use std::env;
use std::fs::File;
use std::io::Read;
use std::path::Path;

use enemize::PatchSet;
use enemize::asar;
use enemize::rom::RomData;

fn main() -> Result<(), anyhow::Error> {
    let mut args = env::args();

    let output_path = args.next_back().expect("No output file");
    let symbols_path = args.next_back().expect("No symbols file");
    let patch_path = args.next_back().expect("No patch file");
    let rom_path = args.next_back().expect("No ROM file");

    let mut rom_bytes = vec![];
    let mut rom_file = File::open(&rom_path)?;
    rom_file.read_to_end(&mut rom_bytes)?;

    rom_bytes = if rom_bytes.len() % 1024 == 512 {
        rom_bytes.into_iter().skip(512).collect()
    } else {
        rom_bytes
    };

    let expected = [
        0x03, 0xa6, 0x39, 0x45, 0x39, 0x81, 0x91, 0x33, 0x7e, 0x89, 0x6e, 0x57, 0x71, 0xf7, 0x71,
        0x73,
    ];
    let actual: [u8; 16] = md5::compute(&rom_bytes).into();
    assert_eq!(expected, actual, "Invalid rom file");

    println!("Applying Patch to rom");

    rom_bytes.resize(4 * 1024 * 1024, 0);

    let symbols = asar::load_symbols(Path::new(&symbols_path))?;

    let mut rom = RomData::new(symbols, rom_bytes);

    let mut patches = PatchSet::load(Path::new(&patch_path))?;
    patches.patch_rom(&mut rom);

    rom.move_room_headers();

    let rom_patches = rom.generate_patch();
    patches.add_patches(rom_patches);

    println!("Writing output file {}", output_path);
    let out_file = File::create(&output_path)?;
    serde_json::to_writer(out_file, &patches)?;

    Ok(())
}