+use std::env;
+use std::fs::{create_dir_all, write, File};
+use std::io::{Read, Result};
+use std::path::PathBuf;
+use serde::{Deserialize, Serialize};
+use serde_json;
+
+const CONFIG_ENV_VARIABLE: &str = "LYRICLI_CONFIG_DIRECTORY";
+const CONFIG_DEFAULT_LOCATION: &str = "XDG_CONFIG_HOME";
+const CONFIG_FALLBACK_LOCATION: &str = ".config";
+const CONFIG_SUBDIRECTORY: &str = ".config";
+const CONFIG_FILENAME: &str = "lyricli.conf";
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct Configuration {
+ enabled_sources: Vec<String>
+}
+
+impl Configuration {
+
+ pub fn new() -> Self {
+
+ if let Some(configuration) = Configuration::read() {
+ return configuration;
+ }
+
+ let configuration = Configuration::default();
+
+ // Write the defaults.
+ Configuration::write(&configuration).ok();
+ configuration
+ }
+
+ // Public API
+
+ pub fn is_enabled(&self, source_name: &String) -> bool {
+ self.enabled_sources.contains(source_name)
+ }
+
+ pub fn enable_source(&mut self, source_name: &String) -> Result<()> {
+ if !self.enabled_sources.contains(source_name) {
+ self.enabled_sources.push(source_name.to_owned())
+ }
+ Configuration::write(self)
+ }
+
+ pub fn disable_source(&mut self, source_name: &String) -> Result<()> {
+ self.enabled_sources.retain(|source| source != source_name);
+ Configuration::write(self)
+ }
+
+ // Helpers
+
+ fn default() -> Configuration {
+ Configuration {
+ enabled_sources: vec![
+ "apple_music".to_string(),
+ "spotify".to_string()
+ ]
+ }
+ }
+
+ fn read() -> Option<Configuration> {
+ let config_file_path = Configuration::file_path();
+
+ let mut config_file = File::open(&config_file_path).ok()?;
+ let mut config_contents = String::new();
+ config_file.read_to_string(&mut config_contents).ok()?;
+ serde_json::from_str(&config_contents).ok()?
+ }
+
+ fn write(configuration: &Configuration) -> Result<()> {
+ let config_file_path = Configuration::file_path();
+ if let Ok(serialized_configuration) = serde_json::to_string(&configuration) {
+ write(&config_file_path, serialized_configuration)?;
+ }
+ Ok(())
+ }
+
+ fn file_path() -> PathBuf {
+ let config_directory = Configuration::directory();
+ create_dir_all(&config_directory).ok();
+ config_directory.join(CONFIG_FILENAME)
+ }
+
+ fn directory() -> PathBuf {
+ match env::var(CONFIG_ENV_VARIABLE) {
+ Ok(directory) => PathBuf::from(directory),
+ Err(_) => match env::var(CONFIG_DEFAULT_LOCATION) {
+ Ok(directory) => PathBuf::from(directory),
+ Err(_) => match env::var("HOME") {
+ Ok(directory) => PathBuf::from(directory).join(CONFIG_FALLBACK_LOCATION),
+ Err(_) => panic!("Could not find required directory, {} or {} should be set and readable.", CONFIG_ENV_VARIABLE, CONFIG_DEFAULT_LOCATION),
+ },
+ },
+ }.join(CONFIG_SUBDIRECTORY)
+ }
+}