use std::env;
use config::File;
use serde::Deserialize;
use crate::err::AppError;
use crate::Result;

#[derive(Deserialize)]
pub struct MysqlConfig {
    pub dsn: String,
    pub max_cons: u32,
}


#[derive(Deserialize)]
pub struct WebConfig {
    pub addr: String,
}


#[derive(Deserialize)]
pub struct AppConfig {
    pub mysql: MysqlConfig,
    pub web: WebConfig,
}

impl AppConfig {
    pub fn new() -> Result<Self> {
        let run_mode = env::var("RUN_MODE").unwrap_or_else(|_| "dev".into());

        // https://github.com/mehcode/config-rs/blob/master/examples/hierarchical-env/settings.rs
        config::Config::builder()
            // Start off by merging in the "default" configuration file
            .add_source(File::with_name("config/default"))
            // Add in the current environment file
            // Default to 'dev' env
            // Note that this file is _optional_
            .add_source(
                File::with_name(&format!("config/{}", run_mode)).required(false),
            )
            .build()
            .map_err(AppError::from)?
            .try_deserialize()
            .map_err(AppError::from)
    }
}