#!/bin/sh

# Copyright (C) 2016  Jonas Bernoulli
#
# Author: Jonas Bernoulli <jonas@bernoul.li>
# License: GPL v3 <https://www.gnu.org/licenses/gpl-3.0.txt>

# Commentary:

# This script is a replacement for `git submodule update'.  The
# main differences are that this script resets the current branch
# if necessary instead of detaching HEAD and that it is capable of
# adding and configuring additional remotes.

# The following variables can be set in ".gitmodules":
#
# * submodule.DRONE.remote = NAME URL
#
#   This variable specifies an additional remote named DRONE that is
#   fetched from URL.
#
# * borg.collective = REMOTE
#
#   This variable specifies the name used for remotes that reference
#   a repository that has been patched by the collective.  If a NAME
#   matches REMOTE, then it is configured as the upstream of the
#   current branch of the respective DRONE.
#
# * borg.pushDefault = DEFAULT
#
#   This variable specifies a name used for push-remotes.  If a NAME
#   matches DEFAULT, then it is configured as the push-remote of the
#   current branch of the respective DRONE.

# If an error occurs while `make bootstrap' runs this script, then
# fix the error(s) and run `bin/borg-bootstrap' directly, followed
# by `make build'.

hive_remote=$(git config -f .gitmodules borg.collective)
push_remote=$(git config -f .gitmodules borg.pushDefault)

git submodule--helper list |
while read mode sha1 stage path
do
    if test -e "$path" && ! test -e "$path"/.git
    then
        name=$(git submodule--helper name "$path")

        echo "\n--- [$name] ---\n"

        git submodule--helper clone \
            --name "$name" \
            --path "$path" \
            --url $(git config -f .gitmodules submodule."$name".url)

        git config -f .gitmodules --get-all submodule."$name".remote |
        while read remote remote_url
        do
            if ! test -e "$path"/.git
            then
                git submodule--helper clone \
                    --name "$name" \
                    --path "$path" \
                    --url "$remote_url" &&
                git remote rename origin "$remote"
            else
                (
                    cd "$path"
                    git remote add "$remote" "$remote_url"
                    git fetch "$remote"
                )
            fi

            if test -e "$path"/.git
            then
                (
                    cd "$path"
                    if test "$remote" = "$hive_remote"
                    then
                        git config branch.master.remote "$remote"

                    elif test "$remote" = "$push_remote"
                    then
                        git config remote.pushDefault "$remote"
                    fi
                )
            fi
        done

        if test -e "$path"/.git
        then
            (
                cd "$path"
                git reset --hard "$sha1" ||
                echo >&2 "futile: checkout of '$sha1' into submodule path '$path' failed"
            )
        else
            echo >&2 "futile: clone of any remote into submodule path '$path' failed"
        fi
    fi
done