/*
 * meli
 *
 * Copyright 2017-2018 Manos Pitsidianakis
 *
 * This file is part of meli.
 *
 * meli 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.
 *
 * meli 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 meli. If not, see <http://www.gnu.org/licenses/>.
 */

/*! Components visual and logical separations of application interfaces.
 *
 * They can draw on the terminal and receive events, but also do other stuff as well. (For example, see the `notifications` module.)
 * See the `Component` Trait for more details.
 */

use super::*;

pub mod mail;
pub use crate::mail::*;

pub mod notifications;

pub mod utilities;
pub use self::utilities::*;

pub mod contacts;
pub use crate::contacts::*;

use std::fmt;
use std::fmt::{Debug, Display};

use fnv::FnvHashMap;
use uuid::Uuid;

use super::{Key, StatusEvent, UIEvent};
/// The upper and lower boundary char.
const HORZ_BOUNDARY: char = '─';
/// The left and right boundary char.
const VERT_BOUNDARY: char = '│';

/// The top-left corner
const _TOP_LEFT_CORNER: char = '┌';
/// The top-right corner
const _TOP_RIGHT_CORNER: char = '┐';
/// The bottom-left corner
const _BOTTOM_LEFT_CORNER: char = '└';
/// The bottom-right corner
const _BOTTOM_RIGHT_CORNER: char = '┘';

const LIGHT_VERTICAL_AND_RIGHT: char = '├';

const _LIGHT_VERTICAL_AND_LEFT: char = '┤';

const LIGHT_DOWN_AND_HORIZONTAL: char = '┬';

const LIGHT_UP_AND_HORIZONTAL: char = '┴';

const _DOUBLE_DOWN_AND_RIGHT: char = '╔';
const _DOUBLE_DOWN_AND_LEFT: char = '╗';
const _DOUBLE_UP_AND_LEFT: char = '╝';
const _DOUBLE_UP_AND_RIGHT: char = '╚';

type ComponentId = Uuid;

pub type ShortcutMap = FnvHashMap<&'static str, Key>;
pub type ShortcutMaps = FnvHashMap<&'static str, ShortcutMap>;

/// Types implementing this Trait can draw on the terminal and receive events.
/// If a type wants to skip drawing if it has not changed anything, it can hold some flag in its
/// fields (eg self.dirty = false) and act upon that in their `draw` implementation.
pub trait Component: Display + Debug + Send {
    fn draw(&mut self, grid: &mut CellBuffer, area: Area, context: &mut Context);
    fn process_event(&mut self, event: &mut UIEvent, context: &mut Context) -> bool;
    fn is_dirty(&self) -> bool;
    fn is_visible(&self) -> bool {
        true
    }
    fn can_quit_cleanly(&mut self, _context: &Context) -> bool {
        true
    }
    fn set_dirty(&mut self, value: bool);
    fn kill(&mut self, _id: ComponentId, _context: &mut Context) {}
    fn set_id(&mut self, _id: ComponentId) {}
    fn id(&self) -> ComponentId;

    fn get_shortcuts(&self, _context: &Context) -> ShortcutMaps {
        Default::default()
    }

    fn get_status(&self, _context: &Context) -> Option<String> {
        None
    }
}

fn bin_to_ch(b: u32) -> char {
    match b {
        0b0001 => '╶',
        0b0010 => '╵',
        0b0011 => '└',
        0b0100 => '╴',
        0b0101 => '─',
        0b0110 => '┘',
        0b0111 => '┴',
        0b1000 => '╷',
        0b1001 => '┌',
        0b1010 => '│',
        0b1011 => '├',
        0b1100 => '┐',
        0b1101 => '┬',
        0b1110 => '┤',
        0b1111 => '┼',
        _ => unsafe { std::hint::unreachable_unchecked() },
    }
}

fn ch_to_bin(ch: char) -> Option<u32> {
    match ch {
        '└' => Some(0b0011),
        '─' => Some(0b0101),
        '┘' => Some(0b0110),
        '┴' => Some(0b0111),
        '┌' => Some(0b1001),

        '│' => Some(0b1010),

        '├' => Some(0b1011),
        '┐' => Some(0b1100),
        '┬' => Some(0b1101),

        '┤' => Some(0b1110),

        '┼' => Some(0b1111),
        '╷' => Some(0b1000),

        '╵' => Some(0b0010),
        '╴' => Some(0b0100),
        '╶' => Some(0b0001),
        _ => None,
    }
}

#[allow(clippy::never_loop)]
fn set_and_join_vert(grid: &mut CellBuffer, idx: Pos) -> u32 {
    let (x, y) = idx;
    let mut bin_set = 0b1010;
    /* Check left side
     *
     *        1
     *   -> 2 │ 0
     *        3
     */
    loop {
        if x > 0 {
            if let Some(cell) = grid.get_mut(x - 1, y) {
                if let Some(adj) = ch_to_bin(cell.ch()) {
                    if (adj & 0b0001) > 0 {
                        bin_set |= 0b0100;
                        break;
                    } else if adj == 0b0100 {
                        cell.set_ch(bin_to_ch(0b0101));
                        cell.set_fg(Color::Byte(240));
                        bin_set |= 0b0100;
                        break;
                    }
                }
            }
        }
        bin_set &= 0b1011;
        break;
    }

    /* Check right side
     *
     *        1
     *      2 │ 0 <-
     *        3
     */
    loop {
        if let Some(cell) = grid.get_mut(x + 1, y) {
            if let Some(adj) = ch_to_bin(cell.ch()) {
                if (adj & 0b0100) > 0 {
                    bin_set |= 0b0001;
                    break;
                }
            }
        }
        bin_set &= 0b1110;
        break;
    }

    /* Set upper side
     *
     *        1 <-
     *      2 │ 0
     *        3
     */
    loop {
        if y > 0 {
            if let Some(cell) = grid.get_mut(x, y - 1) {
                if let Some(adj) = ch_to_bin(cell.ch()) {
                    cell.set_ch(bin_to_ch(adj | 0b1000));
                    cell.set_fg(Color::Byte(240));
                } else {
                    bin_set &= 0b1101;
                }
            }
        }
        break;
    }

    /* Set bottom side
     *
     *        1
     *      2 │ 0
     *        3 <-
     */
    loop {
        if let Some(cell) = grid.get_mut(x, y + 1) {
            if let Some(adj) = ch_to_bin(cell.ch()) {
                cell.set_ch(bin_to_ch(adj | 0b0010));
                cell.set_fg(Color::Byte(240));
            } else {
                bin_set &= 0b0111;
            }
        }
        break;
    }

    if bin_set == 0 {
        bin_set = 0b1010;
    }

    bin_set
}

#[allow(clippy::never_loop)]
fn set_and_join_horz(grid: &mut CellBuffer, idx: Pos) -> u32 {
    let (x, y) = idx;
    let mut bin_set = 0b0101;
    /* Check upper side
     *
     *        1 <-
     *      2 ─ 0
     *        3
     */
    loop {
        if y > 0 {
            if let Some(cell) = grid.get_mut(x, y - 1) {
                if let Some(adj) = ch_to_bin(cell.ch()) {
                    if (adj & 0b1000) > 0 {
                        bin_set |= 0b0010;
                        break;
                    } else if adj == 0b0010 {
                        bin_set |= 0b0010;
                        cell.set_ch(bin_to_ch(0b1010));
                        cell.set_fg(Color::Byte(240));
                        break;
                    }
                }
            }
        }
        bin_set &= 0b1101;
        break;
    }

    /* Check bottom side
     *
     *        1
     *      2 ─ 0
     *        3 <-
     */
    loop {
        if let Some(cell) = grid.get_mut(x, y + 1) {
            if let Some(adj) = ch_to_bin(cell.ch()) {
                if (adj & 0b0010) > 0 {
                    bin_set |= 0b1000;
                    break;
                } else if adj == 0b1000 {
                    bin_set |= 0b1000;
                    cell.set_ch(bin_to_ch(0b1010));
                    cell.set_fg(Color::Byte(240));
                    break;
                }
            }
        }
        bin_set &= 0b0111;
        break;
    }

    /* Set left side
     *
     *        1
     *   -> 2 ─ 0
     *        3
     */
    loop {
        if x > 0 {
            if let Some(cell) = grid.get_mut(x - 1, y) {
                if let Some(adj) = ch_to_bin(cell.ch()) {
                    cell.set_ch(bin_to_ch(adj | 0b0001));
                    cell.set_fg(Color::Byte(240));
                } else {
                    bin_set &= 0b1011;
                }
            }
        }
        break;
    }

    /* Set right side
     *
     *        1
     *      2 ─ 0 <-
     *        3
     */
    loop {
        if let Some(cell) = grid.get_mut(x + 1, y) {
            if let Some(adj) = ch_to_bin(cell.ch()) {
                cell.set_ch(bin_to_ch(adj | 0b0100));
                cell.set_fg(Color::Byte(240));
            } else {
                bin_set &= 0b1110;
            }
        }
        break;
    }

    if bin_set == 0 {
        bin_set = 0b0101;
    }

    bin_set
}

pub enum BoxBoundary {
    Horizontal,
    Vertical,
}

pub(crate) fn set_and_join_box(grid: &mut CellBuffer, idx: Pos, ch: BoxBoundary) {
    /* Connected sides:
     *
     *        1
     *      2 c 0
     *        3
     *
     *     #3210
     *    0b____
     */

    if grid.ascii_drawing {
        grid[idx].set_ch(match ch {
            BoxBoundary::Vertical => '|',
            BoxBoundary::Horizontal => '-',
        });

        grid[idx].set_fg(Color::Byte(240));
        return;
    }

    let bin_set = match ch {
        BoxBoundary::Vertical => set_and_join_vert(grid, idx),
        BoxBoundary::Horizontal => set_and_join_horz(grid, idx),
    };

    grid[idx].set_ch(bin_to_ch(bin_set));
    grid[idx].set_fg(Color::Byte(240));
}

pub fn create_box(grid: &mut CellBuffer, area: Area) {
    if !is_valid_area!(area) {
        return;
    }
    let upper_left = upper_left!(area);
    let bottom_right = bottom_right!(area);

    if !grid.ascii_drawing {
        for x in get_x(upper_left)..get_x(bottom_right) {
            grid[(x, get_y(upper_left))].set_ch(HORZ_BOUNDARY);
            grid[(x, get_y(bottom_right))].set_ch(HORZ_BOUNDARY);
            grid[(x, get_y(bottom_right))].set_fg(Color::Byte(240));
        }

        for y in get_y(upper_left)..get_y(bottom_right) {
            grid[(get_x(upper_left), y)].set_ch(VERT_BOUNDARY);
            grid[(get_x(bottom_right), y)].set_ch(VERT_BOUNDARY);
            grid[(get_x(bottom_right), y)].set_fg(Color::Byte(240));
        }
        set_and_join_box(grid, upper_left, BoxBoundary::Horizontal);
        set_and_join_box(
            grid,
            set_x(upper_left, get_x(bottom_right)),
            BoxBoundary::Horizontal,
        );
        set_and_join_box(
            grid,
            set_y(upper_left, get_y(bottom_right)),
            BoxBoundary::Vertical,
        );
        set_and_join_box(grid, bottom_right, BoxBoundary::Vertical);
    }
}