// Copyright 2014 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 (
	"bytes"
)

// Tag represents a Git tag.
type Tag struct {
	Name       string
	ID         sha1
	repo       *Repository
	Object     sha1 // The id of this commit object
	Type       string
	Tagger     *Signature
	TagMessage string
}

func (tag *Tag) Commit() (*Commit, error) {
	return tag.repo.getCommit(tag.Object)
}

// Parse commit information from the (uncompressed) raw
// data from the commit object.
// \n\n separate headers from message
func parseTagData(data []byte) (*Tag, error) {
	tag := new(Tag)
	// we now have the contents of the commit object. Let's investigate...
	nextline := 0
l:
	for {
		eol := bytes.IndexByte(data[nextline:], '\n')
		switch {
		case eol > 0:
			line := data[nextline : nextline+eol]
			spacepos := bytes.IndexByte(line, ' ')
			reftype := line[:spacepos]
			switch string(reftype) {
			case "object":
				id, err := NewIdFromString(string(line[spacepos+1:]))
				if err != nil {
					return nil, err
				}
				tag.Object = id
			case "type":
				// A commit can have one or more parents
				tag.Type = string(line[spacepos+1:])
			case "tagger":
				sig, err := newSignatureFromCommitline(line[spacepos+1:])
				if err != nil {
					return nil, err
				}
				tag.Tagger = sig
			}
			nextline += eol + 1
		case eol == 0:
			tag.TagMessage = string(data[nextline+1:])
			break l
		default:
			break l
		}
	}
	return tag, nil
}