weathr 1.3.0

use crate::render::TerminalRenderer;
use crossterm::style::Color;
use rand::prelude::*;
use std::io;

struct Bird {
    x: f32,
    y: f32,
    speed: f32,
    character: char,
    flap_state: bool, // true = wings up, false = wings down/flat
    flap_timer: u8,
}

pub struct BirdSystem {
    birds: Vec<Bird>,
    terminal_width: u16,
    terminal_height: u16,
}

impl BirdSystem {
    pub fn new(terminal_width: u16, terminal_height: u16) -> Self {
        Self {
            birds: Vec::with_capacity(3),
            terminal_width,
            terminal_height,
        }
    }

    pub fn update(&mut self, terminal_width: u16, terminal_height: u16, rng: &mut impl Rng) {
        self.terminal_width = terminal_width;
        self.terminal_height = terminal_height;

        for bird in &mut self.birds {
            bird.x += bird.speed;
            bird.flap_timer += 1;
            if bird.flap_timer > 5 {
                bird.flap_state = !bird.flap_state;
                bird.flap_timer = 0;
            }
            bird.character = if bird.flap_state { 'v' } else { '-' };
        }

        self.birds.retain(|b| b.x < terminal_width as f32);
        if self.birds.len() < 3 && rng.random::<f32>() < 0.01 {
            let y = (rng.random::<u16>() % (terminal_height / 3)) as f32;
            let speed = 0.2 + (rng.random::<f32>() * 0.2);
            self.birds.push(Bird {
                x: 0.0,
                y,
                speed,
                character: 'v',
                flap_state: true,
                flap_timer: 0,
            });
        }
    }

    pub fn render(&self, renderer: &mut TerminalRenderer) -> io::Result<()> {
        for bird in &self.birds {
            let x = bird.x as u16;
            let y = bird.y as u16;
            if x < self.terminal_width && y < self.terminal_height {
                renderer.render_char(x, y, bird.character, Color::Yellow)?;
            }
        }
        Ok(())
    }
}