#!/usr/bin/env python3

# Zulip notification post-receive hook.
#
# The "post-receive" script is run after receive-pack has accepted a pack
# and the repository has been updated.  It is passed arguments in through
# stdin in the form
#  <oldrev> <newrev> <refname>
# For example:
#  aa453216d1b3e49e7f6f98441fa56946ddcd6a20 68f7abf4e6f922807889f52bc043ecd31b79f814 refs/heads/main

import os
import os.path
import subprocess
import sys

sys.path.insert(0, os.path.dirname(__file__))
import zulip_git_config as config

VERSION = "0.9"

if config.ZULIP_API_PATH is not None:
    sys.path.append(config.ZULIP_API_PATH)

import zulip

client = zulip.Client(
    email=config.ZULIP_USER,
    site=config.ZULIP_SITE,
    api_key=config.ZULIP_API_KEY,
    client="ZulipGit/" + VERSION,
)


def git_repository_name() -> str:
    output = subprocess.check_output(["git", "rev-parse", "--is-bare-repository"])
    if output.strip() == "true":
        return os.path.basename(os.getcwd())[: -len(".git")]
    else:
        return os.path.basename(os.path.dirname(os.getcwd()))


def git_commit_range(oldrev: str, newrev: str) -> str:
    log_cmd = ["git", "log", "--reverse", "--pretty=%aE %H %s", f"{oldrev}..{newrev}"]
    commits = ""
    for ln in subprocess.check_output(log_cmd, universal_newlines=True).splitlines():
        author_email, commit_id, subject = ln.split(None, 2)
        if hasattr(config, "format_commit_message"):
            commits += config.format_commit_message(author_email, subject, commit_id)
        else:
            commits += f"!avatar({author_email}) {subject}\n"
    return commits


def send_bot_message(oldrev: str, newrev: str, refname: str) -> None:
    repo_name = git_repository_name()
    branch = refname.replace("refs/heads/", "")
    destination = config.commit_notice_destination(repo_name, branch, newrev)
    if destination is None:
        # Don't forward the notice anywhere
        return

    new_head = newrev[:12]
    old_head = oldrev[:12]

    if (
        oldrev == "0000000000000000000000000000000000000000"
        or newrev == "0000000000000000000000000000000000000000"
    ):
        # New branch pushed or old branch removed
        added = ""
        removed = ""
    else:
        added = git_commit_range(oldrev, newrev)
        removed = git_commit_range(newrev, oldrev)

    if oldrev == "0000000000000000000000000000000000000000":
        message = f"`{new_head}` was pushed to new branch `{branch}`"
    elif newrev == "0000000000000000000000000000000000000000":
        message = f"branch `{branch}` was removed (was `{old_head}`)"
    elif removed:
        message = f"`{new_head}` was pushed to `{branch}`, **REMOVING**:\n\n{removed}"
        if added:
            message += "\n**and adding**:\n\n" + added
        message += "\n**A HISTORY REWRITE HAS OCCURRED!**"
        message += "\n@everyone: Please check your local branches to deal with this."
    elif added:
        message = f"`{new_head}` was deployed to `{branch}` with:\n\n{added}"
    else:
        message = f"`{new_head}` was pushed to `{branch}`... but nothing changed?"

    message_data = {
        "type": "stream",
        "to": destination["stream"],
        "subject": destination["subject"],
        "content": message,
    }
    client.send_message(message_data)


for ln in sys.stdin:
    oldrev, newrev, refname = ln.strip().split()
    send_bot_message(oldrev, newrev, refname)