From 62ec21584be61868d309d7c827facd58c8d4adb4 Mon Sep 17 00:00:00 2001
From: Josh <josh@joshthomas.dev>
Date: Fri, 13 Dec 2024 00:17:28 -0600
Subject: [PATCH] implement basic config

---
 crates/djlc-cli/Cargo.toml    |  6 ++-
 crates/djlc-cli/src/config.rs | 94 +++++++++++++++++++++++++++++++++++
 crates/djlc-cli/src/main.rs   | 15 +++++-
 3 files changed, 112 insertions(+), 3 deletions(-)
 create mode 100644 crates/djlc-cli/src/config.rs

diff --git a/crates/djlc-cli/Cargo.toml b/crates/djlc-cli/Cargo.toml
index 7349989..3e7ccda 100644
--- a/crates/djlc-cli/Cargo.toml
+++ b/crates/djlc-cli/Cargo.toml
@@ -9,10 +9,14 @@ djls-ipc = { workspace = true }
 djls-server = { workspace = true }
 
 anyhow = { workspace = true }
+serde = { workspace = true }
 serde_json = { workspace = true }
+thiserror = { workspace = true }
 tokio = { workspace = true }
 
-clap = { version = "4.5.23", features = ["derive"] }
+clap = { version = "4.5.23", features = ["derive", "env"] }
+dirs = "5.0.1"
+figment = { version = "0.10.19", features = ["env", "toml"] }
 tower-lsp = { version = "0.20.0", features = ["proposed"] }
 
 [[bin]]
diff --git a/crates/djlc-cli/src/config.rs b/crates/djlc-cli/src/config.rs
new file mode 100644
index 0000000..49b0cb5
--- /dev/null
+++ b/crates/djlc-cli/src/config.rs
@@ -0,0 +1,94 @@
+use clap::Args;
+use figment::providers::{Env, Format, Serialized, Toml};
+use figment::Figment;
+use serde::{Deserialize, Serialize};
+use std::path::{Path, PathBuf};
+
+const CONFIG_FILES: [&str; 3] = [
+    "djls.toml", // highest priority
+    ".djls.toml",
+    "pyproject.toml", // lowest priority
+];
+
+#[derive(Args, Debug, Serialize, Deserialize)]
+pub struct Config {
+    /// Override the virtual environment path
+    #[arg(long, env = "DJLS_VENV_PATH")]
+    pub venv_path: Option<PathBuf>,
+
+    /// Django settings module
+    #[arg(long, env = "DJANGO_SETTINGS_MODULE")]
+    pub django_settings_module: String,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Config {
+            venv_path: std::env::var("VIRTUAL_ENV").ok().map(PathBuf::from),
+            django_settings_module: std::env::var("DJANGO_SETTINGS_MODULE").unwrap_or_default(),
+        }
+    }
+}
+
+impl Config {
+    fn validate(self) -> Result<Self, ConfigError> {
+        if self.django_settings_module.is_empty() {
+            return Err(ConfigError::MissingDjangoSettings);
+        }
+        Ok(self)
+    }
+}
+
+fn find_config_up_tree(start_dir: &Path) -> Vec<PathBuf> {
+    let mut configs = Vec::new();
+    let mut current_dir = start_dir.to_path_buf();
+
+    while let Some(parent) = current_dir.parent() {
+        for &config_name in CONFIG_FILES.iter() {
+            let config_path = current_dir.join(config_name);
+            if config_path.exists() {
+                configs.push(config_path);
+            }
+        }
+        current_dir = parent.to_path_buf();
+    }
+
+    configs
+}
+
+pub fn load_config(cli_config: &Config) -> Result<Config, ConfigError> {
+    let platform_config = dirs::config_dir()
+        .map(|dir| dir.join("djls/config.toml"))
+        .filter(|p| p.exists());
+
+    let mut figment = Figment::new()
+        .merge(Serialized::defaults(Config::default()))
+        .merge(
+            platform_config
+                .map(|p| Toml::file(&p))
+                .unwrap_or_else(|| Toml::file("/dev/null")),
+        );
+
+    let current_dir = std::env::current_dir().map_err(ConfigError::CurrentDir)?;
+    for path in find_config_up_tree(&current_dir) {
+        figment = figment.merge(Toml::file(&path));
+    }
+
+    let config: Config = figment
+        .merge(Env::raw().only(&["DJANGO_SETTINGS_MODULE"]))
+        .merge(Env::prefixed("DJLS_").split("_"))
+        .merge(Serialized::defaults(cli_config))
+        .extract()?;
+
+    config.validate()
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ConfigError {
+    #[error("Django settings module not specified")]
+    MissingDjangoSettings,
+    #[error("could not determine current directory: {0}")]
+    CurrentDir(std::io::Error),
+    #[error("figment error: {0}")]
+    Figment(#[from] figment::Error),
+}
diff --git a/crates/djlc-cli/src/main.rs b/crates/djlc-cli/src/main.rs
index 385e208..4b01de7 100644
--- a/crates/djlc-cli/src/main.rs
+++ b/crates/djlc-cli/src/main.rs
@@ -1,6 +1,9 @@
+mod config;
+
+use crate::config::{load_config, Config};
+use anyhow::Context;
 use clap::{Args, Parser, Subcommand};
-use djls_ipc::v1::*;
-use djls_ipc::{ProcessError, PythonProcess, TransportError};
+use djls_ipc::PythonProcess;
 use std::ffi::OsStr;
 use std::time::Duration;
 
@@ -8,6 +11,9 @@ use std::time::Duration;
 struct Cli {
     #[command(subcommand)]
     command: Commands,
+
+    #[command(flatten)]
+    config: Config,
 }
 
 #[derive(Debug, Args)]
@@ -40,16 +46,21 @@ enum Commands {
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let cli = Cli::parse();
+    let config = load_config(&cli.config).context("failed to load configuration")?;
 
     match cli.command {
         Commands::Serve(opts) => {
             println!("Starting LSP server...");
+            println!("With config: {:?}", config);
+
             let python = PythonProcess::new::<Vec<&OsStr>, &OsStr>(
                 "djls.agent",
                 None,
                 opts.health_check_interval(),
             )?;
+
             println!("LSP server started, beginning to serve...");
+
             djls_server::serve(python).await?
         }
     }