1 files changed, 184 insertions, 0 deletions
diff --git a/src/launcher/settings.rs b/src/launcher/settings.rs
new file mode 100644
index 0000000..5a96589
--- /dev/null
+++ b/src/launcher/settings.rs
@@ -0,0 +1,184 @@
+use std::collections::HashMap;
+use std::error::Error;
+use std::fmt::{Display, Formatter};
+use std::io::ErrorKind;
+use std::path::{Path, PathBuf};
+use log::warn;
+use serde::{Deserialize, Serialize};
+use tokio::{fs, io};
+use tokio::fs::File;
+use tokio::io::AsyncWriteExt;
+use super::constants;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+struct SettingsInner {
+    profiles: HashMap<String, Profile>,
+    instances: HashMap<String, Instance>
+}
+
+pub struct Settings {
+    path: Option<PathBuf>,
+    inner: SettingsInner
+}
+
+#[derive(Debug)]
+pub enum SettingsError {
+    IO { what: &'static str, error: io::Error },
+    Format(serde_json::Error),
+    Inconsistent(String)
+}
+
+impl Display for SettingsError {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self {
+            SettingsError::IO { what, error } => write!(f, "settings i/o error ({}): {}", what, error),
+            SettingsError::Format(err) => write!(f, "settings format error: {}", err),
+            SettingsError::Inconsistent(err) => write!(f, "inconsistent settings: {}", err),
+        }
+    }
+}
+
+impl Error for SettingsError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        match self {
+            SettingsError::IO { error: err, .. } => Some(err),
+            SettingsError::Format(err) => Some(err),
+            _ => None
+        }
+    }
+}
+
+impl Default for SettingsInner {
+    fn default() -> Self {
+        SettingsInner {
+            instances: [(String::from(constants::DEF_INSTANCE_NAME), PathBuf::from(constants::DEF_INSTANCE_NAME).into())].into_iter().collect(),
+            profiles: [(String::from(constants::DEF_PROFILE_NAME), Profile::new(constants::DEF_INSTANCE_NAME))].into_iter().collect()
+        }
+    }
+}
+
+impl Settings {
+    async fn load_inner(path: impl AsRef<Path>) -> Result<SettingsInner, SettingsError> {
+        match fs::read_to_string(&path).await {
+            Ok(data) => serde_json::from_str(data.as_str()).map_err(SettingsError::Format),
+            Err(e) if e.kind() == ErrorKind::NotFound => Ok(SettingsInner::default()),
+            Err(e) => Err(SettingsError::IO { what: "loading settings", error: e })
+        }
+    }
+
+    fn check_consistent(mut inner: SettingsInner, path: Option<impl AsRef<Path>>) -> Result<Settings, SettingsError> {
+        inner.profiles.retain(|name, profile| {
+            if !inner.instances.contains_key(&profile.instance) {
+                warn!("Settings inconsistency: profile {} refers to instance {}, which does not exist. Ignoring this profile.", name, profile.instance);
+                false
+            } else {
+                true
+            }
+        });
+
+        // there will be more checks later maybe
+
+        Ok(Settings {
+            path: path.map(|p| p.as_ref().to_owned()),
+            inner
+        })
+    }
+
+    pub async fn load(path: impl AsRef<Path>) -> Result<Settings, SettingsError> {
+        Self::check_consistent(Self::load_inner(&path).await?, Some(path))
+    }
+
+    pub fn get_path(&self) -> Option<&Path> {
+        self.path.as_ref().map(|p| p.as_path())
+    }
+
+    pub async fn save_to(&self, path: impl AsRef<Path>) -> Result<(), SettingsError> {
+        let path = path.as_ref();
+
+        if let Some(parent) = path.parent() {
+            fs::create_dir_all(parent).await
+                .map_err(|e| SettingsError::IO { what: "saving settings (creating directory)", error: e })?;
+        }
+
+        let mut file = File::create(path).await
+            .map_err(|e| SettingsError::IO { what: "saving settings (open)", error: e })?;
+
+        file.write_all(serde_json::to_string_pretty(&self.inner).map_err(SettingsError::Format)?.as_bytes()).await
+            .map_err(|e| SettingsError::IO { what: "saving settings (write)", error: e })?;
+
+        Ok(())
+    }
+
+    pub async fn save(&self) -> Result<(), SettingsError> {
+        self.save_to(self.path.as_ref().expect("save() called on Settings instance not loaded from file")).await
+    }
+
+    pub fn get_instance(&self, name: &str) -> Option<&Instance> {
+        self.inner.instances.get(name)
+    }
+
+    pub fn get_profile(&self, name: &str) -> Option<&Profile> {
+        self.inner.profiles.get(name)
+    }
+
+    pub fn get_instance_for(&self, profile: &Profile) -> &Instance {
+        self.inner.instances.get(&profile.instance).unwrap()
+    }
+}
+
+#[derive(Deserialize, Serialize, Debug, Clone)]
+pub struct Instance {
+    path: PathBuf // relative to launcher home (or absolute)
+}
+
+#[derive(Deserialize, Serialize, Debug, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum ProfileVersion {
+    LatestSnapshot,
+    LatestRelease,
+    #[serde(untagged)]
+    Specific(String)
+}
+
+#[derive(Deserialize, Serialize, Debug, Clone)]
+pub struct Profile {
+    game_version: ProfileVersion,
+    java_runtime: Option<String>,
+    instance: String // ugly that this is a string instead of reference to an Instance but whatever I'm lazy
+}
+
+impl<P: AsRef<Path>> From<P> for Instance {
+    fn from(path: P) -> Self {
+        Self { path: path.as_ref().into() }
+    }
+}
+
+impl Instance {
+    pub async fn get_path(&self, home: impl AsRef<Path>) -> Result<PathBuf, io::Error> {
+        let path = self.path.as_path();
+
+        if path.is_relative() {
+            Ok([home.as_ref(), Path::new("instances"), path].iter().collect::<PathBuf>())
+        } else {
+            fs::canonicalize(path).await
+        }
+    }
+}
+
+impl Profile {
+    fn new(instance_name: &str) -> Self {
+        Self {
+            game_version: ProfileVersion::LatestRelease,
+            java_runtime: None,
+            instance: instance_name.into()
+        }
+    }
+
+    pub fn get_version(&self) -> &ProfileVersion {
+        &self.game_version
+    }
+
+    pub fn get_instance_name(&self) -> &str {
+        &self.instance
+    }
+}