oxwm

use std::collections::HashMap;

use std::io::{ErrorKind, Result};

use std::process::Command;

use serde::Deserialize;

use x11rb::connection::Connection;

use x11rb::protocol::xproto::*;

use crate::errors::X11Error;

use crate::keyboard::keysyms::{self, Keysym};

#[derive(Debug, Copy, Clone, Deserialize)]

pub enum KeyAction {

    Spawn,

    KillClient,

    FocusStack,

    FocusDirection,

    SwapDirection,

    Quit,

    Restart,

    Recompile,

    ViewTag,

    ToggleGaps,

    ToggleFullScreen,

    ToggleFloating,

    ChangeLayout,

    CycleLayout,

    MoveToTag,

    FocusMonitor,

    SmartMoveWin,

    ExchangeClient,

    None,

}

#[derive(Debug, Clone)]

pub enum Arg {

    None,

    Int(i32),

    Str(String),

    Array(Vec<String>),

}

impl Arg {

    pub const fn none() -> Self {

        Arg::None

    }

}

#[derive(Clone, Debug)]

pub struct KeyPress {

    pub(crate) modifiers: Vec<KeyButMask>,

    pub(crate) keysym: Keysym,

}

#[derive(Clone)]

pub struct KeyBinding {

    pub(crate) keys: Vec<KeyPress>,

    pub(crate) func: KeyAction,

    pub(crate) arg: Arg,

}

impl KeyBinding {

    pub fn new(keys: Vec<KeyPress>, func: KeyAction, arg: Arg) -> Self {

        Self { keys, func, arg }

    }

    pub fn single_key(

        modifiers: Vec<KeyButMask>,

        keysym: Keysym,

        func: KeyAction,

        arg: Arg,

    ) -> Self {

        Self {

            keys: vec![KeyPress { modifiers, keysym }],

            func,

            arg,

        }

    }

}

pub type Key = KeyBinding;

#[derive(Debug, Clone)]

pub enum KeychordState {

    Idle,

    InProgress {

        candidates: Vec<usize>,

        keys_pressed: usize,

    },

}

pub enum KeychordResult {

    Completed(KeyAction, Arg),

    InProgress(Vec<usize>),

    None,

    Cancelled,

}

pub fn modifiers_to_mask(modifiers: &[KeyButMask]) -> u16 {

    modifiers

        .iter()

        .fold(0u16, |acc, &modifier| acc | u16::from(modifier))

}

fn build_keysym_maps(

    connection: &impl Connection,

) -> std::result::Result<(HashMap<Keysym, Vec<Keycode>>, HashMap<Keycode, Keysym>), X11Error> {

    let setup = connection.setup();

    let min_keycode = setup.min_keycode;

    let max_keycode = setup.max_keycode;

    let keyboard_mapping = connection

        .get_keyboard_mapping(min_keycode, max_keycode - min_keycode + 1)?

        .reply()?;

    let mut keysym_to_keycode: HashMap<Keysym, Vec<Keycode>> = HashMap::new();

    let mut keycode_to_keysym: HashMap<Keycode, Keysym> = HashMap::new();

    let keysyms_per_keycode = keyboard_mapping.keysyms_per_keycode;

    for keycode in min_keycode..=max_keycode {

        let index = (keycode - min_keycode) as usize * keysyms_per_keycode as usize;

        for i in 0..keysyms_per_keycode as usize {

            if let Some(&keysym) = keyboard_mapping.keysyms.get(index + i) {

                if keysym != 0 {

                    keysym_to_keycode

                        .entry(keysym)

                        .or_insert_with(Vec::new)

                        .push(keycode);

                    keycode_to_keysym.entry(keycode).or_insert(keysym);

                }

            }

        }

    }

    Ok((keysym_to_keycode, keycode_to_keysym))

}

pub fn setup_keybinds(

    connection: &impl Connection,

    root: Window,

    keybindings: &[KeyBinding],

) -> std::result::Result<(), X11Error> {

    use std::collections::HashSet;

    let (keysym_to_keycode, _) = build_keysym_maps(connection)?;

    let mut grabbed_keys: HashSet<(u16, Keycode)> = HashSet::new();

    for keybinding in keybindings {

        if keybinding.keys.is_empty() {

            continue;

        }

        let first_key = &keybinding.keys[0];

        let modifier_mask = modifiers_to_mask(&first_key.modifiers);

        if let Some(keycodes) = keysym_to_keycode.get(&first_key.keysym) {

            if let Some(&keycode) = keycodes.first() {

                let key_tuple = (modifier_mask, keycode);

                if grabbed_keys.insert(key_tuple) {

                    connection.grab_key(

                        false,

                        root,

                        modifier_mask.into(),

                        keycode,

                        GrabMode::ASYNC,

                        GrabMode::ASYNC,

                    )?;

                }

            }

        }

    }

    Ok(())

}

pub fn handle_key_press(

    event: KeyPressEvent,

    keybindings: &[KeyBinding],

    keychord_state: &KeychordState,

    connection: &impl Connection,

) -> std::result::Result<KeychordResult, X11Error> {

    let (_, keycode_to_keysym) = build_keysym_maps(connection)?;

    let event_keysym = keycode_to_keysym.get(&event.detail).copied().unwrap_or(0);

    if event_keysym == keysyms::XK_ESCAPE {

        return Ok(match keychord_state {

            KeychordState::InProgress { .. } => KeychordResult::Cancelled,

            KeychordState::Idle => KeychordResult::None,

        });

    }

    Ok(match keychord_state {

        KeychordState::Idle => handle_first_key(event, event_keysym, keybindings),

        KeychordState::InProgress {

            candidates,

            keys_pressed,

        } => handle_next_key(event, event_keysym, keybindings, candidates, *keys_pressed),

    })

}

fn handle_first_key(

    event: KeyPressEvent,

    event_keysym: Keysym,

    keybindings: &[KeyBinding],

) -> KeychordResult {

    let mut candidates = Vec::new();

    for (keybinding_index, keybinding) in keybindings.iter().enumerate() {

        if keybinding.keys.is_empty() {

            continue;

        }

        let first_key = &keybinding.keys[0];

        let modifier_mask = modifiers_to_mask(&first_key.modifiers);

        if event_keysym == first_key.keysym && event.state == modifier_mask.into() {

            if keybinding.keys.len() == 1 {

                return KeychordResult::Completed(keybinding.func, keybinding.arg.clone());

            } else {

                candidates.push(keybinding_index);

            }

        }

    }

    if candidates.is_empty() {

        KeychordResult::None

    } else {

        KeychordResult::InProgress(candidates)

    }

}

fn handle_next_key(

    event: KeyPressEvent,

    event_keysym: Keysym,

    keybindings: &[KeyBinding],

    candidates: &[usize],

    keys_pressed: usize,

) -> KeychordResult {

    let mut new_candidates = Vec::new();

    for &candidate_index in candidates {

        let keybinding = &keybindings[candidate_index];

        if keys_pressed >= keybinding.keys.len() {

            continue;

        }

        let next_key = &keybinding.keys[keys_pressed];

        let required_mask = modifiers_to_mask(&next_key.modifiers);

        let event_state: u16 = event.state.into();

        let modifiers_match = if next_key.modifiers.is_empty() {

            true

        } else {

            (event_state & required_mask) == required_mask

        };

        if event_keysym == next_key.keysym && modifiers_match {

            if keys_pressed + 1 == keybinding.keys.len() {

                return KeychordResult::Completed(keybinding.func, keybinding.arg.clone());

            } else {

                new_candidates.push(candidate_index);

            }

        }

    }

    if new_candidates.is_empty() {

        KeychordResult::Cancelled

    } else {

        KeychordResult::InProgress(new_candidates)

    }

}

pub fn handle_spawn_action(action: KeyAction, arg: &Arg) -> Result<()> {

    if let KeyAction::Spawn = action {

        match arg {

            Arg::Str(command) => match Command::new(command.as_str()).spawn() {

                Err(error) if error.kind() == ErrorKind::NotFound => {

                    eprintln!(

                        "KeyAction::Spawn failed: could not spawn \"{}\", command not found",

                        command

                    );

                }

                Err(error) => Err(error)?,

                _ => (),

            },

            Arg::Array(command) => {

                let Some((cmd, args)) = command.split_first() else {

                    return Ok(());

                };

                let args_str: Vec<&str> = args.iter().map(|s| s.as_str()).collect();

                match Command::new(cmd.as_str()).args(&args_str).spawn() {

                    Err(error) if error.kind() == ErrorKind::NotFound => {

                        eprintln!(

                            "KeyAction::Spawn failed: could not spawn \"{}\", command not found",

                            cmd

                        );

                    }

                    Err(error) => Err(error)?,

                    _ => (),

                }

            }

            _ => {}

        }

    }

    Ok(())

}