use image::{GrayImage, Luma};
use rusttype::{point, Font, Point, Scale};
use std::env;
use std::fs::{self, File};
use std::io::{self, Write};
use std::path::Path;

fn exec(font_path: &str, characters: Vec<char>, font_name: &str) -> io::Result<()> {
  let font_data = fs::read(font_path)?;
  let font = Font::try_from_vec(font_data).expect("Failed to load font");

  let scale = Scale::uniform(32.0); // Set the font size

  for &c in &characters {
    let image = render_character(&font, scale, c);
    save_bits_to_file(font_name, c, &image)?;
  }

  Ok(())
}

fn render_character(font: &Font, scale: Scale, character: char) -> Vec<u8> {
  let glyph = font.glyph(character).scaled(scale);
  let bounding_box = glyph.exact_bounding_box().unwrap();
  let width = bounding_box.width() as u32;
  let height = bounding_box.height() as u32;

  let mut image: Vec<u8> = Vec::new();

  fn define_item(a: &mut Vec<u8>, i: usize, v: u8) {
    if a.len() <= i {
      while a.len() < i {
        a.push(0x00);
      }
      a.push(v)
    } else {
      a[i] = v;
    }
  }
  define_item(&mut image, 2 + ((width as usize) * (height as usize)), 0x00);

  image[0] = (width & 0b0000_0000_1111_1111) as u8;
  image[1] = (width & 0b1111_1111_0000_0000 << 8) as u8;
  if (image[0] as u16) | (image[1] as u16 >> 8) != width as u16 {
    panic!("Width missmatch!");
  }

  glyph
    .positioned(Point { x: 0.0, y: 0.0 })
    .draw(|gx: u32, gy: u32, v| {
      let bit = (v * 255.0) as u8;
      if gx < width {
        define_item(&mut image,(2 + (gy * width) + gx) as usize, bit);
      }
    });
  image
}
fn img_to_hex(image: Vec<u8>) -> Vec<u8> {
  let mut image2: Vec<u8> = Vec::new();
  let width = (image[0] as u16) | (image[1] as u16 >> 8);

  let mut i: i32 = -3;
  for bit in image {
    i += 1;
    if i >= 0 {
      if i as u16 == width {
        i = 0;
        image2.push('\n' as u8);
      }
      let v = format!("{:x?}", bit);
      let v = if v.len() == 1 { format!("0{}", v) } else { v };
      for char in v.chars() {
        image2.push(char as u8);
      }
      // image2.push(if bit < 80 {' ' as u8} else if bit < 150 {'-' as u8} else {'#' as u8})
    }
  }
  image2
}

fn save_bits_to_file(font_name: &str, character: char, bits: &[u8]) -> io::Result<()> {
  fs::create_dir_all(format!("assets/computed-fonts/{}/", font_name))?;
  let filename = format!(
    "assets/computed-fonts/{}/{}.bin",
    font_name, character as u8
  );
  let mut file = File::create(&filename)?;
  file.write_all(bits)?;
  let filename = format!(
    "assets/computed-fonts/{}/{}.txt",
    font_name, character as u8
  );
  let mut file = File::create(&filename)?;
  file.write_all(&img_to_hex(bits.to_vec()))?;
  Ok(())
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
  exec(
    "assets/fonts/Galmuri11.ttf",
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz2053:"
      .chars()
      .collect(),
    "Galmuri",
  )?;
  exec(
    "assets/fonts/CherryBombOne.ttf",
    "UwUSpace".chars().collect(),
    "CherryBombOne",
  )?;
  Ok(())
}