NEDIT_require_macro_file("RSextensions.nm")
NEDIT_require_macro_file("RScolor.nm")

# ==============================================================================
# ManHelp(): calls man(1) for either the selected text or for the current word
#       or a user-supplied man subject. The result is written to a window, with
#       the "Man page output" language set, which may replace or append to
#       previous output of this command. Rangesets are used instead of bold
#       and underline/italic.
# ==============================================================================

define ManHelp
  {
  # set up regex shortcuts

  w_ = "[-\\w.]"        # word and '-', '.' (for valid man page names)
  W_ = "[^-\\w.]"       # not (word and '-', '.')
  n_ = "\\d"            # digit
  wS_ = w_"*"           # 0-or-more word and '-'
  wP_ = w_"+"           # 1-or-more word and '-'
  aS_ = "[\\l_]*"       # 0-or-more letter and '_'
  nP_ = n_"+"           # 1-or-more digit
  po_ = "\\("           # open parenthesis
  pp_ = "[][!\"#$%&'*+,./:;<=>?@\\\\^_`{|}~-]*" # punctuations
  pc_ = "\\)"           # close parenthesis
  naa_ = n_ aS_ pp_     # digit then letters (for valid man section, eg 1M)
                        #   add punctuations for things like 3C++
  NAA_ = po_ naa_ pc_   # parenthesised man section

  hNL_ = "-\n\\s*"      # hyphenated newline and space sequence

  #*old version - not allowing space between man word and parenthesised section*
  #  xref = wP_ "(?:" hNL_ wP_ ")?" NAA_
  #  sub_1_po_2_pc = "([^(]+)" po_ "([^)]+)" pc_
  # xref allows spaces between a man word and its parenthesised section
  xref = wP_ "(?:" hNL_ wP_ ")?[\t ]*" NAA_
  # sub_1_po_2_pc extracts the man word and its parenthesised section
  # to build the man command line
  sub_1_po_2_pc = "([^(\\s]+)[\t ]*" po_ "([^)]+)" pc_

  s = ""
  sel = get_selection()

  allowReplace = 0

  if ($language_mode == "Man page output" && $highlight_syntax)
    {
    allowReplace = 2
    # first step is to find the extent of the man reference: use highlighting
    pos = $cursor
    ok = 0
    while (1)
      {
      pattern = ""
      if (pos < $text_length)
        {
        aPattern = get_pattern_at_pos(pos)
        if ("pattern" in aPattern)
          pattern = aPattern["pattern"]
        }

      if (search_string(pattern, "cross reference.*", 0, "regex") >= 0)
        pos--
      else
        {
        if (pos < $cursor) # we did move back - so we did have a reference
          {
          pos++
          ok = 1
          break
          }
        else
          break
        }
      }
    if (ok)
      {
      if (pos == search(xref, pos, "regex"))
        {
        endpos = $search_end
        s = get_range(pos, endpos)
        s = replace_in_string(s, hNL_, "", "regex", "copy")
        s = replace_in_string(s, sub_1_po_2_pc, "-s \\2 \\1", "regex")
        }
      }
    }

  # if that didn't work, try this:
  if (s == "")
    {
    # use regexes to attempt to find either something like wwww(naaa)
    # or just pick up the current word
    pos = $cursor
    # if we are just after a ")", move in front of it
    if (search(")", pos - 1, "literal") >= 0)
      pos--
    # if we have aaa), move to front of aaa
    while (pos == search(aS_ pc_, pos, "regex"))
      pos--
    # do we have a digit (single) in front of that? if so, step back
    if (pos == search(naa_ pc_, pos, "regex"))
      pos--
    # now do we have wwww(naaa)? if so step back in front of that
    while (pos == search(wS_ NAA_, pos, "regex"))
      pos--

    # move back past preceding spaces, a single newline, hyphen and word chars
    front = search("("W_"|^)"wP_ hNL_, pos + 1, "regex", "backward")
    if (front >= 0)
      {
      if (pos == $search_end - 1)
        {
        pos = front
        if (pos == search(w_, pos, "regex"))
          pos--
        }
      }

    # what if we're already at the first part of a hyphenated reference?
    while (pos == search(xref, pos, "regex"))
      pos--

    # by the time we get here we have stepped back one too far (or not at all)
    if (pos < $cursor) # did move back - so we may be in front of a reference
      pos++

    # right: now what have we got??? does it match aaaa(naaa)?
    if (pos == search(xref, pos, "regex"))
      {
      s = get_range(pos, $search_end)
      s = replace_in_string(s, hNL_, "", "regex", "copy")
      s = replace_in_string(s, sub_1_po_2_pc, "-s \\2 \\1", "regex")
      }
    else # ok: that didn't work - try a plain word...
      {
      pos = $cursor
      if (search(w_, pos - 1, "regex") == pos - 1)
        pos--
      while (pos == search(w_, pos, "regex"))
        pos--
      if (pos < $cursor) # did move back so we may be in front of a reference
        pos++
      if (pos == search(wP_, pos, "regex"))
        s = get_range(pos, $search_end) # pick up the word
      }
    }

  # what about a selection?
  subject = ""
  if (sel != "")
    {
    # remove spaces from the selection string back-word(1two)
    sel = replace_in_string(sel, "[\\s\n]+", "", "regex", "copy")
    # we only allow a selection if it matches wwww or wwww(naaa)
    if (sel != "" && \
        search_string(sel, wP_"(?:"NAA_")?", 0, "regex") == 0)
      {
      str = replace_in_string(sel, sub_1_po_2_pc, "-s \\2 \\1", "regex")
      if (str == "")
        {
        if (search_string(sel, W_, 0, "regex") >= 0)    # non-word chars?
          {
#dialog("Quoting "sel"\nReason: "W_" found at "search_string(sel,W_,0,"regex"))
          str = "'" sel "'"                             # then quote the rest
          }
        else
          str = sel
        }
      sel = str
      # choose between selection and word?
      if (s == "")
        s = sel
      else if (s != sel)
        {
        prompt = "man (-s section) subject"
        prompt = prompt "\nselection: " sel
        prompt = prompt "\nword found: " s
        str = string_dialog(prompt, "Selection", "Word found", "Cancel")
        if ($string_dialog_button < 1 || $string_dialog_button > 2)
          return
        if (str == "")
          {
          if ($string_dialog_button == 1)
            str = sel
          else
            str = s
          }
        s = str
        subject = s
        }
      }
    }

  button = 0
  if (subject == "")
    {
    subject = s
    prompt = "man (-s section) subject"
    if (subject != "")
      prompt = prompt "\ndefault: " subject

    if (allowReplace)
      s = string_dialog(prompt, "New Window", "Replace", \
                                "Add at end", "Cancel")
    else
      s = string_dialog(prompt, "OK", "Cancel")

    if (s == "")
    s = subject
    button = $string_dialog_button
    }
  else
    {
    prompt = "man " subject

    if (allowReplace)
      button = dialog(prompt, "New Window", "Replace", "Add at end", "Cancel")
    else
      button = dialog(prompt, "OK", "Cancel")
    }

  if (button < 1 || button > 1 + allowReplace)
    return

  tryAgain = 1
  while (tryAgain)
    {
    manargs = s
    mancmd = "/bin/sh -c 'man \"$@\" 2>/dev/null' - " manargs
    # mancmd = "man " manargs
    manout = shell_command(mancmd, "")

    # test results: shell return value may not work
    # (man always "succeeds" on Sun)
    manOK = ($shell_cmd_status == 0)
    BadManSolaris = "No manual entry for "
    if (substring(manout, 0, length(BadManSolaris)) == BadManSolaris)
      manOK = 0
    # any more platform-specific messages?

    # Linux (BSD?) doesn't accept -s for section argument
    # try again without it if we failed
    if (!manOK)
      {
      sectArg = search_string(s, "(?<=^|\\s)-s", 0, "regex")
      if (sectArg >= 0)
        {
        # cut out the -s
        s = substring(s, 0, sectArg) substring(s, $search_end)
        }
      else
        tryAgain = 0
      }
    else
      tryAgain = 0
    }

  if (manOK)
  {
    if (button == 1)
      {
      if ($language_mode == "Man page output")
        new("tab")
      else
        new("window")

      focus_window("last")
      set_incremental_backup(0)
      set_make_backup_copy(0)
      set_show_line_numbers(0)
      set_statistics_line(0)
      set_use_tabs(0)
      set_wrap_text("none")
      set_language_mode("Man page output")
      set_highlight_syntax(1)
      }
    else
      {
      if (button == 2)
        replace_range(0, $text_length, "")
      else if (button == 3)
        {
        set_cursor_pos($text_length)
        insert_string("\n")
        rso = rangeset_fetch("break", \
                             "color", RangeSet_mapToDark("#4080c0"), \
                             "mode", "exclude")
        rangeset_add(rso, $text_length - 1, $text_length)
        }
      }

    deselect_all()
    s = manout
    # remove repeated blank lines
    s = replace_in_string(s, "\n(?:\\s*\n)+\n", "\n\n", "regex", "copy")
    # lo and hi mark beginning and end of man text
    lo = $cursor
    orig = lo
    insert_string(s)
    hi = $cursor
    set_cursor_pos(lo)
    # replace +/_ combination with plus-or-minus character
    if (search("+\b_", 0) >= 0)
      replace_all("+\b_", "±")
    # create and color rangesets for bold/underline highlights
    rsm = rangeset_fetch("underlined", "color", RangeSet_mapToDark("#80C0FF"))
    rsn = rangeset_fetch("bold", "color", RangeSet_mapToDark("#80FFFF"))
    while (1)
      {
#     nlo = search("_\b.", lo, "regex")
      nlo = search("(?:_\b.)+", lo, "regex")
      if (nlo == -1 || nlo >= hi)
        break
#     replace_range(nlo, nlo + 2, "")   # remove underscore+backspace
#     hi = hi - 2                       # change end marker position
#     lo = nlo                          # advance search position
#     rangeset_add("m", lo, lo + 1)     # color the "underlined" character
      nle = $search_end
      s = get_range(nlo, nle)
      s = replace_in_string(s, "_\b", "", "copy")
      replace_range(nlo, nle, s)
      rangeset_add(rsm, nlo, nlo + length(s))
      lo = nlo                          # advance search position
      }
    lo = orig
    while (1)
      {
      # strictly bold is a repetition of a single character with a backspace,
      # but bullets are often rendered as an overlay of "o" and "+", so we
      # treat both together, retaining only the character after the backspace.
#     nlo = search(".\b.", lo, "regex")
      nlo = search("(?:.\b.)+", lo, "regex")
      if (nlo == -1 || nlo >= hi)
        break
#     replace_range(nlo, nlo + 2, "")   # remove 1st-char+backspace
#     hi = hi - 2                       # change end marker position
#     lo = nlo                          # advance search position
#     rangeset_add("n", lo, lo + 1)     # color the "bold" character
      nle = $search_end
      s = get_range(nlo, nle)
      s = replace_in_string(s, ".\b", "", "regex", "copy")
      replace_range(nlo, nle, s)
      rangeset_add(rsn, nlo, nlo + length(s))
      lo = nlo                          # advance search position
      }
    }
  else
    {
    s = shell_command("man " manargs " | head", "")
    s = replace_in_string(s, ".\b", "", "regex", "copy")
    dialog("Command 'man "manargs"' failed: " $shell_cmd_status "\n\n" s)
    }
  }