feat: add compare pages

2 files changed, 71 insertions, 0 deletions

diff --git a/internal/git/compare.go b/internal/git/compare.go
new file mode 100644
index 0000000..4b8f120
--- /dev/null
+++ b/internal/git/compare.go
@@ -0,0 +1,70 @@
+package git
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func CompareDiff(base, head, repoDir string) (string, error) {
+	out, err := gitCmd(repoDir, "diff", base+"..."+head)
+	if err != nil {
+		return "", err
+	}
+	return string(out), nil
+}
+
+func CompareCommits(base, head Ref, repoDir string) ([]Commit, error) {
+	format := []string{"%H", "%h", "%s", "%b", "%an", "%ae", "%ad", "%cn", "%ce", "%cd", "%P", "%D"}
+	out, err := gitCmd(repoDir,
+		"log",
+		"--date=unix",
+		"--pretty=format:"+strings.Join(format, "\x1F"),
+		"-z",
+		base.String()+".."+head.String(),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	lines := strings.Split(string(out), "\x00")
+	commits := make([]Commit, 0, len(lines))
+	for _, line := range lines {
+		if line == "" {
+			continue
+		}
+		parts := strings.Split(line, "\x1F")
+		if len(parts) != len(format) {
+			return nil, fmt.Errorf("unexpected commit format: %s", line)
+		}
+		full, short, subject, body, author, email, date :=
+			parts[0], parts[1], parts[2], parts[3], parts[4], parts[5], parts[6]
+		committerName, committerEmail, committerDate, parents, refs :=
+			parts[7], parts[8], parts[9], parts[10], parts[11]
+
+		timestampInt, err := strconv.Atoi(date)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse commit date: %w", err)
+		}
+		committerTimestampInt, err := strconv.Atoi(committerDate)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse committer date: %w", err)
+		}
+		commits = append(commits, Commit{
+			Hash:           full,
+			ShortHash:      short,
+			Subject:        subject,
+			Body:           body,
+			Author:         author,
+			Email:          email,
+			Date:           time.Unix(int64(timestampInt), 0),
+			CommitterName:  committerName,
+			CommitterEmail: committerEmail,
+			CommitterDate:  time.Unix(int64(committerTimestampInt), 0),
+			Parents:        strings.Fields(parents),
+			RefNames:       parseRefNames(refs),
+		})
+	}
+	return commits, nil
+}
diff --git a/internal/git/git.go b/internal/git/git.go
index 41031e4..4e09d19 100644
--- a/internal/git/git.go
+++ b/internal/git/git.go
@@ -329,3 +329,4 @@ func CommitDiff(hash, repoDir string) (string, error) {
 	}
 	return string(out), nil
 }
+