mod gyehoek;
mod internal;
mod types;

use std::io;
use std::io::Read;
use clio::*;
use clap::Parser;
use wasmtime::*;

/// A Wasm runtime for Gyehoek scheme.
#[derive(Parser, Debug)]
#[command(name = "gyehoek", version, about, long_about = None)]
struct Args {
    /// Path to Wasm binary or textual source
    #[clap(value_parser)]
    wasm: Input,
}

fn read<R : Read> (mut rdr : R) -> io::Result<Vec<u8>> {
    let mut buf = vec! [];
    rdr.read_to_end (&mut buf)?;
    Ok (buf)
}

fn get_config () -> Config {
    let mut cfg = Config::new ();
    cfg.wasm_reference_types (true);
    cfg.wasm_function_references (true);
    cfg.wasm_tail_call (true);
    cfg.wasm_gc (true);
    cfg
}

fn link_primitives (linker : &mut Linker<u32>) -> wasmtime::Result<()> {
    linker.func_wrap ("gyehoek", "write", gyehoek::write)?;
    linker.func_wrap ("gyehoek", "truthy?", gyehoek::truthy_p)?;
    Ok (())
}

pub fn main () -> wasmtime::Result<()> {
    let args = Args::parse ();
    let wasm_config = get_config ();
    let engine = Engine::new (&wasm_config)?;
    let module = Module::new (&engine, read (args.wasm)?)?;
    let mut linker = Linker::new (&engine);
    link_primitives (&mut linker)?;
    let mut store : Store<u32> = Store::new (&engine, 4);
    let instance = linker.instantiate (&mut store, &module)?;
    let main = instance.get_typed_func::<(),()> (&mut store, "main")?;
    main.call (&mut store, ())?;
    Ok (())
}