From 8aabe6b35bf084e6c558e5907e0f4ed92640b974 Mon Sep 17 00:00:00 2001
From: Pierre-Yves Chibon <pingou@pingoured.fr>
Date: Tue, 28 Jan 2020 11:15:55 +0100
Subject: [PATCH] First pass on the POC of the generate_changelog script

Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>
---
 generate_changelog.py | 111 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 generate_changelog.py

diff --git a/generate_changelog.py b/generate_changelog.py
new file mode 100644
index 0000000..51354c6
--- /dev/null
+++ b/generate_changelog.py
@@ -0,0 +1,111 @@
+#!/usr/bin/python3
+
+import collections
+import datetime
+import logging
+import os
+import subprocess
+import sys
+import textwrap
+
+import pygit2
+
+_log = logging.getLogger(__name__)
+
+
+def run_command(command, cwd=None):
+    """ Run the specified command in a specific working directory if one
+    is specified.
+    """
+    output = None
+    try:
+        output = subprocess.check_output(
+            command, cwd=cwd, stderr=subprocess.PIPE
+        )
+    except subprocess.CalledProcessError as e:
+        _log.error(
+            "Command `{}` return code: `{}`".format(
+                " ".join(command), e.returncode
+            )
+        )
+        _log.error("stdout:\n-------\n{}".format(e.stdout))
+        _log.error("stderr:\n-------\n{}".format(e.stderr))
+        raise Exception("Command failed to run")
+
+    return output
+
+
+def main(args):
+    """ Main method. """
+    repo_obj = pygit2.Repository(args[0])
+    name = os.path.basename(args[0])
+
+    branch = repo_obj.lookup_branch(repo_obj.head.shorthand)
+    commit = branch.peel(pygit2.Commit)
+    nvr = None
+    new_nvr = None
+    changed = False
+    data = collections.defaultdict(list)
+    for commit in repo_obj.walk(commit.hex, pygit2.GIT_SORT_TIME):
+        if len(commit.parents) > 1:
+            # Ignore merge commits
+            continue
+
+        commit_dt = datetime.datetime.utcfromtimestamp(commit.commit_time)
+        if commit_dt < (datetime.datetime.utcnow() - datetime.timedelta(days=730)):
+            # Ignore all commits older than 2 years
+            break
+
+        repo_obj.checkout_tree(
+            commit,
+            strategy=pygit2.GIT_CHECKOUT_FORCE | pygit2.GIT_CHECKOUT_RECREATE_MISSING)
+        if os.path.exists(os.path.join(args[0], f"{name}.spec")):
+            try:
+                output = run_command([
+                    "rpm", "--qf", '%{name}  %{version}  %{release}\n',
+                    "--specfile", f"{name}.spec",
+                ], cwd=args[0])
+            except Exception:
+                continue
+            output = tuple(
+                output.decode('utf-8').strip().split('\n')[0].rsplit('.', 1)[0].split('  ')
+            )
+            nvr = '-'.join(output)
+
+            if commit.parents:
+                diff = repo_obj.diff(commit.parents[0], commit)
+            else:
+                # First commit in the repo
+                diff = commit.tree.diff_to_tree(swap=True)
+
+            if diff.stats.files_changed:
+                files_changed = [d.new_file.path for d in diff.deltas]
+                ignore = True
+                for filename in files_changed:
+                    if filename.endswith(('.spec', '.patch')):
+                        ignore = False
+                if not ignore:
+                    data[output].append(commit)
+        else:
+            print("No more spec file, bailing")
+            break
+
+    for nvr in data:
+        commits = data[nvr].reverse()
+        for idx, commit in enumerate(data[nvr]):
+            last_commit = idx + 1 == len(data[nvr])
+            commit_dt = datetime.datetime.utcfromtimestamp(commit.commit_time)
+            wrapper = textwrap.TextWrapper(width=75, subsequent_indent="  ")
+            message = wrapper.fill(commit.message.split('\n')[0].strip('- '))
+
+            if last_commit:
+                print(f"* {commit_dt.strftime('%a %b %d %Y')} {commit.author.name} <{commit.author.email}> - {nvr[1]}-{nvr[2]}")
+            else:
+                print(f"* {commit_dt.strftime('%a %b %d %Y')} {commit.author.name} <{commit.author.email}>")
+            print("- %s" % message)
+            print()
+
+
+
+if __name__ == '__main__':
+    main(sys.argv[1:])