#!/bin/bash 

# environment and environment file functions
module_load iecho

clean_env_file () {
  local compact
  module_load helpers 
  # -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 
}

# https://stackoverflow.com/questions/19331497/set-environment-variables-from-file-of-key-value-pairs
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
}  
  
# ignore non assignment lines
list_env_file_vars () {
  env=$(env_file $1)
  cat $env
  [[ ! $env ]] && { iecho "Env file ${1} doesn't exist"; return 1; }
  clean_env_file $env | grep -v '^#'| sed -n -E 's/(.*)=[^ =].*/\1/p' | xargs
}

function load_env_file() {
  # second argument, "-x"  will export within function (or anything called), "-gx" is equivalent of export and is global
  env=$(env_file $1)
  [[ ! $env ]] && { iecho "Env file ${1} doesn't exist"; return 1; }
  while read line; do
  # echo var to add $line
  declare $2 "$(echo "${line}" | sed 's/\"//g' )"
  done < <(clean_env_file -c $env) 
}

# list_env_file_vals() {
#    local vars
#    vars=$(list_env_file_vars $1)
#    echo $vars
#    [[ $? -gt 0 ]] && return 1
#    export_env_file $1
#    for var in $vars ;
#    do
#    "$var=${!var}"
#    done
# }

export_env_file () {
  load_env_file $1 -gx
}

unset_env_file () {
  env=$(env_file $1)
  [[ ! $env ]] && { iecho "Env file ${1} doesn't exist"; return 1; }
  unset $(clean_env_file -c ${env} | sed -E 's/(.*)=.*/\1/' | xargs)
}


testenv () {
    echo in testenv
    echo TEST Variable $TEST
    env | grep TEST
    echo done testenv
}

# https://www.baeldung.com/linux/envsubst-command
# todo allow input file -o overwrite or to another file -f <name>
env_subs_file () {
 local fin; local fenv; local useenv; local tout; local fout; local fenv; local tout2
 [[ $1 == "-e" ]] && useenv=true && shift 1
 [[ $1 == "-o" ]] && { shift 1; fout=$1; }
 [[ $1 == "-f" ]] && { fout=$2; shift 2; }
 fin=$1; fenv=$2
#  echo useenv $useenv, fout $fout, fin  $fin, fenv $fenv
 [[ ! $fin ]] && iecho "nothing was passed to merge with environment" && return 1
 [[ ! -f "$fin" ]] && iecho "file $fin does not exit nothing to merge with environment" && return 1
 [[ ! $(cat $fin | grep -F "$") ]] && iecho "no variables in $fin to merge" && return 2
 tout=/tmp/${USER}-mergedenvfile
 if [[ $useenv ]] && [[ -f $fenv ]]; then 
  tout2=/tmp/${USER}-mergedenvfile2
  cat $fin | envsubst "$(printf '${%s} ' $(env | cut -d'=' -f1) )" > $tout2
  fin=$tout2
 fi 
 if [[ -f $fenv ]]; then
    (export_env_file $fenv; cat $fin | envsubst "$(printf '${%s} ' $(clean_env_file -c $fenv | cut -d'=' -f1) )") 
   else
    cat $fin | envsubst "$(printf '${%s} ' $(env | cut -d'=' -f1) )" 
 fi > $tout
 [[ -f $tout2 ]] && rm -f  $tout2
 [[ $fout ]] && mv -f $tout $fout || { echo merged; cat "$tout"; }
#  env | grep BASE
# #  unset_env_file $2
}