//! Copyright (C) 2022, Dmitriy Pleshevskiy <dmitriy@ideascup.me>
//!
//! vnetod is free software: you can redistribute it and/or modify
//! it under the terms of the GNU General Public License as published by
//! the Free Software Foundation, either version 3 of the License, or
//! (at your option) any later version.
//!
//! vnetod is distributed in the hope that it will be useful,
//! but WITHOUT ANY WARRANTY; without even the implied warranty of
//! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//! GNU General Public License for more details.
//!
//! You should have received a copy of the GNU General Public License
//! along with vnetod.  If not, see <https://www.gnu.org/licenses/>.
//!

use crate::{cli::Args, domain};
use std::fs::File;
use std::io::{stdout, Write};

#[derive(Debug)]
pub enum Error {
    OpenFile,
    Switch(domain::switch::Error),
}

impl std::fmt::Display for Error {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Error::OpenFile => f.write_str("Cannot open file"),
            Error::Switch(inner) => write!(f, "Cannot switch between states: {}", inner),
        }
    }
}

impl std::error::Error for Error {}

pub fn execute(args: &Args) -> Result<(), Error> {
    let content = std::fs::read_to_string(&args.file).map_err(|_| Error::OpenFile)?;

    let writer: Box<dyn Write> = if args.dry_run {
        Box::new(stdout())
    } else {
        Box::new(
            File::create(args.output.as_ref().unwrap_or(&args.file))
                .map_err(|_| Error::OpenFile)?,
        )
    };

    domain::switch::execute(domain::switch::Request {
        content: &content,
        writer,
        sections: &args.sections,
    })
    .map_err(Error::Switch)
}