#!/bin/bash
set -o errexit

# Uncomment to have verboswe debug output
#debug=1

# for use with git-remote-hg:
#   http://felipec.wordpress.com/2012/11/13/git-remote-hg-bzr-2/

LSI_SRV=/mnt/server/research/Projects/HG_Repo

print_usage()
{
    echo "$(basename $0) -- HG subrepository importer for git-remote-hg"
    echo "Usage: $(basename $0) [OPTIONS...]"
}

# Map a revision to a branch name in HG subrepository
# Use hg log (in original repo) to get branch name corresponding to that
# revision.
#
# Arg 1: subrepository URL
# Arg 2: id
# Arg 3: revision
subrepo_find_branch() {
    local src="${1}"
    local id="${2}"
    local rev="${3}"

    pushd "${LSI_SRV}/${src}"

    branch=$(hg log -r ${rev} | grep "branch:" | sed "s/branch:\ *//")

    if [ -z "${branch}" ]; then
        # If "branch:" is null, this indicate we are on the default branch
        branch=default
    fi

    if [ -n "${debug}" ]; then
        echo "  branch: ${branch}"
    fi

    popd
}

if [ "x${1}" = "x--help" ]; then
    print_usage
    exit 1
fi

if [ ! -f .hgsub ]; then
    echo "No Mercurial subrepositories found"
    exit 1
fi

# Read lines from .hgsub
while read sub; do
    # Remove CR (DOS)
    sub="${sub//$'\r'/}"

    if [ "${sub}" != "" ]; then
        # Get subrepository URL
        src="${sub//*\/HG_REPO/}"

        # Get subrepository local alias or label
        dest="${sub// =*}"

        # Get project ID (example: S0289)
        id=$(echo ${sub} | sed "s/.*HG_REPO\(S[0-9][0-9][0-9][0-9]\).*/\1/")

        # Get revision of subrepository (remove CR from .hgsubstate)
        rev=$(cat .hgsubstate | tr -d '\r' | grep "${id}" | sed "s/ .*//")

        if [ -n "${debug}" ]; then
            echo "repo: ${src}"
            echo "  id:     ${id}"
            echo "  rev:    ${rev}"
            echo "  dest:   ${dest}"
        fi

        if [ ! -d "${dest}" ]; then
            subrepo_find_branch "${src}" ${id} ${rev}

            # git-remote-hg seems to replace
            #   "BRANCH - NAME"
            # with
            #   "BRANCH___-___NAME"
            branch="${branch// /___}"

            git clone "hg::${LSI_SRV}/${src}" "${dest}"

            if [ "x${branch}" != "xdefault" ]; then
                cd "${dest}"
                git checkout "branches/${branch}"
                cd ..
            fi
        else
            pushd "${dest}"
            git pull
            popd
        fi
    fi
done < .hgsub