Add Config System instead of hardcoding values

Config is read from `$XDG_CONFIG_DIRECTORY/ibis/config.toml`
falling back to `~/.config/ibis/config.toml` if `$XDG_CONFIG_DIRECTORY`
is not set.

Cargo.toml

@@ -16,6 +16,8 @@ glob = "0.3"
 anyhow = "1"
 chrono = {version = "0.4.19", features = ["serde"]}
 rofi = {version = "0.2", optional = true}
+lazy_static = "1.4.0"
+directories = "4.0.1"
 
 [lib]
 name = "ibis"

src/config.rs

@@ -1,14 +1,83 @@
-use serde::{Deserialize, Serialize};
+use directories::{BaseDirs, ProjectDirs};
+use serde::{de::Error, Deserialize, Deserializer, Serialize};
 use std::path::PathBuf;
 use structopt::StructOpt;
 
-#[derive(Serialize, Deserialize)]
+lazy_static! {
+    pub static ref CONFIG: Config = {
+        let config_path = ProjectDirs::from("", "Phobos", "ibis")
+            .expect("no valid home directory found")
+            .config_dir()
+            .to_owned()
+            .join("config.toml");
+        if !config_path.exists() {
+            return Config::default();
+        }
+        let config_str = std::fs::read_to_string(&config_path);
+        if let Ok(config_str) = config_str {
+            toml::from_str(&config_str).unwrap_or_else(|e| {
+                panic!("Error while parsing config at {:?} \n{}", &config_path, e);
+            })
+        } else {
+            panic!(
+                "Error while reading config at {:?}\n{}",
+                &config_path,
+                config_str.unwrap_err()
+            );
+        }
+    };
+}
+
+/// A struct representing the config options
+#[derive(Serialize, Deserialize, Debug)]
 pub struct Config {
+    /// The location of the link pointing to the current course.
+    /// This is treated as the single source of truth as to what the current course is.
+    /// This needs to be a absolute path.
+    #[serde(deserialize_with = "ensure_absolute_path")]
     pub link_path: PathBuf,
+    /// The folder under which all other folders of "courses" are located.
+    /// "courses" are folders containing a `course.toml`
+    /// This needs to be an absolute path.
+    #[serde(deserialize_with = "ensure_absolute_path")]
     pub files_root: PathBuf,
+    /// File extensions that should be treated as lecture notes
     pub note_extensions: Vec<String>,
 }
 
+fn ensure_absolute_path<'de, D>(deserializer: D) -> Result<PathBuf, D::Error>
+where
+    D: Deserializer<'de>,
+    D::Error: Error,
+{
+    let path = PathBuf::deserialize(deserializer)?;
+    if path.is_absolute() {
+        Ok(path)
+    } else {
+        Err(D::Error::invalid_value(
+            serde::de::Unexpected::Str(path.to_string_lossy().as_ref()),
+            &"an absolute path",
+        ))
+    }
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        let home = BaseDirs::new()
+            .expect("no valid home directory found")
+            .home_dir()
+            .to_owned();
+        Self {
+            link_path: home.join("current-course"),
+            files_root: home
+                .join("uni")
+                .canonicalize()
+                .expect("\"~/uni\" could not be canonicalized"),
+            note_extensions: vec![String::from("tex"), String::from("md"), String::from("org")],
+        }
+    }
+}
+
 #[derive(StructOpt, Default)]
 pub struct ListOptions {
     #[structopt(short, long)]

src/courses.rs

@@ -1,4 +1,4 @@
-use crate::config::{Config, ListOptions};
+use crate::config::{ListOptions, CONFIG};
 use crate::util;
 use anyhow::Result;
 use glob::glob;
@@ -53,16 +53,17 @@ impl Course {
         &self.meetings
     }
 
-    pub fn set(&self, conf: &Config) -> Result<()> {
-        remove_file(&conf.link_path)?;
-        symlink(&self.path, &conf.link_path)?;
+    pub fn set(&self) -> Result<()> {
+        // TODO: make sure this is actually a link, and we are not removing some other file of the user
+        remove_file(&CONFIG.link_path)?;
+        symlink(&self.path, &CONFIG.link_path)?;
         Ok(())
     }
 
-    pub fn list(conf: &Config, options: &ListOptions) -> Result<CourseList> {
+    pub fn list(options: &ListOptions) -> Result<CourseList> {
         let mut courses: Vec<Course> = vec![];
         let pattern = [
-            conf.files_root.canonicalize().unwrap().to_str().unwrap(),
+            CONFIG.files_root.canonicalize().unwrap().to_str().unwrap(),
             "/*/course.toml",
         ]
         .concat();
@@ -82,9 +83,9 @@ impl Course {
         Ok(CourseList::new(courses))
     }
 
-    pub fn check(conf: &Config, list_options: &ListOptions) -> Result<()> {
+    pub fn check(list_options: &ListOptions) -> Result<()> {
         let mut problematic_course_count = 0;
-        let toml_list = Self::list(conf, list_options)?;
+        let toml_list = Self::list(list_options)?;
         println!("Checking course.toml's");
         for c in toml_list.iter() {
             let mut problems = Vec::new();

src/lib.rs

@@ -1,3 +1,6 @@
+#[macro_use]
+extern crate lazy_static;
+
 pub mod config;
 pub mod courses;
 pub mod rofi;

src/main.rs

@@ -4,8 +4,8 @@ use std::io::prelude::*;
 use std::path::PathBuf;
 use structopt::StructOpt;
 
-use ibis::config::{Config, ListOptions};
-use ibis::courses::Course;
+use ibis::config::{ListOptions, CONFIG};
+use ibis::courses::{Course, Meeting};
 use ibis::{rofi, util};
 
 #[derive(StructOpt)]
@@ -18,6 +18,7 @@ struct Cli {
 
 #[derive(StructOpt)]
 enum Command {
+    ShowConfig,
     ListCourses(ListOptions),
     ListLectures(ListOptions),
     SelectCourse(ListOptions),
@@ -41,42 +42,36 @@ enum Object {
 }
 
 fn main() -> Result<()> {
-    let conf = Config {
-        link_path: PathBuf::from("/home/jana/current-course"),
-        files_root: PathBuf::from("/home/jana/uni"),
-        note_extensions: vec![String::from("tex"), String::from("md"), String::from("org")],
-    };
     let args = Cli::from_args();
     match args.cmd {
-        // Some(subcommand) => match subcommand {
         Command::ListCourses(options) => {
-            for c in Course::list(&conf, &options)?.iter() {
+            for c in Course::list(&options)?.iter() {
                 println!("{}", c);
             }
         }
         Command::ListLectures(options) => {
-            for l in list_lectures(&conf, options)? {
+            for l in list_lectures(options)? {
                 println!("{:?}", l);
             }
         }
-        Command::AddCourse(course) => add(course, &conf, args.debug)?,
+        Command::AddCourse(course) => add(course, args.debug)?,
         Command::AddLecture => (),
-        Command::SelectCourse(options) => rofi::select_course(&conf, &options)?,
+        Command::SelectCourse(options) => rofi::select_course(&options)?,
         Command::SelectLecture => (),
         Command::Init => (),
-        Command::Check(list_options) => Course::check(&conf, &list_options)?,
-        Command::Meetings(options) => rofi::select_meeting(&conf, &options)?,
-        //},
-        // None => println!("No command given"),
+        Command::Check(list_options) => Course::check(&list_options)?,
+        Command::Meetings(options) => rofi::select_meeting(&options)?,
+        Command::ShowConfig => println!("{:?}", *CONFIG),
     };
     Ok(())
 }
 
-fn add(course: Course, conf: &Config, debug: bool) -> Result<()> {
+fn add(course: Course, debug: bool) -> Result<()> {
     let toml = toml::to_string(&course)?;
     println!("{}", toml);
     let target_dir = [
-        conf.files_root
+        CONFIG
+            .files_root
             .canonicalize()?
             .to_str()
             .expect("I hate paths"), // TODO
@@ -86,9 +81,9 @@ fn add(course: Course, conf: &Config, debug: bool) -> Result<()> {
     .concat();
     let toml_path = PathBuf::from([&target_dir, "/course.toml"].concat());
     if !(cfg!(debug_assertions) || debug) {
-        if !conf.files_root.is_dir() {
-            std::fs::create_dir_all(conf.files_root.canonicalize().with_context(|| {
-                format!("The root path {:?} seems malformed", conf.files_root)
+        if !CONFIG.files_root.is_dir() {
+            std::fs::create_dir_all(CONFIG.files_root.canonicalize().with_context(|| {
+                format!("The root path {:?} seems malformed", CONFIG.files_root)
             })?)?;
         }
         if !PathBuf::from(&target_dir).is_dir() {
@@ -104,12 +99,12 @@ fn add(course: Course, conf: &Config, debug: bool) -> Result<()> {
     Ok(())
 }
 
-fn list_lectures(conf: &Config, options: ListOptions) -> Result<Vec<PathBuf>> {
+fn list_lectures(options: ListOptions) -> Result<Vec<PathBuf>> {
     let lectures = util::glob_paths(
         if options.all {
-            &conf.files_root
+            &CONFIG.files_root
         } else {
-            &conf.link_path
+            &CONFIG.link_path
         },
         "/**/lecture*",
     );
@@ -119,7 +114,7 @@ fn list_lectures(conf: &Config, options: ListOptions) -> Result<Vec<PathBuf>> {
         .filter(|path| {
             if let Some(ext) = path.extension() {
                 let ext = ext.to_owned().to_string_lossy().into();
-                conf.note_extensions.contains(&ext)
+                CONFIG.note_extensions.contains(&ext)
             } else {
                 false
             }

src/rofi.rs

@@ -1,4 +1,3 @@
-use crate::config::Config;
 use crate::{config::ListOptions, courses::*};
 use anyhow::Result;
 use rofi::Rofi;
@@ -6,18 +5,18 @@ use std::io::Write;
 use std::process::Command;
 use std::process::Stdio;
 
-pub fn select_course(conf: &Config, options: &ListOptions) -> Result<()> {
-    let courses = Course::list(conf, options)?;
+pub fn select_course(options: &ListOptions) -> Result<()> {
+    let courses = Course::list(options)?;
     let course_names: Vec<_> = courses.iter().map(|c| &c.name).collect();
     let element = Rofi::new(&course_names).run_index()?;
     courses
         .get(element)
         .expect("Could not find selected Course")
-        .set(conf)
+        .set()
 }
 
-pub fn select_meeting(conf: &Config, options: &ListOptions) -> Result<()> {
-    let meetings: Vec<_> = Course::list(conf, options)?
+pub fn select_meeting(options: &ListOptions) -> Result<()> {
+    let meetings: Vec<_> = Course::list(options)?
         .iter()
         .cloned()
         .flat_map(|c: Course| {