firework-rs 0.3.1

//! `term` module provides functions of rendering in terminal

use std::io::{Stdout, Write};

use crossterm::{cursor::MoveTo, queue, style, terminal};
use glam::Vec2;
use rand::{seq::IteratorRandom, thread_rng};

use crate::{
    config::Config,
    fireworks::{FireworkManager, FireworkState},
    particle::LifeState,
    utils::distance_squared,
};

/// Wrap a character with color
#[derive(Debug, Clone, Copy)]
pub struct Char {
    pub text: char,
    pub color: style::Color,
}

#[allow(unused)]
impl Char {
    /// Create a new `Char`
    fn new(text: char, color: style::Color) -> Self {
        Self { text, color }
    }
}

/// Struct that represents a terminal
pub struct Terminal {
    pub size: (u16, u16),
    pub screen: Vec<Vec<Char>>,
}

impl Default for Terminal {
    fn default() -> Self {
        let size = terminal::size().expect("Fail to get terminal size.");
        let screen = vec![
            vec![
                Char {
                    text: ' ',
                    color: style::Color::White
                };
                size.0 as usize
            ];
            size.1 as usize
        ];
        Self { size, screen }
    }
}

impl Terminal {
    pub fn new(cfg: &Config) -> Self {
        let mut size = terminal::size().expect("Fail to get terminal size.");
        if cfg.enable_cjk {
            size.0 = (size.0 - 1) / 2;
        }
        let screen = vec![
            vec![
                Char {
                    text: ' ',
                    color: style::Color::White
                };
                size.0 as usize
            ];
            size.1 as usize
        ];
        Self { size, screen }
    }

    /// Reload terminal to adapt new window size
    pub fn reinit(&mut self, cfg: &Config) {
        let mut size = terminal::size().expect("Fail to get terminal size.");
        if cfg.enable_cjk {
            size.0 = (size.0 - 1) / 2;
        }
        self.size = size;
        self.screen = vec![
            vec![
                Char {
                    text: ' ',
                    color: style::Color::White
                };
                size.0 as usize
            ];
            size.1 as usize
        ];
    }

    /// Clear the terminal screen by setting all the characters in terminal to space
    pub fn clear_screen(&mut self) {
        let size = terminal::size().expect("Fail to get terminal size.");
        self.screen = vec![
            vec![
                Char {
                    text: ' ',
                    color: style::Color::White
                };
                size.0 as usize
            ];
            size.1 as usize
        ];
    }

    /// Print the data out to terminal
    pub fn print(&self, w: &mut Stdout, cfg: &Config) {
        self.screen.iter().enumerate().for_each(|(y, line)| {
            line.iter().enumerate().for_each(|(x, c)| {
                queue!(
                    w,
                    MoveTo(
                        if cfg.enable_cjk {
                            (x * 2) as u16
                        } else {
                            x as u16
                        },
                        y as u16
                    ),
                    style::SetForegroundColor(c.color),
                    style::Print(c.text)
                )
                .expect("Std io error.")
            });
        });
        w.flush().expect("Std io error.");
    }

    /// Write the rendering data of all `Fireworks` and `Particles` to `Terminal`
    pub fn render(&mut self, fm: &FireworkManager, cfg: &Config) {
        self.clear_screen();
        for firework in fm.fireworks.iter().rev() {
            if firework.state == FireworkState::Alive {
                for particle in firework.current_particles.iter().rev() {
                    let grad = if firework.config.enable_gradient {
                        Some((firework.config.gradient_scale)(
                            particle.time_elapsed.as_secs_f32()
                                / particle.config.life_time.as_secs_f32(),
                        ))
                    } else {
                        None
                    };
                    particle
                        .trail
                        .iter()
                        .map(|p| {
                            if cfg.enable_cjk {
                                *p
                            } else {
                                Vec2::new(p.x * 2., p.y)
                            }
                        })
                        .rev()
                        .collect::<Vec<_>>()
                        .windows(2)
                        .enumerate()
                        .for_each(|(idx, v)| {
                            let density = (particle.config.trail_length - idx - 1) as f32
                                / particle.config.trail_length as f32;
                            construct_line(v[0], v[1]).iter().for_each(|p| {
                                if self.inside(*p)
                                    && self.screen[p.1 as usize][p.0 as usize].text == ' '
                                {
                                    if let Some(c) = match particle.life_state {
                                        LifeState::Alive => {
                                            Some(get_char_alive(density, cfg.enable_cjk))
                                        }
                                        LifeState::Declining => {
                                            Some(get_char_declining(density, cfg.enable_cjk))
                                        }
                                        LifeState::Dying => {
                                            Some(get_char_dying(density, cfg.enable_cjk))
                                        }
                                        LifeState::Dead => None,
                                    } {
                                        self.screen[p.1 as usize][p.0 as usize] = Char {
                                            text: c,
                                            color: {
                                                let color_u8 = if let Some(g) = grad {
                                                    shift_gradient(particle.config.color, g)
                                                } else {
                                                    particle.config.color
                                                };
                                                style::Color::Rgb {
                                                    r: color_u8.0,
                                                    g: color_u8.1,
                                                    b: color_u8.2,
                                                }
                                            },
                                        }
                                    }
                                }
                            });
                        });
                }
            }
        }
    }

    fn inside(&self, (x, y): (isize, isize)) -> bool {
        x < self.size.0 as isize && y < self.size.1 as isize && x >= 0 && y >= 0
    }
}

fn construct_line(a: Vec2, b: Vec2) -> Vec<(isize, isize)> {
    const STEP: f32 = 0.2;
    let (x0, y0) = (a.x, a.y);
    let (x1, y1) = (b.x, b.y);
    let mut path = Vec::new();
    let mut x = x0;
    let mut y = y0;
    let slope = (y1 - y0) / (x1 - x0);
    let dx = if x0 == x1 {
        0.
    } else if x1 > x0 {
        1.
    } else {
        -1.
    };
    let dy = if y0 == y1 {
        0.
    } else if y1 > y0 {
        1.
    } else {
        -1.
    };
    let mut ds = distance_squared(a, b) + f32::EPSILON;
    path.push((x0.round() as isize, y0.round() as isize));
    if (x1 - x0).abs() >= (y1 - y0).abs() {
        while distance_squared(Vec2::new(x, y), b) <= ds {
            if *path.last().unwrap() != (x.round() as isize, y.round() as isize) {
                path.push((x.round() as isize, y.round() as isize));
                ds = distance_squared(Vec2::new(x, y), b);
            }
            x += dx * STEP;
            y += dy * (STEP * slope).abs();
        }
    } else {
        while distance_squared(Vec2::new(x, y), b) <= ds {
            if *path.last().unwrap() != (x.round() as isize, y.round() as isize) {
                path.push((x.round() as isize, y.round() as isize));
                ds = distance_squared(Vec2::new(x, y), b);
            }
            y += dy * STEP;
            x += dx * (STEP / slope).abs();
        }
    }
    path
}

fn shift_gradient(color: (u8, u8, u8), scale: f32) -> (u8, u8, u8) {
    (
        (color.0 as f32 * scale) as u8,
        (color.1 as f32 * scale) as u8,
        (color.2 as f32 * scale) as u8,
    )
}

fn get_char_alive(density: f32, cjk: bool) -> char {
    let palette = if density < 0.3 {
        if cjk {
            "。，”“』 『￥"
        } else {
            "`'. "
        }
    } else if density < 0.5 {
        if cjk {
            "一二三二三五十十已于上下义天"
            // "いうよへくひとフーク "
        } else {
            "/\\|()1{}[]?"
        }
    } else if density < 0.7 {
        if cjk {
            "时中自字木月日目火田左右点以"
            // "探しているのが誰かなのかどこかなのかそれともただ単に就職先なのか自分でもよくわからない"
        } else {
            "oahkbdpqwmZO0QLCJUYXzcvunxrjft*"
        }
    } else if cjk {
        "龖龠龜"
        // "東京福岡横浜縄"
    } else {
        "$@B%8&WM#"
    };
    palette
        .chars()
        .choose(&mut thread_rng())
        .expect("Fail to choose character.")
}

fn get_char_declining(density: f32, cjk: bool) -> char {
    let palette = if density < 0.2 {
        if cjk {
            "？。， 『』 ||"
        } else {
            "` '. "
        }
    } else if density < 0.6 {
        if cjk {
            "（）【】*￥|十一二三六"
            // "（）【】*￥|ソファー"
        } else {
            "-_ +~<> i!lI;:,\"^"
        }
    } else if density < 0.85 {
        if cjk {
            "人中亿入上下火土"
            // "人ならざるものに出会うかもしれない"
        } else {
            "/\\| ()1{}[ ]?"
        }
    } else if cjk {
        "繁荣昌盛国泰民安龍龖龠龜耋"
        // "時間言葉目覚"
    } else {
        "xrjft*"
    };
    palette
        .chars()
        .choose(&mut thread_rng())
        .expect("Fail to choose character.")
}

fn get_char_dying(density: f32, cjk: bool) -> char {
    let palette = if density < 0.6 {
        if cjk {
            "。 『 』 、： |。，— ……"
        } else {
            ".  ,`.    ^,' . "
        }
    } else if cjk {
        "|￥人 上十入乙小 下"
        // "イントマトナイフ"
    } else {
        " /\\| ( )  1{} [  ]?i !l I;: ,\"^ "
    };
    palette
        .chars()
        .choose(&mut thread_rng())
        .expect("Fail to choose character.")
}