use imageproc::{
    drawing::draw_filled_rect_mut,
    image::{Rgb, RgbImage},
    rect::Rect,
};

pub struct StackedConfig {
    pub width_px_per_sample: u32,
    pub height_px: u32,
    pub series: Vec<StackedSeriesConfig>,
    pub max_samples: u32,
}

pub struct StackedSeriesConfig {
    pub color: (u8, u8, u8),
}

pub struct StackedSeries<'a> {
    pub config: &'a StackedConfig,
    pub data: Vec<&'a Vec<f32>>,
}

pub fn stacked(graph: StackedSeries) -> RgbImage {
    let mut image = RgbImage::new(
        graph.config.width_px_per_sample * graph.config.max_samples,
        graph.config.height_px as u32,
    );
    draw_scaled_graph(&mut image, &graph);

    image
}

/// return scale factor to scale stacked series sum to range 0..1
fn get_scale(series: &Vec<&Vec<f32>>) -> f32 {
    let len = series.iter().map(|s| s.len()).max().unwrap_or(0);

    let max = (0..len)
        .map(|i| series.iter().map(|s| s[i]).sum::<f32>())
        .max_by(|f1, f2| f1.total_cmp(f2))
        .unwrap_or(1f32);

    1f32 / max
}

fn draw_scaled_graph(image: &mut RgbImage, graph: &StackedSeries) {
    let scale = get_scale(&graph.data);
    let colors = graph
        .config
        .series
        .iter()
        .map(|s| Rgb([s.color.0, s.color.1, s.color.2]))
        .collect::<Vec<Rgb<u8>>>();

    let mut x_offset = 0f32;
    let mut series_idx = 0usize;

    let rows = graph.data.len();
    let cols = graph.data[0].len();
    let transposed_series: Vec<Vec<f32>> = (0..cols)
        .map(|col| (0..rows).map(|row| graph.data[row][col]).collect())
        .collect();

    for timeseries in transposed_series {
        let mut y_offset = graph.config.height_px as f32;

        for sample in timeseries.iter() {
            println!("VAL {}", sample);
            let color = colors[series_idx];
            let height_px = (graph.config.height_px as f32) * sample * scale;
            let rect = Rect::at(x_offset as i32, (y_offset - height_px) as i32)
                .of_size(graph.config.width_px_per_sample, height_px as u32);
            draw_filled_rect_mut(image, rect, color);
            x_offset += graph.config.width_px_per_sample as f32;
            y_offset -= height_px;
            println!("rect: {:?}, height {}, yoff {}", rect, height_px, y_offset);
        }

        println!("BRK");

        // FIXME:
        // series_idx += 1;
    }
}

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

    #[test]
    fn test_get_scale() {
        let conf = vec![
            vec![1., 2., 3., 4., 5.],
            vec![0., 1., 0., 0., 0.],
            vec![0., 0., 0., 0., 5.],
        ];
        assert_eq!(0, 1); // FIX 
        // assert_eq!(get_scale(&conf), 0.1);
    }
}