// Copyright 2015 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package git

import (
	"strings"
)

// Tree represents a flat directory listing.
type Tree struct {
	ID   SHA1
	repo *Repository

	// parent tree
	ptree *Tree

	entries       Entries
	entriesParsed bool
}

// NewTree create a new tree according the repository and commit id
func NewTree(repo *Repository, id SHA1) *Tree {
	return &Tree{
		ID:   id,
		repo: repo,
	}
}

// SubTree get a sub tree by the sub dir path
func (t *Tree) SubTree(rpath string) (*Tree, error) {
	if len(rpath) == 0 {
		return t, nil
	}

	paths := strings.Split(rpath, "/")
	var (
		err error
		g   = t
		p   = t
		te  *TreeEntry
	)
	for _, name := range paths {
		te, err = p.GetTreeEntryByPath(name)
		if err != nil {
			return nil, err
		}

		g, err = t.repo.getTree(te.ID)
		if err != nil {
			return nil, err
		}
		g.ptree = p
		p = g
	}
	return g, nil
}

// ListEntries returns all entries of current tree.
func (t *Tree) ListEntries() (Entries, error) {
	if t.entriesParsed {
		return t.entries, nil
	}

	stdout, err := NewCommand("ls-tree", t.ID.String()).RunInDirBytes(t.repo.Path)
	if err != nil {
		return nil, err
	}
	t.entries, err = parseTreeEntries(stdout, t)
	return t.entries, err
}