use crate::*;

/// Configuration.
///
/// Contains mode, view, and bind definitions.
#[derive(Default, Debug)]
pub struct Config {
    pub dirs:  BaseDirectories,
    pub modes: Modes,
    pub views: Views,
    pub binds: Binds,
}

impl Config {
    const CONFIG: &'static str = "tek.edn";
    const DEFAULTS: &'static str = include_str!("./tek.edn");

    pub fn new (dirs: Option<BaseDirectories>) -> Self {
        Self {
            dirs: dirs.unwrap_or_else(||BaseDirectories::with_profile("tek", "v0")),
            ..Default::default()
        }
    }
    pub fn init (&mut self) -> Usually<()> {
        self.init_file(Self::CONFIG, Self::DEFAULTS, |cfgs, dsl|cfgs.load(&dsl))?;
        Ok(())
    }
    pub fn init_file (
        &mut self, path: &str, defaults: &str, mut each: impl FnMut(&mut Self, &str)->Usually<()>
    ) -> Usually<()> {
        if self.dirs.find_config_file(path).is_none() {
            println!("Creating {path:?}");
            std::fs::write(self.dirs.place_config_file(path)?, defaults)?;
        }
        Ok(if let Some(path) = self.dirs.find_config_file(path) {
            println!("Loading {path:?}");
            let src = std::fs::read_to_string(&path)?;
            src.as_str().each(move|item|each(self, item))?;
        } else {
            return Err(format!("{path}: not found").into())
        })
    }
    pub fn load (&mut self, dsl: impl Dsl) -> Usually<()> {
        dsl.each(|item|if let Some(expr) = item.expr()? {
            let head = expr.head()?;
            let tail = expr.tail()?;
            let name = tail.head()?;
            let body = tail.tail()?;
            println!("Config::load: {} {} {}", head.unwrap_or_default(), name.unwrap_or_default(), body.unwrap_or_default());
            match head {
                Some("mode") if let Some(name) = name =>
                    Mode::<Arc<str>>::load_into(&self.modes, &name, &body)?,
                Some("keys") if let Some(name) = name =>
                    EventMap::<TuiEvent, Arc<str>>::load_into(&self.binds, &name, &body)?,
                Some("view") if let Some(name) = name => {
                    self.views.write().unwrap().insert(name.into(), body.src()?.unwrap_or_default().into());
                },
                _ => return Err(format!("Config::load: expected view/keys/mode, got: {item:?}").into())
            }
            Ok(())
        } else {
            return Err(format!("Config::load: expected expr, got: {item:?}").into())
        })
    }
}