Implement better error system and segregate errors and commands (#23)

* chore: Progress on amend_settings command

Signed-off-by: quexeky <git@quexeky.dev>

* chore(errors): Progress on better error handling with segragation of files

* chore: Progress on amend_settings command

Signed-off-by: quexeky <git@quexeky.dev>

* chore(commands): Separated commands under each subdirectory into respective commands.rs files

Signed-off-by: quexeky <git@quexeky.dev>

* chore(errors): Almost all errors and commands have been segregated

* chore(errors): Added drop server error

Signed-off-by: quexeky <git@quexeky.dev>

* feat(core): Update to using nightly compiler

Signed-off-by: quexeky <git@quexeky.dev>

* chore(errors): More progress on error handling

Signed-off-by: quexeky <git@quexeky.dev>

* chore(errors): Implementing Try and FromResidual for UserValue

Signed-off-by: quexeky <git@quexeky.dev>

* refactor(errors): Segregated errors and commands from code, and made commands return UserValue struct

Signed-off-by: quexeky <git@quexeky.dev>

* fix(errors): Added missing files

* chore(errors): Convert match statement to map_err

* feat(settings): Implemented settings editing from UI

* feat(errors): Clarified return values from retry_connect command

* chore(errors): Moved autostart commands to autostart.rs

* chore(process manager): Converted launch_process function for games to use game_id

---------

Signed-off-by: quexeky <git@quexeky.dev>

src-tauri/src/database/commands.rs

@@ -0,0 +1,83 @@
+use std::{
+    fs::create_dir_all,
+    io::{Error, ErrorKind},
+    path::{Path, PathBuf},
+};
+
+use serde_json::Value;
+
+use crate::{database::settings::Settings, error::user_error::UserValue, DB};
+
+use super::{db::DATA_ROOT_DIR, debug::SystemData};
+
+// Will, in future, return disk/remaining size
+// Just returns the directories that have been set up
+#[tauri::command]
+pub fn fetch_download_dir_stats() -> Vec<PathBuf> {
+    let lock = DB.borrow_data().unwrap();
+    lock.applications.install_dirs.clone()
+}
+
+#[tauri::command]
+pub fn delete_download_dir(index: usize) {
+    let mut lock = DB.borrow_data_mut().unwrap();
+    lock.applications.install_dirs.remove(index);
+    drop(lock);
+    DB.save().unwrap();
+}
+
+#[tauri::command]
+pub fn add_download_dir(new_dir: PathBuf) -> UserValue<(), Error> {
+    // Check the new directory is all good
+    let new_dir_path = Path::new(&new_dir);
+    if new_dir_path.exists() {
+        let dir_contents = new_dir_path.read_dir()?;
+        if dir_contents.count() != 0 {
+            return UserValue::Err(Error::new(
+                ErrorKind::DirectoryNotEmpty,
+                "Selected directory cannot contain any existing files",
+            ));
+        }
+    } else {
+        create_dir_all(new_dir_path)?;
+    }
+
+    // Add it to the dictionary
+    let mut lock = DB.borrow_data_mut().unwrap();
+    if lock.applications.install_dirs.contains(&new_dir) {
+        return UserValue::Err(Error::new(
+            ErrorKind::AlreadyExists,
+            "Selected directory already exists in database",
+        ));
+    }
+    lock.applications.install_dirs.push(new_dir);
+    drop(lock);
+    DB.save().unwrap();
+
+    UserValue::Ok(())
+}
+
+#[tauri::command]
+pub fn update_settings(new_settings: Value) {
+    println!("{}", new_settings);
+    let mut db_lock = DB.borrow_data_mut().unwrap();
+    let mut current_settings = serde_json::to_value(db_lock.settings.clone()).unwrap();
+    for (key, value) in new_settings.as_object().unwrap() {
+        current_settings[key] = value.clone();
+    }
+    println!("New settings unset: {}", &current_settings);
+    let new_settings: Settings = serde_json::from_value(current_settings).unwrap();
+    db_lock.settings = new_settings;
+    println!("New Settings: {:?}", db_lock.settings);
+}
+
+#[tauri::command]
+pub fn fetch_system_data() -> SystemData {
+    let db_handle = DB.borrow_data().unwrap();
+    SystemData::new(
+        db_handle.auth.as_ref().unwrap().client_id.clone(),
+        db_handle.base_url.clone(),
+        DATA_ROOT_DIR.lock().unwrap().to_string_lossy().to_string(),
+        std::env::var("RUST_LOG").unwrap_or_else(|_| "info".to_string()),
+    )
+}