use crate::{EnvironmentFile};
use std::fmt::Display;
use std::fs::File;
use std::io::Read;
use std::path::Path;

#[derive(Debug, thiserror::Error)]
#[allow(clippy::enum_variant_names)]
pub enum EnvFsError {
	#[error(transparent)]
	IoError(#[from] std::io::Error),
	#[error(transparent)]
	ParseError(#[from] crate::EnvironmentFileError),
	#[error("The target environment variable exists, but is not Unicode")]
	EnvironmentError,
}

pub fn env_file() -> Result<EnvironmentFile, EnvFsError> {
	env_file_from_path(".env")
}

pub fn env_file_suffix(environment: impl Display) -> Result<EnvironmentFile, EnvFsError> {
	env_file_from_path(format!(".env.{}", environment))
}

pub fn env_file_from_path(path: impl AsRef<Path>) -> Result<EnvironmentFile, EnvFsError> {
	let mut file = File::open(path)?;
	let mut buffer = String::new();
	file.read_to_string(&mut buffer)?;
	Ok(buffer.parse()?)
}

pub fn dotenv() -> Result<(), EnvFsError> {
	let file = env_file()?;
	file.apply().map_err(|_| EnvFsError::EnvironmentError)
}

pub fn dotenv_suffix(environment: impl Display) -> Result<(), EnvFsError> {
	let file = env_file_suffix(environment)?;
	file.apply().map_err(|_| EnvFsError::EnvironmentError)
}

pub fn dotenv_from(path: impl AsRef<Path>) -> Result<(), EnvFsError> {
	let file = env_file_from_path(path)?;
	file.apply().map_err(|_| EnvFsError::EnvironmentError)
}