package worker

import (
	"bufio"
	"bytes"
	"fmt"
	"os/exec"
)

type RunOps struct {
	Log        Logger
	Path       string
	FuncConfig *FuncConfig
	Env        []string
}

func RunFunction(opt *RunOps, input []byte) ([]byte, error) {
	if opt.FuncConfig.Runtime != "exec" {
		return nil, fmt.Errorf("unsupported runtime: %s", opt.FuncConfig.Runtime)
	}

	cmd := exec.Command(opt.Path)
	cmd.Env = opt.Env
	cmd.Stdin = bytes.NewReader(input)

	var out bytes.Buffer
	cmd.Stdout = &out
	stderrPipe, err := cmd.StderrPipe()
	if err != nil {
		return nil, err
	}
	go func() {
		scanner := bufio.NewScanner(stderrPipe)
		for scanner.Scan() {
			line := scanner.Text()
			opt.Log.Write(line)
		}
	}()

	if err := cmd.Start(); err != nil {
		return nil, err
	}

	if err := cmd.Wait(); err != nil {
		return nil, fmt.Errorf("failed: %w\noutput: %s", err, out.String())
	}

	return out.Bytes(), nil
}