use crate::*;
use std::time::Duration;
use std::thread::{spawn, JoinHandle};
use crossterm::event::{poll, read};
#[derive(Debug, Clone)] pub struct TuiIn(pub Arc<AtomicBool>, pub Event);
impl Input for TuiIn {
    type Event = Event;
    type Handled = bool;
    fn event   (&self) -> &Event { &self.1 }
    fn is_done (&self) -> bool { self.0.fetch_and(true, Relaxed) }
    fn done    (&self) { self.0.store(true, Relaxed); }
}
impl TuiIn {
    /// Spawn the input thread.
    pub fn run_input <T: Handle<TuiIn> + 'static> (
        engine: &Arc<RwLock<Tui>>,
        state:  &Arc<RwLock<T>>,
        timer:  Duration
    ) -> JoinHandle<()> {
        let exited = engine.read().unwrap().exited.clone();
        let state  = state.clone();
        spawn(move || loop {
            if exited.fetch_and(true, Relaxed) {
                break
            }
            if poll(timer).is_ok() {
                let event = read().unwrap();
                match event {

                    crossterm::event::Event::Key(KeyEvent {
                        code:      KeyCode::Char('c'),
                        modifiers: KeyModifiers::CONTROL,
                        kind:      KeyEventKind::Press,
                        state:     KeyEventState::NONE
                    }) => {
                        exited.store(true, Relaxed);
                    },
                    _ => {
                        let exited = exited.clone();
                        if let Err(e) = state.write().unwrap().handle(&TuiIn(exited, event)) {
                            panic!("{e}")
                        }
                    }
                }
            }
        })
    }
}
impl AtomInput for TuiIn {
    fn matches_atom (&self, token: &str) -> bool {
        if let Some(event) = KeyMatcher::new(token).build() {
            &event == self.event()
        } else {
            false
        }
    }
    //fn get_event (item: &AtomItem<impl AsRef<str>>) -> Option<Event> {
        //match item { AtomItem::Sym(s) => KeyMatcher::new(s).build(), _ => None }
    //}
}
struct KeyMatcher {
    valid: bool,
    key:   Option<KeyCode>,
    mods:  KeyModifiers,
}
impl KeyMatcher {
    fn new (token: impl AsRef<str>) -> Self {
        let token = token.as_ref();
        if token.len() < 2 {
            Self { valid: false, key: None, mods: KeyModifiers::NONE }
        } else if token.chars().next() != Some('@') {
            Self { valid: false, key: None, mods: KeyModifiers::NONE }
        } else {
            Self { valid: true, key: None, mods: KeyModifiers::NONE }.next(&token[1..])
        }
    }
    fn next (mut self, token: &str) -> Self {
        let mut tokens = token.split('-').peekable();
        while let Some(token) = tokens.next() {
            if tokens.peek().is_some() {
                match token {
                    "ctrl"  | "Ctrl"  | "c" | "C" => self.mods |= KeyModifiers::CONTROL,
                    "alt"   | "Alt"   | "m" | "M" => self.mods |= KeyModifiers::ALT,
                    "shift" | "Shift" | "s" | "S" => {
                        self.mods |= KeyModifiers::SHIFT;
                        // + TODO normalize character case, BackTab, etc.
                    },
                    _ => panic!("unknown modifier {token}"),
                }
            } else {
                self.key = if token.len() == 1 {
                    Some(KeyCode::Char(token.chars().next().unwrap()))
                } else {
                    Some(Self::named_key(token).unwrap_or_else(||panic!("unknown character {token}")))
                }
            }
        }
        self
    }
    fn named_key (token: &str) -> Option<KeyCode> {
        use KeyCode::*;
        Some(match token {
            "up"                => Up,
            "down"              => Down,
            "left"              => Left,
            "right"             => Right,
            "enter"  | "return" => Enter,
            "delete" | "del"    => Delete,
            "tab"               => Tab,
            "space"             => Char(' '),
            "comma"             => Char(','),
            "period"            => Char('.'),
            "plus"              => Char('+'),
            "minus" | "dash"    => Char('-'),
            "equal" | "equals"  => Char('='),
            "underscore"        => Char('_'),
            "backtick"          => Char('`'),
            "lt"                => Char('<'),
            "gt"                => Char('>'),
            "openbracket"       => Char('['),
            "closebracket"      => Char(']'),
            _ => return None,
        })
    }
    fn build (self) -> Option<Event> {
        if self.valid && self.key.is_some() {
            Some(Event::Key(KeyEvent::new(self.key.unwrap(), self.mods)))
        } else {
            None
        }
    }
}
#[cfg(test)] #[test] fn test_parse_key () {
    use KeyModifiers as Mods;
    let test = |x: &str, y|assert_eq!(KeyMatcher::new(x).build(), Some(Event::Key(y)));
    //test(":x",
        //KeyEvent::new(KeyCode::Char('x'), Mods::NONE));
    //test(":ctrl-x",
        //KeyEvent::new(KeyCode::Char('x'), Mods::CONTROL));
    //test(":alt-x",
        //KeyEvent::new(KeyCode::Char('x'), Mods::ALT));
    //test(":shift-x",
        //KeyEvent::new(KeyCode::Char('x'), Mods::SHIFT));
    //test(":ctrl-alt-shift-x",
        //KeyEvent::new(KeyCode::Char('x'), Mods::CONTROL | Mods::ALT | Mods::SHIFT ));
}