a3s-tui 0.1.5

use std::time::Duration;

use crate::cmd::{self, Cmd};
use crate::element::{Element, TextElement};
use crate::style::Color;

pub struct Spinner {
    frames: Vec<&'static str>,
    current: usize,
    title: String,
    active: bool,
    color: Color,
}

#[derive(Debug, Clone)]
pub struct SpinnerTick;

impl Spinner {
    pub fn new() -> Self {
        Self {
            frames: vec![
                "\u{28cb}", "\u{2819}", "\u{2839}", "\u{2838}", "\u{283c}", "\u{2834}", "\u{2826}",
                "\u{2827}", "\u{2807}", "\u{280f}",
            ],
            current: 0,
            title: String::new(),
            active: true,
            color: Color::Cyan,
        }
    }

    pub fn with_title(mut self, title: impl Into<String>) -> Self {
        self.title = title.into();
        self
    }

    pub fn with_frames(mut self, frames: Vec<&'static str>) -> Self {
        if !frames.is_empty() {
            self.frames = frames;
            self.clamp_current();
        }
        self
    }

    pub fn with_color(mut self, color: Color) -> Self {
        self.color = color;
        self
    }

    pub fn tick(&mut self) {
        if self.active && !self.frames.is_empty() {
            let current = self.normalized_current();
            self.current = if current + 1 == self.frames.len() {
                0
            } else {
                current + 1
            };
        }
    }

    pub fn tick_cmd<M: From<SpinnerTick> + Send + 'static>() -> Cmd<M> {
        cmd::tick(Duration::from_millis(80), SpinnerTick.into())
    }

    pub fn start(&mut self) {
        self.active = true;
    }

    pub fn stop(&mut self) {
        self.active = false;
    }

    pub fn is_active(&self) -> bool {
        self.active
    }

    pub fn element<Msg>(&self) -> Element<Msg> {
        if self.active {
            let text = format!("{} {}", self.current_frame(), self.title);
            Element::Text(TextElement::new(text).fg(self.color))
        } else {
            Element::Text(TextElement::new(&self.title))
        }
    }

    pub fn view(&self) -> String {
        if self.active {
            format!("{} {}", self.current_frame(), self.title)
        } else {
            self.title.clone()
        }
    }

    fn current_frame(&self) -> &str {
        self.frames
            .get(self.normalized_current())
            .or_else(|| self.frames.first())
            .copied()
            .unwrap_or("")
    }

    fn normalized_current(&self) -> usize {
        if self.frames.is_empty() {
            0
        } else {
            self.current % self.frames.len()
        }
    }

    fn clamp_current(&mut self) {
        self.current = self.normalized_current();
    }
}

impl Default for Spinner {
    fn default() -> Self {
        Self::new()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn new_spinner_is_active() {
        let s = Spinner::new();
        assert!(s.is_active());
    }

    #[test]
    fn tick_advances_frame() {
        let mut s = Spinner::new();
        let first = s.frames[0];
        s.tick();
        assert_eq!(s.current, 1);
        assert_ne!(s.frames[s.current], first);
    }

    #[test]
    fn tick_wraps_around() {
        let mut s = Spinner::new();
        for _ in 0..s.frames.len() {
            s.tick();
        }
        assert_eq!(s.current, 0);
    }

    #[test]
    fn empty_custom_frames_are_ignored() {
        let mut s = Spinner::new().with_frames(Vec::new());

        s.tick();

        assert!(!s.frames.is_empty());
        assert_eq!(s.current, 1);
        assert!(!s.view().is_empty());
    }

    #[test]
    fn custom_frames_clamp_current_frame() {
        let mut s = Spinner::new();
        s.current = 9;
        let s = s.with_frames(vec!["a"]);

        assert_eq!(s.current, 0);
        assert_eq!(s.view(), "a ");
    }

    #[test]
    fn current_frame_normalizes_stale_current_frame() {
        let mut s = Spinner::new().with_frames(vec!["a", "b", "c"]);
        s.current = usize::MAX;

        assert_eq!(
            s.view(),
            format!("{} ", s.frames[usize::MAX % s.frames.len()])
        );
    }

    #[test]
    fn tick_normalizes_stale_current_frame() {
        let mut s = Spinner::new().with_frames(vec!["a", "b", "c"]);
        s.current = usize::MAX;

        s.tick();

        assert!(s.current < s.frames.len());
        assert_eq!(
            s.current,
            (usize::MAX % s.frames.len() + 1) % s.frames.len()
        );
    }

    #[test]
    fn stop_prevents_tick() {
        let mut s = Spinner::new();
        s.stop();
        assert!(!s.is_active());
        s.tick();
        assert_eq!(s.current, 0);
    }

    #[test]
    fn with_title() {
        let s = Spinner::new().with_title("Loading");
        let view = s.view();
        assert!(view.contains("Loading"));
    }
}