#!/bin/bash
set -o errexit

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

# Uncomment to have verbose debug output
#debug=1

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

# git-remote-hg doesn't work with Mercurial subpaths extension,
# so use it manually
hg_subpaths_config() {
    subpaths=$(hg showconfig | grep "subpaths")

    if [ -n ${subpaths} ]; then
        sp_src=${subpaths//subpaths./}
        sp_src=${sp_src//=*/}
        sp_src=${sp_src//\\/} # Remove windows separator (LSI)
        sp_dst=${subpaths//*=/}

        if [ -n "${debug}" ]; then
            echo "sp_src = $sp_src"
            echo "sp_dst = $sp_dst"
        fi
    fi
}

# 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 "${src}" 1> /dev/null

    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

    num=$(hg log --branch "${branch}" --template '{node}\n' | \
        grep -n ${rev} | awk -F ':' '{print $1}')

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

    popd 1> /dev/null
}

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

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

if [ ! -f .gitignore ]; then
    # We do not want to track .gitignore itself
    echo ".gitignore" > .gitignore
fi

hg_subpaths_config

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

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

        # Replace using subpaths extension content
        src=${src/${sp_src}/${sp_dst}}

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

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

        pushd "${dest}" 1> /dev/null
        echo "============================"
        echo "subrepo: ${dest}"
        git pull
        popd 1> /dev/null
    fi
done < .hgsub