#!/usr/bin/env bash
# ui-block.sh - TTY-safe status "block" indicator (no special fonts)
#
#   busy : blue block that "breathes" (background colour pulses)
#   ok   : solid green block
#   fail : solid red block (changed from red X per YuKu's spec)
#
# Why this works on a bare TTY: the "block" is a BACKGROUND-COLOURED SPACE,
# not a U+2588 glyph. No fonts, no UTF-8, no locale dependency.
#
# Draws on /dev/tty, never stdout: ui_choose/ui_confirm capture stdout with $(),
# so a status line on stdout would corrupt every captured answer.

_UB_FD=""
_UB_PID=""
_UB_MSG=""

_ub_tty() {
  if [[ -z "$_UB_FD" ]]; then
    # probe first: a bare `exec {fd}>/dev/tty` failure still prints its error
    { : >/dev/tty; } 2>/dev/null || { _UB_FD=""; return 1; }
    exec {_UB_FD}>/dev/tty 2>/dev/null || { _UB_FD=""; return 1; }
  fi
  [[ -n "$_UB_FD" ]]
}

_ub_depth() {
  local n
  n=$(tput colors 2>/dev/null || echo 0)
  case "$n" in ''|*[!0-9]*) n=0 ;; esac
  if   [[ "$n" -ge 256 ]]; then echo 256
  elif [[ "$n" -ge 8   ]]; then echo 16
  else echo 0; fi
}

# paint one background-coloured block (a SPACE) + message
_ub_paint() {
  printf '\r\033[%sm \033[0m %s' "$1" "$2" >&"$_UB_FD"
}

_ub_busy_loop() {
  local depth pal=() i
  depth=$(_ub_depth)
  case "$depth" in
    256) pal=(17 18 19 20 21 27 33 27 21 20 19 18) ;;  # blue breathe
    16)  pal=(44 104 44 104) ;;                          # blue / bright blue
    *)   pal=("|" "/" "-" "\\") ;;                       # last-resort spinner
  esac
  while :; do
    for i in "${pal[@]}"; do
      if [[ "$depth" -eq 256 ]]; then
        _ub_paint "48;5;$i" "$_UB_MSG"       # 256-colour cube background
      elif [[ "$depth" -eq 16 ]]; then
        _ub_paint "$i" "$_UB_MSG"            # plain ANSI background (44/104)
      else
        printf '\r[%s] %s' "$i" "$_UB_MSG" >&"$_UB_FD"
      fi
      sleep 0.08 || return 0
    done
  done
}

_ub_stop() {
  if [[ -n "$_UB_PID" ]]; then
    kill "$_UB_PID" 2>/dev/null
    wait "$_UB_PID" 2>/dev/null
    _UB_PID=""
  fi
}

ui_block_start() {
  _UB_MSG="${1:-Working}"
  _ub_tty || return 0                       # no tty: silent no-op
  _ub_stop
  _ub_busy_loop &
  _UB_PID=$!
}

ui_block_ok() {
  local msg="${1:-Done}" d
  _ub_tty || return 0
  _ub_stop
  d=$(_ub_depth)
  case "$d" in
    256) _ub_paint "48;5;34" "$msg" ;;
    16)  _ub_paint "42"      "$msg" ;;
    *)   printf '\r[OK] %s' "$msg" >&"$_UB_FD" ;;
  esac
  printf '\033[0m\n' >&"$_UB_FD"
}

ui_block_fail() {
  local msg="${1:-Failed}" d
  _ub_tty || return 0
  _ub_stop
  d=$(_ub_depth)
  case "$d" in
    256) printf '\r\033[48;5;196m \033[0m %s' "$msg" >&"$_UB_FD" ;;
    16)  printf '\r\033[41m \033[0m %s'      "$msg" >&"$_UB_FD" ;;
    *)   printf '\r[!] %s'                    "$msg" >&"$_UB_FD" ;;
  esac
  printf '\n' >&"$_UB_FD"
}

ui_block_close() {
  _ub_stop
  if [[ -n "$_UB_FD" ]]; then
    exec {_UB_FD}>&- 2>/dev/null
    _UB_FD=""
  fi
  return 0   # an EXIT trap's status becomes the script's exit code — never fail here
}

# ALWAYS install a cleanup trap in the sourcing script:
#   trap 'ui_block_close' EXIT INT TERM