#!/usr/bin/env zsh
# -------------------------------------------------------------------------------------------------
# Copyright (c) 2010-2011 zsh-syntax-highlighting contributors
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification, are permitted
# provided that the following conditions are met:
#
#  * Redistributions of source code must retain the above copyright notice, this list of conditions
#    and the following disclaimer.
#  * Redistributions in binary form must reproduce the above copyright notice, this list of
#    conditions and the following disclaimer in the documentation and/or other materials provided
#    with the distribution.
#  * Neither the name of the zsh-syntax-highlighting contributors nor the names of its contributors
#    may be used to endorse or promote products derived from this software without specific prior
#    written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
# FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
# IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# -------------------------------------------------------------------------------------------------
# -*- mode: zsh; sh-indentation: 2; indent-tabs-mode: nil; sh-basic-offset: 2; -*-
# vim: ft=zsh sw=2 ts=2 et
# -------------------------------------------------------------------------------------------------


# Define default styles.
: ${ZSH_HIGHLIGHT_STYLES[default]:=none}
: ${ZSH_HIGHLIGHT_STYLES[unknown-token]:=fg=red,bold}
: ${ZSH_HIGHLIGHT_STYLES[reserved-word]:=fg=yellow}
: ${ZSH_HIGHLIGHT_STYLES[alias]:=fg=green}
: ${ZSH_HIGHLIGHT_STYLES[builtin]:=fg=green}
: ${ZSH_HIGHLIGHT_STYLES[function]:=fg=green}
: ${ZSH_HIGHLIGHT_STYLES[command]:=fg=green}
: ${ZSH_HIGHLIGHT_STYLES[precommand]:=fg=green,underline}
: ${ZSH_HIGHLIGHT_STYLES[commandseparator]:=none}
: ${ZSH_HIGHLIGHT_STYLES[hashed-command]:=fg=green}
: ${ZSH_HIGHLIGHT_STYLES[path]:=underline}
: ${ZSH_HIGHLIGHT_STYLES[path_prefix]:=underline}
: ${ZSH_HIGHLIGHT_STYLES[path_approx]:=fg=yellow,underline}
: ${ZSH_HIGHLIGHT_STYLES[globbing]:=fg=blue}
: ${ZSH_HIGHLIGHT_STYLES[history-expansion]:=fg=blue}
: ${ZSH_HIGHLIGHT_STYLES[single-hyphen-option]:=none}
: ${ZSH_HIGHLIGHT_STYLES[double-hyphen-option]:=none}
: ${ZSH_HIGHLIGHT_STYLES[back-quoted-argument]:=none}
: ${ZSH_HIGHLIGHT_STYLES[single-quoted-argument]:=fg=yellow}
: ${ZSH_HIGHLIGHT_STYLES[double-quoted-argument]:=fg=yellow}
: ${ZSH_HIGHLIGHT_STYLES[dollar-double-quoted-argument]:=fg=cyan}
: ${ZSH_HIGHLIGHT_STYLES[back-double-quoted-argument]:=fg=cyan}
: ${ZSH_HIGHLIGHT_STYLES[assign]:=none}

# Whether the highlighter should be called or not.
_zsh_highlight_main_highlighter_predicate()
{
  _zsh_highlight_buffer_modified
}

# Main syntax highlighting function.
_zsh_highlight_main_highlighter()
{
  emulate -L zsh
  setopt localoptions extendedglob bareglobqual
  local start_pos=0 end_pos highlight_glob=true new_expression=true arg style
  typeset -a ZSH_HIGHLIGHT_TOKENS_COMMANDSEPARATOR
  typeset -a ZSH_HIGHLIGHT_TOKENS_PRECOMMANDS
  typeset -a ZSH_HIGHLIGHT_TOKENS_FOLLOWED_BY_COMMANDS
  region_highlight=()

  ZSH_HIGHLIGHT_TOKENS_COMMANDSEPARATOR=(
    '|' '||' ';' '&' '&&'
  )
  ZSH_HIGHLIGHT_TOKENS_PRECOMMANDS=(
    'builtin' 'command' 'exec' 'nocorrect' 'noglob' 'sudo'
  )
  # Tokens that are always immediately followed by a command.
  ZSH_HIGHLIGHT_TOKENS_FOLLOWED_BY_COMMANDS=(
    $ZSH_HIGHLIGHT_TOKENS_COMMANDSEPARATOR $ZSH_HIGHLIGHT_TOKENS_PRECOMMANDS
  )

  for arg in ${(z)BUFFER}; do
    local substr_color=0
    local style_override=""
    [[ $start_pos -eq 0 && $arg = 'noglob' ]] && highlight_glob=false
    ((start_pos+=${#BUFFER[$start_pos+1,-1]}-${#${BUFFER[$start_pos+1,-1]##[[:space:]]#}}))
    ((end_pos=$start_pos+${#arg}))
    if $new_expression; then
      new_expression=false
     if [[ -n ${(M)ZSH_HIGHLIGHT_TOKENS_PRECOMMANDS:#"$arg"} ]]; then
      style=$ZSH_HIGHLIGHT_STYLES[precommand]
     else
      res=$(LC_ALL=C builtin type -w $arg 2>/dev/null)
      case $res in
        *': reserved')  style=$ZSH_HIGHLIGHT_STYLES[reserved-word];;
        *': alias')     style=$ZSH_HIGHLIGHT_STYLES[alias]
                        local aliased_command="${"$(alias -- $arg)"#*=}"
                        [[ -n ${(M)ZSH_HIGHLIGHT_TOKENS_FOLLOWED_BY_COMMANDS:#"$aliased_command"} && -z ${(M)ZSH_HIGHLIGHT_TOKENS_FOLLOWED_BY_COMMANDS:#"$arg"} ]] && ZSH_HIGHLIGHT_TOKENS_FOLLOWED_BY_COMMANDS+=($arg)
                        ;;
        *': builtin')   style=$ZSH_HIGHLIGHT_STYLES[builtin];;
        *': function')  style=$ZSH_HIGHLIGHT_STYLES[function];;
        *': command')   style=$ZSH_HIGHLIGHT_STYLES[command];;
        *': hashed')    style=$ZSH_HIGHLIGHT_STYLES[hashed-command];;
        *)              if _zsh_highlight_main_highlighter_check_assign; then
                          style=$ZSH_HIGHLIGHT_STYLES[assign]
                          new_expression=true
                        elif _zsh_highlight_main_highlighter_check_path; then
                          style=$ZSH_HIGHLIGHT_STYLES[path]
                        elif [[ $arg[0,1] = $histchars[0,1] ]]; then
                          style=$ZSH_HIGHLIGHT_STYLES[history-expansion]
                        else
                          style=$ZSH_HIGHLIGHT_STYLES[unknown-token]
                        fi
                        ;;
      esac
     fi
    else
      case $arg in
        '--'*)   style=$ZSH_HIGHLIGHT_STYLES[double-hyphen-option];;
        '-'*)    style=$ZSH_HIGHLIGHT_STYLES[single-hyphen-option];;
        "'"*"'") style=$ZSH_HIGHLIGHT_STYLES[single-quoted-argument];;
        '"'*'"') style=$ZSH_HIGHLIGHT_STYLES[double-quoted-argument]
                 region_highlight+=("$start_pos $end_pos $style")
                 _zsh_highlight_main_highlighter_highlight_string
                 substr_color=1
                 ;;
        '`'*'`') style=$ZSH_HIGHLIGHT_STYLES[back-quoted-argument];;
        *"*"*)   $highlight_glob && style=$ZSH_HIGHLIGHT_STYLES[globbing] || style=$ZSH_HIGHLIGHT_STYLES[default];;
        *)       if _zsh_highlight_main_highlighter_check_path; then
                   style=$ZSH_HIGHLIGHT_STYLES[path]
                 elif [[ $arg[0,1] = $histchars[0,1] ]]; then
                   style=$ZSH_HIGHLIGHT_STYLES[history-expansion]
                 elif [[ -n ${(M)ZSH_HIGHLIGHT_TOKENS_COMMANDSEPARATOR:#"$arg"} ]]; then
                   style=$ZSH_HIGHLIGHT_STYLES[commandseparator]
                 else
                   style=$ZSH_HIGHLIGHT_STYLES[default]
                 fi
                 ;;
      esac
    fi
    # if a style_override was set (eg in _zsh_highlight_main_highlighter_check_path), use it
    [[ -n $style_override ]] && style=$ZSH_HIGHLIGHT_STYLES[$style_override]
    [[ $substr_color = 0 ]] && region_highlight+=("$start_pos $end_pos $style")
    [[ -n ${(M)ZSH_HIGHLIGHT_TOKENS_FOLLOWED_BY_COMMANDS:#"$arg"} ]] && new_expression=true
    start_pos=$end_pos
  done
}

# Check if the argument is variable assignment
_zsh_highlight_main_highlighter_check_assign()
{
    setopt localoptions extended_glob
    [[ ${(Q)arg} == [[:alpha:]_]([[:alnum:]_])#=* ]]
}

# Check if the argument is a path.
_zsh_highlight_main_highlighter_check_path()
{
  setopt localoptions nonomatch
  local expanded_path; : ${expanded_path:=${(Q)~arg}}
  [[ -z $expanded_path ]] && return 1
  [[ -e $expanded_path ]] && return 0
  # Search the path in CDPATH
  local cdpath_dir
  for cdpath_dir in $cdpath ; do
    [[ -e "$cdpath_dir/$expanded_path" ]] && return 0
  done
  [[ ! -e ${expanded_path:h} ]] && return 1
  if [[ ${BUFFER[1]} != "-" && ${#BUFFER} == $end_pos ]]; then
    local -a tmp
    # got a path prefix?
    tmp=( ${expanded_path}*(N) )
    (( $#tmp > 0 )) && style_override=path_prefix && return 0
    # or maybe an approximate path?
    tmp=( (#a1)${expanded_path}*(N) )
    (( $#tmp > 0 )) && style_override=path_approx && return 0
  fi
  return 1
}

# Highlight special chars inside double-quoted strings
_zsh_highlight_main_highlighter_highlight_string()
{
  setopt localoptions noksharrays
  local i j k style varflag
  # Starting quote is at 1, so start parsing at offset 2 in the string.
  for (( i = 2 ; i < end_pos - start_pos ; i += 1 )) ; do
    (( j = i + start_pos - 1 ))
    (( k = j + 1 ))
    case "$arg[$i]" in
      '$' ) style=$ZSH_HIGHLIGHT_STYLES[dollar-double-quoted-argument]
            (( varflag = 1))
            ;;
      "\\") style=$ZSH_HIGHLIGHT_STYLES[back-double-quoted-argument]
            for (( c = i + 1 ; c < end_pos - start_pos ; c += 1 )); do
              [[ "$arg[$c]" != ([0-9,xX,a-f,A-F]) ]] && break
            done
            AA=$arg[$i+1,$c-1]
            # Matching for HEX and OCT values like \0xA6, \xA6 or \012
            if [[ "$AA" =~ "^(0*(x|X)[0-9,a-f,A-F]{1,2})" || "$AA" =~ "^(0[0-7]{1,3})" ]];then
              (( k += $#MATCH ))
              (( i += $#MATCH ))
            else
              (( k += 1 )) # Color following char too.
              (( i += 1 )) # Skip parsing the escaped char.
            fi
              (( varflag = 0 )) # End of variable
            ;;
      ([^a-zA-Z0-9_]))
            (( varflag = 0 )) # End of variable
            continue
            ;;
      *) [[ $varflag -eq 0 ]] && continue ;;

    esac
    region_highlight+=("$j $k $style")
  done
}