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#!/bin/bash
# NOTE: didn't use BATS framework due to interactive usage

## Test 1: read_safe() does discards unwanted characters and affects outer scope
test_read_safe_affects_outer_scope() {
  # variable in outer scope
  local x=0

  # unwanted input
  echo "please enter random unwanted lines of characters within 5 seconds:"
  sleep 5

  read_safe x "please enter 11 for x value"
  # test
  if (( x == 11 )); then
    echo "$(date +%T) [INFO] test_read_safe_affects_outer_scope OK!"
    echo ""
  else
    echo "$(date +%T) [ERROR] Bad x value: $x"
    echo "$(date +%T) [ERROR] test_read_safe_affects_outer_scope Failed!"
    exit 1
  fi
}

test_read_safe_affects_outer_scope


## Test 2: read_safe() affects the closest outer scope only

# create an intermediate scope
read_safe_innerscope() {
  # inner scope x
  local x=1

  # do
  echo "$(date +%T) [DEBUG] inner x value before read_safe(): $x"
  read_safe $1 "$2"
  echo "$(date +%T) [DEBUG] inner x value after read_safe(): $x"
}

# outermost scope executing read_safe()
test_read_safe_closest_outer_scope_only() {
  # outer scope x
  local x=0

  # unwanted input
  echo "please enter random unwanted lines of characters within 5 seconds:"
  sleep 5

  # do
  echo "$(date +%T) [DEBUG] outer x value before read_safe(): $x"
  read_safe_innerscope "x" "please enter 11 for x value"
  echo "$(date +%T) [DEBUG] outer x value after read_safe(): $x"

  # test
  if (( x == 0 )); then
    echo "$(date +%T) [DEBUG] test_read_safe_closest_outer_scope_only OK!"
  else
    echo "$(date +%T) [ERROR] Bad x value: $x"
    echo "$(date +%T) [ERROR] test_read_safe_closest_outer_scope_only Failed!"
    exit 1
  fi
}

test_read_safe_closest_outer_scope_only

read_safe() {
  #
  #   discard accidental input before read.
  #
  # parameters
  #   $1  variable name to read into
  #   $2  prompt

  echo "$(date +%T) [DEBUG] read_safe(\"$1\" \"$2\") begins..."
  local __discarded

  # check number of arguments
  if (( $# != 2 )); then
    echo "$(date +%T) [ERROR] Wrong argument count: $#"
    exit 1
  fi

  # discard unwanted characters
  echo "$(date +%T) [DEBUG] discarding unwanted characters...."
  read -N 100000 -t 0.01 __discarded

  # read (non-local)
  read -p "***USER INPUT*** $2:" "$1"

  echo "$(date +%T) [DEBUG] read_safe(\"$1\" \"$2\") done!"
}