use std::fmt;

#[derive(Clone, Copy, Debug, Default)]
pub struct PixelColor {
    pub(crate) red: u8,
    pub(crate) green: u8,
    pub(crate) blue: u8,
}

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

impl fmt::Display for PixelColor {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "[{},{},{}]", self.red, self.green, self.blue)
    }
}

#[derive(Copy, Clone)]
pub struct Strip<const N: usize> {
    pub strip: [PixelColor; N],
}

impl<const N: usize> Strip<N> {
    pub fn to_array(self) -> Vec<u8> {
        let mut data: Vec<u8> = vec![];

        for i in 0..N {
            data.append(&mut vec![
                self.strip[i].green,
                self.strip[i].red,
                self.strip[i].blue,
            ]);
        }
        data
    }

    pub fn fill(&mut self, color: PixelColor) {
        self.strip = [color; N];
    }
}

impl<const N: usize> Default for Strip<N> {
    fn default() -> Self {
        Strip {
            strip: [PixelColor::new(); N],
        }
    }
}

/// Rainbow pattern /////////////////////////////////////////////////

pub struct Rainbow<const N: usize> {
    pub(crate) current_iteration: usize,
    pub(crate) max_iteration: Option<usize>,
    pub(crate) step: Option<usize>,
}

impl<const N: usize> Iterator for Rainbow<N> {
    type Item = Strip<N>;

    fn next(&mut self) -> Option<Self::Item> {
        if let Some(nbr_iteration) = self.max_iteration {
            if nbr_iteration == self.current_iteration {
                return None;
            }
        }
        let mut strip = Strip::default();
        let step = self.step.unwrap_or(255 / N);
        for i in 0..N {
            let pos = (i * step + self.current_iteration) as u8;
            strip.strip[i] = wheel(pos)
        }
        self.current_iteration += 1;
        Some(strip)
    }
}

fn wheel(index: u8) -> PixelColor {
    let pos = 255 - index;
    match pos {
        0..=85 => PixelColor {
            red: 255 - (pos * 3),
            green: 0,
            blue: pos * 3,
        },
        86..=170 => {
            let pos = pos - 85;
            PixelColor {
                red: 0,
                green: pos * 3,
                blue: 255 - (pos * 3),
            }
        }
        _ => {
            let pos = pos - 170;
            PixelColor {
                red: pos * 3,
                green: 255 - (pos * 3),
                blue: 0,
            }
        }
    }
}

//////////////////////////////////////////////////////////////////////////
/// Colorwipe pattern ////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////

pub struct ColorWipe<const N: usize> {
    pub(crate) current_iteration: usize,
    pub(crate) color: PixelColor,
    pub(crate) infinite: bool,
}

impl<const N: usize> Iterator for ColorWipe<N> {
    type Item = Strip<N>;

    fn next(&mut self) -> Option<Self::Item> {
        let mut strip = Strip::default();
        if self.infinite {
            self.current_iteration %= N;
        } else if self.current_iteration >= N {
            return None;
        }

        for i in 0..self.current_iteration {
            strip.strip[i] = self.color;
        }
        self.current_iteration += 1;
        Some(strip)
    }
}

//////////////////////////////////////////////////////////////////////////
/// fade pattern ////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////

pub struct Fade<const N: usize> {
    pub(crate) current_iteration: usize,
    pub(crate) nbr_iterations: usize,
    pub(crate) begin_color: PixelColor,
    pub(crate) end_color: PixelColor,
}

fn fade_value(value_start: u8, value_end: u8, index: usize, nbr_iter: usize) -> u8 {
    ((value_start as usize * (nbr_iter - index) + value_end as usize * index) / nbr_iter) as u8
}

impl<const N: usize> Iterator for Fade<N> {
    type Item = Strip<N>;

    fn next(&mut self) -> Option<Self::Item> {
        let mut strip = Strip::default();

        if self.current_iteration >= self.nbr_iterations {
            return None;
        }

        let red = fade_value(
            self.begin_color.red,
            self.end_color.red,
            self.current_iteration,
            self.nbr_iterations,
        );
        let green = fade_value(
            self.begin_color.green,
            self.end_color.green,
            self.current_iteration,
            self.nbr_iterations,
        );
        let blue = fade_value(
            self.begin_color.blue,
            self.end_color.blue,
            self.current_iteration,
            self.nbr_iterations,
        );

        let current_color = PixelColor { red, green, blue };

        strip.fill(current_color);

        self.current_iteration += 1;
        Some(strip)
    }
}