package helmexec

import (
	"os"
	"os/exec"
	"strings"
)

const (
	tmpPrefix = "helmfile-"
	tmpSuffix = "-exec"
)

// Runner interface for shell commands
type Runner interface {
	Execute(cmd string, args []string, env map[string]string) ([]byte, error)
}

// ShellRunner implemention for shell commands
type ShellRunner struct {
	Dir string
}

// Execute a shell command
func (shell ShellRunner) Execute(cmd string, args []string, env map[string]string) ([]byte, error) {
	preparedCmd := exec.Command(cmd, args...)
	preparedCmd.Dir = shell.Dir
	preparedCmd.Env = mergeEnv(os.Environ(), env)
	return preparedCmd.CombinedOutput()
}

func mergeEnv(orig []string, new map[string]string) []string {
	wanted := env2map(orig)
	for k, v := range new {
		wanted[k] = v
	}
	return map2env(wanted)
}

func map2env(wanted map[string]string) []string {
	result := []string{}
	for k, v := range wanted {
		result = append(result, k+"="+v)
	}
	return result
}

func env2map(env []string) map[string]string {
	wanted := map[string]string{}
	for _, cur := range env {
		pair := strings.SplitN(cur, "=", 2)
		wanted[pair[0]] = pair[1]
	}
	return wanted
}