#!/bin/sh

set -e
set -u

export PATH="/usr/local/bin:/usr/local/sbin:/bin:/sbin:/usr/bin:/usr/sbin:$PATH"

deps_dir='deps'
rebar_script='rebar.config.script'
temp_file=$(mktemp "$rebar_script.XXXXXX")

trap 'rm -f $temp_file' EXIT INT TERM

die()
{
    echo >&2 "FATAL: $@."
    exit 1
}

get_dep_list()
{
    sed -n '
        /.*{ *\([^,]*\),[^,]*, *{ *git, *"\([^"]*\)" *} *}.*/ {
            s//\1,\2,master/
            p
        }
        /.*{ *\([^,]*\),[^,]*, *{ *git, *"\([^"]*\)" *, *{ *branch, *"\([^"]*\)".*/ {
            s//\1,\2,\3/
            p
        }' "$rebar_script"
}

get_dep_name()
{
    printf '%s' "${1%%,*}"
}

get_dep_url()
{
    dep_url=${1#*,}
    dep_url=${dep_url%,*}

    printf '%s' "$dep_url"
}

get_dep_branch()
{
    printf '%s' "${1##*,}"
}

get_dep_rev()
{
    dep_name=$(get_dep_name "$1")
    dep_dir="$deps_dir/$dep_name"

    test -d "$dep_dir" || clone_repo "$dep"
    cd "$dep_dir"
    printf '%s' "$(git rev-parse --verify HEAD)"
    cd "$OLDPWD"
}

clone_repo()
{
    dep_name=$(get_dep_name "$1")
    dep_url=$(get_dep_url "$1")
    dep_branch=$(get_dep_branch "$1")

    cd "$deps_dir"
    git clone -q -b "$dep_branch" "$dep_url" "$dep_name"
    cd "$OLDPWD"
}

edit_rebar_script()
{
    dep_name=$(get_dep_name "$1")
    dep_url=$(get_dep_url "$1")
    dep_rev=$(get_dep_rev "$1")

    echo "Using revision $dep_rev of $dep_name"
    sed -e "s|\"$dep_url\".*{ *branch[^}]*} *}|\"$dep_url\", \"$dep_rev\"}|" \
        -e "s|\"$dep_url\"[^}]*}|\"$dep_url\", \"$dep_rev\"}|" \
        "$rebar_script" >"$temp_file"
    mv "$temp_file" "$rebar_script"
}

test -e "$rebar_script" || die 'Please change to ejabberd source directory'
test -d "$deps_dir" || mkdir -p "$deps_dir"

for dep in $(get_dep_list)
do
    edit_rebar_script "$dep"
done