From 2e3eb1b7a894e7511648da4d500157c257407519 Mon Sep 17 00:00:00 2001
From: Martin Thoma <info@martin-thoma.de>
Date: Mon, 18 Apr 2022 10:55:44 +0200
Subject: [PATCH] DEV: Add tool to generate changelog

---
 make_changelog.py | 136 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 make_changelog.py

diff --git a/make_changelog.py b/make_changelog.py
new file mode 100644
index 000000000..de93c813e
--- /dev/null
+++ b/make_changelog.py
@@ -0,0 +1,136 @@
+"""Internal tool to update the changelog."""
+
+import subprocess
+from dataclasses import dataclass
+from datetime import datetime
+from typing import List
+
+
+@dataclass(frozen=True)
+class Change:
+    commit_hash: str
+    prefix: str
+    message: str
+
+
+def main(changelog_path: str):
+    changelog = get_changelog(changelog_path)
+    git_tag = get_most_recent_git_tag()
+    changes = get_formatted_changes(git_tag)
+    print("-" * 80)
+    print(changes)
+    # TODO: Write changes to changelog
+    new_version = version_bump(git_tag)
+    today = datetime.now()
+    header = f"Version {new_version}, {today:%Y-%m-%d}\n"
+    header = header + "-" * (len(header) - 1) + "\n"
+    trailer = f"All changes: https://github.com/py-pdf/PyPDF2/compare/{git_tag}...{new_version}"
+    new_entry = header + changes + trailer
+    print(new_entry)
+
+    # TODO: Make idempotent - multiple calls to this script
+    # should not change the changelog
+    new_changelog = new_entry + changelog
+    write_changelog(new_changelog, changelog_path)
+
+
+def version_bump(git_tag: str) -> str:
+    # just assume a patch version change
+    major, minor, patch = git_tag.split(".")
+    return f"{major}.{minor}.{int(patch) + 1}"
+
+
+def get_changelog(changelog_path: str) -> str:
+    with open(changelog_path, "r") as fh:
+        changelog = fh.read()
+    return changelog
+
+
+def write_changelog(new_changelog: str, changelog_path: str) -> None:
+    with open(changelog_path, "w") as fh:
+        fh.write(new_changelog)
+
+
+def get_formatted_changes(git_tag: str) -> str:
+    commits = get_git_commits_since_tag(git_tag)
+
+    # Group by prefix
+    grouped = {}
+    for commit in commits:
+        if commit.prefix not in grouped:
+            grouped[commit.prefix] = []
+        grouped[commit.prefix].append({"msg": commit.message})
+
+    # Order prefixes
+    order = ["DEP", "ENH", "BUG", "ROB", "DOC", "DEV", "MAINT", "TST", "STY"]
+    abbrev2long = {
+        "DEP": "Deprecations",
+        "ENH": "New Features",
+        "BUG": "Bug Fixes",
+        "ROB": "Robustness",
+        "DOC": "Documentation",
+        "DEV": "Developer Experience",
+        "MAINT": "Maintenance",
+        "TST": "Testing",
+        "STY": "Code Style",
+    }
+
+    # Create output
+    output = ""
+    for prefix in order:
+        if prefix not in grouped:
+            continue
+        output += f"\n{abbrev2long[prefix]} ({prefix}):\n"  # header
+        for commit in grouped[prefix]:
+            output += f"- {commit['msg']}\n"
+        del grouped[prefix]
+
+    if grouped:
+        print("@" * 80)
+        output += "\nYou forgot something!:\n"
+        for prefix in grouped:
+            output += f"- {prefix}: {grouped[prefix]}\n"
+        print("@" * 80)
+
+    return output
+
+
+def get_most_recent_git_tag():
+    git_tag = str(
+        subprocess.check_output(
+            ["git", "describe", "--abbrev=0"], stderr=subprocess.STDOUT
+        )
+    ).strip("'b\\n")
+    return git_tag
+
+
+def get_git_commits_since_tag(git_tag) -> List[Change]:
+    commits = str(
+        subprocess.check_output(
+            ["git", "--no-pager", "log", f"{git_tag}..HEAD", "--oneline"],
+            stderr=subprocess.STDOUT,
+        )
+    ).strip("'b\\n")
+    return [parse_commit_line(line) for line in commits.split("\\n")]
+
+
+def parse_commit_line(line) -> Change:
+    commit_hash, rest = line[: len("d5a5eea")], line[len("d5a5eea") :]
+    if ":" in rest:
+        prefix, message = rest.split(":", 1)
+    else:
+        prefix = ""
+        message = rest
+
+    # Standardize
+    message.strip()
+
+    prefix = prefix.strip()
+    if prefix == "DOCS":
+        prefix = "DOC"
+
+    return Change(commit_hash=commit_hash, prefix=prefix, message=message)
+
+
+if __name__ == "__main__":
+    main("CHANGELOG")