/*
 * This file is part of espanso.
 *
 * Copyright (C) 2019-2021 Federico Terzi
 *
 * espanso is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * espanso is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with espanso.  If not, see <https://www.gnu.org/licenses/>.
 */

use std::{
  cell::RefCell,
  time::{Duration, Instant},
};

use log::info;

use super::super::Middleware;
use crate::event::{
  input::{Key, KeyboardEvent, Status, Variant},
  Event, EventType,
};

pub struct DisableOptions {
  pub toggle_key: Option<Key>,
  pub toggle_key_variant: Option<Variant>,
  pub toggle_key_maximum_window: Duration,
  // TODO: toggle shortcut?
}

pub struct DisableMiddleware {
  enabled: RefCell<bool>,
  last_toggle_press: RefCell<Option<Instant>>,
  options: DisableOptions,
}

impl DisableMiddleware {
  pub fn new(options: DisableOptions) -> Self {
    Self {
      enabled: RefCell::new(true),
      last_toggle_press: RefCell::new(None),
      options,
    }
  }
}

impl Middleware for DisableMiddleware {
  fn name(&self) -> &'static str {
    "disable"
  }

  fn next(&self, event: Event, dispatch: &mut dyn FnMut(Event)) -> Event {
    let mut has_status_changed = false;
    let mut enabled = self.enabled.borrow_mut();

    match &event.etype {
      EventType::Keyboard(m_event) => {
        if is_toggle_key(m_event, &self.options) {
          let mut last_toggle_press = self.last_toggle_press.borrow_mut();
          if let Some(previous_press) = *last_toggle_press {
            if previous_press.elapsed() < self.options.toggle_key_maximum_window {
              *enabled = !*enabled;
              *last_toggle_press = None;
              has_status_changed = true;
            } else {
              *last_toggle_press = Some(Instant::now());
            }
          } else {
            *last_toggle_press = Some(Instant::now());
          }
        }
      }
      EventType::EnableRequest => {
        *enabled = true;
        has_status_changed = true;
      }
      EventType::DisableRequest => {
        *enabled = false;
        has_status_changed = true;
      }
      _ => {}
    }

    if has_status_changed {
      info!("toggled enabled state, is_enabled = {}", *enabled);
      dispatch(Event::caused_by(
        event.source_id,
        if *enabled {
          EventType::Enabled
        } else {
          EventType::Disabled
        },
      ))
    }

    // Block keyboard events when disabled
    if let EventType::Keyboard(_) = &event.etype {
      if !*enabled {
        return Event::caused_by(event.source_id, EventType::NOOP);
      }
    }
    // TODO: also ignore hotkey and mouse events

    event
  }
}

fn is_toggle_key(event: &KeyboardEvent, options: &DisableOptions) -> bool {
  if event.status != Status::Released {
    return false;
  }

  if options
    .toggle_key
    .as_ref()
    .map(|key| key == &event.key)
    .unwrap_or(false)
  {
    if let (Some(variant), Some(e_variant)) = (&options.toggle_key_variant, &event.variant) {
      variant == e_variant
    } else {
      true
    }
  } else {
    false
  }
}

// TODO: test