#compdef -value-,PROMPT,-default- -value-,PROMPT2,-default- -value-,PROMPT3,-default- -value-,PROMPT4,-default- -value-,RPROMPT,-default- -value-,RPROMPT2,-default- -value-,PS1,-default- -value-,PS2,-default- -value-,PS3,-default- -value-,PS4,-default- -value-,RPS1,-default- -value-,RPS2,-default- -value-,SPROMPT,-default-

local -a specs ccol
local expl grp cols bs suf pre changed=1 ret=1
local -A ansi

[[ -z $compstate[quote] ]] && bs='\'

# first strip off any complete prompt specifications leaving only the
# current, incomplete, one
while (( changed )); do
  changed=0
  compset -P '%[DFK](\\|){[^}]#}' && changed=1 # formats with arg: %x{...}
  compset -P '%[0-9-\\]#[^DFK(0-9-<>\\\[]' && changed=1 # normal formats
  compset -P '%[0-9-\\]#(<[^<]#<|>[^>]#>|\[[^\]]#\])' && changed=1 # truncations
  compset -P '%[0-9-\\]#(\\|)\([0-9-]#[^0-9]?|[^%]' && changed=1 # start of ternary
  compset -P '[^%]##' && changed=1 # sundry other characters
  # %D/%F/%K without a following { ... }
  [[ $PREFIX = %(-|)<->#[DFK](\\[^{]|[^{\\])* ]] &&
      compset -P '%[0-9\\-]#[DFK]' && changed=1
done
[[ $PREFIX = %(-|)<->[FK](#e) ]] && compset -P '*' # F/K with number

if compset -P '%[FK]'; then
  # this should use -P but that somehow causes single quotes to be stripped
  compset -P '(\\|){' || pre=( -p '{' )
  compset -S '(\\|)}*' || suf=( -S "$bs}" )
  ansi=(
    black 30
    red 31
    green 32
    yellow 33
    blue 34
    magenta 35
    cyan 36
    white 37
    default 39
  )

  _description -V ansi-colors expl 'ansi color'
  grp="$expl[expl[(i)-V]+1]"
  print -v ccol -f "($grp)=%s=%s" ${(kv)ansi}
  _comp_colors+=( $ccol )
  compadd "$expl[@]" $suf $pre -k ansi && ret=0
  if (( $#suf )) && compset -P "(<->|%v)"; then
    _wanted ansi-colors expl 'closing brace' compadd -S '' \} && ret=0
  elif (( $+terminfo[colors] )); then
    (( cols = $terminfo[colors] - 1 ))
    (( cols = cols > 255 ? 255 : cols ))
    _description -V terminal-colors expl 'terminal color'
    grp="$expl[expl[(i)-V]+1]"
    compadd "$expl[@]" $suf $pre {0..$cols}
    for c in {0..$cols}; do
      _comp_colors+=( "($grp)=${c}=${${$(print -P "%F{$c}")#?\[}%m}" )
    done
  else
    _message -e terminal-colors "number"
  fi
fi

if compset -P '%[0-9-\\]#(\\|)\([0-9-]#[^0-9]'; then
  # ternary conditional: first delimiter
  compset -S '*'
  _delimiters && ret=0
elif compset -P '%[0-9-\\]#[<>\]]'; then
  # truncation
  _message -e replacements 'replacement string'
elif compset -P '%[0-9-\\]#(\\|)\([0-9-]#'; then
  # ternary conditional: condition character
  compset -S '[.:+/-%]*' || suf=( -S . )
  compset -S '*'
  specs=(
    '!:running with privileges'
    '#:effective uid'
    '?:exit status'
    '_:at least n shell constructs started'
    'C:at least n path elements'
    '/:at least n path elements'
    '.:at least n path elements'
    'c:at least n path elements'
    '~:at least n path elements'
    'D:month'
    'd:day of month'
    'g:effective gid'
    'j:number of jobs'
    'L:SHLVL'
    'l:number of characters already printed'
    'S:SECONDS parameter at least n'
    'T:current hour'
    't:current minute'
    'v:psvar has at least n elements'
    'V:element n of psvar is set and non-empty'
    'w:day of week (Sunday = 0)'
  )
  [[ $IPREFIX != *- ]] && _describe -t ternary-prompt-expressions \
      'ternary prompt format test character' specs $suf && ret=0
  _message -e numbers number
elif compset -P '%D(\\|){'; then
  compset -S '(\\|)}*'
  _date_formats zsh && ret=0
elif [[ -prefix '%' ]] ||
      ! zstyle -t ":completion:${curcontext}:prompt-format-specifiers" prefix-needed
then
  specs=(
    'm:hostname up to first .'
    '_:status of parser'
    '^:reversed status of parser'
    'd:current working directory'
    '/:current working directory'
    '~:current working directory, with ~ replacement'
    'N:name of current script or shell function'
    'x:name of file containing code being executed'
    'c:deprecated'
    '.:deprecated'
    'C:deprecated'
    'F:start using fg color'
    'K:start using bg color'
    'G:counts as extra character inside %{...%}'
    '(:ternary expression %(x.true-string.false-string)'
  )
  compset -P '%' || pre=( -p '%' )
  if ! compset -P '(-|)<->'; then
    if [[ $service == -value-,SPROMPT,* ]]; then
      specs+=(
	'r:suggested correction'
	'R:corrected string'
      )
    fi
    specs+=(
      '%:A %'
      '):A )'
      'l:current line (tty) with /dev/tty stripped'
      'M:full hostname'
      'n:username'
      'y:current line (tty)'
      '#:a # when root, % otherwise'
      '?:return status of last command'
      'h:current history event number'
      '!:current history event number'
      'i:current line number'
      'I:current source line number'
      'j:number of jobs'
      'L:$SHLVL'
      'D:date in yy-mm-dd format'
      'T:current time of day, 24-hour format'
      't:current time of day, 12-hour am/pm format'
      '@:current time of day, 12-hour am/pm format'
      '*:current time of day, 24-hour format with seconds'
      'w:the date in day-dd format'
      'W:the date in mm/dd/yy format'
      'D{:format string like strftime'
      'B:start bold'
      'b:stop bold'
      'E:clear to end of line'
      'U:start underline'
      'u:stop underline'
      'S:start standout'
      's:stop standout'
      'f:reset fg color'
      'k:reset bg color'
      '{:start literal escape sequence'
      '}:stop literal escape sequence'
      'v:value from $psvar array'
      '<:truncation from left %len<string<'
      '>:truncation from right %len>string>'
      '[:truncation from who knows where'
    )
  fi
  _describe -t prompt-format-specifiers 'prompt format specifier' \
      specs -S '' $pre && ret=0
  (( ! $#pre )) && _message -e prompt-format-specifiers number
fi

return ret