use anyhow::Result;
use helix_core::Position;
use helix_view::args::parse_file;
use std::path::PathBuf;

#[derive(Default)]
pub struct Args {
    pub display_help: bool,
    pub display_version: bool,
    pub health: bool,
    pub health_arg: Option<String>,
    pub load_tutor: bool,
    pub fetch_grammars: bool,
    pub build_grammars: bool,
    pub verbosity: u64,
    pub files: Vec<(PathBuf, Position)>,
}

impl Args {
    pub fn parse_args() -> Result<Args> {
        let mut args = Args::default();
        let mut argv = std::env::args().peekable();

        argv.next(); // skip the program, we don't care about that

        while let Some(arg) = argv.next() {
            match arg.as_str() {
                "--" => break, // stop parsing at this point treat the remaining as files
                "--version" => args.display_version = true,
                "--help" => args.display_help = true,
                "--tutor" => args.load_tutor = true,
                "--health" => {
                    args.health = true;
                    args.health_arg = argv.next_if(|opt| !opt.starts_with('-'));
                }
                "-g" | "--grammar" => match argv.next().as_deref() {
                    Some("fetch") => args.fetch_grammars = true,
                    Some("build") => args.build_grammars = true,
                    _ => {
                        anyhow::bail!("--grammar must be followed by either 'fetch' or 'build'")
                    }
                },
                arg if arg.starts_with("--") => {
                    anyhow::bail!("unexpected double dash argument: {}", arg)
                }
                arg if arg.starts_with('-') => {
                    let arg = arg.get(1..).unwrap().chars();
                    for chr in arg {
                        match chr {
                            'v' => args.verbosity += 1,
                            'V' => args.display_version = true,
                            'h' => args.display_help = true,
                            _ => anyhow::bail!("unexpected short arg {}", chr),
                        }
                    }
                }
                arg => args.files.push(parse_file(arg)),
            }
        }

        // push the remaining args, if any to the files
        for arg in argv {
            args.files.push(parse_file(&arg));
        }

        Ok(args)
    }
}