From 1e9fd7d5ede337da30fcbfba49952d1612a666ec Mon Sep 17 00:00:00 2001
From: Pekka Enberg <penberg@iki.fi>
Date: Mon, 7 Jul 2025 15:41:01 +0300
Subject: [PATCH] Add scripts/gen-changelog.py

---
 scripts/gen-changelog.py | 106 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100755 scripts/gen-changelog.py

diff --git a/scripts/gen-changelog.py b/scripts/gen-changelog.py
new file mode 100755
index 000000000..6e39297a8
--- /dev/null
+++ b/scripts/gen-changelog.py
@@ -0,0 +1,106 @@
+#!/usr/bin/env python3
+import subprocess
+import re
+import sys
+from collections import defaultdict
+
+def get_git_merges(prev_version):
+    """Get merge commits since the previous version tag."""
+    try:
+        command = f"git log {prev_version}..HEAD | grep 'Merge '"
+        result = subprocess.run(command, shell=True, check=True, text=True, capture_output=True)
+        
+        merge_lines = []
+        for line in result.stdout.strip().split('\n'):
+            if not line.strip() or "Merge:" in line:
+                continue
+                
+            # Extract the commit message and author
+            match = re.search(r"Merge '([^']+)' from ([^(]+)", line)
+            if match:
+                message = match.group(1).strip()
+                author = match.group(2).strip()
+                merge_lines.append((message, author))
+                
+        return merge_lines
+    except subprocess.CalledProcessError as e:
+        print(f"Error: Failed to get git merge logs: {e}")
+        return []
+
+def categorize_commits(merge_lines):
+    """Categorize commits into Added, Updated, Fixed."""
+    categories = defaultdict(list)
+    
+    for message, author in merge_lines:
+        # Format the line for our output
+        formatted_line = f"* {message} ({author})"
+        
+        # Categorize based on keywords in the commit message
+        message_lower = message.lower()
+        if re.search(r'add|new|implement|support|initial|introduce', message_lower):
+            categories['Added'].append(formatted_line)
+        elif re.search(r'fix|bug|issue|error|crash|resolve|typo', message_lower):
+            categories['Fixed'].append(formatted_line)
+        else:
+            categories['Updated'].append(formatted_line)
+            
+    return categories
+
+def format_changelog(categories):
+    """Format the categorized commits into a changelog."""
+    changelog = "## Unreleased\n"
+    
+    for category in ['Added', 'Updated', 'Fixed']:
+        changelog += f"### {category}\n"
+        
+        if not categories[category]:
+            changelog += "\n"
+            continue
+            
+        for commit_message in categories[category]:
+            changelog += f"{commit_message}\n"
+        
+        changelog += "\n"
+    
+    return changelog
+
+def main():
+    if len(sys.argv) != 2:
+        print("Usage: python changelog_generator.py <previous_version_tag>")
+        print("Example: python changelog_generator.py v0.0.17")
+        sys.exit(1)
+    
+    prev_version = sys.argv[1]
+    
+    # Get merge commits since previous version
+    merge_lines = get_git_merges(prev_version)
+    
+    if not merge_lines:
+        print(f"No merge commits found since {prev_version}")
+        return
+    
+    # Categorize commits
+    categories = categorize_commits(merge_lines)
+    
+    # Format changelog
+    changelog = format_changelog(categories)
+    
+    # Output changelog
+    print(changelog)
+    
+    # Optionally write to file
+    write_to_file = input("Write to CHANGELOG.md? (y/n): ")
+    if write_to_file.lower() == 'y':
+        try:
+            with open("CHANGELOG.md", "r") as f:
+                content = f.read()
+            with open("CHANGELOG.md", "w") as f:
+                f.write(changelog + content)
+            print("Changelog written to CHANGELOG.md")
+        except FileNotFoundError:
+            with open("CHANGELOG.md", "w") as f:
+                f.write(changelog)
+            print("Created new CHANGELOG.md file")
+
+if __name__ == "__main__":
+    main()