use cosmic_text::{Attrs, Buffer, Family, FontSystem, Metrics, Shaping, SwashCache};
use image::{Rgba, RgbaImage};

use crate::{
    layout::{TextureHandle, Textures, UiColor, Vec2},
    util::HashMap,
};

pub struct TextData {
    font_system: FontSystem,
    swash_cache: SwashCache,
}

impl Default for TextData {
    fn default() -> Self {
        Self {
            font_system: FontSystem::new(),
            swash_cache: SwashCache::new(),
        }
    }
}

#[derive(Clone, Copy)]
pub struct TextAttrs {
    pub color: UiColor,
    pub size: f32,
    pub line_height: f32,
    pub family: Family<'static>,
}

pub type TextBuffer = Buffer;

impl Default for TextAttrs {
    fn default() -> Self {
        let size = 14.0;
        Self {
            color: UiColor::WHITE,
            size,
            line_height: size * 1.2,
            family: Family::SansSerif,
        }
    }
}

impl TextData {
    pub fn draw(
        &mut self,
        buffer: &mut TextBuffer,
        content: &str,
        attrs: &TextAttrs,
        textures: &mut Textures,
    ) -> (TextureHandle, TextOffset) {
        buffer.set_metrics(
            &mut self.font_system,
            Metrics::new(attrs.size, attrs.line_height),
        );
        buffer.set_text(
            &mut self.font_system,
            content,
            &Attrs::new().family(attrs.family),
            Shaping::Advanced,
        );
        let mut pixels = HashMap::new();
        let mut min_x = 0;
        let mut min_y = 0;
        let mut max_x = 0;
        let mut max_y = 0;
        let c = attrs.color;
        let mut max_width = 0.0f32;
        for run in buffer.layout_runs() {
            for glyph in run.glyphs.iter() {
                let physical_glyph = glyph.physical((0., 0.), 1.0);

                let glyph_color = match glyph.color_opt {
                    Some(some) => some,
                    None => cosmic_text::Color::rgba(c.r, c.g, c.b, c.a),
                };

                self.swash_cache.with_pixels(
                    &mut self.font_system,
                    physical_glyph.cache_key,
                    glyph_color,
                    |x, y, color| {
                        let x = physical_glyph.x + x;
                        let y = run.line_y as i32 + physical_glyph.y + y;
                        min_x = min_x.min(x);
                        min_y = min_y.min(y);
                        max_x = max_x.max(x);
                        max_y = max_y.max(y);
                        pixels.insert((x, y), Rgba(color.as_rgba()));
                    },
                );
            }
            max_width = max_width.max(run.line_w);
        }
        let width = (max_x - min_x + 1) as u32;
        let height = (max_y - min_y + 1) as u32;
        let mut image = RgbaImage::new(width, height);
        for ((x, y), color) in pixels {
            let x = (x - min_x) as u32;
            let y = (y - min_y) as u32;
            image.put_pixel(x, y, color);
        }
        let offset = TextOffset {
            top_left: Vec2::new(min_x as f32, min_y as f32),
            bot_right: Vec2::new(
                max_width - max_x as f32,
                attrs.line_height * buffer.lines.len() as f32 - max_y as f32,
            ),
        };
        (textures.add(image), offset)
    }
}

#[derive(Clone, Copy)]
pub struct TextOffset {
    pub top_left: Vec2,
    pub bot_right: Vec2,
}

impl TextOffset {
    pub fn size(&self, handle: &TextureHandle) -> Vec2 {
        handle.size() - self.top_left + self.bot_right
    }
}