use std::{fs::File, path::Path, io::Read};

const GLYPH_WIDTH:  usize = 8;
const GLYPH_HEIGHT: usize = 14;
const GLYPH_AREA:   usize = GLYPH_WIDTH * GLYPH_HEIGHT;
#[allow(dead_code)]
type Glyph = [[bool; GLYPH_WIDTH]; GLYPH_HEIGHT];

/// Reads the file and turns it into a Vec of u8s
fn read_file(file_name: String) -> Vec<u8> {
    let path = Path::new(&file_name);

    if !path.exists() {
        return String::from("Not Found!").into();
    }

    let mut file_content = Vec::new();
    let mut file = File::open(&file_name).expect("Unable to open file");
    file.read_to_end(&mut file_content).expect("Unable to read");

    file_content
}

pub fn get_font() {
    // Retrieve font data from file
    let file_path = String::from("./fonts/Terminus14x8.data");
    println!("In file {file_path}");

    let contents = read_file(file_path);

    let width_left_byte  = contents[0];
    let width_right_byte = contents[1];
    let number = [width_left_byte, width_right_byte];
    let width = u16::from_be_bytes(number);

    println!("Left Byte: {width_left_byte}, Right Byte: {width_right_byte}, Byte Pair {width}");

    /*
    let gtable_prune = contents[2..].iter()
                                    .filter(|x| **x % 3 == 0)
                                    .collect::<Vec<_>>();
     */
    // Remove useless Green and Blue data
    let gtable_prune: Vec<u8> = contents[2..].iter()
                                             .enumerate()
                                             .filter(|x| x.0 % 3 == 0)
                                             .map(|(_, x)| *x)
                                             .collect();

    println!("Pruned Glyph Table is {} long; it should be {}.",
             gtable_prune.len(),
             (contents.len() - 2) / 3
    );

    let glyph_atlas: Vec<Glyph>;
    for glyph in 0..95 {
        let new_glyph: Glyph = [[false; GLYPH_WIDTH]; GLYPH_HEIGHT];
        for p in 0..GLYPH_AREA as u16 {
            let multiplier = p / GLYPH_WIDTH as u16 * width;
            let offset = glyph * GLYPH_WIDTH as u16;
            let position = (p % GLYPH_WIDTH as u16 + multiplier + offset) as usize;

            println!("Glyph num: {glyph:2.} | Addr: {p:3.} | Line: {multiplier:5.} | Pos: {position:5.}");

            if gtable_prune[position] == 255 {
            }
        }
    }
}