use clap::Parser;
use evc::{
    block::{Block, BlockInner},
    frame::Frame,
    ser::Sink,
    view::View,
};
use std::io::{self, BufReader, BufWriter};

#[derive(Parser)]
#[clap(about, version)]
pub struct EncodeArgs {
    #[arg(short = 'W', long)]
    width: usize,
    #[arg(short = 'H', long)]
    height: usize,
}

fn main() -> io::Result<()> {
    let args = EncodeArgs::parse();

    let mut input = BufReader::new(std::io::stdin());
    let mut output = BufWriter::new(std::io::stdout());

    let size = (args.width, args.height);

    let mut prev_frame = Frame::new(size);
    for i in 0.. {
        println!("frame {i}");
        let frame = Frame::read(&mut input, size)?;

        let v1 = frame.view((0, 0), size);
        let v2 = prev_frame.view((0, 0), size);

        let root = encode_block(v1, v2);
        root.write(&mut output)?;

        prev_frame = frame;
    }

    Ok(())
}

fn encode_block(view: View, prev: View) -> Block {
    let diff = View::diff(&view, &prev);

    let inner = if diff < 10_000.0 {
        BlockInner::Reference {
            translation: (0, 0),
        }
    } else {
        if view.size.0 < 32 {
            BlockInner::Literal(view.pixels())
        } else {
            let [a, b] = view.split();
            let [ap, bp] = prev.split();
            BlockInner::Split(Box::new([encode_block(a, ap), encode_block(b, bp)]))
        }
    };

    Block {
        size: view.size,
        inner,
    }
}