#!/usr/bin/env python3
import common

import argparse
import sys
from gitlab import Gitlab, GitlabCreateError
from accept_merge_request import accept_merge_request
from create_merge_request import create_merge_request
from get_merge_requests import get_merge_requests
from update_submodule import update_submodule


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--gitlab-url",
        help="""URL to the GitLab instance""",
        dest="gitlab_url",
        required=True,
    )
    parser.add_argument(
        "--token",
        help="""GitLab REST API private access token""",
        dest="token",
        required=True,
    )
    parser.add_argument(
        "--project",
        help="""name of the GitLab project""",
        dest="project",
        required=True,
    )
    parser.add_argument(
        "--submodule",
        help="""submodule to update""",
        dest="submodule",
        required=True,
    )
    parser.add_argument(
        "--revision",
        help="""new revision for submodule""",
        dest="revision",
        required=True,
    )
    parser.add_argument(
        "--branch",
        help="""project branch (if not default branch)""",
        dest="branch",
        required=False,
        default=None,
    )
    parser.add_argument(
        "--merge",
        help="""if set, perform merge after integration""",
        dest="merge",
        action="store_true",
        required=False,
        default=False,
    )

    args, _ = parser.parse_known_args()

    gitlab = Gitlab(args.gitlab_url, private_token=args.token)
    project = common.get_project(gitlab, args.project)

    # Update submodule
    integration_branch, integration_commit, submodule_project = update_submodule(
        project, args.submodule, args.revision, args.branch
    )

    # Get source merge request
    mrs = get_merge_requests(
        submodule_project,
        target_branch="master",
        commit=args.revision,
    )
    if not mrs:
        sys.exit(
            "ERROR: could not determine source merge request for commit %s"
            % args.revision
        )
    source_mr = mrs[0]

    # Create merge request
    mr, created = create_merge_request(
        project, integration_branch, project.default_branch
    )
    if created:
        common.crosslink_merge_requests(source_mr, mr)
        print("Created new merge request:\n%s" % mr.web_url)
    else:
        print("Existing integration merge request:\n%s" % mr.web_url)

    # Explicitly trigger a pipeline on the integration branch if it has not run for the
    # head commit yet (automatic pipelines are disabled for integration branches)
    if not project.pipelines.list(sha=integration_commit):
        try:
            project.pipelines.create({"ref": integration_branch})
        except GitlabCreateError as e:
            sys.exit("ERROR: could not create merge request pipeline: %s" % e)

    if not args.merge:
        print(
            "Skipping automatic merge in MR context. If you like to extend the "
            "integration MR by hand, please do it now. Afterwards you can either merge "
            "it by hand or re-run this job on the master branch after the source MR "
            "has been merged."
        )
        sys.exit(0)

    # Wait until GitLab has checked merge status
    common.wait_until_merge_status_is_set(project, mr)

    # Attempt to merge
    merged = accept_merge_request(project, mr, rebase=True)

    if not merged:
        sys.exit(
            "Integration MR could not be merged. You have two possibilities to fix "
            "this:\n"
            "  1. Checkout the MR and rebase it on the current master manually, or\n"
            "  2. Delete the MR (Edit -> Delete in the MR UI)\n"
            "In either case restart this job afterwards in order to get it merged."
        )

    print("Successfully merged")


if __name__ == "__main__":
    main()