package gitcmd

import (
	"context"
	"os"
	"path/filepath"
	"strings"
)

type Repository struct {
	Path string
	ctx  context.Context
}

func OpenRepository(ctx context.Context, repoPath string) (*Repository, error) {
	abs, err := filepath.Abs(repoPath)
	if err != nil {
		return nil, err
	}
	if _, err := os.Stat(abs); err != nil {
		return nil, err
	}

	if _, err := os.Stat(filepath.Join(abs, "objects")); os.IsNotExist(err) {
		return nil, os.ErrNotExist
	}
	if _, err := os.Stat(filepath.Join(abs, "refs")); os.IsNotExist(err) {
		return nil, os.ErrNotExist
	}
	return &Repository{Path: abs, ctx: ctx}, nil
}

func (r *Repository) Context() context.Context {
	return r.ctx
}

func (r *Repository) WithContext(ctx context.Context) *Repository {
	return &Repository{Path: r.Path, ctx: ctx}
}

func (r *Repository) Command(args ...string) *Command {
	return NewCommand(args...).WithDir(r.Path)
}

func (r *Repository) IsEmpty() (bool, error) {
	stdout, _, err := NewCommand("rev-list", "-n", "1", "--all").
		WithDir(r.Path).
		RunStdString(r.ctx)
	if err != nil {

		if strings.Contains(err.Error(), "exit status 1") || strings.Contains(err.Error(), "exit status 129") {
			return true, nil
		}
		return false, err
	}
	return strings.TrimSpace(stdout) == "", nil
}

func (r *Repository) DefaultBranch() (string, error) {
	data, err := os.ReadFile(filepath.Join(r.Path, "HEAD"))
	if err != nil {
		return "", err
	}
	const prefix = "ref: refs/heads/"
	line := strings.TrimSpace(string(data))
	if after, ok := strings.CutPrefix(line, prefix); ok {
		return after, nil
	}
	return "", nil
}