package git

import (
	"bytes"
	"errors"
	"fmt"
	"os/exec"
	"strings"
)

func Ignored(worktree string, paths []string) (map[string]bool, error) {
	ignored := map[string]bool{}
	if len(paths) == 0 {
		return ignored, nil
	}

	cmd := exec.Command("git", "check-ignore", "--stdin", "-z")
	cmd.Dir = worktree
	cmd.Stdin = strings.NewReader(strings.Join(paths, "\x00") + "\x00")
	stderr := &strings.Builder{}
	cmd.Stderr = stderr
	out, err := cmd.Output()
	exit := &exec.ExitError{}
	if errors.As(err, &exit) && exit.ExitCode() == 1 {
		return ignored, nil
	}
	if err != nil {
		return nil, fmt.Errorf("git check-ignore: %w: %s", err, strings.TrimSpace(stderr.String()))
	}

	for _, p := range bytes.Split(out, []byte{0}) {
		if len(p) > 0 {
			ignored[string(p)] = true
		}
	}
	return ignored, nil
}