use std::path::Path;

use figment::{
    Figment,
    providers::{Env, Format, Toml},
};

use crate::AppConfig;
use crate::error::ConfigError;

pub const ENV_PREFIX: &str = "APP_";
pub const ENV_SEPARATOR: &str = "__";
pub const DEFAULT_CONFIG_PATH: &str = "config/default.toml";
pub const LOCAL_CONFIG_PATH: &str = "config/local.toml";

pub fn figment() -> Figment {
    let _ = dotenvy::dotenv();

    let mut figment = Figment::new();
    if Path::new(DEFAULT_CONFIG_PATH).exists() {
        figment = figment.merge(Toml::file(DEFAULT_CONFIG_PATH));
    }
    if Path::new(LOCAL_CONFIG_PATH).exists() {
        figment = figment.merge(Toml::file(LOCAL_CONFIG_PATH));
    }
    figment.merge(Env::prefixed(ENV_PREFIX).split(ENV_SEPARATOR))
}

pub fn load_default() -> Result<AppConfig, ConfigError> {
    let cfg: AppConfig = figment().extract().map_err(ConfigError::from)?;
    cfg.validate()?;
    Ok(cfg)
}

pub fn load_from_env() -> Result<AppConfig, ConfigError> {
    let _ = dotenvy::dotenv();
    let figment = Figment::new().merge(Env::prefixed(ENV_PREFIX).split(ENV_SEPARATOR));
    let cfg: AppConfig = figment.extract().map_err(ConfigError::from)?;
    cfg.validate()?;
    Ok(cfg)
}