rfc

#!/usr/bin/env bash


RFC_DRAFT_FIRST=${RFC_DRAFT_FIRST:-0}


set_hooks_commit_msg()
{
    dirname=".git/hooks"
    filename="$dirname/commit-msg";
    if [ -x "$filename" ]; then
        return;
    fi
    url=$(git config --get remote.origin.url)
    host=$(echo $url | cut -d '/' -f 3)
    port_arg=""
    if grep -q ':' <<<"$host" ; then
        port_arg="-P $(echo $host | cut -d ':' -f 2)"
        host=$(echo $host | cut -d ':' -f 1)
    fi
    mkdir -p $dirname
    [ ! -f "$filename" ] && scp $port_arg $host:hooks/commit-msg $dirname || { echo "Couldn't download commit-msg hook"; exit 1; }
    chmod +x $filename;
}


rebase_changes()
{
    git fetch origin;
    GIT_EDITOR=$0 git rebase -i origin/$BRANCH;
}


editor_mode()
{
    if [ $(basename "$1") = "git-rebase-todo" ]; then
        sed 's/^pick /reword /g' "$1" > $1.new && mv $1.new $1;
        return;
    fi

    if [ $(basename "$1") = "COMMIT_EDITMSG" ]; then
        while true; do
            echo Commit: "\"$(head -n 1 $1)\""
            return;
        done
    fi

    cat <<EOF
$0 - editor_mode called on unrecognized file $1 with content:
$(cat $1)
EOF
    return 1;
}


assert_diverge()
{
    git diff origin/$BRANCH..HEAD | grep -q .;
}


main()
{
    br=$(git branch | grep "*");
    current_branch=${br#* };

    # Go to top-level in the working directory
    cd $(git rev-parse --show-toplevel);

    if [ -z "$1" ]; then
        echo "You have not mentioned the branch, exiting.";
        return;
    fi

    if [ "$current_branch" != "$1" ] && [ "$GIT_EDITOR" != "$0" ]; then
        echo "your current branch is $current_branch and you want to push to $1. We do not allow this." ;
        return;
    fi

    if [ -e "$1" ]; then
        editor_mode "$@";
        return;
    fi

    export BRANCH="$1";

    set_hooks_commit_msg;

    rebase_changes;

    assert_diverge;

    if [ $RFC_DRAFT_FIRST -eq 1 ]; then
        echo "pushing drafts to gerrit branch = $BRANCH";
        git push origin HEAD:refs/drafts/$BRANCH;
    else
        echo "pushing changes to gerrit branch = $BRANCH";
        git push origin HEAD:refs/for/$BRANCH;
    fi
}

main "$@"