#!/bin/bash

isAbsPath() {
    if [[ "${1:0:1}" == / || "${1:0:2}" == ~[/a-z] ]]
    then
        echo "true"
        return 0
    else
        return 1
    fi
}

sed_ignore_comments () {
    cmd="sed -r 'h;s/[^#]*//1;x;s/#.*//;${1};G;s/(.*)\n/\1/'"
    if (( $# == 2 )) ; then
        eval $cmd <<< "$2"
    else
        eval $cmd < /dev/stdin
    fi
}

clean_env_file () {
  local compact
  # -c will also remove comments and all empty lines
  [[ $1 == "-c" ]] && compact=true && shift 1
  # 
  #  remove trailing spaces | remove double quotes 
  # | remove blanks after equals and quote value | remove any spaces before afer =
  # remove blank lines | remove comment lines if requested
  cat $1 | sed_ignore_comments s/\\s*$//g  | sed_ignore_comments s/\"//g \
  | sed_ignore_comments s/\(=[[:blank:]]*\)\(.*\)/\\1\"\\2\"/  \
  | sed_ignore_comments s/\\s*=\\s*/=/g \
  | sed -rz 's/^\n+//; s/\n+$/\n/g' | if [[ $compact ]]; then grep -v '^#' | grep -v "^$" ; else cat; fi 
}

env_file () {
   env=${1:-.env}
   [[ -f "${env}" ]] && { echo $env; return 0; } # || echo not $env
   [[ -f "${env}.env" ]] && { echo "${env}.env"; return 0; } # || echo not ${env}.env
   [[ -f "${env}/.env" ]] && { echo "${env}/.env"; return 0; } # || echo not ${env}/.env
   return 1
}  

read_env_file() {
  while read line; do
  evar=$(echo $line | cut -d '=' -f1)
  if [[ ! ${!evar}  ]]; then
        # echo DECLARE $evar via $line 
        if declare -gx "$(echo "${line}" | sed 's/\"//g' )"; then
        echo loaded: ${evar}=${!evar} 
        else
            echo error setting $evar
            return 1
            
        fi
    else 
    echo $evar already set to ${!evar}    
  fi
  done < <(clean_env_file -c $1) 
}

source_env_file () {
    local default
    if efile=$(env_file $1); then 
      [[ $efile == ".env" ]] && default=true
      [[ ! $(isAbsPath $efile) ]] && efile=$(realpath $efile)
      echo -e "\e[1;37m********************\e[0;37m"
      echo loading build environment with environment file
      echo $efile
      echo ----------------
      cat $efile
      echo ----------------
      if read_env_file "$efile"; then 
        [[ $default ]] && echo -e "\e[1;31mNOTE: sourced default .env file in present directory\e[0;37m"
        echo -e "\e[1;37m********************\e[0;37m"
        else
        echo error occured while loading environment file 
        echo $efile
        echo exiting
        echo -e "\e[1;37m********************\e[0;37m"
        return 2
      fi
     else
        if [[ $efile ]]; then
            echo unable to find an environment file with passed ${1}
         else 
            echo unable to find default environment file .env 
            echo using passed and default build options
        fi
        return 2
    fi

}

docker_image_distro() {
local temp=/tmp/os-release.tmp
docker create --name dummy $1 > /dev/null
docker cp -L dummy:/etc/os-release $temp
docker rm -f dummy > /dev/null
echo $(cat $temp | tr [:upper:] [:lower:] | grep -Poi '(debian|ubuntu|red hat|centos|arch|alpine)' | uniq)
rm $temp
}

(return 0 2>/dev/null) || docker_image_distro $@