keybinding.rs

use std::{collections::HashMap, path::PathBuf};

use color_eyre::eyre::Result;
use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
use derive_deref::{Deref, DerefMut};
use serde::{de::Deserializer, Deserialize};

use crate::{action::Action, mode::Mode};

const DEFAULT_KEY_CONFIG: &str = include_str!("../assets/keybinding.toml");

pub type KeyBindingHelps = HashMap<Mode, HashMap<Action, Vec<String>>>;

#[derive(Clone, Debug, Default, Deref, DerefMut)]
pub struct KeyBindings(pub HashMap<Mode, HashMap<Vec<KeyEvent>, Action>>);
impl KeyBindings {
    pub fn new(user_keybinding: Option<PathBuf>) -> Result<Self, config::ConfigError> {
        let mut keybindings: KeyBindings = toml::from_str(DEFAULT_KEY_CONFIG).unwrap();

        if let Some(user_keybinding) = user_keybinding
            && let Ok(content) = std::fs::read_to_string(user_keybinding)
        {
            let mut loaded_keybindings: KeyBindings = toml::from_str(&content).unwrap();
            log::trace!("Loaded keybindings:\n{loaded_keybindings:#?}");

            for (mode, bindings) in loaded_keybindings.iter_mut() {
                let user_bindings = keybindings.entry(*mode).or_default();
                for (key, cmd) in bindings.iter() {
                    user_bindings
                        .entry(key.clone())
                        .or_insert_with(|| cmd.clone());
                }
            }
        }

        log::debug!("Final keybindings:\n{keybindings:#?}");

        Ok(keybindings)
    }
    pub fn help_info(&self) -> KeyBindingHelps {
        let mut help = KeyBindingHelps::new();
        for (m, keybinding) in self.0.iter() {
            let mut mod_keybinding = HashMap::<Action, Vec<String>>::new();
            for (key_events, value) in keybinding {
                if let Some(key_list) = mod_keybinding.get_mut(value) {
                    key_list.push(key_events_to_string(key_events));
                } else {
                    mod_keybinding.insert(value.clone(), vec![key_events_to_string(key_events)]);
                }
            }
            help.insert(*m, mod_keybinding);
        }
        help
    }
}

fn key_events_to_string(key_events: &Vec<KeyEvent>) -> String {
    let mut out = String::new();
    for key_event in key_events {
        out.push('<');
        if !key_event.modifiers.is_empty() {
            for m in key_event.modifiers.iter_names() {
                out += m.0;
                out.push('+');
            }
        }
        out += &key_event_to_string(key_event);
        out.push('>');
    }
    out
}

impl<'de> Deserialize<'de> for KeyBindings {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        let parsed_map = HashMap::<Mode, HashMap<String, Action>>::deserialize(deserializer)?;

        let keybindings = parsed_map
            .into_iter()
            .map(|(mode, inner_map)| {
                let converted_inner_map = inner_map
                    .into_iter()
                    .map(|(key_str, cmd)| (parse_key_sequence(&key_str).unwrap(), cmd))
                    .collect();
                (mode, converted_inner_map)
            })
            .collect();

        Ok(KeyBindings(keybindings))
    }
}

fn parse_key_event(raw: &str) -> Result<KeyEvent, String> {
    let raw_lower = raw.to_ascii_lowercase();
    let (remaining, modifiers) = extract_modifiers(&raw_lower);
    parse_key_code_with_modifiers(remaining, modifiers)
}

fn extract_modifiers(raw: &str) -> (&str, KeyModifiers) {
    let mut modifiers = KeyModifiers::empty();
    let mut current = raw;

    loop {
        match current {
            rest if rest.starts_with("ctrl-") => {
                modifiers.insert(KeyModifiers::CONTROL);
                current = &rest[5..];
            }
            rest if rest.starts_with("alt-") => {
                modifiers.insert(KeyModifiers::ALT);
                current = &rest[4..];
            }
            rest if rest.starts_with("shift-") => {
                modifiers.insert(KeyModifiers::SHIFT);
                current = &rest[6..];
            }
            _ => break, // break out of the loop if no known prefix is detected
        };
    }

    (current, modifiers)
}

fn parse_key_code_with_modifiers(
    raw: &str,
    mut modifiers: KeyModifiers,
) -> Result<KeyEvent, String> {
    let c = match raw {
        "esc" => KeyCode::Esc,
        "enter" => KeyCode::Enter,
        "left" => KeyCode::Left,
        "right" => KeyCode::Right,
        "up" => KeyCode::Up,
        "down" => KeyCode::Down,
        "home" => KeyCode::Home,
        "end" => KeyCode::End,
        "pageup" => KeyCode::PageUp,
        "pagedown" => KeyCode::PageDown,
        "backtab" => {
            modifiers.insert(KeyModifiers::SHIFT);
            KeyCode::BackTab
        }
        "backspace" => KeyCode::Backspace,
        "delete" => KeyCode::Delete,
        "insert" => KeyCode::Insert,
        "f1" => KeyCode::F(1),
        "f2" => KeyCode::F(2),
        "f3" => KeyCode::F(3),
        "f4" => KeyCode::F(4),
        "f5" => KeyCode::F(5),
        "f6" => KeyCode::F(6),
        "f7" => KeyCode::F(7),
        "f8" => KeyCode::F(8),
        "f9" => KeyCode::F(9),
        "f10" => KeyCode::F(10),
        "f11" => KeyCode::F(11),
        "f12" => KeyCode::F(12),
        "space" => KeyCode::Char(' '),
        "hyphen" => KeyCode::Char('-'),
        "minus" => KeyCode::Char('-'),
        "tab" => KeyCode::Tab,
        c if c.len() == 1 => {
            let mut c = c.chars().next().unwrap();
            if modifiers.contains(KeyModifiers::SHIFT) {
                c = c.to_ascii_uppercase();
            }
            KeyCode::Char(c)
        }
        _ => return Err(format!("Unable to parse {raw}")),
    };
    Ok(KeyEvent::new(c, modifiers))
}

pub fn key_event_to_string(key_event: &KeyEvent) -> String {
    let char;
    let key_code = match key_event.code {
        KeyCode::Backspace => "backspace",
        KeyCode::Enter => "enter",
        KeyCode::Left => "left",
        KeyCode::Right => "right",
        KeyCode::Up => "up",
        KeyCode::Down => "down",
        KeyCode::Home => "home",
        KeyCode::End => "end",
        KeyCode::PageUp => "pageup",
        KeyCode::PageDown => "pagedown",
        KeyCode::Tab => "tab",
        KeyCode::BackTab => "backtab",
        KeyCode::Delete => "delete",
        KeyCode::Insert => "insert",
        KeyCode::F(c) => {
            char = format!("f({c})");
            &char
        }
        KeyCode::Char(' ') => "space",
        KeyCode::Char(c) => {
            char = c.to_string();
            &char
        }
        KeyCode::Esc => "esc",
        KeyCode::Null => "",
        KeyCode::CapsLock => "",
        KeyCode::Menu => "",
        KeyCode::ScrollLock => "",
        KeyCode::Media(_) => "",
        KeyCode::NumLock => "",
        KeyCode::PrintScreen => "",
        KeyCode::Pause => "",
        KeyCode::KeypadBegin => "",
        KeyCode::Modifier(_) => "",
    };

    let mut modifiers = Vec::with_capacity(3);

    if key_event.modifiers.intersects(KeyModifiers::CONTROL) {
        modifiers.push("ctrl");
    }

    if key_event.modifiers.intersects(KeyModifiers::SHIFT) {
        modifiers.push("shift");
    }

    if key_event.modifiers.intersects(KeyModifiers::ALT) {
        modifiers.push("alt");
    }

    let mut key = modifiers.join("-");

    if !key.is_empty() {
        key.push('-');
    }
    key.push_str(key_code);

    key
}

pub fn parse_key_sequence(raw: &str) -> Result<Vec<KeyEvent>, String> {
    if raw.chars().filter(|c| *c == '>').count() != raw.chars().filter(|c| *c == '<').count() {
        return Err(format!("Unable to parse `{}`", raw));
    }
    let raw = if !raw.contains("><") {
        let raw = raw.strip_prefix('<').unwrap_or(raw);
        let raw = raw.strip_prefix('>').unwrap_or(raw);
        raw
    } else {
        raw
    };
    let sequences = raw
        .split("><")
        .map(|seq| {
            if let Some(s) = seq.strip_prefix('<') {
                s
            } else if let Some(s) = seq.strip_suffix('>') {
                s
            } else {
                seq
            }
        })
        .collect::<Vec<_>>();

    sequences.into_iter().map(parse_key_event).collect()
}
#[cfg(test)]
mod tests {
    use pretty_assertions::assert_eq;

    use super::*;

    #[test]
    fn test_config() -> Result<()> {
        let c = KeyBindings::new(None)?;
        assert_eq!(
            c.get(&Mode::Navigate)
                .and_then(|kb| kb.get(&parse_key_sequence("<esc>").unwrap_or_default())),
            Some(&Action::Quit)
        );
        Ok(())
    }

    #[test]
    fn test_simple_keys() {
        assert_eq!(
            parse_key_event("a").unwrap(),
            KeyEvent::new(KeyCode::Char('a'), KeyModifiers::empty())
        );

        assert_eq!(
            parse_key_event("enter").unwrap(),
            KeyEvent::new(KeyCode::Enter, KeyModifiers::empty())
        );

        assert_eq!(
            parse_key_event("esc").unwrap(),
            KeyEvent::new(KeyCode::Esc, KeyModifiers::empty())
        );
    }

    #[test]
    fn test_with_modifiers() {
        assert_eq!(
            parse_key_event("ctrl-a").unwrap(),
            KeyEvent::new(KeyCode::Char('a'), KeyModifiers::CONTROL)
        );

        assert_eq!(
            parse_key_event("alt-enter").unwrap(),
            KeyEvent::new(KeyCode::Enter, KeyModifiers::ALT)
        );

        assert_eq!(
            parse_key_event("shift-esc").unwrap(),
            KeyEvent::new(KeyCode::Esc, KeyModifiers::SHIFT)
        );
    }

    #[test]
    fn test_multiple_modifiers() {
        assert_eq!(
            parse_key_event("ctrl-alt-a").unwrap(),
            KeyEvent::new(
                KeyCode::Char('a'),
                KeyModifiers::CONTROL | KeyModifiers::ALT
            )
        );

        assert_eq!(
            parse_key_event("ctrl-shift-enter").unwrap(),
            KeyEvent::new(KeyCode::Enter, KeyModifiers::CONTROL | KeyModifiers::SHIFT)
        );
    }

    #[test]
    fn test_reverse_multiple_modifiers() {
        assert_eq!(
            key_event_to_string(&KeyEvent::new(
                KeyCode::Char('a'),
                KeyModifiers::CONTROL | KeyModifiers::ALT
            )),
            "ctrl-alt-a".to_string()
        );
    }

    #[test]
    fn test_invalid_keys() {
        assert!(parse_key_event("invalid-key").is_err());
        assert!(parse_key_event("ctrl-invalid-key").is_err());
    }

    #[test]
    fn test_case_insensitivity() {
        assert_eq!(
            parse_key_event("CTRL-a").unwrap(),
            KeyEvent::new(KeyCode::Char('a'), KeyModifiers::CONTROL)
        );

        assert_eq!(
            parse_key_event("AlT-eNtEr").unwrap(),
            KeyEvent::new(KeyCode::Enter, KeyModifiers::ALT)
        );
    }
}