" Vim syntax support file
" Maintainer:       Nikolai Weibull <nikolai@bitwi.se>
" Latest Revision:  2005-12-03

function! s:Format(text, group)
  let formatted = strtrans(a:text)

  " TODO: Replace the reserved ConTeXt characters.

  return "\\highlight[" . a:group . ']{' . formatted . '}'
endfun

" Set up options.
let s:old_title = &title
let s:old_icon = &icon
let s:old_et = &l:et
let s:old_report = &report
let s:old_search = @/
set notitle noicon
setlocal et
set report=1000000

" Split window to create a buffer with the HTML file.
let s:org_bufnr = winbufnr(0)
if expand("%") == ""
  new untitled.tex
else
  new %.tex
endif
let s:new_win = winnr()
let s:org_win = bufwinnr(s:org_bufnr)

" Set up options in the new buffer.
set modifiable
%d
let s:old_paste = &paste
set paste
let s:old_magic = &magic
set magic

" Set up the buffer’s “header”.
exe "normal! a\\startlines\n\e"

" Switch to the original window.
exe s:org_win . 'wincmd w'

" Variables to keep track of the range to convert.
let s:lnum = 1
let s:end = line('$')

" Set up stuff for handling folding.
if has('folding') && !exists('context_ignore_folding')
  let s:foldfillchar = &fillchars[matchend(&fillchars, 'fold:')]
  if s:foldfillchar == ''
    let s:foldfillchar = '-'
  endif
endif

" Set up stuff for handling diffs.
let s:difffillchar = &fillchars[matchend(&fillchars, 'diff:')]
if s:difffillchar == ''
  let s:difffillchar = '-'
endif

" Now, loop over all lines in the range.
while s:lnum <= s:end
  " If there are filler lines for diff mode, show these above the line.
  let s:filler = diff_filler(s:lnum)
  if s:filler > 0
    let s:n = s:filler
    while s:n > 0
      let s:new = repeat(s:difffillchar, 3)

      if s:n > 2 && s:n < s:filler && !exists('context_whole_filler')
	let s:new = s:new . " " . s:filler . ' inserted lines '
	let s:n = 2
      endif

      let s:new = s:new . repeat(s:difffillchar, &columns - strlen(s:new))

      let s:new = s:Format(s:new, 'DiffDelete')
      exe s:new_win . 'wincmd w'
      exe 'normal! a' . s:new . "\n\e"
      exe s:org_win . 'wincmd w'

      let s:n -= 1
    endwhile
    unlet s:n
  endif
  unlet s:filler

  let s:new = ""
  if has('folding') && !exists('context_ignore_folding') && foldclosed(s:lnum) > -1
    let s:new = s:Format(s:new . foldtextresult(s:lnum), 'Folded')
    let s:lnum = foldclosedend(s:lnum)
  else
    let s:line = getline(s:lnum)
    let s:len = strlen(s:line)
    let s:diffattr = diff_hlID(s:lnum, 1)

    let s:col = 1
    while s:col <= s:len || (s:col == 1 && s:diffattr)
      let s:startcol = s:col " The start column for processing text.
      if s:diffattr
	let s:id = diff_hlID(s:lnum, s:col)
	let s:col += 1
	while s:col <= s:len && s:id == diff_hlID(s:lnum, s:col) | let s:col += 1 | endwhile
        if s:len < &columns
	  " Add spaces at the end to mark the changed line.
          let s:line = s:line . repeat(' ', &columns - s:len)
          let s:len = &columns
        endif
      else
	let s:id = synID(s:lnum, s:col, 1)
	let s:col += 1
	while s:col <= s:len && s:id == synID(s:lnum, s:col, 1) | let s:col += 1 | endwhile
      endif

      " Expand tabs.
      let s:expanded = strpart(s:line, s:startcol - 1, s:col - s:startcol)
      let idx = stridx(s:expanded, "\t")
      while idx >= 0
        let i = &ts - (idx + s:startcol - 1) % &ts
        let s:expanded = substitute(s:expanded, '\t', repeat(' ', i), '')
        let idx = stridx(s:expanded, "\t")
      endwhile

      " Output the text with the same synID, with class set to {s:id_name}.
      let s:id = synIDtrans(s:id)
      let s:id_name = synIDattr(s:id, 'name')
      if s:expanded !~ '^\s*$'
        let s:new = s:new . s:Format(s:expanded, s:id_name)
      else
        let s:new = s:new . s:expanded
      endif
    endwhile
  endif

  exe s:new_win . 'wincmd w'
  exe 'normal! a' . s:new . "\n\e"
  exe s:org_win . 'wincmd w'
  let s:lnum = s:lnum + 1
endwhile

" Cleanup.
exe s:new_win . 'wincmd w'
exe "normal! a\\stoplines\n\e"
%s:\s\+$::e
$g/^$/d

" Restore old settings
let &report = s:old_report
let &title = s:old_title
let &icon = s:old_icon
let &paste = s:old_paste
let &magic = s:old_magic
let @/ = s:old_search
exe s:org_win . 'wincmd w'
let &l:et = s:old_et
exe s:new_win . 'wincmd w'

" Save a little bit of memory (worth doing?)
unlet s:old_et s:old_paste s:old_icon s:old_report s:old_title s:old_search
unlet s:lnum s:end s:old_magic
unlet! s:col s:id s:attr s:len s:line s:new s:expandedtab
unlet s:org_win s:new_win s:org_bufnr
if !v:profiling
  delfunc s:Format
endif
silent! unlet s:diffattr s:difffillchar s:foldfillchar