use crate::platform::{self, Platform};
use crate::result::{Context, Result};

pub enum Mode {
    Spawn,
    Exec,
}

pub struct Config {
    pub platform: Option<Box<dyn Platform>>,
    pub mode: Mode,
    pub target: String,
}

pub fn get_config() -> Result<Config> {
    let mut values = std::collections::HashMap::<&str, String>::new();
    let cmdline = std::fs::read_to_string("/proc/cmdline")
        .context(format_args!("could not read kernel cmdline"))?;

    for word in cmdline.split_whitespace() {
        if let Some((lhs, rhs)) = word.split_once('=') {
            if let Some(("nit", name)) = lhs.split_once('.') {
                values.insert(name, rhs.to_string());
            }
        }
    }

    let mode = if let Some(mode) = values.remove("mode") {
        match &*mode {
            "spawn" => Mode::Spawn,
            "exec" => Mode::Exec,
            m => panic!("Bad mode: {m}"),
        }
    } else {
        Mode::Spawn
    };

    let platform = platform::get_current_platform(values.remove("platform").as_deref())?;

    let target = values.remove("target").unwrap();

    Ok(Config { platform, mode, target })
}