use tempfile::NamedTempFile;

use std::fs::File;
use std::io::{self, Read, Seek, SeekFrom, Write};
use std::{env, fs};

// Offset within the bank file to the version number within the BKHD section.
// TODO: Check if this may change.
const OFFSET_VERSION_NUMBER: u64 = 52;
// Retrieved by philipdestroyer by inspecting the game's sound banks in memory at runtime.
const BANK_VERSION: [u8; 4] = [0x28, 0xbc, 0x11, 0x92];

fn main() {
    let path = env::args().nth(1).expect("Path to sound bank required");

    let tmp_path = {
        let mut f = File::open(&path).expect("failed to open sound bank file");
        let mut tmp = NamedTempFile::new().expect("failed to open temporary file");

        // Copy everything until the version number
        io::copy(
            &mut std::io::Read::by_ref(&mut f).take(OFFSET_VERSION_NUMBER),
            &mut tmp,
        )
        .expect("failed to copy to tempfile");

        // Write the hard coded version number
        tmp.write(&BANK_VERSION).expect("failed to write version number");

        // Copy the rest of the file
        f.seek(SeekFrom::Start(OFFSET_VERSION_NUMBER + 4))
            .expect("failed to skip to rest of content");
        io::copy(&mut f, &mut tmp).expect("failed to copy to tempfile");
        tmp.into_temp_path()
    };

    if let Err(err) = fs::rename(&tmp_path, &path) {
        let tmp_path = tmp_path.keep().expect("failed to persist temporary file");
        eprintln!(
            "failed to rename temporary file to override the sound bank {}.\n\
                Please manually copy the file from {} to {}",
            err,
            tmp_path.display(),
            path
        );
    }
}