#! /bin/sh

#
# Parses a database URL in the format schema://user:
#

DB_URL="$1";
DB_VAR_PREFIX="${DB_VAR_PREFIX:-DB_}";
DB_ARG_VAR_PREFIX="${DB_ARG_VAR_PREFIX:-db_arg_}";

# get URL's query args
query_args="${DB_URL#*\?}";
queryless_url="${DB_URL%%\?*}";

# get URL's schema
schema="${queryless_url%//*}";
if test "${schema}" = "${queryless_url}"; then
    echo >&2 "database URLs must start with schema (i.e.: mysql://)"\
    && echo >&2 "URL_INVALID_ERROR: \"${DB_URL}\""\
    && exit 2;
fi
schemaless_url=${queryless_url#*//};

# left hand is everything until the first @ (the user part)
#  with no @ there's no difference from $schemaless_url
#  so $username and $password will be blank
left_hand=${schemaless_url%@*};
if test ! ${left_hand} = ${schemaless_url}; then
    username=$(echo ${left_hand} | cut -d ':' -f 1);
    if test ! ${username} = ${left_hand}; then
        password=$(echo ${left_hand} | cut -d ':' -f 2);
    fi
fi

# the right hand is the host part (after @) and will be always present
right_hand=${schemaless_url#*@};
host=$(echo ${right_hand} | cut -d ':' -f 1 | cut -d '/' -f 1);
if test -n "$(echo ${right_hand} | grep -o ':')"; then
    port=$(echo ${right_hand} | cut -d ':' -f 2 | cut -d '/' -f 1);
fi
if test -n "$(echo ${right_hand} | grep -o '/')"; then
    database=$(echo ${right_hand} | cut -d ':' -f 2 | cut -d '/' -f 2);
fi

# throw an error if $DB_URL is empty and so is $host
if test -z "${host}"; then
    echo "database URL providen was invalid" && exit 1;
fi

cat << HEREDOC
${DB_VAR_PREFIX}SCHEMA=${schema%:}
${DB_VAR_PREFIX}USERNAME=${username}
${DB_VAR_PREFIX}PASSWORD=${password}
${DB_VAR_PREFIX}HOST=${host}
${DB_VAR_PREFIX}PORT=${port}
${DB_VAR_PREFIX}NAME=${database}
$(
    echo ${query_args}\
    | sed 's/[&;]/\n/g'\
    | while read arg_item; do
        echo "${DB_ARG_VAR_PREFIX}${arg_item}";
    done
)
HEREDOC