feat(dtmm): Add config file

crates/dtmm/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2021"
 
 [dependencies]
 bitflags = "1.3.2"
-clap = { version = "4.0.15", features = ["color", "derive", "std", "cargo", "unicode"] }
+clap = { version = "4.0.15", features = ["color", "derive", "std", "cargo", "string", "unicode"] }
 color-eyre = "0.6.2"
 confy = "0.5.1"
 druid = { git = "https://github.com/linebender/druid.git", features = ["im"] }

crates/dtmm/src/main.rs

@@ -1,10 +1,16 @@
 #![recursion_limit = "256"]
 #![feature(let_chains)]
 
+use std::fs;
+use std::io::ErrorKind;
+use std::path::PathBuf;
 use std::sync::Arc;
 
 use clap::command;
+use clap::parser::ValueSource;
+use clap::value_parser;
 use clap::Arg;
+use color_eyre::eyre::Context;
 use color_eyre::Report;
 use color_eyre::Result;
 use druid::AppLauncher;
@@ -12,6 +18,8 @@ use druid::ExtEventSink;
 use druid::SingleUse;
 use druid::Target;
 use engine::import_mod;
+use serde::Deserialize;
+use serde::Serialize;
 use state::ACTION_FINISH_ADD_MOD;
 use tokio::runtime::Runtime;
 use tokio::sync::mpsc::UnboundedReceiver;
@@ -30,6 +38,12 @@ mod state;
 mod theme;
 mod widget;
 
+#[derive(Clone, Debug, Serialize, Deserialize)]
+struct Config {
+    data_dir: Option<PathBuf>,
+    game_dir: Option<PathBuf>,
+}
+
 fn work_thread(
     event_sink: Arc<RwLock<ExtEventSink>>,
     action_queue: Arc<RwLock<UnboundedReceiver<AsyncAction>>>,
@@ -76,11 +90,52 @@ fn work_thread(
     Ok(())
 }
 
+#[cfg(not(arget_os = "windows"))]
+fn get_default_config_path() -> String {
+    let config_dir = std::env::var("XDG_CONFIG_DIR").unwrap_or_else(|_| {
+        let home = std::env::var("HOME").unwrap_or_else(|_| {
+            let user = std::env::var("USER").expect("user env variable not set");
+            format!("/home/{user}")
+        });
+        format!("{home}/.config")
+    });
+
+    format!("{config_dir}/dtmm/dtmm.cfg")
+}
+
+#[cfg(target_os = "windows")]
+fn get_default_config_path() -> String {
+    let config_dir = std::env::var("APPDATA").expect("appdata env var not set");
+    format!("{config_dir}\\dtmm\\dtmm.cfg")
+}
+
+#[cfg(not(arget_os = "windows"))]
+fn get_default_data_dir() -> String {
+    let data_dir = std::env::var("XDG_DATA_DIR").unwrap_or_else(|_| {
+        let home = std::env::var("HOME").unwrap_or_else(|_| {
+            let user = std::env::var("USER").expect("user env variable not set");
+            format!("/home/{user}")
+        });
+        format!("{home}/.local/share")
+    });
+
+    format!("{data_dir}/dtmm")
+}
+
+#[cfg(target_os = "windows")]
+fn get_default_data_dir() -> String {
+    let data_dir = std::env::var("APPDATA").expect("appdata env var not set");
+    format!("{data_dir}\\dtmm")
+}
+
 #[tracing::instrument]
-#[tokio::main]
-async fn main() -> Result<()> {
+fn main() -> Result<()> {
     color_eyre::install()?;
 
+    let default_config_path = get_default_config_path();
+
+    tracing::trace!(default_config_path);
+
     let matches = command!()
         .arg(Arg::new("oodle").long("oodle").help(
             "The oodle library to load. This may either be:\n\
@@ -88,6 +143,14 @@ async fn main() -> Result<()> {
                         - A file path relative to the current working directory.\n\
                         - An absolute file path.",
         ))
+        .arg(
+            Arg::new("config")
+                .long("config")
+                .short('c')
+                .help("Path to the config file")
+                .value_parser(value_parser!(PathBuf))
+                .default_value(&default_config_path),
+        )
         .get_matches();
 
     {
@@ -121,7 +184,48 @@ async fn main() -> Result<()> {
         oodle_sys::init(matches.get_one::<String>("oodle"));
     }
 
-    let initial_state = State::new();
+    let config: Config = {
+        let path = matches
+            .get_one::<PathBuf>("config")
+            .expect("argument missing despite default");
+        match fs::read(path) {
+            Ok(data) => {
+                let data = String::from_utf8(data).wrap_err_with(|| {
+                    format!("config file {} contains invalid UTF-8", path.display())
+                })?;
+                serde_sjson::from_str(&data)
+                    .wrap_err_with(|| format!("invalid config file {}", path.display()))?
+            }
+            Err(err) if err.kind() == ErrorKind::NotFound => {
+                if matches.value_source("config") != Some(ValueSource::DefaultValue) {
+                    return Err(err).wrap_err_with(|| {
+                        format!("failed to read config file {}", path.display())
+                    })?;
+                }
+
+                let config = Config {
+                    data_dir: Some(PathBuf::from(get_default_data_dir())),
+                    game_dir: None,
+                };
+
+                {
+                    let data = serde_sjson::to_string(&config)
+                        .wrap_err("failed to serialize default config value")?;
+                    fs::write(&default_config_path, data).wrap_err_with(|| {
+                        format!("failed to write default config to {default_config_path}")
+                    })?;
+                }
+
+                config
+            }
+            Err(err) => {
+                return Err(err)
+                    .wrap_err_with(|| format!("failed to read config file {}", path.display()))?;
+            }
+        }
+    };
+
+    let initial_state = State::new(config);
 
     let (sender, receiver) = tokio::sync::mpsc::unbounded_channel();
     let delegate = Delegate::new(sender);

crates/dtmm/src/state.rs

@@ -9,6 +9,8 @@ use druid::{
 };
 use tokio::sync::mpsc::UnboundedSender;
 
+use crate::Config;
+
 pub(crate) const ACTION_SELECT_MOD: Selector<usize> = Selector::new("dtmm.action.select-mod");
 pub(crate) const ACTION_SELECTED_MOD_UP: Selector = Selector::new("dtmm.action.selected-mod-up");
 pub(crate) const ACTION_SELECTED_MOD_DOWN: Selector =
@@ -105,26 +107,17 @@ impl State {
     #[allow(non_upper_case_globals)]
     pub const selected_mod: SelectedModLens = SelectedModLens;
 
-    pub fn new() -> Self {
+    pub fn new(config: Config) -> Self {
         let ctx = sdk::Context::new();
 
-        let (game_dir, data_dir) = if cfg!(debug_assertions) {
-            (
-                std::env::current_dir().expect("PWD is borked").join("data"),
-                PathBuf::from("/tmp/dtmm"),
-            )
-        } else {
-            (PathBuf::new(), PathBuf::new())
-        };
-
         Self {
             ctx: Arc::new(ctx),
             current_view: View::default(),
             mods: Vector::new(),
             selected_mod_index: None,
             is_deployment_in_progress: false,
-            game_dir: Arc::new(game_dir),
-            data_dir: Arc::new(data_dir),
+            game_dir: Arc::new(config.game_dir.unwrap_or_default()),
+            data_dir: Arc::new(config.data_dir.unwrap_or_default()),
         }
     }