use std::fs;
use std::env;
use serde::{Deserialize, Serialize};
use toml;

#[derive(Debug, Deserialize, Serialize)]
#[serde(rename_all = "lowercase")]
pub enum Loglevel {
    Trace,
    Debug,
    Info,
    Warn,
    Error
}


/// `mesk.toml` configuration fields here
#[derive(Deserialize, Debug, Serialize)]
pub struct Config {
    pub repo:     Repo,
    pub log:      Log,
    pub paths:    Paths,
}

#[derive(Deserialize, Debug, Serialize)]
pub struct Log {
    #[serde(rename = "log_file")]
    pub log_file: String,
    #[serde(rename = "log_level")]
    pub log_level: Loglevel,
}

// Rename needed for editing mesk.toml file fields but dont touch code. 
#[derive(Deserialize, Debug, Serialize)]
pub struct Repo {
    #[serde(rename = "repo_url")] 
    pub repo_url: String,
    #[serde(rename = "auto_update")] 
    pub auto_update: bool,
}

#[derive(Deserialize, Debug, Serialize)]
pub struct Paths {
    #[serde(rename = "cache_dir")] 
    pub cache_dir: String,
    #[serde(rename = "build_dir")] 
    pub build_dir: String,
}

impl Config {

    /// Parse the /etc/mesk.toml file and return the Config object.
    ///
    /// This function reads the /etc/mesk.toml file, parses it and returns the Config object.
    pub fn parse() -> Result<Config, toml::de::Error> {
        let contents = fs::read_to_string("/etc/mesk.toml").unwrap();
        let result: Config = toml::from_str(&contents)?;
        Ok(result)
    }


    /// Return the default configuration as a toml string.
    ///
    /// This function returns the default configuration as a toml string.
    pub fn default() -> Result<String, toml::ser::Error> {
        let default: Config = Config {
            repo: Repo {
                repo_url: format!("https://mesk.anthrill.i2p/repo/{}/",
                                       std::env::consts::ARCH), 
                auto_update: true,
            },
            log: Log {
                log_file: String::from("/var/log/mesk.log"),
                log_level: Loglevel::Info,
            },
            paths: Paths {
                cache_dir: String::from("/var/cache/mesk"),
                build_dir: String::from("/var/lib/mesk"),
            },
        };

        let toml_str = toml::to_string(&default)?;
        Ok(toml_str)
    }
}