#!/bin/sh
# ensure-locale.sh
# Ensures UTF-8 locale is generated and persisted system-wide.
# Safe, idempotent. Requires root (or sudo) for system-wide changes.
# Usage:
#   sudo ./ensure-locale.sh
#   ./ensure-locale.sh cmd args   # entrypoint wrapper

_locale_log() { printf '[ensure-locale] %s\n' "$*" >&2; }

_utf8_active() {
  _eff="${LC_ALL:-${LC_CTYPE:-$LANG}}"
  case "$_eff" in
  *[Uu][Tt][Ff]8* | *[Uu][Tt][Ff]-8*) return 0 ;;
  esac
  return 1
}

_locale_exists() {
  locale -a 2>/dev/null | grep -qi "$1"
}

ensure_locale_generated() {
  if _locale_exists '^en_US\.utf'; then
    _locale_log "en_US.UTF-8 already generated."
    return 0
  fi

  if ! command -v locale-gen >/dev/null 2>&1; then
    _locale_log "locale-gen not found; skipping generation."
    return 1
  fi

  if [ "$(id -u)" != "0" ]; then
    _locale_log "Not root; cannot generate locale. Run with sudo."
    return 1
  fi

  _locale_log "Generating en_US.UTF-8..."
  [ -w /etc/locale.gen ] &&
    sed -i 's/^# *\(en_US.UTF-8 UTF-8\)/\1/' /etc/locale.gen 2>/dev/null || true
  locale-gen en_US.UTF-8 >/dev/null 2>&1
  update-locale LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8 2>/dev/null || true
  _locale_log "Generated en_US.UTF-8."
}

ensure_zshenv() {
  _zshenv=/etc/zsh/zshenv
  _marker="en_US.UTF-8"

  if [ "$(id -u)" != "0" ]; then
    _locale_log "Not root; cannot write $_zshenv. Run with sudo."
    return 1
  fi

  if [ -f "$_zshenv" ] && grep -q "$_marker" "$_zshenv" 2>/dev/null; then
    _locale_log "$_zshenv already contains UTF-8 locale settings."
    return 0
  fi

  _locale_log "Writing locale exports to $_zshenv..."
  mkdir -p "$(dirname $_zshenv)"
  cat >>"$_zshenv" <<'EOF'

# UTF-8 locale — added by ensure-locale.sh
export LANG=en_US.UTF-8
export LC_ALL=en_US.UTF-8
EOF
  _locale_log "Done. Open a new shell or run: exec zsh"
}

ensure_locale_generated
ensure_zshenv

# Export for the current session too
if _locale_exists '^en_US\.utf' && ! _utf8_active; then
  export LANG=en_US.UTF-8
  export LC_ALL=en_US.UTF-8
fi

# Entrypoint wrapper: ./ensure-locale.sh python app.py
if [ $# -gt 0 ]; then
  exec "$@"
fi