#!/usr/bin/env bash
unset PATH; readonly PATH
source ./utils/main.sh

count_patterns_occurences() {
  local input="$1"; shift
  local patterns=("$@") result=0

  for pattern in "${patterns[@]}"; do
    local text="$input"
    while [[ -n "$text" ]]; do
      if [[ "$text" =~ $pattern ]]; then
        ((result++))
        text="${text#*"${BASH_REMATCH[0]}"}"
        text="${BASH_REMATCH[0]:1}$text"
      else
        text=''
      fi
    done
  done

  printf '%d' "$result"
}

p1() {
  local input="$1" line result=0 cols=0

  read -ra line <<< "$input"
  cols="$((${#line}+1))"

  local patterns=(
    "XMAS"
    "SAMX"
    "X.{$((cols))}M.{$((cols))}A.{$((cols))}S"
    "S.{$((cols))}A.{$((cols))}M.{$((cols))}X"
    "X.{$((cols-1))}M.{$((cols-1))}A.{$((cols-1))}S"
    "S.{$((cols-1))}A.{$((cols-1))}M.{$((cols-1))}X"
    "X.{$((cols-2))}M.{$((cols-2))}A.{$((cols-2))}S"
    "S.{$((cols-2))}A.{$((cols-2))}M.{$((cols-2))}X"
  )

  count_patterns_occurences "$input" "${patterns[@]}"
}

p2() {
  local input="$1" line result=0 cols=0

  read -ra line <<< "$input"
  cols="$((${#line}+1))"

  local patterns=(
    "M.M.{$((cols-2))}A.{$((cols-2))}S.S"
    "M.S.{$((cols-2))}A.{$((cols-2))}M.S"
    "S.M.{$((cols-2))}A.{$((cols-2))}S.M"
    "S.S.{$((cols-2))}A.{$((cols-2))}M.M"
  )

  count_patterns_occurences "$input" "${patterns[@]}"
}

main "$@"