/*
    This file is part of Takwrap.

    Takwrap 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.

    Foobar 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 Foobar.  If not, see <https://www.gnu.org/licenses/>.
*/

use fltk::{app::*, button::*, draw::*, frame::*, menu::*, text::*, window::*};

use crate::game::*;

struct BoardRendererBackend {
    xorg: i32,
    yorg: i32,
    square_size: i32,
}

impl BoardRendererBackend {
    fn initialise(frame: &Frame, frame_pad: i32, game_size: i32) -> BoardRendererBackend {
        let x0 = frame.x();
        let y0 = frame.y();
        let xorg = x0 + frame_pad;
        let yorg = y0 + frame_pad;
        let board_size = i32::min(frame.width(), frame.height()) - frame_pad * 2;

        BoardRendererBackend {
            xorg,
            yorg,
            square_size: board_size / game_size,
        }
    }
}

#[derive(Clone, Copy)]
struct BoardRenderer {
    even_square_colour: Color,
    odd_square_colour: Color,
    black_colour: Color,
    white_colour: Color,
    stone_size: f32,
    game_size: i32,
}

impl BoardRenderer {
    fn default() -> BoardRenderer {
        BoardRenderer {
            // Sandy brown
            odd_square_colour: Color::from_rgb(244, 164, 96),
            // Moccasin
            even_square_colour: Color::from_rgb(255, 228, 181),
            // Colours for pieces
            black_colour: Color::from_rgb(178, 34, 34),
            white_colour: Color::from_rgb(250, 235, 215),
            // Gap between stones and edged of square
            stone_size: 0.8,
            // I'm not sure where this should go
            game_size: 5,
        }
    }

    fn with_size(mut self, size: i32) -> BoardRenderer {
        self.game_size = size;
        return self;
    }

    fn render_stone(
        &self,
        backend: &BoardRendererBackend,
        player: Player,
        stone: Stone,
        row: i32,
        col: i32,
        shift: i32,
    ) {
        set_draw_color(match player {
            Player::Black => self.black_colour,
            Player::White => self.white_colour,
        });

        // Gap scales with square size
        let stone_gap = (backend.square_size as f32 * (1.00 - self.stone_size)).round() as i32;
        let d = backend.square_size - stone_gap * 2;
        let shift = (shift * d) / 8;
        let x1 = backend.xorg + col * backend.square_size + stone_gap + shift;
        let y1 = backend.yorg + row * backend.square_size + stone_gap - shift;

        // Outline with thickness varying by stone size
        let setup_border_pen = || {
            set_line_style(LineStyle::Solid, i32::max(1, d / 24));
            set_draw_color(Color::Black);
        };

        match stone {
            Stone::Capstone => {
                draw_pie(x1, y1, d, d, 0.0, 360.0);
                setup_border_pen();
                let r = (d as f64) / 2.0;
                draw_circle(r + x1 as f64, r + y1 as f64, r);
            }
            Stone::Flat => {
                draw_rectf(x1, y1, d, d);
                setup_border_pen();
                draw_rect_with_color(x1, y1, d, d, Color::Black);
            }
            Stone::Standing => {
                // These look bad shifted so we shift it back if was
                let df = d as f64;
                // and we have to fudge it a little? Some rounding things presumably
                let ds = if shift > 0 { df / 8.0 - 0.5 } else { 0.0 };
                let x1 = x1 as f64 - ds;
                let y1 = y1 as f64 + ds;

                let verts = [
                    (x1 + df * 0.3, y1 + df * 0.075),
                    (x1 + df * 0.925, y1 + df * 0.7),
                    (x1 + df * 0.7, y1 + df * 0.925),
                    (x1 + df * 0.075, y1 + df * 0.3),
                ];

                begin_polygon();
                for (x, y) in verts.iter() {
                    vertex(*x, *y)
                }
                end_polygon();

                setup_border_pen();
                begin_loop();
                for (x, y) in verts.iter() {
                    vertex(*x, *y);
                }
                end_loop();
            }
        }
        set_line_style(LineStyle::Solid, 1);
    }

    fn render_icons(
        &self,
        backend: &BoardRendererBackend,
        player: Player,
        row: i32,
        col: i32,
        shift: i32,
    ) {
        let stone_gap = backend.square_size as f32 * (1.00 - self.stone_size);
        let icon_gap = (stone_gap * 0.15).round() as i32;
        let icon_width = (stone_gap * 0.7).round() as i32;
        let icon_height = icon_width / 2;

        let x1 = backend.xorg + col * backend.square_size + icon_gap;
        let y1 = backend.yorg + (row + 1) * backend.square_size - icon_gap;

        set_line_style(LineStyle::Solid, i32::max(1, icon_width / 8));
        set_draw_color(Color::Black);

        set_draw_color(match player {
            Player::Black => self.black_colour,
            Player::White => self.white_colour,
        });
        let y2 = y1 - icon_height * (1 + shift as i32);
        draw_rectf(x1, y2, icon_width, icon_height);
        draw_rect_with_color(x1, y2, icon_width, icon_height, Color::Black);

        set_line_style(LineStyle::Solid, 1);
    }

    fn render_stack(&self, backend: &BoardRendererBackend, row: i32, col: i32, stack: &Stack) {
        // Is there a better way than usize::min((...), i32::MAX as usize) as i32 ?
        let cutoff = stack.len() as i32 - self.game_size;

        for (shift, piece) in stack.iter().enumerate() {
            let shift = shift as i32; // TODO: please don't overflow
            if shift < cutoff {
                self.render_icons(backend, piece.player, row, col, shift);
            } else {
                self.render_stone(
                    backend,
                    piece.player,
                    piece.stone,
                    row,
                    col,
                    shift - i32::max(0, cutoff),
                );
            }
        }
    }

    fn render_board(&self, backend: &BoardRendererBackend) {
        for x in 0..self.game_size {
            for y in 0..self.game_size {
                if (x + y) % 2 == 0 {
                    set_draw_color(self.even_square_colour);
                } else {
                    set_draw_color(self.odd_square_colour);
                }
                draw_rectf(
                    backend.xorg + x * backend.square_size,
                    backend.yorg + y * backend.square_size,
                    backend.square_size,
                    backend.square_size,
                );
            }
        }
    }
}

struct GUIBoard {
    frame: Frame,
    renderer: BoardRenderer,
    size: i32,
}

impl GUIBoard {
    fn new(frame: Frame, size: i32) -> GUIBoard {
        let renderer = BoardRenderer::default().with_size(size);
        let mut g = GUIBoard {
            frame,
            size,
            renderer,
        };
        g.frame.draw2(g.render());
        return g;
    }

    fn render(&self) -> impl Fn(&mut Frame) {
        let renderer = self.renderer;
        let game_size = self.size;

        let stack = vec![
            Piece {
                player: Player::Black,
                stone: Stone::Flat,
            },
            Piece {
                player: Player::White,
                stone: Stone::Flat,
            },
            Piece {
                player: Player::White,
                stone: Stone::Flat,
            },
            Piece {
                player: Player::Black,
                stone: Stone::Flat,
            },
            Piece {
                player: Player::White,
                stone: Stone::Flat,
            },
            Piece {
                player: Player::Black,
                stone: Stone::Flat,
            },
            Piece {
                player: Player::Black,
                stone: Stone::Flat,
            },
            Piece {
                player: Player::White,
                stone: Stone::Flat,
            },
            Piece {
                player: Player::Black,
                stone: Stone::Flat,
            },
            Piece {
                player: Player::White,
                stone: Stone::Standing,
            },
        ];

        move |frame: &mut Frame| {
            let backend = BoardRendererBackend::initialise(frame, 5, game_size);
            renderer.render_board(&backend);

            // Test code for now
            renderer.render_stack(&backend, 1, 4, &stack);
            renderer.render_stone(&backend, Player::Black, Stone::Capstone, 1, 2, 0);
            renderer.render_stone(&backend, Player::Black, Stone::Standing, 2, 2, 0);
        }
    }
}

#[derive(Clone, Copy)]
enum GUIMessage {
    None,
    Test,
}

pub struct GUI {
    app: App,
    window: Window,
    board: GUIBoard,
    log: TextDisplay,
    sender: Sender<GUIMessage>,
    receiver: Receiver<GUIMessage>,
}

impl GUI {
    pub fn new() -> GUI {
        let app = App::default();

        // TODO: Why is this not the same as
        /*
               let mut window = Window::default()
                   .with_size(800, 600)
                   .with_label("Takwrap")
                   .center_screen();
        */
        // Windows made that way are not resizable?

        let mut window = Window::new(0, 0, 800, 600, "Takwrap").center_screen();

        let (sender, receiver) = channel::<GUIMessage>();

        const MENU_HEIGHT: i32 = 24;
        let mut menu = SysMenuBar::default().with_size(800, MENU_HEIGHT);
        // menu.set_text_font(Font::Helvetica);
        menu.set_color(Color::Light2);
        menu.add_emit(
            "&File/New...\t",
            Shortcut::None,
            MenuFlag::Normal,
            sender,
            GUIMessage::None,
        );
        menu.add_emit(
            "&File/Open...\t",
            Shortcut::None,
            MenuFlag::Normal,
            sender,
            GUIMessage::Test,
        );

        const LOG_WIDTH: i32 = 800 - 600 + MENU_HEIGHT;
        let mut log = TextDisplay::default()
            .with_size(LOG_WIDTH, 600 - menu.height())
            .with_pos(800 - LOG_WIDTH, menu.height());
        log.set_buffer(Some(TextBuffer::default()));
        log.insert("test");

        let mut board_frame = Frame::default()
            .with_size(800 - LOG_WIDTH, 600 - menu.height())
            .below_of(&menu, 0);
        board_frame.set_frame(FrameType::EmbossedBox);

        window.resizable(&mut board_frame);
        window.end();
        window.show();

        let board = GUIBoard::new(board_frame, 5);

        // button.emit(sender, GUIMessage::Foo);

        GUI {
            app,
            board,
            window,
            log,
            sender,
            receiver,
        }
    }

    pub fn run(&mut self) -> Result<(), fltk::prelude::FltkError> {
        while self.app.wait() {
            if let Some(msg) = self.receiver.recv() {
                match msg {
                    _ => (),
                }
            }
        }
        Ok(())
    }
}