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import re
import sys
from argparse import ArgumentParser, Namespace, RawTextHelpFormatter
from subprocess import check_output, Popen, PIPE
from typing import Dict, List, Tuple

content_header = """Qt for Python @VERSION is a @TYPE release.

For more details, refer to the online documentation included in this
distribution. The documentation is also available online:

https://doc.qt.io/qtforpython/

Some of the changes listed in this file include issue tracking numbers
corresponding to tasks in the Qt Bug Tracker:

https://bugreports.qt.io/

Each of these identifiers can be entered in the bug tracker to obtain more
information about a particular change.

****************************************************************************
*                                  PySide2                                 *
****************************************************************************
"""

shiboken_header = """****************************************************************************
*                                  Shiboken2                               *
****************************************************************************
"""


def parse_options() -> Namespace:
    tag_msg = ("Tags, branches, or SHA to compare\n"
               "e.g.: v5.12.1..5.12\n"
               "      v5.12.0..v5.12.1\n"
               "      cebc32a5..5.12")

    options = ArgumentParser(description="PySide2 changelog tool",
                             formatter_class=RawTextHelpFormatter)
    options.add_argument("-d",
                         "--directory",
                         type=str,
                         help="Repository directory, '.' is default.")
    options.add_argument("-v",
                         "--versions",
                         type=str,
                         help=tag_msg,
                         required=True)
    options.add_argument("-r",
                         "--release",
                         type=str,
                         help="Release version: e.g.: 5.12.4",
                         required=True)
    options.add_argument("-t",
                         "--type",
                         type=str,
                         help="Release type: bug-fix, minor, or major",
                         default="bug-fix")

    args = options.parse_args()
    if args.type not in ("bug-fix", "minor", "major"):
        print("Error:"
              "-y/--type needs to be: bug-fix (default), minor, or major")
        sys.exit(-1)

    return args


def check_tag(tag: str) -> bool:
    output = False

    if tag[0] == "v":
        # Git tag
        command = "git tag -l {}".format(tag)
        print("{}: {}".format(check_tag.__name__, command), file=sys.stderr)
        if check_output(command.split()):
            output = True
    elif re.match(r"^\d\.\d?", tag):
        # Git branch (origin)
        command = "git show-ref {}".format(tag)
        print("{}: {}".format(check_tag.__name__, command), file=sys.stderr)
        if check_output(command.split()):
            output = True
    else:
        # Git sha
        command = "git cat-file -t {}".format(tag)
        print("{}: {}".format(check_tag.__name__, command), file=sys.stderr)
        if check_output(command.split()):
            output = True

    return output


def get_commit_content(sha: str) -> str:
    command = "git log {} -n 1 --pretty=format:%s%n%n%b".format(sha)
    print("{}: {}".format(get_commit_content.__name__, command),
          file=sys.stderr)
    out, err = Popen(command, stdout=PIPE, shell=True).communicate()
    if err:
        print(err, file=sys.stderr)
    return out.decode("utf-8")

def git_get_sha1s(versions: List[str], pattern: str):
    """Return a list of SHA1s matching a pattern"""
    command = "git rev-list --reverse --grep '^{}'".format(pattern)
    command += " {}..{}".format(versions[0], versions[1])
    command += " | git cat-file --batch"
    command += " | grep -o -E \"^[0-9a-f]{40}\""
    print("{}: {}".format(git_command.__name__, command), file=sys.stderr)
    out_sha1, err = Popen(command, stdout=PIPE, shell=True).communicate()
    if err:
        print(err, file=sys.stderr)
    return [s.decode("utf-8") for s in out_sha1.splitlines()]


def git_command(versions: List[str], pattern: str):
    task_number_re = re.compile(r'^.*-(\d+)\s*$')
    for sha in git_get_sha1s(versions, pattern):
        content = get_commit_content(sha).splitlines()
        # First line is title
        title = content[0]
        # Look for PYSIDE-XXXX
        task = None
        for line in content[::-1]:
            if line.startswith(pattern):
                task = line.replace("{}:".format(pattern), "").strip()
                break

        if not task:
            continue
        task_number = -1
        task_number_match = task_number_re.match(task)
        if task_number_match:
            task_number = int(task_number_match.group(1))
        entry = {"title": title, "task": task, "task-number": task_number}
        if "shiboken" in title:
            if sha not in shiboken2_commits:
                shiboken2_commits[sha] = entry
        else:
            if sha not in pyside2_commits:
                pyside2_commits[sha] = entry


def create_fixes_log(versions: List[str]) -> None:
    git_command(versions, "Fixes: ")


def create_task_log(versions: List[str]) -> None:
    git_command(versions, "Task-number: ")


def extract_change_log(commit_message: List[str]) -> Tuple[str, List[str]]:
    """Extract a tuple of (component, change log lines) from a commit message
       of the form [ChangeLog][shiboken2] description..."""
    result = []
    component = 'pyside'
    within_changelog = False
    for line in commit_message:
        if within_changelog:
            if line:
                result.append('   ' + line.strip())
            else:
                break
        else:
            if line.startswith('[ChangeLog]'):
                log_line = line[11:]
                if log_line.startswith('['):
                    end = log_line.find(']')
                    if end > 0:
                        component = log_line[1:end]
                        log_line = log_line[end + 1:]
                result.append(' * ' + log_line.strip())
                within_changelog = True
    return (component, result)


def create_change_log(versions: List[str]) -> None:
    for sha in git_get_sha1s(versions, r"\[ChangeLog\]"):
        change_log = extract_change_log(get_commit_content(sha).splitlines())
        if change_log[0].startswith('shiboken'):
            shiboken2_changelogs.extend(change_log[1])
        else:
            pyside2_changelogs.extend(change_log[1])


def gen_list(d: Dict[str, Dict[str, str]]) -> str:
    return "".join(" - [{}] {}\n".format(v["task"], v["title"])
                   for _, v in d.items())


def sort_dict(d: Dict[str, Dict[str, str]]) -> Dict[str, Dict[str, str]]:
    return dict(sorted(d.items(), key=lambda kv: kv[1]['task-number']))


if __name__ == "__main__":

    args = parse_options()
    pyside2_commits: Dict[str, Dict[str, str]] = {}
    shiboken2_commits: Dict[str, Dict[str, str]] = {}
    pyside2_changelogs: List[str] = []
    shiboken2_changelogs: List[str] = []

    # Getting commits information
    directory = args.directory if args.directory else "."
    versions = args.versions.split("..")
    if len(versions) == 2:
        if check_tag(versions[0]) and check_tag(versions[1]):
            create_fixes_log(versions)
            create_task_log(versions)
            create_change_log(versions)

    # Sort commits
    pyside2_commits = sort_dict(pyside2_commits)
    shiboken2_commits = sort_dict(shiboken2_commits)

    # Generate message
    print(content_header.replace("@VERSION", args.release).
          replace("@TYPE", args.type))
    print('\n'.join(pyside2_changelogs))
    print(gen_list(pyside2_commits))
    if not pyside2_changelogs and not pyside2_commits:
        print(" - No changes")
    print(shiboken_header)
    print('\n'.join(shiboken2_changelogs))
    print(gen_list(shiboken2_commits))
    if not shiboken2_changelogs and not shiboken2_commits:
        print(" - No changes")
