#!/usr/bin/env python
"""Update the What's New doc (development version)

This collects the snippets from whatsnew/pr/, moves their content into
whatsnew/development.rst (chronologically ordered), and deletes the snippets.
"""

import io
import sys
from pathlib import Path
from subprocess import check_call, check_output

repo_root = Path(__file__).resolve().parent.parent
whatsnew_dir = repo_root / "docs" / "source" / "whatsnew"
pr_dir = whatsnew_dir / "pr"
target = whatsnew_dir / "development.rst"

FEATURE_MARK = ".. DO NOT EDIT THIS LINE BEFORE RELEASE. FEATURE INSERTION POINT."
INCOMPAT_MARK = ".. DO NOT EDIT THIS LINE BEFORE RELEASE. INCOMPAT INSERTION POINT."

# 1. Collect the whatsnew snippet files ---------------------------------------

files = set(pr_dir.glob("*.rst"))
# Ignore explanatory and example files
files.difference_update(
    {pr_dir / f for f in {"incompat-switching-to-perl.rst", "antigravity-feature.rst"}}
)

if not files:
    print("No automatic update available for what's new")
    sys.exit(0)


def getmtime(f):
    return check_output(["git", "log", "-1", '--format="%ai"', "--", f])


files = sorted(files, key=getmtime)

features, incompats = [], []
for path in files:
    with io.open(path, encoding="utf-8") as f:
        try:
            content = f.read().rstrip()
        except Exception as e:
            raise Exception('Error reading "{}"'.format(f)) from e

    if path.name.startswith("incompat-"):
        incompats.append(content)
    else:
        features.append(content)

# Put the insertion markers back on the end, so they're ready for next time.
feature_block = "\n\n".join(features + [FEATURE_MARK])
incompat_block = "\n\n".join(incompats + [INCOMPAT_MARK])

# 2. Update the target file ---------------------------------------------------

with io.open(target, encoding="utf-8") as f:
    content = f.read()

assert content.count(FEATURE_MARK) == 1
assert content.count(INCOMPAT_MARK) == 1

content = content.replace(FEATURE_MARK, feature_block)
content = content.replace(INCOMPAT_MARK, incompat_block)

# Clean trailing whitespace
content = "\n".join(l.rstrip() for l in content.splitlines())

with io.open(target, "w", encoding="utf-8") as f:
    f.write(content)

# 3. Stage the changes in git -------------------------------------------------

for file in files:
    check_call(["git", "rm", file])

check_call(["git", "add", target])

print("Merged what's new changes. Check the diff and commit the change.")