gh-ca

#!/usr/bin/env python3 -u
# coding=utf-8

import argparse
import subprocess
import sys
import webbrowser
import json
import collections
import urllib.parse


def _check_output(cmd):
    """
    Captures the output of `cmd`, exiting the program if the command fails.
    """
    proc = subprocess.run(cmd, stdout=subprocess.PIPE)
    output = proc.stdout.decode("utf-8").strip()
    if proc.returncode != 0:
        print(output, end="", file=sys.stdout)
        sys.exit(proc.returncode)
    return output


def create_pr(args):
    """
    The PR subcommand for the CodeApprove CLI. This pushes the current branch and then calls gh pr create.
    """
    repo_info = json.loads(
        _check_output(
            [
                "gh",
                "repo",
                "view",
                "--json",
                "defaultBranchRef,owner,name",
            ]
        )
    )
    branch_name = _check_output([
        "git",
        "rev-parse",
        "--abbrev-ref",
        "HEAD",
    ])
    # TODO(rockwood): Don't assume the remote is named "origin", but look it up.
    remote = "origin"
    base = args.base if args.base is not None else repo_info["defaultBranchRef"]["name"]
    if not args.no_push:
        # Check that we're not pushing the main branch
        master_check_proc = subprocess.run(
            [
                "git",
                "merge-base",
                "--is-ancestor",
                "HEAD",
                f"remotes/{remote}/{base}",
            ]
        )
        if master_check_proc.returncode == 0:
            print(f"You are on the {base} branch", file=sys.stderr)
            sys.exit(1)
        # Push this branch to the origin.
        push_proc = subprocess.run(["git", "push", "--set-upstream", remote, "HEAD"])
        if push_proc.returncode != 0:
            sys.exit(push_proc.returncode)
    # Supported Query Params for this page:
    # owner - GitHub repo owner
    # repo - the repo name
    # base - the base branch name
    # head - the head branch name
    # title - the pr title
    # body - the pr body
    base_url = "https://codeapprove.com/create"
    query = collections.OrderedDict()
    query["owner"] = repo_info["owner"]["login"]
    query["repo"] = repo_info["name"]
    query["base"] = base
    query["head"] = branch_name
    # TODO(rockwood): Autofill the title and body if there is only a single commit in this branch. 
    webbrowser.open_new_tab(base_url + "?" + urllib.parse.urlencode(query))

if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="A GitHub CLI extension for CodeApprove"
    )

    subparsers = parser.add_subparsers(
        title="subcommands", help="The subcommand to issue"
    )

    # PR START
    pr_parser = subparsers.add_parser(
        "pr", help="Create a PR on CodeApprove - similar to `gh pr create`"
    )
    # This is a trick from the python documentation to get dynamic dispatch for each subcommand.
    pr_parser.set_defaults(cmd=create_pr)

    pr_parser.add_argument(
        "--no_push",
        action="store_true",
        help="Disable pushing this branch to the origin first",
    )
    pr_parser.add_argument(
        "-B",
        "--base",
        metavar="branch",
        type=str,
        help="The branch into which you want your code merged",
    )
    # PR END

    args = parser.parse_args()

    if not hasattr(args, "cmd"):
        parser.print_help()
        sys.exit(1)

    args.cmd(args)