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

#[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 =
        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)
}