#autoload

# Utility function for in-path completion. This allows `/u/l/b<TAB>'
# to complete to `/usr/local/bin'.

local linepath realpath donepath prepath testpath exppath skips skipped
local tmp1 tmp2 tmp3 tmp4 i orig eorig pre suf tpre tsuf opre osuf cpre
local pats haspats=no ignore pfxsfx rem remt sopt gopt opt
local nm=$compstate[nmatches] menu matcher mopts atmp sort match

typeset -U prepaths exppaths

setopt localoptions nullglob rcexpandparam
unsetopt markdirs globsubst shwordsplit nounset

exppaths=()

# Get the options.

zparseopts -a mopts \
    'P:=pfxsfx' 'S:=pfxsfx' 'q=pfxsfx' 'r:=pfxsfx' 'R:=pfxsfx' \
    'W:=prepaths' 'F:=ignore' 'M+:=matcher' \
    J+: V+: X+: 1: 2: n: 'f=tmp1' '/=tmp1' 'g+:-=tmp1'

sopt="-${(@j::M)${(@)tmp1#-}#?}"
(( $tmp1[(I)-[/g]*] )) && haspats=yes
(( $tmp1[(I)-g*] )) && gopt=yes
if (( $tmp1[(I)-/] )); then
  pats=( '*(-/)' ${=${(M)tmp1:#-g*}#-g} )
else
  pats=( "${(@)=${(@M)tmp1:#-g*}#-g}" )
fi
pats=( "${(@)pats:# #}" )

if (( $#prepaths )); then
  tmp1="${prepaths[2]}"
  if [[ "$tmp1[1]" = '(' ]]; then
    prepaths=( ${^=tmp1[2,-2]%/}/ )
  elif [[ "$tmp1[1]" = '/' ]]; then
    prepaths=( "${tmp1%/}/" )
  else
    prepaths=( ${(P)^tmp1%/}/ )
    (( ! $#prepaths )) && prepaths=( ${tmp1%/}/ )
  fi
  (( ! $#prepaths )) && prepaths=( '' )
else
  prepaths=( '' )
fi

if (( $#ignore )); then
  if [[ "${ignore[2]}" = \(* ]]; then
    ignore=( ${=ignore[2][2,-2]} )
  else
    ignore=( ${(P)ignore[2]} )
  fi
fi  

# If we were given no file selection option, we behave as if we were given
# a `-f'.

if [[ "$sopt" = -(f|) ]]; then
  if [[ -z "$gopt" ]]; then
    sopt='-f'
    pats=('*')
  else
    unset sopt
  fi
fi

if (( ! $mopts[(I)-[JVX]] )); then
  local expl

  if [[ -z "$gopt" && "$sopt" = -/ ]]; then
    _description directories expl directory
  else
    _description files expl file
  fi
  tmp1=$expl[(I)-M*]
  if (( tmp1 )); then
    if (( $#matcher )); then
      matcher[2]="$matcher[2] $expl[1+tmp1]"
    else
      matcher=(-M "$expl[1+tmp1]")
    fi
  fi
  mopts=( "$mopts[@]" "$expl[@]" )
fi

if zstyle -s ":completion:${curcontext}:files" sort tmp1; then
  case "$tmp1" in
  *size*)             sort=oL;;
  *links*)            sort=ol;;
  *(time|date|modi)*) sort=om;;
  *access*)           sort=oa;;
  *(inode|change)*)   sort=oc;;
  *)                  sort=on;;
  esac
  [[ "$tmp1" = *rev* ]] && sort[1]=O

  if [[ "$sort" = on ]]; then
    sort=''
  else
    mopts=( "${(@)mopts/#-J/-V}" )

    tmp2=()
    for tmp1 in "$pats[@]"; do
      if [[ "$tmp1" = (#b)(?*)(\(\([^\|~]##\)\)) ]]; then
        tmp2=( "$tmp2[@]" "${match[1]}((${sort}${match[2][3,-1]}" )
      elif [[ "$tmp1" = (#b)(?*)(\([^\|~]##\)) ]]; then
        tmp2=( "$tmp2[@]" "${match[1]}(${sort}${match[2][2,-1]}" )
      else
        tmp2=( "$tmp2[@]" "${tmp1}(${sort})" )
      fi
    done
    pats=( "$tmp2[@]" )
  fi
fi

# Check if we have to skip over sequences of slashes. The value of $skips
# is used below to match the pathname components we always have to accept
# immediatly.

if zstyle -t ":completion:${curcontext}:paths" squeeze-slashes; then
  skips='((.|..|)/)##'
else
  skips='((.|..)/)##'
fi

# We get the prefix and the suffix from the line and save the whole
# original string. Then we see if we will do menucompletion.

pre="$PREFIX"
suf="$SUFFIX"
opre="$PREFIX"
osuf="$SUFFIX"
orig="${PREFIX}${SUFFIX}"
eorig="$orig"

[[ $compstate[insert] = (*menu|[0-9]*) || -n "$_comp_correct" ||
   ( -n "$compstate[pattern_match]" &&
     "${orig#\~}" != "${${orig#\~}:q}" ) ]] && menu=yes

# If given no `-F' option, we may want to use $fignore, turned into patterns.

[[ $#ignore -eq 0 && ( -z $gopt || "$pats" = \ #\*\ # ) && -n $FIGNORE ]] && 
   ignore=( "?*${^fignore[@]}" )

if (( $#ignore )); then
  _comp_ignore=( "$_comp_ignore[@]" "$ignore[@]" )
  (( $mopts[(I)-F] )) || mopts=( "$mopts[@]" -F _comp_ignore )
fi

(( $#matcher )) && mopts=( "$mopts[@]" "$matcher[@]" )

# Now let's have a closer look at the string to complete.

if [[ "$pre[1]" = \~ ]]; then
  # It begins with `~', so remember anything before the first slash to be able
  # to report it to the completion code. Also get an expanded version of it
  # (in `realpath'), so that we can generate the matches. Then remove that
  # prefix from the string to complete, set `donepath' to build the correct
  # paths and make sure that the loop below is run only once with an empty
  # prefix path by setting `prepaths'.

  linepath="${pre[2,-1]%%/*}"
  if [[ -z "$linepath" ]]; then
    realpath="${HOME%/}/"
  elif (( $+userdirs[$linepath] )); then
    realpath="${userdirs[$linepath]%/}/"
  elif (( $+nameddirs[$linepath] )); then
    realpath="${nameddirs[$linepath]%/}/"
  else
    _message "unknown user \`$linepath'"
    return 1
  fi
  linepath="~${linepath}/"
  [[ "$realpath" = "$linepath" ]] && return 1
  pre="${pre#*/}"
  orig="${orig#*/}"
  donepath=''
  prepaths=( '' )
elif [[ "$pre" = *\$*/* ]]; then

  # If there is a parameter expansion in the word from the line, we try
  # to complete the beast by expanding the prefix and completing anything
  # after the first slash after the parameter expansion.
  # This fails for things like `f/$foo/b/<TAB>' where the first `f' is
  # meant as a partial path.

  linepath="${(M)pre##*\$[^/]##/}"
  realpath=${(e)~linepath}
  [[ "$realpath" = "$linepath" ]] && return 1
  pre="${pre#${linepath}}"
  i="${#linepath//[^\\/]}"
  orig="${orig[1,(in:i:)/][1,-2]}"
  donepath=''
  prepaths=( '' )
else
  # If the string does not start with a `~' we don't remove a prefix from the
  # string.

  linepath=''
  realpath=''

  if [[ "$pre[1]" = / ]]; then
    # If it is a absolut path name, we remove the first slash and put it in
    # `donepath' meaning that we treat it as the path that was already handled.
    # Also, we don't use the paths from `-W'.

    pre="$pre[2,-1]"
    orig="$orig[2,-1]"
    donepath='/'
    prepaths=( '' )
  else
    # The common case, we just use the string as it is, unless it begins with
    # `./' or `../' in which case we don't use the paths from `-W'.
    
    [[ "$pre" = (.|..)/* ]] && prepaths=( '' )
    donepath=''
  fi
fi

# Now we generate the matches. First we loop over all prefix paths given
# with the `-W' option.

for prepath in "$prepaths[@]"; do

  # Get local copies of the prefix, suffix, and the prefix path to use
  # in the following loop, which walks through the pathname components
  # in the string from the line.

  tpre="$pre"
  tsuf="$suf"
  testpath="$donepath"

  tmp2="${(M)tpre##${~skips}}"
  tpre="${tpre#$tmp2}"

  tmp1=( "$prepath$realpath$donepath$tmp2" )

  while true; do

    # Get the prefix and suffix for matching.

    if [[ "$tpre" = */* ]]; then
      PREFIX="${tpre%%/*}"
      SUFFIX=""
    else
      PREFIX="${tpre}"
      SUFFIX="${tsuf%%/*}"
    fi

    # Get the matching files by globbing.

    tmp2=( "$tmp1[@]" )
    if [[ "$tpre$tsuf" = */* ]]; then
      if [[ ! -o globdots && "$PREFIX" = .* ]]; then
        tmp1=( ${^tmp1}${skipped}*(-/) ${^tmp1}${skipped}.*(-/) )
      else
        tmp1=( ${^tmp1}${skipped}*(-/) )
      fi
      if [[ -o globdots || "$PREFIX" = .* ]] &&
         zstyle -s ":completion:${curcontext}:paths" special-dirs atmp; then
	if [[ "$atmp" = (yes|true|1|on) ]]; then
	  tmp1=( "$tmp1[@]" . .. )
	elif [[ "$atmp" = .. ]]; then
	  tmp1=( "$tmp1[@]" .. )
        fi
      fi
    else
      if [[ ! -o globdots && "$PREFIX" = .* ]]; then
        tmp1=( ${^tmp1}${skipped}${^~pats} ${^tmp1}${skipped}.${^~pats:#.*} )
      else
        tmp1=( ${^tmp1}${skipped}${^~pats} )
      fi
      if [[ "$sopt" = *[/f]* && ( -o globdots || "$PREFIX" = .* ) ]] &&
	  zstyle -s ":completion:${curcontext}:paths" special-dirs atmp; then
	if [[ "$atmp" = (yes|true|1|on) ]]; then
	  tmp1=( "$tmp1[@]" . .. )
	elif [[ "$atmp" = .. ]]; then
	  tmp1=( "$tmp1[@]" .. )
        fi
      fi
    fi

    if [[ -n "$PREFIX$SUFFIX" ]]; then
      # See which of them match what's on the line.

      if [[ -n "$_comp_correct" ]]; then
        tmp2=( "$tmp1[@]" )
        builtin compadd -D tmp1 -F _comp_ignore "$matcher[@]" - "${(@)tmp1:t}"

        if [[ $#tmp1 -eq 0 ]]; then
          tmp1=( "$tmp2[@]" )
	  compadd -D tmp1 -F _comp_ignore "$matcher[@]" - "${(@)tmp2:t}"
        fi
      else
        [[ "$tmp1[1]" = */* ]] && tmp2=( "$tmp1[@]" )

        builtin compadd -D tmp1 -F _comp_ignore "$matcher[@]" - "${(@)tmp1:t}"
      fi

      # If no file matches, save the expanded path and continue with
      # the outer loop.

      if (( ! $#tmp1 )); then
 	if [[ "$tmp2[1]" = */* ]]; then
	  tmp2=( "${(@)tmp2#${prepath}${realpath}}" )
	  if [[ "$tmp2[1]" = */* ]]; then
	    tmp2=( "${(@)tmp2:h}" )
	    compquote tmp2
	    if [[ "$tmp2" = */ ]]; then
	      exppaths=( "$exppaths[@]" ${^tmp2}${tpre}${tsuf} )
	    else
	      exppaths=( "$exppaths[@]" ${^tmp2}/${tpre}${tsuf} )
	    fi
          else
	    exppaths=( "$exppaths[@]" ${tpre}${tsuf} )
	  fi
        fi
        continue 2
      fi
    elif (( ! $#tmp1 )); then
      # A little extra hack: if we were completing `foo/<TAB>' and `foo'
      # contains no files, this will normally produce no matches and other
      # completers might think that's it's their time now. But if the next
      # completer is _correct or something like that, this will result in
      # an attempt to correct a valid directory name. So we just add the
      # original string in such a case so that the command line doesn't 
      # change but other completers still think there are matches.
      # We do this only if we weren't given a `-g' or `-/' option because
      # otherwise this would keep `_files' from completing all filenames
      # if none of the patterns match.

      if [[ -z "$tpre$tsuf" && -n "$pre$suf" ]]; then
	pfxsfx=(-S '' "$pfxsfx[@]")
	### Don't remember what the break was good for. We explicitly
	### execute this only when there are no matches in the directory,
	### so why continue?
	###
        ### tmp1=( "$tmp2[@]" )
	### break
      elif [[ "$haspats" = no && -z "$tpre$tsuf" &&
	"$pre" = */ && -z "$suf" ]]; then
	PREFIX="${opre}"
	SUFFIX="${osuf}"
        compadd -nQS '' - "$linepath$donepath$orig"
        tmp4=-
      fi
      continue 2
    fi

    if [[ "$tpre$tsuf" != */* && $#tmp1 -ne 0 ]] &&
       zstyle -s ":completion:${curcontext}:files" ignore-parents rem &&
       [[ ( "$rem" != *dir* || "$pats" = '*(-/)' ) &&
	  ( "$rem" != *..* || "$tmp1" = *../* ) ]]; then
      if [[ "$rem" = *parent* ]]; then
	for i in ${(M)^tmp1:#*/*}(-/); do
	  remt="${${i#$prepath$realpath$donepath}%/*}"
	  while [[ "$remt" = */* &&
	           ! "$prepath$realpath$donepath$remt" -ef "$i" ]]; do
	    remt="${remt%/*}"
	  done
	  [[ "$remt" = */* || "$remt" -ef "$i" ]] &&
	      _comp_ignore=( "$_comp_ignore[@]" "${(q)i}" )
	done
      fi
      if [[ "$rem" = *pwd* ]]; then
        for i in ${^tmp1}(-/); do
	  [[ "$i" -ef "$PWD" ]] && _comp_ignore=( "$_comp_ignore[@]" "${(q)i}" )
	done
      fi
      (( $#_comp_ignore && $mopts[(I)-F] )) || mopts=( "$mopts[@]" -F _comp_ignore )
    fi

    # Step over to the next component, if any.

    if [[ "$tpre" = */* ]]; then
      tpre="${tpre#*/}"
    elif [[ "$tsuf" = */* ]]; then
      tpre="${tsuf#*/}"
      tsuf=""
    else
      break
    fi

    # There are more components, so skip over the next components and make a
    # slash be added.

    tmp2="${(M)tpre##((.|..|)/)##}"
    if [[ -n "$tmp2" ]]; then
      skipped="/$tmp2"
      tpre="${tpre#$tmp2}"
    else
      skipped=/
    fi
  done

  # The next loop searches the first ambiguous component.

  tmp3="$pre$suf"
  tpre="$pre"
  tsuf="$suf"
  tmp1=( "${(@)tmp1#${prepath}${realpath}${testpath}}" )

  while true; do

    # First we check if some of the files match the original string
    # for this component. If there are some we remove all other
    # names. This avoids having `foo' complete to `foo' and `foobar'.

    if [[ "$tmp3" = */* ]]; then
      tmp4=( "${(@M)tmp1:#${tmp3%%/*}/*}" )
      (( $#tmp4 )) && tmp1=( "$tmp4[@]" )
    fi

    # Next we see if this component is ambiguous.

    if [[ "$tmp3" = */* ]]; then
       tmp4=$tmp1[(I)^${(q)tmp1[1]%%/*}/*]
    else
       tmp4=$tmp1[(I)^${(q)tmp1[1]}]
    fi

    if [[ "$tpre" = */* ]]; then
      tmp2="${cpre}${tpre%%/*}"
      PREFIX="${donepath}${linepath}${tmp2}"
      SUFFIX="/${tpre#*/}${tsuf#*/}"
    else
      tmp2="${cpre}${tpre}"
      PREFIX="${donepath}${linepath}${tmp2}"
      SUFFIX="${tsuf}"
    fi

    if (( tmp4 )) ||
       [[ -n "$compstate[pattern_match]" && "$tmp2" != "${(q)tmp2}" ]]; then
      # It is. For menucompletion we now add the possible completions
      # for this component with the unambigous prefix we have built
      # and the rest of the string from the line as the suffix.
      # For normal completion we add the rests of the filenames
      # collected as the suffixes to make the completion code expand
      # it as far as possible.

      tmp2="$testpath"
      compquote tmp1 tmp2

      if [[ -n $menu || -z "$compstate[insert]" ]] ||
         ! zstyle -t ":completion:${curcontext}:paths" expand suffix; then
        (( tmp4 )) && zstyle -t ":completion:${curcontext}:paths" cursor &&
            compstate[to_end]=''
        if [[ "$tmp3" = */* ]]; then
	  compadd -Qf "$mopts[@]" -p "$linepath$tmp2" -s "/${tmp3#*/}" \
	          -W "$prepath$realpath$testpath" \
		  "$pfxsfx[@]" -M "r:|/=* r:|=*" \
		  - "${(@)tmp1%%/*}"
	else
	  compadd -Qf "$mopts[@]" -p "$linepath$tmp2" \
	          -W "$prepath$realpath$testpath" \
		   "$pfxsfx[@]" -M "r:|/=* r:|=*" \
		   - "$tmp1[@]"
	fi
      else
        if [[ "$tmp3" = */* ]]; then
	  atmp=( -Qf "$mopts[@]" -p "$linepath$tmp2"
	         -W "$prepath$realpath$testpath"
	         "$pfxsfx[@]" -M "r:|/=* r:|=*" )
          for i in "$tmp1[@]"; do
	    compadd "$atmp[@]" -s "/${i#*/}" - "${i%%/*}"
	  done
        else
	  compadd -Qf "$mopts[@]" -p "$linepath$tmp2" \
                  -W "$prepath$realpath$testpath" \
		  "$pfxsfx[@]" -M "r:|/=* r:|=*" \
		  - "$tmp1[@]"
        fi
      fi
      tmp4=-
      break
    fi

    # If we have checked all components, we stop now and add the 
    # strings collected after the loop.

    if [[ "$tmp3" != */* ]]; then
      tmp4=""
      break
    fi

    # Otherwise we add the unambiguous component to `testpath' and
    # take it from the filenames.

    testpath="${testpath}${tmp1[1]%%/*}/"
    tmp1=( "${(@)tmp1#*/}" )

    tmp3="${tmp3#*/}"

    if [[ "$tpre" = */* ]]; then
      cpre="${cpre}${tpre%%/*}/"
      tpre="${tpre#*/}"
    elif [[ "$tsuf" = */* ]]; then
      cpre="${cpre}${tpre}/"
      tpre="${tsuf#*/}"
      tsuf=""
    else
      tpre=""
      tsuf=""
    fi
  done

  if [[ -z "$tmp4" ]]; then
    if [[ "$osuf" = */* ]]; then
      PREFIX="${opre}${osuf}"
      SUFFIX=""
    else
      PREFIX="${opre}"
      SUFFIX="${osuf}"
    fi
    tmp4="$testpath"
    compquote tmp4 tmp1
    compadd -Qf "$mopts[@]" -p "$linepath$tmp4" -W "$prepath$realpath$testpath" \
	    "$pfxsfx[@]" -M "r:|/=* r:|=*" - "$tmp1[@]"
  fi
done

# If we are configured to expand paths as far as possible and we collected
# expanded paths that are different from the string on the line, we add
# them as possible matches.

if zstyle -t ":completion:${curcontext}:paths" expand prefix &&
   [[ nm -eq compstate[nmatches] ]]; then

  exppaths=( "${(@)exppaths:#$eorig}" )

  if (( $#exppaths )); then
    PREFIX="${opre}"
    SUFFIX="${osuf}"
    compadd -Q "$mopts[@]" -S '' -M "r:|/=* r:|=*" -p "$linepath" - "$exppaths[@]"
  fi
fi

[[ nm -ne compstate[nmatches] ]]