#!/usr/bin/env sh
set -eu

usage() {
  cat <<'EOF'
Usage:
  fakeid <cc> [count]

Examples:
  fakeid pl
  fakeid de 5
  fakeid fr 2

Supported cc -> Faker locale mapping:
  pl -> pl_PL
  de -> de_DE
  fr -> fr_FR
  en -> en_US
  it -> it_IT
  es -> es_ES
  nl -> nl_NL
  pt -> pt_PT
  cz -> cs_CZ
  sk -> sk_SK
  se -> sv_SE
  no -> nb_NO
  dk -> da_DK
EOF
}

cc="${1:-}"
count="${2:-1}"

[ -n "$cc" ] || { usage; exit 2; }

case "$cc" in
  pl) locale="pl_PL" ;;
  de) locale="de_DE" ;;
  fr) locale="fr_FR" ;;
  en) locale="en_US" ;;
  it) locale="it_IT" ;;
  es) locale="es_ES" ;;
  nl) locale="nl_NL" ;;
  pt) locale="pt_PT" ;;
  cz) locale="cs_CZ" ;;
  sk) locale="sk_SK" ;;
  se) locale="sv_SE" ;;
  no) locale="nb_NO" ;;
  dk) locale="da_DK" ;;
  *)
    echo "Unsupported country code: $cc" >&2
    usage >&2
    exit 2
    ;;
esac

case "$count" in
  ''|*[!0-9]*)
    echo "Count must be a positive integer." >&2
    exit 2
    ;;
esac
[ "$count" -ge 1 ] || { echo "Count must be >= 1." >&2; exit 2; }

have_iconv=0
command -v iconv >/dev/null 2>&1 && have_iconv=1

# Convert to an ASCII-ish gmail-safe slug.
# - transliterate diacritics where possible
# - lowercase
# - allow only [a-z0-9.] (dots used as separators)
# - collapse multiple dots
# - trim leading/trailing dots
slugify() {
  s="$1"
  if [ "$have_iconv" -eq 1 ]; then
    s="$(printf "%s" "$s" | iconv -f UTF-8 -t ASCII//TRANSLIT 2>/dev/null || printf "%s" "$s")"
  fi

  # lowercase
  s="$(printf "%s" "$s" | tr '[:upper:]' '[:lower:]')"

  # normalize common separators to dot (no tr ranges involved)
  s="$(printf "%s" "$s" | sed "s/[[:space:]_'’\"-]\+/\./g")"

  # keep only a-z0-9 and dots
  s="$(printf "%s" "$s" | tr -cd 'a-z0-9.')"

  # collapse repeated dots + trim leading/trailing dots
  s="$(printf "%s" "$s" | sed 's/\.\{2,\}/./g; s/^\.*//; s/\.*$//')"

  printf "%s" "$s"
}

# Reasonable gmail local-part length (keep it human-like).
# Gmail allows longer, but typical addresses are short.
clip_len() {
  s="$1"
  max="${2:-24}"
  # POSIX-ish: use cut on bytes (fine for ASCII output)
  printf "%s" "$s" | cut -c1-"$max"
}

rand_int() {
  # faker random_int sometimes expects args; simplest:
  faker -l "$locale" random_int
}

# Weighted pattern selection per country.
# Return an integer "pattern id" used by gmail_localpart().
pick_pattern() {
  r="$(rand_int)"
  # reduce r to 0..99
  r=$((r % 100))

  case "$cc" in
    # Poland: firstname.lastname and firstlast are common; some initials.
    pl)
      if   [ "$r" -lt 55 ]; then echo 1
      elif [ "$r" -lt 80 ]; then echo 2
      elif [ "$r" -lt 92 ]; then echo 3
      else                        echo 4
      fi
      ;;
    # Germany: firstname.lastname strong; initials less frequent.
    de)
      if   [ "$r" -lt 65 ]; then echo 1
      elif [ "$r" -lt 85 ]; then echo 2
      elif [ "$r" -lt 95 ]; then echo 3
      else                        echo 4
      fi
      ;;
    # France: firstname.lastname and first.last; sometimes first initial + last.
    fr)
      if   [ "$r" -lt 60 ]; then echo 1
      elif [ "$r" -lt 82 ]; then echo 2
      elif [ "$r" -lt 94 ]; then echo 3
      else                        echo 4
      fi
      ;;
    # US: firstlast + numbers more common.
    en)
      if   [ "$r" -lt 35 ]; then echo 2
      elif [ "$r" -lt 70 ]; then echo 1
      elif [ "$r" -lt 90 ]; then echo 3
      else                        echo 4
      fi
      ;;
    # Default: balanced
    *)
      if   [ "$r" -lt 55 ]; then echo 1
      elif [ "$r" -lt 80 ]; then echo 2
      elif [ "$r" -lt 92 ]; then echo 3
      else                        echo 4
      fi
      ;;
  esac
}

# Build localpart from first/last with realistic patterns:
# 1: firstname.lastname
# 2: firstlast
# 3: f.lastname
# 4: firstname.l
gmail_localpart() {
  first="$1"
  last="$2"

  f="$(slugify "$first")"
  l="$(slugify "$last")"

  # Fallback if Faker returns odd strings
  [ -n "$f" ] || f="user"
  [ -n "$l" ] || l="name"

  pat="$(pick_pattern)"

  case "$pat" in
    1) base="${f}.${l}" ;;
    2) base="${f}${l}" ;;
    3) base="$(printf "%s" "$f" | cut -c1).${l}" ;;
    4) base="${f}.$(printf "%s" "$l" | cut -c1)" ;;
    *) base="${f}.${l}" ;;
  esac

  base="$(slugify "$base")"
  base="$(clip_len "$base" 24)"

  # Add numeric suffix sometimes (more common in en, but possible everywhere).
  rr="$(rand_int)"; rr=$((rr % 100))
  add_num=0
  case "$cc" in
    en) [ "$rr" -lt 45 ] && add_num=1 ;;
    *)  [ "$rr" -lt 25 ] && add_num=1 ;;
  esac

  if [ "$add_num" -eq 1 ]; then
    # Use a 2–3 digit suffix; avoid looking too synthetic.
    n="$(rand_int)"
    n=$(( (n % 900) + 10 ))  # 10..909
    base="$(clip_len "$base" 21)${n}"
    base="$(slugify "$base")"
  fi

  # Final safety: ensure non-empty
  [ -n "$base" ] || base="user$(( ( $(rand_int) % 9000 ) + 1000 ))"

  printf "%s" "$base"
}

gmail_email() {
  first="$(faker -l "$locale" first_name)"
  last="$(faker -l "$locale" last_name)"

  lp="$(gmail_localpart "$first" "$last")"

  # De-dup within this run: if collision, append digits.
  # (We store as newline-delimited list in $seen)
  if printf "%s\n" "${seen:-}" | grep -qx "$lp" 2>/dev/null; then
    k="$(rand_int)"; k=$(( (k % 900) + 10 ))
    lp="$(clip_len "$lp" 21)${k}"
    lp="$(slugify "$lp")"
  fi
  seen="${seen:-}
$lp"

  printf "%s@gmail.com\n" "$lp"
}

i=1
seen=""
while [ "$i" -le "$count" ]; do
  faker -l "$locale" name
  faker -l "$locale" address
  faker -l "$locale" phone_number
  gmail_email

  if [ "$i" -lt "$count" ]; then
    printf "\n"
  fi

  i=$((i + 1))
done