#!/bin/bash
#
# kbgit-set-main
# John Simpson <jms1@jms1.net> 2022-01-08
#
# Set the primary branch of a Keybase git repo
#
# 2023-06-26 jms1 - renamed to 'kbgit-set-main'
#
# 2024-07-27 jms1 - detect team/repo name if not supplied

set -e

###############################################################################
#
# usage

function usage {
    MSG="${*:-}"

    cat <<EOF
$0 [-r REPO] [-t TEAM] [BRANCH]

Set the primary branch of a Keybase git repo. If no branch name is specified,
show the current primary branch name instead.

-r ___  Specify the name of the repo. If not specified, try to identify the
        repo and team name automatically (using 'git remote -v').

-t ___  If specifying a repo name with the '-r' option, specify the team name.
        If not specified, the repo is owned by the current Keybase user.

EOF

    if [[ -n "$MSG" ]]
    then
        echo "$MSG"
        exit 1
    fi

    exit 0
}

###############################################################################
###############################################################################
###############################################################################
#
# Parse command line

REPO=""
TEAM=""
BRANCH=""
DO_SET=false

while getopts ':hr:t:' OPT
do
    case $OPT in
        h)  usage
            ;;
        r)  REPO="$OPTARG"
            ;;
        t)  TEAM="$OPTARG"
            ;;
        *)  usage "ERROR: unknown option '$OPTARG'"
            ;;
    esac
done

shift $((OPTIND-1))

BRANCH="${1:-}"

############################################################
# If no repo name was specified, run 'git branch -v'
# to try and identify the repo

if [[ -z "$REPO" ]]
then
    if [[ -n "$TEAM" ]]
    then
        usage "ERROR: do not use '-t' without '-r'"
    fi

    GRV="$( git remote -v || true )"
    if [[ -z "$GRV" ]]
    then
        echo "ERROR: the current directory is not a git repo with a remote"
        exit 1
    fi

    RE_TEAM='keybase://team/([a-z0-9][^/]+)/([^ ]*)'
    RE_USER='keybase://private/([a-z0-9][^/]+)/([^ ]*)'
    if [[ "$GRV" =~ $RE_TEAM ]]
    then
        TEAM="${BASH_REMATCH[1]}"
        REPO="${BASH_REMATCH[2]}"
    elif [[ "$GRV" =~ $RE_USER ]]
    then
        TEAM=""
        REPO="${BASH_REMATCH[2]}"
    else
        cat <<EOF
ERROR: no keybase git remotes found

+ git remote -v
$GRV
EOF
        exit 1
    fi
fi

############################################################
# Figure out where KBFS is mounted

if [[ -d "/keybase/private" ]]
then
    KBFS="/keybase"
elif [[ -d "/Volumes/Keybase/private" ]]
then
    KBFS="/Volumes/Keybase"
else
    echo "Unable to find KBFS, cannot continue"
    exit 1
fi

########################################
# Find the repo's back-end storage directory and HEAD file

if [[ -n "$TEAM" ]]
then
    RDIR="$KBFS/team/$TEAM/.kbfs_git/$REPO"
else
    USER="$( keybase whoami )"
    RDIR="$KBFS/private/$USER/.kbfs_git/$REPO"
fi

HEAD="$RDIR/HEAD"

echo "+ cd $RDIR" 1>&2
cd "$RDIR"

########################################
# Show the current HEAD file

( set -x ; cat HEAD )

###############################################################################
#
# If we're changing it, do the deed

if [[ -n "$BRANCH" ]]
then
    ########################################
    # Does the branch exist in the repo?

    BRF="$( git branch -a | grep " $BRANCH\$" || true )"

    if [[ -n "$BRF" ]]
    then
        ( set -x ; echo "ref: refs/heads/$BRANCH" > HEAD )
        ( set -x ; cat HEAD )
    else
        echo "ERROR: branch '$BRANCH' does not exist in this repo"
        exit 1
    fi
fi