#!/bin/sh
# =====================================================================================
# Safe .env reader for the host-side scripts.
#
# Do NOT `. ./.env`. A file that is perfectly valid for docker-compose is NOT valid shell:
#     AD_DNS_FORWARDER=1.1.1.1 8.8.8.8     # compose: fine.  shell: runs "8.8.8.8"!
# That exact thing silently broke a backup run. So we parse the file instead of executing it.
#
# Behaviour:
#   * KEY=VALUE, first '=' splits; the value keeps any later '=' (LDAP URIs, passwords)
#   * surrounding quotes are stripped; inline "  # ..." is dropped on unquoted values
#   * full-line comments and blanks are ignored
#   * an existing environment variable WINS, so tests/CI can override:
#         AD_ADMIN_PASSWORD=x ./scripts/backup.sh
#
# Usage (bash/dash):    . scripts/envfile.sh && ad_env_load .env
# =====================================================================================

ad_env_load() {
    _f="${1:-.env}"
    [ -f "$_f" ] || return 0
    while IFS='=' read -r _k _v || [ -n "$_k" ]; do
        case "$_k" in ''|[\ \#]*) continue ;; esac
        # key: strip whitespace/CR
        _k="$(printf '%s' "$_k" | tr -d '\r' | sed 's/[[:space:]]*$//')"
        case "$_k" in ''|\#*) continue ;; esac
        # value: trim, strip one layer of quotes, or drop an inline comment
        _v="${_v%$'\r'}"
        _v="${_v#"${_v%%[![:space:]]*}"}"
        case "$_v" in
            \"*\") _v="${_v#\"}"; _v="${_v%\"}" ;;
            \'*\') _v="${_v#\'}"; _v="${_v%\'}" ;;
            *)      _v="${_v%%[[:space:]]#*}" ;;
        esac
        _v="${_v%"${_v##*[![:space:]]}"}"     # rtrim
        # don't clobber a value already provided in the environment
        if [ -z "$(printenv "$_k" 2>/dev/null)" ]; then
            export "$_k=$_v"
        fi
    done < "$_f"
    unset _f _k _v
}