Create a configuration system for the Kifu (#46)

This is a nice, typesafe configuration system.

Co-authored-by: Savanni D'Gerinel <savanni@luminescent-dreams.com>
Reviewed-on: savanni/tools#46

kifu/core/Cargo.lock

@@ -163,6 +163,7 @@ version = "0.1.0"
 dependencies = [
  "grid",
  "serde",
+ "serde_json",
  "thiserror",
  "typeshare",
 ]

kifu/core/Cargo.toml

@@ -8,5 +8,6 @@ edition = "2021"
 [dependencies]
 grid        = { version = "0.9" }
 serde       = { version = "1", features = [ "derive" ] }
+serde_json  = { version = "1" }
 thiserror   = { version = "1" }
 typeshare   = { version = "1" }

kifu/core/src/api.rs

@@ -1,6 +1,7 @@
 use crate::{
     types::{AppState, GameState, Player, Rank},
     ui::{new_game, playing_field, NewGameView, PlayingFieldView},
+    Config,
 };
 use serde::{Deserialize, Serialize};
 use std::sync::{Arc, RwLock};
@@ -64,14 +65,16 @@ pub enum CoreResponse {
 
 #[derive(Clone, Debug)]
 pub struct CoreApp {
+    config: Config,
     state: Arc<RwLock<AppState>>,
 }
 
 impl CoreApp {
-    pub fn new() -> Self {
+    pub fn new(config_path: std::path::PathBuf) -> Self {
+        let config = Config::from_path(config_path).expect("configuration to open");
         let state = Arc::new(RwLock::new(AppState::new()));
 
-        Self { state }
+        Self { config, state }
     }
 
     pub async fn dispatch(&self, request: CoreRequest) -> CoreResponse {

kifu/core/src/config.rs

@@ -0,0 +1,139 @@
+use crate::types::Player;
+use serde::{Deserialize, Serialize};
+use std::{
+    collections::HashMap,
+    fs::File,
+    io::{ErrorKind, Read},
+    path::PathBuf,
+};
+use thiserror::Error;
+
+/*
+pub trait ConfigOption {
+    type Value;
+}
+
+pub struct DatabasePath(PathBuf);
+
+impl ConfigOption for DatabasePath {
+    type Value = PathBuf;
+}
+
+impl ConfigOption for Player {
+    type Value = Player;
+}
+
+pub trait Config {
+    // fn set_option(option: ConfigOption);
+    fn get_option<N, C: ConfigOption>(name: Name) -> C<Name = Name>
+}
+*/
+
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
+enum OptionNames {
+    DatabasePath,
+    Me,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub enum ConfigOption {
+    DatabasePath(DatabasePath),
+    Me(Me),
+}
+
+#[derive(Debug, Error)]
+pub enum ConfigReadError {
+    #[error("Cannot read the configuration file: {0}")]
+    CannotRead(std::io::Error),
+    #[error("Cannot open the configuration file for reading: {0}")]
+    CannotOpen(std::io::Error),
+    #[error("Invalid json data found in the configurationfile: {0}")]
+    InvalidJSON(serde_json::Error),
+}
+
+#[derive(Clone, Debug)]
+pub struct Config {
+    config_path: PathBuf,
+    values: HashMap<OptionNames, ConfigOption>,
+}
+
+impl Config {
+    pub fn new(config_path: PathBuf) -> Self {
+        Self {
+            config_path,
+            values: HashMap::new(),
+        }
+    }
+
+    pub fn from_path(config_path: PathBuf) -> Result<Self, ConfigReadError> {
+        let mut settings = config_path.clone();
+        settings.push("config");
+
+        match File::open(settings) {
+            Ok(mut file) => {
+                let mut buf = String::new();
+                file.read_to_string(&mut buf)
+                    .map_err(|err| ConfigReadError::CannotRead(err))?;
+                let values = serde_json::from_str(buf.as_ref())
+                    .map_err(|err| ConfigReadError::InvalidJSON(err))?;
+                Ok(Self {
+                    config_path,
+                    values,
+                })
+            }
+            Err(io_err) => {
+                match io_err.kind() {
+                    ErrorKind::NotFound => {
+                        /* create the path and an empty file */
+                        Ok(Self {
+                            config_path,
+                            values: HashMap::new(),
+                        })
+                    }
+                    _ => Err(ConfigReadError::CannotOpen(io_err)),
+                }
+            }
+        }
+    }
+
+    fn set(&mut self, val: ConfigOption) {
+        let _ = match val {
+            ConfigOption::DatabasePath(_) => self.values.insert(OptionNames::DatabasePath, val),
+            ConfigOption::Me(_) => self.values.insert(OptionNames::Me, val),
+        };
+    }
+
+    fn get<'a, T>(&'a self) -> T
+    where
+        T: From<&'a Self>,
+    {
+        self.into()
+    }
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct DatabasePath(PathBuf);
+
+impl From<&Config> for DatabasePath {
+    fn from(config: &Config) -> Self {
+        match config.values.get(&OptionNames::DatabasePath) {
+            Some(ConfigOption::DatabasePath(path)) => path.clone(),
+            _ => DatabasePath(config.config_path.clone()),
+        }
+    }
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct Me(Player);
+
+impl From<&Config> for Option<Me> {
+    fn from(config: &Config) -> Self {
+        config
+            .values
+            .get(&OptionNames::Me)
+            .and_then(|val| match val {
+                ConfigOption::Me(me) => Some(me.clone()),
+                _ => None,
+            })
+    }
+}

kifu/core/src/lib.rs

@@ -9,3 +9,6 @@ pub mod ui;
 
 mod board;
 pub use board::*;
+
+mod config;
+pub use config::*;

kifu/core/src/types.rs

@@ -91,7 +91,7 @@ impl From<Rank> for String {
     }
 }
 
-#[derive(Debug)]
+#[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct Player {
     pub name: String,
     pub rank: Option<Rank>,

kifu/gtk/Cargo.lock

@@ -787,6 +787,7 @@ version = "0.1.0"
 dependencies = [
  "grid",
  "serde",
+ "serde_json",
  "thiserror",
  "typeshare",
 ]

kifu/gtk/src/main.rs

@@ -44,7 +44,12 @@ fn main() {
             .unwrap(),
     );
 
-    let core = CoreApp::new();
+    let user_home = std::env::var("HOME").expect("the user's home directory isn't set");
+    let mut config_path = std::path::PathBuf::from(user_home);
+    config_path.push(".config");
+    config_path.push("kifu");
+
+    let core = CoreApp::new(config_path);
 
     let core_handle = runtime.spawn({
         let core = core.clone();