// Copyright (c) 2020 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

use std::fs::File;
use std::io::{Read, BufWriter};
use std::error::Error;

fn main() -> Result<(), Box<dyn Error>> {
    let args: Vec<_> = std::env::args().collect();
    if args.len() != 5 {
        eprintln!("Usage: {} <input layer> <output.png> <width> <height>", args[0]);
        panic!();
    }

    let filename = &args[1];
    let output = &args[2];
    let width = args[3].parse()?;
    let height = args[4].parse()?;

    let mut file = File::open(filename)?;
    let mut data = Vec::new();
    file.read_to_end(&mut data)?;
    let layer = krita::PaintLayer::parse(&data).unwrap().1;

    let file = File::create(output)?;
    let ref mut w = BufWriter::new(file);

    let mut encoder = png::Encoder::new(w, width as u32, height as u32);
    encoder.set_color(png::ColorType::RGBA);
    encoder.set_depth(png::BitDepth::Eight);
    let mut writer = encoder.write_header()?;

    let pixels = layer.assemble_tiles([0, 0, 0, 0], width, height);
    writer.write_image_data(&pixels)?; // Save

    Ok(())
}