// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//! Handle input from glutin
//!
//! Certain key combinations should send some escape sequence back to the pty.
//! In order to figure that out, state about which modifier keys are pressed
//! needs to be tracked. Additionally, we need a bit of a state machine to
//! determine what to do when a non-modifier key is pressed.
use std::borrow::Cow;
use std::cmp::min;
use std::cmp::Ordering;
use std::marker::PhantomData;
use std::time::Instant;

use glutin::event::{
    ElementState, KeyboardInput, ModifiersState, MouseButton, MouseScrollDelta, TouchPhase,
};
use glutin::window::CursorIcon;
use log::{debug, trace, warn};

use alacritty_terminal::ansi::{ClearMode, Handler};
use alacritty_terminal::clipboard::ClipboardType;
use alacritty_terminal::event::EventListener;
use alacritty_terminal::grid::Scroll;
use alacritty_terminal::index::{Column, Line, Point, Side};
use alacritty_terminal::message_bar::{self, Message};
use alacritty_terminal::selection::Selection;
use alacritty_terminal::term::mode::TermMode;
use alacritty_terminal::term::{SizeInfo, Term};
use alacritty_terminal::util::start_daemon;

use crate::config::{Action, Binding, Config, Key};
use crate::event::{ClickState, Mouse};
use crate::url::{Url, Urls};
use crate::window::Window;

/// Font size change interval
pub const FONT_SIZE_STEP: f32 = 0.5;

/// Processes input from glutin.
///
/// An escape sequence may be emitted in case specific keys or key combinations
/// are activated.
pub struct Processor<'a, T: EventListener, A: ActionContext<T>> {
    pub ctx: A,
    pub urls: &'a Urls,
    pub highlighted_url: &'a Option<Url>,
    _phantom: PhantomData<T>,
}

pub trait ActionContext<T: EventListener> {
    fn write_to_pty<B: Into<Cow<'static, [u8]>>>(&mut self, _: B);
    fn size_info(&self) -> SizeInfo;
    fn copy_selection(&mut self, _: ClipboardType);
    fn clear_selection(&mut self);
    fn update_selection(&mut self, point: Point, side: Side);
    fn simple_selection(&mut self, point: Point, side: Side);
    fn block_selection(&mut self, point: Point, side: Side);
    fn semantic_selection(&mut self, point: Point);
    fn line_selection(&mut self, point: Point);
    fn selection_is_empty(&self) -> bool;
    fn mouse_mut(&mut self) -> &mut Mouse;
    fn mouse(&self) -> &Mouse;
    fn mouse_coords(&self) -> Option<Point>;
    fn received_count(&mut self) -> &mut usize;
    fn suppress_chars(&mut self) -> &mut bool;
    fn modifiers(&mut self) -> &mut ModifiersState;
    fn scroll(&mut self, scroll: Scroll);
    fn window(&self) -> &Window;
    fn window_mut(&mut self) -> &mut Window;
    fn terminal(&self) -> &Term<T>;
    fn terminal_mut(&mut self) -> &mut Term<T>;
    fn spawn_new_instance(&mut self);
    fn change_font_size(&mut self, delta: f32);
    fn reset_font_size(&mut self);
    fn pop_message(&mut self);
    fn message(&self) -> Option<&Message>;
    fn config(&self) -> &Config;
}

trait Execute<T: EventListener> {
    fn execute<A: ActionContext<T>>(&self, ctx: &mut A, mouse_mode: bool);
}

impl<T, U: EventListener> Execute<U> for Binding<T> {
    /// Execute the action associate with this binding
    #[inline]
    fn execute<A: ActionContext<U>>(&self, ctx: &mut A, mouse_mode: bool) {
        self.action.execute(ctx, mouse_mode)
    }
}

impl<T: EventListener> Execute<T> for Action {
    #[inline]
    fn execute<A: ActionContext<T>>(&self, ctx: &mut A, mouse_mode: bool) {
        match *self {
            Action::Esc(ref s) => {
                ctx.clear_selection();
                ctx.scroll(Scroll::Bottom);
                ctx.write_to_pty(s.clone().into_bytes())
            },
            Action::Copy => {
                ctx.copy_selection(ClipboardType::Clipboard);
            },
            Action::Paste => {
                let text = ctx.terminal_mut().clipboard().load(ClipboardType::Clipboard);
                paste(ctx, &text);
            },
            Action::PasteSelection => {
                // Only paste if mouse events are not captured by an application
                if !mouse_mode {
                    let text = ctx.terminal_mut().clipboard().load(ClipboardType::Selection);
                    paste(ctx, &text);
                }
            },
            Action::Command(ref program, ref args) => {
                trace!("Running command {} with args {:?}", program, args);

                match start_daemon(program, args) {
                    Ok(_) => debug!("Spawned new proc"),
                    Err(err) => warn!("Couldn't run command {}", err),
                }
            },
            Action::ToggleFullscreen => ctx.window_mut().toggle_fullscreen(),
            #[cfg(target_os = "macos")]
            Action::ToggleSimpleFullscreen => ctx.window_mut().toggle_simple_fullscreen(),
            Action::Hide => ctx.window().set_visible(false),
            Action::Minimize => ctx.window().set_minimized(true),
            Action::Quit => ctx.terminal_mut().exit(),
            Action::IncreaseFontSize => ctx.change_font_size(FONT_SIZE_STEP),
            Action::DecreaseFontSize => ctx.change_font_size(FONT_SIZE_STEP * -1.),
            Action::ResetFontSize => ctx.reset_font_size(),
            Action::ScrollPageUp => ctx.scroll(Scroll::PageUp),
            Action::ScrollPageDown => ctx.scroll(Scroll::PageDown),
            Action::ScrollLineUp => ctx.scroll(Scroll::Lines(1)),
            Action::ScrollLineDown => ctx.scroll(Scroll::Lines(-1)),
            Action::ScrollToTop => ctx.scroll(Scroll::Top),
            Action::ScrollToBottom => ctx.scroll(Scroll::Bottom),
            Action::ClearHistory => ctx.terminal_mut().clear_screen(ClearMode::Saved),
            Action::ClearLogNotice => ctx.pop_message(),
            Action::SpawnNewInstance => ctx.spawn_new_instance(),
            Action::ReceiveChar | Action::None => (),
        }
    }
}

fn paste<T: EventListener, A: ActionContext<T>>(ctx: &mut A, contents: &str) {
    if ctx.terminal().mode().contains(TermMode::BRACKETED_PASTE) {
        ctx.write_to_pty(&b"\x1b[200~"[..]);
        ctx.write_to_pty(contents.replace("\x1b", "").into_bytes());
        ctx.write_to_pty(&b"\x1b[201~"[..]);
    } else {
        // In non-bracketed (ie: normal) mode, terminal applications cannot distinguish
        // pasted data from keystrokes.
        // In theory, we should construct the keystrokes needed to produce the data we are
        // pasting... since that's neither practical nor sensible (and probably an impossible
        // task to solve in a general way), we'll just replace line breaks (windows and unix
        // style) with a single carriage return (\r, which is what the Enter key produces).
        ctx.write_to_pty(contents.replace("\r\n", "\r").replace("\n", "\r").into_bytes());
    }
}

#[derive(Debug, Clone, PartialEq)]
pub enum MouseState {
    Url(Url),
    MessageBar,
    MessageBarButton,
    Mouse,
    Text,
}

impl From<MouseState> for CursorIcon {
    fn from(mouse_state: MouseState) -> CursorIcon {
        match mouse_state {
            MouseState::Url(_) | MouseState::MessageBarButton => CursorIcon::Hand,
            MouseState::Text => CursorIcon::Text,
            _ => CursorIcon::Default,
        }
    }
}

impl<'a, T: EventListener, A: ActionContext<T>> Processor<'a, T, A> {
    pub fn new(ctx: A, urls: &'a Urls, highlighted_url: &'a Option<Url>) -> Self {
        Self { ctx, urls, highlighted_url, _phantom: Default::default() }
    }

    #[inline]
    pub fn mouse_moved(&mut self, x: usize, y: usize) {
        let size_info = self.ctx.size_info();

        self.ctx.mouse_mut().x = x;
        self.ctx.mouse_mut().y = y;

        let inside_grid = size_info.contains_point(x, y);
        let point = size_info.pixels_to_coords(x, y);
        let cell_side = self.get_mouse_side();

        let cell_changed =
            point.line != self.ctx.mouse().line || point.col != self.ctx.mouse().column;

        // If the mouse hasn't changed cells, do nothing
        if !cell_changed
            && self.ctx.mouse().cell_side == cell_side
            && self.ctx.mouse().inside_grid == inside_grid
        {
            return;
        }

        self.ctx.mouse_mut().inside_grid = inside_grid;
        self.ctx.mouse_mut().cell_side = cell_side;
        self.ctx.mouse_mut().line = point.line;
        self.ctx.mouse_mut().column = point.col;

        // Don't launch URLs if mouse has moved
        self.ctx.mouse_mut().block_url_launcher = true;

        // Update mouse state and check for URL change
        let mouse_state = self.mouse_state();
        self.update_url_state(&mouse_state);
        self.ctx.window_mut().set_mouse_cursor(mouse_state.into());

        let last_term_line = self.ctx.terminal().grid().num_lines() - 1;
        if self.ctx.mouse().left_button_state == ElementState::Pressed
            && (self.ctx.modifiers().shift()
                || !self.ctx.terminal().mode().intersects(TermMode::MOUSE_MODE))
        {
            // Treat motion over message bar like motion over the last line
            let line = min(point.line, last_term_line);

            self.ctx.update_selection(Point { line, col: point.col }, cell_side);
        } else if inside_grid
            && cell_changed
            && point.line <= last_term_line
            && self.ctx.terminal().mode().intersects(TermMode::MOUSE_MOTION | TermMode::MOUSE_DRAG)
        {
            if self.ctx.mouse().left_button_state == ElementState::Pressed {
                self.mouse_report(32, ElementState::Pressed);
            } else if self.ctx.mouse().middle_button_state == ElementState::Pressed {
                self.mouse_report(33, ElementState::Pressed);
            } else if self.ctx.mouse().right_button_state == ElementState::Pressed {
                self.mouse_report(34, ElementState::Pressed);
            } else if self.ctx.terminal().mode().contains(TermMode::MOUSE_MOTION) {
                self.mouse_report(35, ElementState::Pressed);
            }
        }
    }

    fn get_mouse_side(&self) -> Side {
        let size_info = self.ctx.size_info();
        let x = self.ctx.mouse().x;

        let cell_x = x.saturating_sub(size_info.padding_x as usize) % size_info.cell_width as usize;
        let half_cell_width = (size_info.cell_width / 2.0) as usize;

        let additional_padding =
            (size_info.width - size_info.padding_x * 2.) % size_info.cell_width;
        let end_of_grid = size_info.width - size_info.padding_x - additional_padding;

        if cell_x > half_cell_width
            // Edge case when mouse leaves the window
            || x as f32 >= end_of_grid
        {
            Side::Right
        } else {
            Side::Left
        }
    }

    fn normal_mouse_report(&mut self, button: u8) {
        let (line, column) = (self.ctx.mouse().line, self.ctx.mouse().column);
        let utf8 = self.ctx.terminal().mode().contains(TermMode::UTF8_MOUSE);

        let max_point = if utf8 { 2015 } else { 223 };

        if line >= Line(max_point) || column >= Column(max_point) {
            return;
        }

        let mut msg = vec![b'\x1b', b'[', b'M', 32 + button];

        let mouse_pos_encode = |pos: usize| -> Vec<u8> {
            let pos = 32 + 1 + pos;
            let first = 0xC0 + pos / 64;
            let second = 0x80 + (pos & 63);
            vec![first as u8, second as u8]
        };

        if utf8 && column >= Column(95) {
            msg.append(&mut mouse_pos_encode(column.0));
        } else {
            msg.push(32 + 1 + column.0 as u8);
        }

        if utf8 && line >= Line(95) {
            msg.append(&mut mouse_pos_encode(line.0));
        } else {
            msg.push(32 + 1 + line.0 as u8);
        }

        self.ctx.write_to_pty(msg);
    }

    fn sgr_mouse_report(&mut self, button: u8, state: ElementState) {
        let (line, column) = (self.ctx.mouse().line, self.ctx.mouse().column);
        let c = match state {
            ElementState::Pressed => 'M',
            ElementState::Released => 'm',
        };

        let msg = format!("\x1b[<{};{};{}{}", button, column + 1, line + 1, c);
        self.ctx.write_to_pty(msg.into_bytes());
    }

    fn mouse_report(&mut self, button: u8, state: ElementState) {
        // Calculate modifiers value
        let mut mods = 0;
        let modifiers = self.ctx.modifiers();
        if modifiers.shift() {
            mods += 4;
        }
        if modifiers.alt() {
            mods += 8;
        }
        if modifiers.ctrl() {
            mods += 16;
        }

        // Report mouse events
        if self.ctx.terminal().mode().contains(TermMode::SGR_MOUSE) {
            self.sgr_mouse_report(button + mods, state);
        } else if let ElementState::Released = state {
            self.normal_mouse_report(3 + mods);
        } else {
            self.normal_mouse_report(button + mods);
        }
    }

    fn on_mouse_double_click(&mut self, button: MouseButton, point: Point) {
        if button == MouseButton::Left {
            self.ctx.semantic_selection(point);
        }
    }

    fn on_mouse_triple_click(&mut self, button: MouseButton, point: Point) {
        if button == MouseButton::Left {
            self.ctx.line_selection(point);
        }
    }

    fn on_mouse_press(&mut self, button: MouseButton) {
        let now = Instant::now();
        let elapsed = self.ctx.mouse().last_click_timestamp.elapsed();
        self.ctx.mouse_mut().last_click_timestamp = now;

        let button_changed = self.ctx.mouse().last_button != button;

        // Load mouse point, treating message bar and padding as closest cell
        let mouse = self.ctx.mouse();
        let mut point = self.ctx.size_info().pixels_to_coords(mouse.x, mouse.y);
        point.line = min(point.line, self.ctx.terminal().grid().num_lines() - 1);

        self.ctx.mouse_mut().click_state = match self.ctx.mouse().click_state {
            ClickState::Click
                if !button_changed
                    && elapsed < self.ctx.config().ui_config.mouse.double_click.threshold =>
            {
                self.ctx.mouse_mut().block_url_launcher = true;
                self.on_mouse_double_click(button, point);
                ClickState::DoubleClick
            }
            ClickState::DoubleClick
                if !button_changed
                    && elapsed < self.ctx.config().ui_config.mouse.triple_click.threshold =>
            {
                self.ctx.mouse_mut().block_url_launcher = true;
                self.on_mouse_triple_click(button, point);
                ClickState::TripleClick
            }
            _ => {
                // Don't launch URLs if this click cleared the selection
                self.ctx.mouse_mut().block_url_launcher = !self.ctx.selection_is_empty();

                self.ctx.clear_selection();

                // Start new empty selection
                let side = self.ctx.mouse().cell_side;
                if self.ctx.modifiers().ctrl() {
                    self.ctx.block_selection(point, side);
                } else {
                    self.ctx.simple_selection(point, side);
                }

                if !self.ctx.modifiers().shift()
                    && self.ctx.terminal().mode().intersects(TermMode::MOUSE_MODE)
                {
                    let code = match button {
                        MouseButton::Left => 0,
                        MouseButton::Middle => 1,
                        MouseButton::Right => 2,
                        // Can't properly report more than three buttons.
                        MouseButton::Other(_) => return,
                    };
                    self.mouse_report(code, ElementState::Pressed);
                    return;
                }

                ClickState::Click
            },
        };
    }

    fn on_mouse_release(&mut self, button: MouseButton) {
        if !self.ctx.modifiers().shift()
            && self.ctx.terminal().mode().intersects(TermMode::MOUSE_MODE)
        {
            let code = match button {
                MouseButton::Left => 0,
                MouseButton::Middle => 1,
                MouseButton::Right => 2,
                // Can't properly report more than three buttons.
                MouseButton::Other(_) => return,
            };
            self.mouse_report(code, ElementState::Released);
            return;
        } else if let (MouseButton::Left, MouseState::Url(url)) = (button, self.mouse_state()) {
            self.launch_url(url);
        }

        self.copy_selection();
    }

    /// Spawn URL launcher when clicking on URLs.
    fn launch_url(&self, url: Url) {
        if self.ctx.mouse().block_url_launcher {
            return;
        }

        if let Some(ref launcher) = self.ctx.config().ui_config.mouse.url.launcher {
            let mut args = launcher.args().to_vec();
            let start = self.ctx.terminal().visible_to_buffer(url.start());
            let end = self.ctx.terminal().visible_to_buffer(url.end());
            args.push(self.ctx.terminal().bounds_to_string(start, end));

            match start_daemon(launcher.program(), &args) {
                Ok(_) => debug!("Launched {} with args {:?}", launcher.program(), args),
                Err(_) => warn!("Unable to launch {} with args {:?}", launcher.program(), args),
            }
        }
    }

    pub fn mouse_wheel_input(&mut self, delta: MouseScrollDelta, phase: TouchPhase) {
        match delta {
            MouseScrollDelta::LineDelta(_columns, lines) => {
                let new_scroll_px = lines * self.ctx.size_info().cell_height;
                self.scroll_terminal(new_scroll_px as i32);
            },
            MouseScrollDelta::PixelDelta(lpos) => {
                match phase {
                    TouchPhase::Started => {
                        // Reset offset to zero
                        self.ctx.mouse_mut().scroll_px = 0;
                    },
                    TouchPhase::Moved => {
                        self.scroll_terminal(lpos.y as i32);
                    },
                    _ => (),
                }
            },
        }
    }

    fn scroll_terminal(&mut self, new_scroll_px: i32) {
        let height = self.ctx.size_info().cell_height as i32;

        if self.ctx.terminal().mode().intersects(TermMode::MOUSE_MODE) {
            self.ctx.mouse_mut().scroll_px += new_scroll_px;

            let code = if new_scroll_px > 0 { 64 } else { 65 };
            let lines = (self.ctx.mouse().scroll_px / height).abs();

            for _ in 0..lines {
                self.mouse_report(code, ElementState::Pressed);
            }
        } else if self
            .ctx
            .terminal()
            .mode()
            .contains(TermMode::ALT_SCREEN | TermMode::ALTERNATE_SCROLL)
            && !self.ctx.modifiers().shift()
        {
            let multiplier = i32::from(
                self.ctx
                    .config()
                    .scrolling
                    .faux_multiplier()
                    .unwrap_or_else(|| self.ctx.config().scrolling.multiplier()),
            );
            self.ctx.mouse_mut().scroll_px += new_scroll_px * multiplier;

            let cmd = if new_scroll_px > 0 { b'A' } else { b'B' };
            let lines = (self.ctx.mouse().scroll_px / height).abs();

            let mut content = Vec::with_capacity(lines as usize * 3);
            for _ in 0..lines {
                content.push(0x1b);
                content.push(b'O');
                content.push(cmd);
            }
            self.ctx.write_to_pty(content);
        } else {
            let multiplier = i32::from(self.ctx.config().scrolling.multiplier());
            self.ctx.mouse_mut().scroll_px += new_scroll_px * multiplier;

            let lines = self.ctx.mouse().scroll_px / height;

            self.ctx.scroll(Scroll::Lines(lines as isize));
        }

        self.ctx.mouse_mut().scroll_px %= height;
    }

    pub fn on_focus_change(&mut self, is_focused: bool) {
        if self.ctx.terminal().mode().contains(TermMode::FOCUS_IN_OUT) {
            let chr = if is_focused { "I" } else { "O" };

            let msg = format!("\x1b[{}", chr);
            self.ctx.write_to_pty(msg.into_bytes());
        }
    }

    pub fn mouse_input(&mut self, state: ElementState, button: MouseButton) {
        match button {
            MouseButton::Left => self.ctx.mouse_mut().left_button_state = state,
            MouseButton::Middle => self.ctx.mouse_mut().middle_button_state = state,
            MouseButton::Right => self.ctx.mouse_mut().right_button_state = state,
            _ => (),
        }

        // Skip normal mouse events if the message bar has been clicked
        if self.message_close_at_cursor() && state == ElementState::Pressed {
            self.ctx.clear_selection();
            self.ctx.pop_message();

            // Reset cursor when message bar height changed or all messages are gone
            let size = self.ctx.size_info();
            let mouse_mode = self.ctx.terminal().mode().intersects(TermMode::MOUSE_MODE);
            let current_lines = (size.lines() - self.ctx.terminal().grid().num_lines()).0;
            let new_lines = self.ctx.message().map(|m| m.text(&size).len()).unwrap_or(0);

            let new_icon = match current_lines.cmp(&new_lines) {
                Ordering::Less => CursorIcon::Default,
                Ordering::Equal => CursorIcon::Hand,
                Ordering::Greater => {
                    if mouse_mode {
                        CursorIcon::Default
                    } else {
                        CursorIcon::Text
                    }
                },
            };

            self.ctx.window_mut().set_mouse_cursor(new_icon);
        } else {
            match state {
                ElementState::Pressed => {
                    self.process_mouse_bindings(button);
                    self.on_mouse_press(button);
                },
                ElementState::Released => self.on_mouse_release(button),
            }
        }

        self.ctx.mouse_mut().last_button = button;
    }

    /// Process key input.
    pub fn key_input(&mut self, input: KeyboardInput) {
        match input.state {
            ElementState::Pressed => {
                *self.ctx.received_count() = 0;
                self.process_key_bindings(input);
            },
            ElementState::Released => *self.ctx.suppress_chars() = false,
        }
    }

    /// Modifier state change.
    pub fn modifiers_input(&mut self, modifiers: ModifiersState) {
        *self.ctx.modifiers() = modifiers;

        // Update mouse state and check for URL change
        let mouse_state = self.mouse_state();
        self.update_url_state(&mouse_state);
        self.ctx.window_mut().set_mouse_cursor(mouse_state.into());
    }

    /// Process a received character.
    pub fn received_char(&mut self, c: char) {
        if *self.ctx.suppress_chars() {
            return;
        }

        self.ctx.scroll(Scroll::Bottom);
        self.ctx.clear_selection();

        let utf8_len = c.len_utf8();
        let mut bytes = Vec::with_capacity(utf8_len);
        unsafe {
            bytes.set_len(utf8_len);
            c.encode_utf8(&mut bytes[..]);
        }

        if self.ctx.config().alt_send_esc()
            && *self.ctx.received_count() == 0
            && self.ctx.modifiers().alt()
            && utf8_len == 1
        {
            bytes.insert(0, b'\x1b');
        }

        self.ctx.write_to_pty(bytes);

        *self.ctx.received_count() += 1;
        self.ctx.terminal_mut().dirty = false;
    }

    /// Reset mouse cursor based on modifier and terminal state.
    #[inline]
    pub fn reset_mouse_cursor(&mut self) {
        let mouse_state = self.mouse_state();
        self.ctx.window_mut().set_mouse_cursor(mouse_state.into());
    }

    /// Attempt to find a binding and execute its action.
    ///
    /// The provided mode, mods, and key must match what is allowed by a binding
    /// for its action to be executed.
    fn process_key_bindings(&mut self, input: KeyboardInput) {
        let mut suppress_chars = None;

        for i in 0..self.ctx.config().ui_config.key_bindings.len() {
            let mods = *self.ctx.modifiers();
            let binding = &self.ctx.config().ui_config.key_bindings[i];

            let key = match (binding.trigger, input.virtual_keycode) {
                (Key::Scancode(_), _) => Key::Scancode(input.scancode),
                (_, Some(key)) => Key::Keycode(key),
                _ => continue,
            };

            if binding.is_triggered_by(*self.ctx.terminal().mode(), mods, &key, false) {
                // Binding was triggered; run the action
                let binding = binding.clone();
                binding.execute(&mut self.ctx, false);

                // Don't suppress when there has been a `ReceiveChar` action
                *suppress_chars.get_or_insert(true) &= binding.action != Action::ReceiveChar;
            }
        }

        // Don't suppress char if no bindings were triggered
        *self.ctx.suppress_chars() = suppress_chars.unwrap_or(false);
    }

    /// Attempt to find a binding and execute its action.
    ///
    /// The provided mode, mods, and key must match what is allowed by a binding
    /// for its action to be executed.
    fn process_mouse_bindings(&mut self, button: MouseButton) {
        for i in 0..self.ctx.config().ui_config.mouse_bindings.len() {
            let mods = *self.ctx.modifiers();
            let binding = &self.ctx.config().ui_config.mouse_bindings[i];

            if binding.is_triggered_by(*self.ctx.terminal().mode(), mods, &button, true) {
                // binding was triggered; run the action
                let mouse_mode_active =
                    !mods.shift() && self.ctx.terminal().mode().intersects(TermMode::MOUSE_MODE);

                let binding = binding.clone();
                binding.execute(&mut self.ctx, mouse_mode_active);
            }
        }
    }

    /// Check if the cursor is hovering above the message bar.
    fn message_at_cursor(&mut self) -> bool {
        self.ctx.mouse().line >= self.ctx.terminal().grid().num_lines()
    }

    /// Whether the point is over the message bar's close button
    fn message_close_at_cursor(&self) -> bool {
        let mouse = self.ctx.mouse();
        mouse.inside_grid
            && mouse.column + message_bar::CLOSE_BUTTON_TEXT.len() >= self.ctx.size_info().cols()
            && mouse.line == self.ctx.terminal().grid().num_lines()
    }

    /// Copy text selection.
    fn copy_selection(&mut self) {
        if self.ctx.config().selection.save_to_clipboard {
            self.ctx.copy_selection(ClipboardType::Clipboard);
        }
        self.ctx.copy_selection(ClipboardType::Selection);
    }

    /// Trigger redraw when URL highlight changed.
    #[inline]
    fn update_url_state(&mut self, mouse_state: &MouseState) {
        if let MouseState::Url(url) = mouse_state {
            if Some(url) != self.highlighted_url.as_ref() {
                self.ctx.terminal_mut().dirty = true;
            }
        } else if self.highlighted_url.is_some() {
            self.ctx.terminal_mut().dirty = true;
        }
    }

    /// Location of the mouse cursor.
    fn mouse_state(&mut self) -> MouseState {
        // Check message bar before URL to ignore URLs in the message bar
        if self.message_close_at_cursor() {
            return MouseState::MessageBarButton;
        } else if self.message_at_cursor() {
            return MouseState::MessageBar;
        }

        // Check for URL at mouse cursor
        let mods = *self.ctx.modifiers();
        let selection =
            !self.ctx.terminal().selection().as_ref().map(Selection::is_empty).unwrap_or(true);
        let mouse_mode = self.ctx.terminal().mode().intersects(TermMode::MOUSE_MODE);
        let highlighted_url =
            self.urls.highlighted(self.ctx.config(), self.ctx.mouse(), mods, mouse_mode, selection);

        if let Some(url) = highlighted_url {
            return MouseState::Url(url);
        }

        // Check mouse mode if location is not special
        if self.ctx.terminal().mode().intersects(TermMode::MOUSE_MODE)
            && !self.ctx.modifiers().shift()
        {
            MouseState::Mouse
        } else {
            MouseState::Text
        }
    }
}

#[cfg(test)]
mod tests {
    use std::borrow::Cow;
    use std::time::Duration;

    use glutin::event::{
        ElementState, Event, ModifiersState, MouseButton, VirtualKeyCode, WindowEvent,
    };

    use alacritty_terminal::clipboard::{Clipboard, ClipboardType};
    use alacritty_terminal::event::{Event as TerminalEvent, EventListener};
    use alacritty_terminal::grid::Scroll;
    use alacritty_terminal::index::{Point, Side};
    use alacritty_terminal::message_bar::{Message, MessageBuffer};
    use alacritty_terminal::selection::Selection;
    use alacritty_terminal::term::{SizeInfo, Term, TermMode};

    use crate::config::{ClickHandler, Config};
    use crate::event::{ClickState, Mouse};
    use crate::url::Urls;
    use crate::window::Window;

    use super::{Action, Binding, Processor};

    const KEY: VirtualKeyCode = VirtualKeyCode::Key0;

    struct MockEventProxy;

    impl EventListener for MockEventProxy {
        fn send_event(&self, _event: TerminalEvent) {}
    }

    #[derive(PartialEq)]
    enum MultiClick {
        DoubleClick,
        TripleClick,
        None,
    }

    struct ActionContext<'a, T> {
        pub terminal: &'a mut Term<T>,
        pub selection: &'a mut Option<Selection>,
        pub size_info: &'a SizeInfo,
        pub mouse: &'a mut Mouse,
        pub message_buffer: &'a mut MessageBuffer,
        pub last_action: MultiClick,
        pub received_count: usize,
        pub suppress_chars: bool,
        pub modifiers: ModifiersState,
        config: &'a Config,
    }

    impl<'a, T: EventListener> super::ActionContext<T> for ActionContext<'a, T> {
        fn write_to_pty<B: Into<Cow<'static, [u8]>>>(&mut self, _val: B) {}

        fn update_selection(&mut self, _point: Point, _side: Side) {}

        fn simple_selection(&mut self, _point: Point, _side: Side) {}

        fn block_selection(&mut self, _point: Point, _side: Side) {}

        fn copy_selection(&mut self, _: ClipboardType) {}

        fn clear_selection(&mut self) {}

        fn spawn_new_instance(&mut self) {}

        fn change_font_size(&mut self, _delta: f32) {}

        fn reset_font_size(&mut self) {}

        fn terminal(&self) -> &Term<T> {
            &self.terminal
        }

        fn terminal_mut(&mut self) -> &mut Term<T> {
            &mut self.terminal
        }

        fn size_info(&self) -> SizeInfo {
            *self.size_info
        }

        fn semantic_selection(&mut self, _point: Point) {
            // set something that we can check for here
            self.last_action = MultiClick::DoubleClick;
        }

        fn line_selection(&mut self, _point: Point) {
            self.last_action = MultiClick::TripleClick;
        }

        fn selection_is_empty(&self) -> bool {
            true
        }

        fn scroll(&mut self, scroll: Scroll) {
            self.terminal.scroll_display(scroll);
        }

        fn mouse_coords(&self) -> Option<Point> {
            let x = self.mouse.x as usize;
            let y = self.mouse.y as usize;

            if self.size_info.contains_point(x, y) {
                Some(self.size_info.pixels_to_coords(x, y))
            } else {
                None
            }
        }

        #[inline]
        fn mouse_mut(&mut self) -> &mut Mouse {
            self.mouse
        }

        #[inline]
        fn mouse(&self) -> &Mouse {
            self.mouse
        }

        fn received_count(&mut self) -> &mut usize {
            &mut self.received_count
        }

        fn suppress_chars(&mut self) -> &mut bool {
            &mut self.suppress_chars
        }

        fn modifiers(&mut self) -> &mut ModifiersState {
            &mut self.modifiers
        }

        fn window(&self) -> &Window {
            unimplemented!();
        }

        fn window_mut(&mut self) -> &mut Window {
            unimplemented!();
        }

        fn pop_message(&mut self) {
            self.message_buffer.pop();
        }

        fn message(&self) -> Option<&Message> {
            self.message_buffer.message()
        }

        fn config(&self) -> &Config {
            self.config
        }
    }

    macro_rules! test_clickstate {
        {
            name: $name:ident,
            initial_state: $initial_state:expr,
            initial_button: $initial_button:expr,
            input: $input:expr,
            end_state: $end_state:pat,
            last_action: $last_action:expr
        } => {
            #[test]
            fn $name() {
                let mut cfg = Config::default();
                cfg.ui_config.mouse = crate::config::Mouse {
                    double_click: ClickHandler {
                        threshold: Duration::from_millis(1000),
                    },
                    triple_click: ClickHandler {
                        threshold: Duration::from_millis(1000),
                    },
                    hide_when_typing: false,
                    url: Default::default(),
                };

                let size = SizeInfo {
                    width: 21.0,
                    height: 51.0,
                    cell_width: 3.0,
                    cell_height: 3.0,
                    padding_x: 0.0,
                    padding_y: 0.0,
                    dpr: 1.0,
                };

                let mut terminal = Term::new(&cfg, &size, Clipboard::new_nop(), MockEventProxy);

                let mut mouse = Mouse::default();
                mouse.click_state = $initial_state;
                mouse.last_button = $initial_button;

                let mut selection = None;

                let mut message_buffer = MessageBuffer::new();

                let context = ActionContext {
                    terminal: &mut terminal,
                    selection: &mut selection,
                    mouse: &mut mouse,
                    size_info: &size,
                    last_action: MultiClick::None,
                    received_count: 0,
                    suppress_chars: false,
                    modifiers: Default::default(),
                    message_buffer: &mut message_buffer,
                    config: &cfg,
                };

                let urls = Urls::new();
                let mut processor = Processor::new(context, &urls, &None);

                if let Event::WindowEvent {
                    event: WindowEvent::MouseInput {
                        state,
                        button,
                        ..
                    },
                    ..
                } = $input
                {
                    processor.mouse_input(state, button);
                };

                assert!(match processor.ctx.mouse.click_state {
                    $end_state => processor.ctx.last_action == $last_action,
                    _ => false
                });
            }
        }
    }

    macro_rules! test_process_binding {
        {
            name: $name:ident,
            binding: $binding:expr,
            triggers: $triggers:expr,
            mode: $mode:expr,
            mods: $mods:expr,
        } => {
            #[test]
            fn $name() {
                if $triggers {
                    assert!($binding.is_triggered_by($mode, $mods, &KEY, false));
                } else {
                    assert!(!$binding.is_triggered_by($mode, $mods, &KEY, false));
                }
            }
        }
    }

    test_clickstate! {
        name: single_click,
        initial_state: ClickState::None,
        initial_button: MouseButton::Other(0),
        input: Event::<TerminalEvent>::WindowEvent {
            event: WindowEvent::MouseInput {
                state: ElementState::Pressed,
                button: MouseButton::Left,
                device_id: unsafe { ::std::mem::transmute_copy(&0) },
                modifiers: ModifiersState::default(),
            },
            window_id: unsafe { ::std::mem::transmute_copy(&0) },
        },
        end_state: ClickState::Click,
        last_action: MultiClick::None
    }

    test_clickstate! {
        name: double_click,
        initial_state: ClickState::Click,
        initial_button: MouseButton::Left,
        input: Event::<TerminalEvent>::WindowEvent {
            event: WindowEvent::MouseInput {
                state: ElementState::Pressed,
                button: MouseButton::Left,
                device_id: unsafe { ::std::mem::transmute_copy(&0) },
                modifiers: ModifiersState::default(),
            },
            window_id: unsafe { ::std::mem::transmute_copy(&0) },
        },
        end_state: ClickState::DoubleClick,
        last_action: MultiClick::DoubleClick
    }

    test_clickstate! {
        name: triple_click,
        initial_state: ClickState::DoubleClick,
        initial_button: MouseButton::Left,
        input: Event::<TerminalEvent>::WindowEvent {
            event: WindowEvent::MouseInput {
                state: ElementState::Pressed,
                button: MouseButton::Left,
                device_id: unsafe { ::std::mem::transmute_copy(&0) },
                modifiers: ModifiersState::default(),
            },
            window_id: unsafe { ::std::mem::transmute_copy(&0) },
        },
        end_state: ClickState::TripleClick,
        last_action: MultiClick::TripleClick
    }

    test_clickstate! {
        name: multi_click_separate_buttons,
        initial_state: ClickState::DoubleClick,
        initial_button: MouseButton::Left,
        input: Event::<TerminalEvent>::WindowEvent {
            event: WindowEvent::MouseInput {
                state: ElementState::Pressed,
                button: MouseButton::Right,
                device_id: unsafe { ::std::mem::transmute_copy(&0) },
                modifiers: ModifiersState::default(),
            },
            window_id: unsafe { ::std::mem::transmute_copy(&0) },
        },
        end_state: ClickState::Click,
        last_action: MultiClick::None
    }

    test_process_binding! {
        name: process_binding_nomode_shiftmod_require_shift,
        binding: Binding { trigger: KEY, mods: ModifiersState::SHIFT, action: Action::from("\x1b[1;2D"), mode: TermMode::NONE, notmode: TermMode::NONE },
        triggers: true,
        mode: TermMode::NONE,
        mods: ModifiersState::SHIFT,
    }

    test_process_binding! {
        name: process_binding_nomode_nomod_require_shift,
        binding: Binding { trigger: KEY, mods: ModifiersState::SHIFT, action: Action::from("\x1b[1;2D"), mode: TermMode::NONE, notmode: TermMode::NONE },
        triggers: false,
        mode: TermMode::NONE,
        mods: ModifiersState::empty(),
    }

    test_process_binding! {
        name: process_binding_nomode_controlmod,
        binding: Binding { trigger: KEY, mods: ModifiersState::CTRL, action: Action::from("\x1b[1;5D"), mode: TermMode::NONE, notmode: TermMode::NONE },
        triggers: true,
        mode: TermMode::NONE,
        mods: ModifiersState::CTRL,
    }

    test_process_binding! {
        name: process_binding_nomode_nomod_require_not_appcursor,
        binding: Binding { trigger: KEY, mods: ModifiersState::empty(), action: Action::from("\x1b[D"), mode: TermMode::NONE, notmode: TermMode::APP_CURSOR },
        triggers: true,
        mode: TermMode::NONE,
        mods: ModifiersState::empty(),
    }

    test_process_binding! {
        name: process_binding_appcursormode_nomod_require_appcursor,
        binding: Binding { trigger: KEY, mods: ModifiersState::empty(), action: Action::from("\x1bOD"), mode: TermMode::APP_CURSOR, notmode: TermMode::NONE },
        triggers: true,
        mode: TermMode::APP_CURSOR,
        mods: ModifiersState::empty(),
    }

    test_process_binding! {
        name: process_binding_nomode_nomod_require_appcursor,
        binding: Binding { trigger: KEY, mods: ModifiersState::empty(), action: Action::from("\x1bOD"), mode: TermMode::APP_CURSOR, notmode: TermMode::NONE },
        triggers: false,
        mode: TermMode::NONE,
        mods: ModifiersState::empty(),
    }

    test_process_binding! {
        name: process_binding_appcursormode_appkeypadmode_nomod_require_appcursor,
        binding: Binding { trigger: KEY, mods: ModifiersState::empty(), action: Action::from("\x1bOD"), mode: TermMode::APP_CURSOR, notmode: TermMode::NONE },
        triggers: true,
        mode: TermMode::APP_CURSOR | TermMode::APP_KEYPAD,
        mods: ModifiersState::empty(),
    }

    test_process_binding! {
        name: process_binding_fail_with_extra_mods,
        binding: Binding { trigger: KEY, mods: ModifiersState::LOGO, action: Action::from("arst"), mode: TermMode::NONE, notmode: TermMode::NONE },
        triggers: false,
        mode: TermMode::NONE,
        mods: ModifiersState::ALT | ModifiersState::LOGO,
    }
}