#!/usr/bin/env bash
# lib_int.sh - the integer rule for knobs (Issue #26), on its own so scripts
# that run without lib.sh (diff_collect.sh and loop_lock.sh, which the Python
# runner and the tests source alone) read their knobs the same way. lib.sh
# sources it. Functions only: sourcing it has no other effect.

# mam_int <value> <min>
#
# Issue #26: the one integer rule for knobs that reach bash arithmetic (the
# Python twin is lib_py/loop/runner.py::_positive_int). Surrounding blanks are
# allowed, then digits only, read as DECIMAL (bash would read 0700 as octal
# 448 and fail on 0900), and min <= n <= 999999999. Prints n and returns 0, or
# returns 1. The per-knob minimum lives in tests/test_issue26_ints.py.
mam_int() {
  # Spelled-out ASCII sets, not [[:space:]]/[0-9]: those follow the locale, and
  # the runner's _positive_int takes ASCII only (review R2: U+2003 30 U+2003
  # was 30 here under en_US.UTF-8 and invalid there).
  local _ws=$' \t\n\r\v\f' _re
  _re="^[${_ws}]*([0123456789]+)[${_ws}]*\$"
  [[ "${1-}" =~ $_re ]] || return 1
  local d="${BASH_REMATCH[1]}"
  d="${d#"${d%%[!0]*}"}"
  [ ${#d} -le 9 ] || return 1
  local n=$(( 10#${d:-0} ))
  [ "$n" -ge "$2" ] || return 1
  printf '%s\n' "$n"
}

# mam_int_knob <ENV_NAME> <default> <min>
#
# The value of $ENV_NAME through mam_int; unset or empty gives <default>, an
# invalid value gives <default> with a warning on stderr.
mam_int_knob() {
  local raw="${!1-}"
  [ -n "$raw" ] || { printf '%s\n' "$2"; return 0; }
  mam_int "$raw" "$3" && return 0
  echo "WARNING: $1=$raw ignored (not a decimal integer >= $3); using $2" >&2
  printf '%s\n' "$2"
}