From c94a3d0d668b616e01a17dbc3635c44ff27febee Mon Sep 17 00:00:00 2001
From: Songmu <y.songmu@gmail.com>
Date: Thu, 18 Aug 2022 13:48:18 +0900
Subject: [PATCH] create as many changelogs as possible if missing

---
 changelog.go | 11 ++++++++---
 rcpr.go      | 23 ++++++++++++++++++++---
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/changelog.go b/changelog.go
index 694599a..f9f1b7d 100644
--- a/changelog.go
+++ b/changelog.go
@@ -12,7 +12,7 @@ import (
 )
 
 var (
-	versionLinkReg    = regexp.MustCompile(`\*\*Full Changelog\*\*: (https://.*)$`)
+	versionLinkReg    = regexp.MustCompile(`\n\*\*Full Changelog\*\*: (https://.*)$`)
 	semverFromLinkReg = regexp.MustCompile(`.*[./](v?[0-9]+\.[0-9]+\.[0-9]+)`)
 	newContribReg     = regexp.MustCompile(`(?ms)## New Contributors.*\z`)
 )
@@ -45,9 +45,14 @@ func exists(filename string) bool {
 	return err == nil
 }
 
-func insertNewChangelog(orig []byte, section string) string {
+var changelogReg = regexp.MustCompile(`(?i)^# Change\s?log`)
+
+func insertNewChangelog(orig string, section string) string {
+	orig = strings.TrimSpace(orig) + "\n"
+	section = strings.TrimSpace(section) + "\n"
+
 	var bf bytes.Buffer
-	lineSnr := bufio.NewScanner(bytes.NewReader(orig))
+	lineSnr := bufio.NewScanner(strings.NewReader(orig))
 	inserted := false
 	for lineSnr.Scan() {
 		line := lineSnr.Text()
diff --git a/rcpr.go b/rcpr.go
index 4d683f2..11b403f 100644
--- a/rcpr.go
+++ b/rcpr.go
@@ -326,16 +326,33 @@ func Run(ctx context.Context, argv []string, outStream, errStream io.Writer) err
 
 	changelog := convertKeepAChangelogFormat(releases.Body)
 	changelogMd := "CHANGELOG.md"
+
 	var content string
 	if exists(changelogMd) {
 		byt, err := os.ReadFile(changelogMd)
 		if err != nil {
 			return err
 		}
-		content = insertNewChangelog(byt, changelog)
-	} else {
-		content = "# Changelog\n\n" + changelog
+		content = strings.TrimSpace(string(byt)) + "\n"
 	}
+
+	// If the changelog is not in "keep a changelog" format, or if the file does not exist, re-create everything. Is it rough...?
+	if !changelogReg.MatchString(content) {
+		// We are concerned that depending on the release history, API requests may become more frequent.
+		vers := (&gitsemvers.Semvers{}).VersionStrings()
+		logs := []string{"# Changelog\n"}
+		for i := len(vers) - 1; i >= 0 || len(vers)-i < 10; i-- { // Up to 10 most recent versions
+			ver := vers[i]
+			releases, _, _ := rp.gh.Repositories.GenerateReleaseNotes(
+				ctx, rp.owner, rp.repo, &github.GenerateNotesOptions{
+					TagName: ver,
+				})
+			logs = append(logs, strings.TrimSpace(convertKeepAChangelogFormat(releases.Body))+"\n")
+		}
+		content = strings.Join(logs, "\n")
+	}
+
+	content = insertNewChangelog(content, changelog)
 	if err := os.WriteFile(changelogMd, []byte(content), 0644); err != nil {
 		return err
 	}