package gitcmd

import (
	"context"
	"fmt"
	"os"
	"os/exec"
	"strings"
	"sync"
)

var (
	gitExecPath string
	gitOnce     sync.Once
	gitErr      error
)

func SetExecutable(path string) {
	gitExecPath = path
}

func Executable() (string, error) {
	gitOnce.Do(func() {
		if gitExecPath == "" {
			gitExecPath, gitErr = exec.LookPath("git")
		}
	})
	return gitExecPath, gitErr
}

func HomeDir() string {
	if dir := os.Getenv("GIT_HOME"); dir != "" {
		return dir
	}
	return os.TempDir()
}

func CommonEnvs() []string {
	return []string{
		"HOME=" + HomeDir(),
		"GIT_CONFIG_NOSYSTEM=1",
		"GIT_NO_REPLACE_OBJECTS=1",
		"GIT_TERMINAL_PROMPT=0",
		"LC_ALL=C",
	}
}

func Version(ctx context.Context) (string, error) {
	stdout, _, err := NewCommand("version").RunStdString(ctx)
	if err != nil {
		return "", fmt.Errorf("git version: %w", err)
	}
	fields := strings.Fields(stdout)
	if len(fields) >= 3 {
		return fields[2], nil
	}
	return stdout, nil
}