#!/usr/bin/env -S denim
/* Cargo.toml
[package]
name = "oled-to-hex"
version = "0.1.0"
authors = ["Anonymous"]
edition = "2021"

[dependencies]
image = { version = "0.25.8", default-features = false, features = ["png"] }
atty = { version = "0.2.14" }
*/

use image::GenericImageView;
use image::ImageReader;
use image::Pixel;
use std::env;
use std::error::Error;
use std::io::{stdout, Error as IoError, ErrorKind, Write};

/// Example script description
fn main() -> Result<(), Box<dyn Error>> {
    let file = env::args().skip(1).next().ok_or(IoError::new(
        ErrorKind::NotFound,
        "expected PNG 128x32 file path",
    ))?;
    eprintln!("Loading {}", file);

    let img = ImageReader::open(file)?.decode()?;
    let (w, h) = img.dimensions();
    eprintln!("Loaded file {}x{}", w, h);
    if w != 128 && h != 32 {
        return Err(Into::into(IoError::new(
            ErrorKind::InvalidData,
            "bad immage dimensions",
        )));
    }

    let out_hex = atty::is(atty::Stream::Stdout);

    for row in 0..4 {
        for column in 0..128 {
            let mut byte = 0u8;
            for bit in 0..8 {
                byte = byte >> 1;
                let x = column;
                let y = row * 8 + bit;
                let pixel = img.get_pixel(x, y);
                let luma = pixel.to_luma()[0];
                if luma > 128 {
                    byte = byte | 128;
                }
            }
            if out_hex {
                print!("{:02X}", byte);
            } else {
                stdout().write(&[byte]).unwrap();
            }
        }
    }

    Ok(())
}

// vim: ft=rust