> Self {
+        Self(Vec::new())
+    }
+
+    fn process_library(
+        module_name: &str,
+        library: &Bound<'_, PyAny>,
+        tags: &mut Vec<TemplateTag>,
+    ) -> PyResult<()> {
+        let tags_dict = library.getattr("tags")?;
+        let dict = tags_dict.downcast::<PyDict>()?;
+
+        for (key, value) in dict.iter() {
+            let tag_name = key.extract::<String>()?;
+            let doc = value.getattr("__doc__")?.extract().ok();
+
+            let library_name = if module_name.is_empty() {
+                "builtins".to_string()
+            } else {
+                module_name.split('.').last().unwrap_or("").to_string()
+            };
+
+            tags.push(TemplateTag::new(tag_name, library_name, doc));
+        }
+        Ok(())
+    }
+
+    pub fn from_python(py: Python) -> PyResult<TemplateTags> {
+        let mut template_tags = TemplateTags::new();
+
+        let engine = py
+            .import("django.template.engine")?
+            .getattr("Engine")?
+            .call_method0("get_default")?;
+
+        // Built-in template tags
+        let builtins_attr = engine.getattr("template_builtins")?;
+        let builtins = builtins_attr.downcast::<PyList>()?;
+        for builtin in builtins {
+            Self::process_library("", &builtin, &mut template_tags.0)?;
+        }
+
+        // Custom template libraries
+        let libraries_attr = engine.getattr("template_libraries")?;
+        let libraries = libraries_attr.downcast::<PyDict>()?;
+        for (module_name, library) in libraries.iter() {
+            let module_name = module_name.extract::<String>()?;
+            Self::process_library(&module_name, &library, &mut template_tags.0)?;
+        }
+
+        Ok(template_tags)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct TemplateTag {
+    name: String,
+    library: String,
+    doc: Option<String>,
+}
+
+impl TemplateTag {
+    fn new(name: String, library: String, doc: Option<String>) -> Self {
+        Self { name, library, doc }
+    }
+
+    pub fn name(&self) -> &String {
+        &self.name
+    }
+
+    pub fn library(&self) -> &String {
+        &self.library
+    }
+
+    pub fn doc(&self) -> &Option<String> {
+        &self.doc
+    }
+}

crates/djls-server/Cargo.toml

@@ -4,13 +4,13 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+djls-project = { workspace = true }
 djls-template-ast = { workspace = true }
 djls-worker = { workspace = true }
 
 anyhow = { workspace = true }
+pyo3 = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 tokio = { workspace = true }
-
-tower-lsp = { version = "0.20", features = ["proposed"] }
-lsp-types = "0.97"
+tower-lsp = { workspace = true }

crates/djls-server/src/documents.rs

@@ -1,8 +1,10 @@
 use anyhow::{anyhow, Result};
+use djls_project::TemplateTags;
 use std::collections::HashMap;
 use tower_lsp::lsp_types::{
-    DidChangeTextDocumentParams, DidCloseTextDocumentParams, DidOpenTextDocumentParams, Position,
-    Range,
+    CompletionItem, CompletionItemKind, CompletionResponse, DidChangeTextDocumentParams,
+    DidCloseTextDocumentParams, DidOpenTextDocumentParams, Documentation, InsertTextFormat,
+    MarkupContent, MarkupKind, Position, Range,
 };
 
 #[derive(Debug)]
@@ -102,6 +104,56 @@ impl Store {
     pub fn is_version_valid(&self, uri: &str, version: i32) -> bool {
         self.get_version(uri).map_or(false, |v| v == version)
     }
+
+    pub fn get_completions(
+        &self,
+        uri: &str,
+        position: Position,
+        tags: &TemplateTags,
+    ) -> Option<CompletionResponse> {
+        let document = self.get_document(uri)?;
+
+        if document.language_id != LanguageId::HtmlDjango {
+            return None;
+        }
+
+        let context = document.get_template_tag_context(position)?;
+
+        let mut completions: Vec<CompletionItem> = tags
+            .iter()
+            .filter(|tag| {
+                context.partial_tag.is_empty() || tag.name().starts_with(&context.partial_tag)
+            })
+            .map(|tag| {
+                let leading_space = if context.needs_leading_space { " " } else { "" };
+                CompletionItem {
+                    label: tag.name().to_string(),
+                    kind: Some(CompletionItemKind::KEYWORD),
+                    detail: Some(format!("Template tag from {}", tag.library())),
+                    documentation: tag.doc().as_ref().map(|doc| {
+                        Documentation::MarkupContent(MarkupContent {
+                            kind: MarkupKind::Markdown,
+                            value: doc.to_string(),
+                        })
+                    }),
+                    insert_text: Some(match context.closing_brace {
+                        ClosingBrace::None => format!("{}{} %}}", leading_space, tag.name()),
+                        ClosingBrace::PartialClose => format!("{}{} %", leading_space, tag.name()),
+                        ClosingBrace::FullClose => format!("{}{} ", leading_space, tag.name()),
+                    }),
+                    insert_text_format: Some(InsertTextFormat::PLAIN_TEXT),
+                    ..Default::default()
+                }
+            })
+            .collect();
+
+        if completions.is_empty() {
+            None
+        } else {
+            completions.sort_by(|a, b| a.label.cmp(&b.label));
+            Some(CompletionResponse::Array(completions))
+        }
+    }
 }
 
 #[derive(Clone, Debug)]
@@ -181,6 +233,32 @@ impl TextDocument {
     pub fn line_count(&self) -> usize {
         self.index.line_starts.len()
     }
+
+    pub fn get_template_tag_context(&self, position: Position) -> Option<TemplateTagContext> {
+        let line = self.get_line(position.line.try_into().ok()?)?;
+        let prefix = &line[..position.character.try_into().ok()?];
+        let rest_of_line = &line[position.character.try_into().ok()?..];
+        let rest_trimmed = rest_of_line.trim_start();
+
+        prefix.rfind("{%").map(|tag_start| {
+            // Check if we're immediately after {% with no space
+            let needs_leading_space = prefix.ends_with("{%");
+
+            let closing_brace = if rest_trimmed.starts_with("%}") {
+                ClosingBrace::FullClose
+            } else if rest_trimmed.starts_with("}") {
+                ClosingBrace::PartialClose
+            } else {
+                ClosingBrace::None
+            };
+
+            TemplateTagContext {
+                partial_tag: prefix[tag_start + 2..].trim().to_string(),
+                closing_brace,
+                needs_leading_space,
+            }
+        })
+    }
 }
 
 #[derive(Clone, Debug)]
@@ -248,3 +326,17 @@ impl From<String> for LanguageId {
         Self::from(language_id.as_str())
     }
 }
+
+#[derive(Debug)]
+pub enum ClosingBrace {
+    None,
+    PartialClose, // just }
+    FullClose,    // %}
+}
+
+#[derive(Debug)]
+pub struct TemplateTagContext {
+    pub partial_tag: String,
+    pub closing_brace: ClosingBrace,
+    pub needs_leading_space: bool,
+}

crates/djls-server/src/lib.rs

@@ -6,6 +6,7 @@ mod tasks;
 use crate::notifier::TowerLspNotifier;
 use crate::server::{DjangoLanguageServer, LspNotification, LspRequest};
 use anyhow::Result;
+use server::LspResponse;
 use std::sync::Arc;
 use tokio::sync::RwLock;
 use tower_lsp::jsonrpc::Result as LspResult;
@@ -19,11 +20,16 @@ struct TowerLspBackend {
 #[tower_lsp::async_trait]
 impl LanguageServer for TowerLspBackend {
     async fn initialize(&self, params: InitializeParams) -> LspResult<InitializeResult> {
-        self.server
-            .read()
+        match self
+            .server
+            .write()
             .await
             .handle_request(LspRequest::Initialize(params))
-            .map_err(|_| tower_lsp::jsonrpc::Error::internal_error())
+            .map_err(|_| tower_lsp::jsonrpc::Error::internal_error())?
+        {
+            LspResponse::Initialize(result) => Ok(result),
+            _ => Err(tower_lsp::jsonrpc::Error::internal_error()),
+        }
     }
 
     async fn initialized(&self, params: InitializedParams) {
@@ -77,6 +83,19 @@ impl LanguageServer for TowerLspBackend {
             eprintln!("Error handling document close: {}", e);
         }
     }
+
+    async fn completion(&self, params: CompletionParams) -> LspResult<Option<CompletionResponse>> {
+        match self
+            .server
+            .write()
+            .await
+            .handle_request(LspRequest::Completion(params))
+            .map_err(|_| tower_lsp::jsonrpc::Error::internal_error())?
+        {
+            LspResponse::Completion(result) => Ok(result),
+            _ => Err(tower_lsp::jsonrpc::Error::internal_error()),
+        }
+    }
 }
 
 pub async fn serve() -> Result<()> {