package main

import (
	"context"
	"flag"
	"os"

	"github.com/Xe/ln"
)

func main() {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	flag.Parse()

	if flag.NArg() != 1 {
		ln.Fatal(ctx, ln.Info("please pass a webassembly file to run"))
	}

	fname := flag.Arg(0)
	fin, err := os.Open(fname)
	if err != nil {
		ln.FatalErr(ctx, err, ln.F{"msg": "can't open file", "fname": fname})
	}
	defer fin.Close()

	p, err := NewProcess(fin)
	if err != nil {
		ln.FatalErr(ctx, err, ln.F{"msg": "can't create process", "fname": fname})
	}

	foundMain := false
	mainID := uint32(0)
	for name, entry := range p.mod.Export.Entries {
		if name == "main" && entry.FieldStr == "main" {
			mainID = entry.Index
			foundMain = true
			break
		}
	}

	if !foundMain {
		ln.Fatal(ctx, ln.F{"msg": "no main function exported"})
	}

	_, err = p.vm.ExecCode(int64(mainID))
	if err != nil {
		ln.FatalErr(ctx, err)
	}
}