#![doc = include_str!("../README.md")]
use image::{DynamicImage, GenericImageView, SubImage};
use std::{
    collections::HashMap,
    fmt::{Debug, Display},
};

pub type BrushMap = HashMap<u128, char>;

/// The main interface to image to text converion
#[derive(Default)]
pub struct Insa {
    background: Option<(u8, u8, u8)>,
    invert: bool,
    brushes: BrushMap,
}
impl Debug for Insa {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_fmt(format_args!(
            "Insa {{ background: {:?}, invert: {}, brushes:[\n",
            self.background, self.invert
        ))?;
        for (i, c) in self.brushes() {
            f.write_fmt(format_args!("  (0b{i:0128b},'{c}'),\n"))?;
        }
        f.write_str("] }\n")
    }
}
impl Insa {
    /// Initialize using just space brush, no fixed background.
    pub fn plain() -> Insa {
        Self {
            background: None,
            invert: false,
            brushes: [(0, ' ')].into(),
        }
    }
    /// Initialize using well known round chars on dark background
    pub fn simple_on_dark() -> Insa {
        Insa { background: Some((50,50,50)), invert: false, brushes: [
            (0b00000000000000000000000000000000001111000100001001000010010000100011110001000010010000100100001001000010001111000000000000000000,'8'),
            (0b00000000000000000000000000000000000000000000000000111100010000100100001001000010010000100100001001000010001111000000000000000000,'o'),
            (0b00000000000000000000000000000000000110000010010000100100000110000000000000000000000000000000000000000000000000000000000000000000,'°'),
            (0b00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011000000110000000000000000000,'.'),
            (0b00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000,' '),
        ].into() }
    }
    /// Initialize using well known round chars on dark background
    pub fn simple_on_bright() -> Insa {
        let mut me = Self::simple_on_dark();
        me.invert = true;
        me.background = Some((200, 200, 200));
        me
    }
    /// Initialize using well known block drawing elements and using background
    pub fn blocks() -> Insa {
        Insa { background: None, invert:false, brushes: [
            (0b00000000000000000000000000000000111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111,'▆'),
            (0b11110000111100001111000011110000111100001111000011110000111100000000111100001111000011110000111100001111000011110000111100001111,'▚'),
            (0b00000000000000000000000000000000000000000000000000000000000000001111000011110000111100001111000011110000111100001111000011110000,'▖'),
            (0b11111111111111101111111011111100111111001111100011111000111100001111000011100000111000001100000011000000100000001000000010000000,'◤'),
            (0b11111111111111111111111111111111111111111111111111111111111111110000111100001111000011110000111100001111000011110000111100001111,'▜'),
            (0b11110000111100001111000011110000111100001111000011110000111100001111111111111111111111111111111111111111111111111111111111111111,'▙'),
            (0b11110000111100001111000011110000111100001111000011110000111100001111000011110000111100001111000011110000111100001111000011110000,'▌'),
            (0b11000000110000001100000011000000110000001100000011000000110000001100000011000000110000001100000011000000110000001100000011000000,'▎'),
            (0b11111100111111001111110011111100111111001111110011111100111111001111110011111100111111001111110011111100111111001111110011111100,'▊'),
            (0b00000000000000001111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111,'▇'),
            (0b00000000000000000000000000000000000000000000000011111111111111111111111111111111111111111111111111111111111111111111111111111111,'▅'),
            (0b11111000111110001111100011111000111110001111100011111000111110001111100011111000111110001111100011111000111110001111100011111000,'▋'),
            (0b11111111111111111111111111111111111111111111111111111111111111111111000011110000111100001111000011110000111100001111000011110000,'▛'),
            (0b00000000000000000000000000000000000000000000000000000000000000000000000000000000111111111111111111111111111111111111111111111111,'▃'),
            (0b00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000,' '),
            (0b00001111000011110000111100001111000011110000111100001111000011110000000000000000000000000000000000000000000000000000000000000000,'▝'),
            (0b11111110111111101111111011111110111111101111111011111110111111101111111011111110111111101111111011111110111111101111111011111110,'▉'),
            (0b00001111000011110000111100001111000011110000111100001111000011110000111100001111000011110000111100001111000011110000111100001111,'▐'),
            (0b00000000000000000000000000000000000000000000000000000000000000000000111100001111000011110000111100001111000011110000111100001111,'▗'),
            (0b00001111000011110000111100001111000011110000111100001111000011111111000011110000111100001111000011110000111100001111000011110000,'▞'),
            (0b00000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111111111111111111111111111111111111111,'▄'),
            (0b00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111,'▁'),
            (0b11111111011111110111111100111111001111110001111100011111000011110000111100000111000001110000001100000011000000010000000100000001,'◥'),
            (0b00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011111111111111111111111111111111,'▂'),
            (0b11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111,'█'),
            (0b11111111111111110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000,'▔'),
            (0b00001111000011110000111100001111000011110000111100001111000011111111111111111111111111111111111111111111111111111111111111111111,'▟'),
            (0b11100000111000001110000011100000111000001110000011100000111000001110000011100000111000001110000011100000111000001110000011100000,'▍'),
            (0b10000000100000001000000010000000100000001000000010000000100000001000000010000000100000001000000010000000100000001000000010000000,'▏'),
            (0b00000001000000010000000100000011000000110000011100000111000011110000111100011111000111110011111100111111011111110111111111111111,'◢'),
            (0b10000000100000001000000011000000110000001110000011100000111100001111000011111000111110001111110011111100111111101111111011111111,'◣'),
            (0b11111111111111111111111111111111111111111111111111111111111111110000000000000000000000000000000000000000000000000000000000000000,'▀'),
            (0b11110000111100001111000011110000111100001111000011110000111100000000000000000000000000000000000000000000000000000000000000000000,'▘'),
            (0b00000001000000010000000100000001000000010000000100000001000000010000000100000001000000010000000100000001000000010000000100000001,'▕'),
        ].into() }
    }

    #[cfg(feature = "fontdue")]
    /// Load additional brushes from a font
    ///
    /// ```
    /// let font = include_bytes!("../docs/unifont-15.0.01.ttf");
    /// let font = fontdue::Font::from_bytes(font.as_ref(), fontdue::FontSettings::default())
    ///  .expect("tried and tested included font");
    /// let mut insa = insa::Insa::default();
    /// insa.load_brushes(&font, ".oO8°");
    /// println!("{insa:?}")
    /// ```
    pub fn load_brushes(&mut self, font: &fontdue::Font, brushes: impl AsRef<str>) -> &mut Self {
        let brushes = brushes
            .as_ref()
            .chars()
            .map(|c| (rasterize_u128(font, c), c));
        self.brushes.extend(brushes);
        self
    }
    /// ref access the internal brush map
    pub fn brushes(&self) -> &BrushMap {
        &self.brushes
    }
    /// Mut access internal brush map
    pub fn brushes_mut(&mut self) -> &mut BrushMap {
        &mut self.brushes
    }
    /// Does Insa invert dark/light?
    pub fn invert(&self) -> bool {
        self.invert
    }
    /// Mut access to - does Insa invert dark/light?
    pub fn invert_mut(&mut self) -> &mut bool {
        &mut self.invert
    }
    /// Should Insa invert dark/light?
    pub fn set_invert(&mut self, invert: bool) -> &mut Self {
        self.invert = invert;
        self
    }
    /// Does Insa invert dark/light?
    pub fn fixed_background(&self) -> Option<(u8, u8, u8)> {
        self.background
    }
    /// Mut access to - does Insa invert dark/light?
    pub fn fixed_background_mut(&mut self) -> Option<&mut (u8, u8, u8)> {
        self.background.as_mut()
    }
    /// Should Insa invert dark/light?
    pub fn set_fixed_background(&mut self, invert: Option<(u8, u8, u8)>) -> &mut Self {
        self.background = invert;
        self
    }
    /// The width of the brush in pixels
    pub fn brush_width(&self) -> u8 {
        8
    }
    /// The height of the brush in pixels
    pub fn brush_height(&self) -> u8 {
        16
    }
    /// Convert a raster bitmap image to text.
    /// The returned iterator reveals the number of text columns and rows
    pub fn convert<'a>(&'a self, img: &'a DynamicImage) -> ConvertIterator<'a> {
        ConvertIterator::new(img, &self)
    }
    /// Convert a single symbol, assuming position 0,0 and the symbol width and height for input
    pub fn convert_symbol(&self, img: &SubImage<&DynamicImage>) -> Symbol {
        let (bitmap, mut front_color, mut back_color) = self.bitmap(img);
        let (mut brush, score) = self.get_brush(bitmap);
        if self.background.is_none() && score != u8::MAX {
            let (ibrush, iscore) = self.get_brush(!bitmap);
            if iscore > score {
                brush = ibrush;
                //score = iscore;
                std::mem::swap(&mut front_color, &mut back_color);
            }
        }
        let back_color = match self.background {
            Some(_) => None,
            None => Some(back_color),
        };
        let brush = *brush;
        Symbol {
            brush,
            front_color,
            back_color,
        }
    }
    fn get_brush(&self, bitmap: u128) -> (&char, u8) {
        if let Some(brush) = self.brushes.get(&bitmap) {
            return (brush, u8::MAX);
        }
        let mut my_brush = &' ';
        let mut my_score = 0;
        for (candidate, brush) in &self.brushes {
            let xor = candidate ^ bitmap;
            let new_score = 128 - xor.count_ones();
            if new_score >= my_score {
                my_score = new_score;
                my_brush = brush;
                if my_score >= 120 {
                    break;
                }
            }
        }

        (my_brush, my_score as u8)
    }
    fn bitmap(&self, img: &SubImage<&DynamicImage>) -> (u128, (u8, u8, u8), (u8, u8, u8)) {
        // get all the pixels, while at it, avg colors
        let ((tr, tg, tb), pixs) = (0..128).map(|idx| self.bit(idx, img)).fold(
            ((0, 0, 0), vec![]),
            |((tr, tg, tb), mut pixs), (r, g, b, a)| {
                pixs.push((r, g, b, a));
                ((tr + r as u16, tg + g as u16, tb + b as u16), pixs)
            },
        );

        // the average color
        let (ar, ag, ab) = ((tr / 128) as u8, (tg / 128) as u8, (tb / 128) as u8);

        // figure out the threshold
        let (tr, tg, tb) = match self.background {
            None => (ar, ag, ab),
            Some((br, bg, bb)) => (br, bg, bb),
        };

        // combine into bitmap
        let (bm, fr, fg, fb, br, bg, bb) = (0..128).map(|idx| (pixs[idx], idx)).fold(
            (0, 0u16, 0u16, 0u16, 0u16, 0u16, 0u16),
            |(bm, fr, fg, fb, br, bg, bb), ((r, g, b, _a), idx)| {
                let mut distance =
                    r as isize - tr as isize + g as isize - tg as isize + b as isize - tb as isize;
                if self.invert {
                    distance = -distance;
                }
                let p = if distance > 0 { 1 } else { 0 };
                let front = p as u16;
                let back = (p ^ 1) as u16;
                (
                    bm | ((front as u128) << (127 - idx)),
                    fr + front * r as u16,
                    fg + front * g as u16,
                    fb + front * b as u16,
                    br + back * r as u16,
                    bg + back * g as u16,
                    bb + back * b as u16,
                )
            },
        );

        if let Some(bg) = self.background {
            (bm, (ar, ag, ab), bg)
        } else {
            let fs = bm.count_ones() as u16;
            let bs = bm.count_zeros() as u16;

            let mut front_color = if fs == 0 {
                (127, 127, 127)
            } else {
                (
                    (fr.saturating_div(fs)) as u8,
                    (fg.saturating_div(fs)) as u8,
                    (fb.saturating_div(fs)) as u8,
                )
            };
            let back_color = if bs == 0 {
                front_color
            } else {
                (
                    (br.saturating_div(bs)) as u8,
                    (bg.saturating_div(bs)) as u8,
                    (bb.saturating_div(bs)) as u8,
                )
            };
            if fs == 0 {
                front_color = back_color;
            }

            (bm, front_color, back_color)
        }
    }
    fn bit(&self, idx: u8, img: &SubImage<&DynamicImage>) -> (u8, u8, u8, u8) {
        assert!(idx < 128, "It's a u128");

        let x = (idx % self.brush_width()) as u32;
        let y = (idx / self.brush_height()) as u32;
        if x >= img.width() || y >= img.height() {
            return (0, 0, 0, 0);
        }
        let pix = img.get_pixel(x, y);
        let [r, g, b, a] = pix.0;
        (r, g, b, a)
    }
}

pub struct ConvertIterator<'a> {
    img: &'a image::DynamicImage,
    insa: &'a Insa,
    bwidth: u32,
    bheight: u32,
    rows: u32,
    cols: u32,
    idx: u32,
}
impl<'a> ConvertIterator<'a> {
    pub fn cols(&self) -> u32 {
        self.cols
    }
    pub fn rows(&self) -> u32 {
        self.rows
    }
}
impl<'a> ConvertIterator<'a> {
    pub fn new(img: &'a image::DynamicImage, insa: &'a Insa) -> Self {
        let bwidth = insa.brush_width() as u32;
        let bheight = insa.brush_height() as u32;
        let cols = img.width() / bwidth;
        let rows = img.height() / bheight;
        Self {
            img,
            insa,
            bwidth,
            bheight,
            rows,
            cols,
            idx: 0,
        }
    }
}
impl<'a> Iterator for ConvertIterator<'a> {
    type Item = ((u32, u32), Symbol);
    fn next(&mut self) -> Option<Self::Item> {
        // 0 = not iterated yet, 1 = first item, so we reduce idx by 1 for c*r
        self.idx = self.idx.checked_add(1)?;
        let c = (self.idx - 1) % self.cols;
        let r = (self.idx - 1) / self.cols;
        if r >= self.rows {
            return None;
        }

        let x = c * self.bwidth;
        let y = r * self.bheight;
        let w = (self.img.width() - x).clamp(0, self.bwidth);
        let h = (self.img.height() - y).clamp(0, self.bheight);

        let spot = self.img.view(x, y, w, h);

        Some(((c, r), self.insa.convert_symbol(&spot)))
    }
}
#[cfg(feature = "fontdue")]
/// Rasterize a font character into a u128 bitmap.
/// This is used for matching brushes.
pub fn rasterize_u128(font: &fontdue::Font, c: char) -> u128 {
    let mut bitmap = 0u128;
    let (metrics, pixs) = font.rasterize(c, 16.0);

    const WIDTH: isize = 8;
    const HEIGHT: isize = WIDTH * 2;
    const PIX_THRESHOLD: u8 = 50;

    for (i, pix) in pixs.into_iter().enumerate() {
        let x = (i % metrics.width) as isize;
        let y = (i / metrics.width) as isize;

        let x = x + metrics.xmin as isize;
        let y = y + HEIGHT - metrics.height as isize - metrics.ymin as isize - HEIGHT / 6;
        if x < 0 || y < 0 || x >= WIDTH || y >= HEIGHT {
            continue;
        }
        let pix = if pix >= PIX_THRESHOLD {
            1 << (WIDTH - 1 - x) << ((HEIGHT - 1 - y) * WIDTH)
        } else {
            0
        };
        bitmap = bitmap | pix;
    }
    bitmap
}

pub fn dump_bitmap_u128(bitmap: u128) -> String {
    let mut dump = String::default();
    for row in 0..16 {
        let row = 0b11111111 & (bitmap >> 8 * (15 - row));
        dump += &format!("{row:#010b}\n");
    }
    dump
}
pub struct Symbol {
    pub brush: char,
    pub front_color: (u8, u8, u8),
    pub back_color: Option<(u8, u8, u8)>,
}

impl Display for Symbol {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let Self {
            brush,
            front_color: (fr, fg, fb),
            back_color,
        } = &self;

        // ESC[ 38;2;⟨r⟩;⟨g⟩;⟨b⟩ m Select RGB foreground color
        // ESC[ 48;2;⟨r⟩;⟨g⟩;⟨b⟩ m Select RGB background color
        if let Some((br, bg, bb)) = back_color {
            write!(f, "\x1b[48;2;{br};{bg};{bb}m")?;
        }
        write!(f, "\x1b[38;2;{fr};{fg};{fb}m")?;
        write!(f, "\x1b[1m")?;
        write!(f, "{brush}")
    }
}