#!/bin/bash
# =============================================================================
# machine-setup — system configuration
# =============================================================================
#
# Definitions only, like the other lib/ files. Locale, and the system-level
# settings that follow it.

[[ -n "${MACHINE_SETUP_SYSTEM_LOADED:-}" ]] && return 0
MACHINE_SETUP_SYSTEM_LOADED=1

# -----------------------------------------------------------------------------
# Locale
# -----------------------------------------------------------------------------
#
# Two separate facts, and the original only handled one of them:
#
#   what a new login shell is told to use   — LANG in /etc/default/locale
#   whether that locale actually exists     — whether it has been generated
#
# Setting LANG to a locale that was never generated is the state that produces
# "setlocale: LC_ALL: cannot change locale" on every ssh login and every perl
# invocation. Both are checked, so the step can say which one is missing.

# What a new login shell will be handed, or empty if nothing is configured.
locale_current() {
  if [[ -r /etc/default/locale ]]; then
    awk -F= '/^LANG=/ { gsub(/"/, "", $2); print $2 }' /etc/default/locale
  elif [[ -r /etc/locale.conf ]]; then
    awk -F= '/^LANG=/ { gsub(/"/, "", $2); print $2 }' /etc/locale.conf
  fi
}

# Has this locale actually been built?
#
# `locale -a` prints en_US.utf8 where the configuration spells it en_US.UTF-8,
# so both sides are folded to lower case with the dashes removed before
# comparing. A literal match here would report a perfectly good locale missing.
locale_is_generated() {
  local want="${1,,}"
  want="${want//-/}"
  locale -a 2>/dev/null | tr '[:upper:]' '[:lower:]' | tr -d '-' | grep -qx "$want"
}

locale_set() {
  local want="$1"
  local escaped="${want//./\\.}"

  case "$PM" in
    apt)
      # locale-gen comes from the `locales` package, which minimal images and
      # most cloud base images do not ship. Without this the step fails with
      # "locale-gen: command not found" halfway through.
      if ! pkg_is_installed locales; then
        info "     installing locales, which provides locale-gen"
        pkg_install_now locales
      fi

      # Uncomment it if it is there commented out, add it if it is absent.
      # Editing the file rather than passing the name to locale-gen is what makes
      # it survive: a locale generated by argument alone is lost the next time
      # anything regenerates from /etc/locale.gen.
      if grep -qE "^#[[:space:]]*${escaped}[[:space:]]" /etc/locale.gen 2>/dev/null; then
        sed -i "s/^#[[:space:]]*\(${escaped}[[:space:]]\)/\1/" /etc/locale.gen
      elif ! grep -qE "^${escaped}[[:space:]]" /etc/locale.gen 2>/dev/null; then
        # The charset is the part after the dot: en_US.UTF-8 -> UTF-8
        echo "${want} ${want##*.}" >>/etc/locale.gen
      fi

      locale-gen
      update-locale LANG="$want"
      ;;
    pacman)
      if grep -qE "^#[[:space:]]*${escaped}[[:space:]]" /etc/locale.gen 2>/dev/null; then
        sed -i "s/^#[[:space:]]*\(${escaped}[[:space:]]\)/\1/" /etc/locale.gen
      fi
      locale-gen
      echo "LANG=${want}" >/etc/locale.conf
      ;;
    dnf)
      # No locale.gen here — the locales come prebuilt in langpack packages.
      pkg_install_now "glibc-langpack-${want%%_*}"
      localectl set-locale "LANG=${want}"
      ;;
    brew)
      warn "macOS has no system locale to set — it is per-user, from the terminal's settings"
      return 1
      ;;
  esac
}

# -----------------------------------------------------------------------------
# Timezone
# -----------------------------------------------------------------------------

# The shortlist offered at the prompt. Any zone name can be typed instead, so
# this is a convenience rather than a limit.
TZ_OPTIONS=(UTC Europe/Lisbon Europe/London Europe/Berlin Europe/Stockholm US/Eastern US/Pacific Asia/Tokyo)

# What the machine is set to now.
#
# Three sources because they disagree about availability rather than about the
# answer: timedatectl is absent without systemd (containers, WSL), /etc/timezone
# is Debian-specific, and the /etc/localtime symlink is the one thing that is
# always true when any of them are.
timezone_current() {
  if command -v timedatectl &>/dev/null && timedatectl show -p Timezone --value 2>/dev/null | grep -q .; then
    timedatectl show -p Timezone --value 2>/dev/null
  elif [[ -r /etc/timezone ]]; then
    tr -d '[:space:]' </etc/timezone
  elif [[ -L /etc/localtime ]]; then
    readlink -f /etc/localtime | sed 's|.*/zoneinfo/||'
  fi
}

# Checked against the zoneinfo database before it is used. `timedatectl
# set-timezone` on a name that does not exist fails, and under `set -e` that
# takes the whole run down over a typo.
timezone_is_valid() { [[ -f "/usr/share/zoneinfo/$1" ]]; }

timezone_set() {
  local tz="$1"
  case "$PM" in
    brew) systemsetup -settimezone "$tz" >/dev/null ;;
    *)
      # timedatectl where there is a systemd to talk to; the files directly
      # otherwise, which is the same thing it would have written.
      if command -v timedatectl &>/dev/null && [[ "$IS_WSL" != true ]]; then
        timedatectl set-timezone "$tz"
      else
        ln -sf "/usr/share/zoneinfo/${tz}" /etc/localtime
        echo "$tz" >/etc/timezone
      fi
      ;;
  esac
}