1package git
 2
 3import (
 4	"fmt"
 5
 6	"github.com/go-git/go-git/v5"
 7	"github.com/go-git/go-git/v5/plumbing"
 8	"github.com/go-git/go-git/v5/plumbing/object"
 9)
10
11type GitRepo struct {
12	r *git.Repository
13	h plumbing.Hash
14}
15
16func Open(path string, ref string) (*GitRepo, error) {
17	var err error
18	g := GitRepo{}
19	g.r, err = git.PlainOpen(path)
20	if err != nil {
21		return nil, fmt.Errorf("opening %s: %w", path, err)
22	}
23
24	if ref == "" {
25		head, err := g.r.Head()
26		if err != nil {
27			return nil, fmt.Errorf("getting head of %s: %w", path, err)
28		}
29		g.h = head.Hash()
30	} else {
31		hash, err := g.r.ResolveRevision(plumbing.Revision(ref))
32		if err != nil {
33			return nil, fmt.Errorf("resolving rev %s for %s: %w", ref, path, err)
34		}
35		g.h = *hash
36	}
37	return &g, nil
38}
39
40func (g *GitRepo) Commits() ([]*object.Commit, error) {
41	ci, err := g.r.Log(&git.LogOptions{From: g.h})
42	if err != nil {
43		return nil, fmt.Errorf("commits from ref: %w", err)
44	}
45
46	commits := []*object.Commit{}
47	ci.ForEach(func(c *object.Commit) error {
48		commits = append(commits, c)
49		return nil
50	})
51
52	return commits, nil
53}
54
55func (g *GitRepo) LastCommit() (*object.Commit, error) {
56	c, err := g.r.CommitObject(g.h)
57	if err != nil {
58		return nil, fmt.Errorf("last commit: %w", err)
59	}
60	return c, nil
61}
62
63func (g *GitRepo) FileContent(path string) (string, error) {
64	c, err := g.r.CommitObject(g.h)
65	if err != nil {
66		return "", fmt.Errorf("commit object: %w", err)
67	}
68
69	tree, err := c.Tree()
70	if err != nil {
71		return "", fmt.Errorf("file tree: %w", err)
72	}
73
74	file, err := tree.File(path)
75	if err != nil {
76		return "", err
77	}
78
79	return file.Contents()
80}