" surround.vim - Surroundings
" Maintainer:   Tim Pope <vimNOSPAM@tpope.info>
" $Id$
"
" Usage:
"
" "ds" is a mapping which deletes the surroundings of a text object--the
" difference between the "inner" object and "an" object.  See the :help on
" text-objects for details.  This is easiest to understand with some examples;
" in the following, * represents the cursor position.
"
" Old                       Keystroke   New
" "Hello *world!"           ds"         Hello world!
" (123+4*56)/2              ds)         123+456/2
" <div>Yo!</div>            dst         Yo!
"
" "cs" does as above, but rather than remove the surroundings, it replaces
" them with something else.  It takes two arguments.  Once again, examples are
" in order.  (Details about the second argument, the replacement character,
" are below).
"
" Old                       Keystroke   New
" "Hello *world!"           cs"'        'Hello world!'
" "Hello *world!"           cs"<q>      <q>Hello world!</q>
" (123+4*56)/2              cs)]        [123+456]/2
" (123+4*56)/2              cs)[        [ 123+456 ]/2
" <div>Yo!</div>            cst<p>      <p>Yo!</p>
"
" "ys" takes a motion or text object as the first object, and wraps it using
" the second argument as with "cs".
"
" Old                       Keystroke   New
" Hello w*orld!             ysiw)       Hello (world)!
"
" As a special case, "yss" operates on the current line, ignoring leading
" whitespace.
"
" Old                       Keystroke   New
"     Hello w*orld!         yssB            {Hello world!}
"
" In visual mode, a simple "s" with an argument wraps the selection.
" Note that "s" already has a valid meaning in visual mode, but it is
" identical to "c".  If you have muscle memory for "s" and would like to use a
" different key, add your own mapping and the existing one will be disabled.
"
" vmap S <Plug>VSurround
"
" Finally, there is an experimental insert mode mapping on <C-S>.  Beware that
" this won't work on terminals with flow control (if you accidentally freeze
" your terminal, use <C-Q> to unfreeze it).  This inserts the surrounding
" characters and puts the cursor between them.  If, immediately after <C-S>
" and before the replacement carriage return is pressed, the prefix, cursor,
" and suffix will be placed on three separate lines.
"
" Replacements:
"
" A replacement argument is a single character.  The default behavior is to
" insert that character before and after the text.
"
" If ")", "]", "}", or ">" are used, the text is wrapped in the appropriate
" open/close pair of characters.  "(", "[", and "{" behave similarly but add
" an additional space to the inside.  "B" and "b" are synonymous with "}" and
" ")".
"
" If "t" or "<" is used, Vim prompts for an HTML/XML tag to insert.  You may
" specify attributes here and they will be stripped from the closing tag.
" End your input by pressing "<CR>" or ">".
"
" Customizing:
"
" The following adds a potential replacement on "-" (ASCII 45) in PHP files.
" (To determine the ASCII code to use, :echo char2nr("-")).  The newline will
" be replaced by the original text.
"
" autocmd FileType php let b:surround_45 = "<?php \n ?>"
"
" This can be used in a PHP file as in the following example.
"
" Old                       Keystroke   New
" print "Hello *world!"     yss-        <?php print "Hello world!" ?>
"
" Additionally, one can use a global variable for globally available
" replacements.
"
" let g:surround_45 = "<% \n %>"
"
" Issues:
"
" Vim could potentially get confused when deleting/changing occurs at the very
" end of the line.  Pleae report any repeatable instances of this.
"
" Do we need to use inputsave() / inputrestore() with the tag replacement?
"
" Customization isn't very flexible.  Need a system that allows for prompting
" similar to with tags.
"
" Reindenting is handled haphazardly.  Need to decide the most appropriate
" behavior and implement it.  Right now one can do :let b:surround_indent = 1
" (or the global equivalent) to enable automatic reindenting by Vim; should
" this be the default?
"
" It would be nice if . would work to repeat an operation.

" ============================================================================

" Exit quickly when:
" - this plugin was already loaded (or disabled)
" - when 'compatible' is set
if (exists("g:loaded_surround") && g:loaded_surround) || &cp
    finish
endif
let g:loaded_surround = 1

let s:cpo_save = &cpo
set cpo&vim

" Input functions {{{1

function! s:getchar()
    let c = getchar()
    if c =~ '^\d\+$'
        let c = nr2char(c)
    endif
    return c
endfunction

function! s:inputtarget()
    let c = s:getchar()
    if c =~ "\<Esc>\|\<C-C>\|\0"
        return ""
    else
        return c
    endif
endfunction

function! s:inputreplacement()
    "echo '-- SURROUND --'
    let c = s:getchar()
    if c == " "
        let c = c . s:getchar()
    endif
    if c =~ "\<Esc>\|\<C-C>\|\0"
        return ""
    else
        return c
    endif
endfunction

function! s:beep()
    exe "norm! \<Esc>"
    return ""
endfunction

function! s:redraw()
    redraw
    return ""
endfunction

" }}}1

function! s:wrap(string,char,...) " {{{1
    let keeper = a:string
    let newchar = a:char
    let linemode = a:0 ? a:1 : 0
    let before = ""
    let after  = ""
    " Duplicate b's are just placeholders
    let pairs = "b()B{}r[]a<>"
    let extraspace = ""
    if newchar =~ '^ '
        let newchar = strpart(newchar,1)
        let extraspace = ' '
    endif
    let idx = stridx(pairs,newchar)
    if exists("b:surround_".char2nr(newchar))
        let before = matchstr(b:surround_{char2nr(newchar)},'.*\ze\n')
        let after  = matchstr(b:surround_{char2nr(newchar)},'\n\zs.*')
    elseif exists("g:surround_".char2nr(newchar))
        let before = matchstr(g:surround_{char2nr(newchar)},'.*\ze\n')
        let after  = matchstr(g:surround_{char2nr(newchar)},'\n\zs.*')
    elseif newchar == "p"
        let before = "\n"
        let after  = "\n\n"
    elseif newchar == "t" || newchar == "T" || newchar == "<"
        let dounmapr = 0
        let dounmapb = 0
        if !mapcheck("<CR>","c")
            let dounmapr = 1
            cnoremap <CR> ><CR>
        endif
        if !mapcheck(">","c")
            let dounmapb= 1
            cnoremap > ><CR>
        endif
        let default = ""
        if newchar == "T"
            let default = matchstr(@@,'<\zs.\{-\}\ze>')
        endif
        let tag = input("<",default)
        echo "<".substitute(tag,'>*$','>','')
        if dounmapr
            silent! cunmap <CR>
        endif
        if dounmapb
            silent! cunmap >
        endif
        if tag != ""
            let tag = substitute(tag,'>*$','','')
            let before = "<".tag.">"
            let after  = "</".substitute(tag," .*",'','').">"
        endif
    elseif newchar == 'l' || newchar == '\'
        let dounmapr = 0
        if !mapcheck("<CR>","c")
            let dounmapr = 1
            cnoremap <silent> <CR> <C-R>=<SID>closematch()<CR><CR>
        endif
        let env = input('\begin','{')
        echo '\begin'.env
        if dounmapr
            silent! cunmap <CR>
        endif
        if env != ""
            let before = '\begin'.env
            let after  = '\end'.matchstr(env,'[^}]*').'}'
        endif
    elseif newchar == 'f'
        let func = input('function: ')
        if func != ""
            let before = substitute(func,'($','','').'('
            let after  = ')'
        endif
    elseif idx >= 0
        let spc = (idx % 3) == 1 ? " " : ""
        let idx = idx / 3 * 3
        let before = strpart(pairs,idx+1,1) . spc
        let after  = spc . strpart(pairs,idx+2,1)
    else
        let before = newchar
        let after  = newchar
    endif
    if linemode || keeper =~ '\%^\s*\n'
        let before = substitute(before,'\s*\%$','','')
    endif
    if linemode || keeper =~ '\n\s*\%$'
        let after  = substitute(after,'\%^\s*','','')
    endif
    if linemode
        let initspaces = matchstr(keeper,'\%^\s*')
        let keeper = initspaces.before."\n".keeper."\n".initspaces.after
    else
        let keeper = before.extraspace.keeper.extraspace.after
    endif
    return keeper
endfunction " }}}1

function! s:insert(...) " {{{1
    " Optional argument causes the result to appear on 3 lines, not 1
    let linemode = a:0 ? a:1 : 0
    let char = s:inputreplacement()
    while char == "\<CR>"
        " TODO: use total count for additional blank lines
        let linemode = linemode + 1
        let char = s:inputreplacement()
    endwhile
    if char == ""
        return ""
    endif
    " We could just use null, but nooooo, that won't work
    let text = s:wrap("\1",char,0)
    if linemode
        return substitute(text,'\s*\%x01\s*',"\<CR>",'')."\<C-O>O"
    else
        let len = strlen(substitute(substitute(text,'.*\%x01','',''),'.','.','g'))
        let left = ""
        while len > 0
            let len = len - 1
            let left = left . "\<Left>"
        endwhile
        return substitute(text,'\%x01','','') . left
    endif
endfunction " }}}1

function! s:reindent() " {{{1
    if @@ =~ '\n' && (exists("b:surround_indent") || exists("g:surround_indent"))
        silent norm! '[=']
    endif
endfunction " }}}1

function! s:dosurround(...) " {{{1
    let char = (a:0 ? a:1 : s:inputtarget())
    let newchar = ""
    if a:0 > 1
        let newchar = a:2
        if newchar == "\<Esc>" || newchar == "\<C-C>" || newchar == ""
            return s:beep()
        endif
    endif
    let append = ""
    let original = @@
    let @@ = ""
    exe "norm di".char
    "exe "norm vi".char."d"
    let keeper = @@
    if @@ == ""
        let @@ = original
        return ""
    endif
    let oldline = getline('.')
    let oldlnum = line('.')
    if char == "p"
        let append = matchstr(keeper,'\n*\%$')
        let keeper = substitute(keeper,'\n*\%$','','')
        let @@ = ""
    elseif char == "s" || char == "w" || char == "W"
        " Do nothing
        let @@ = ""
    elseif char =~ "[\"'`]"
        exe "norm! i \<Esc>d2i".char
        let @@ = substitute(@@,' ','','')
    else
        exe "norm! da".char
    endif
    let removed = @@
    let rem2 = substitute(removed,'\n.*','','')
    let oldhead = strpart(oldline,0,strlen(oldline)-strlen(rem2))
    let oldtail = strpart(oldline,  strlen(oldline)-strlen(rem2))
    "let g:oldhead = oldhead
    "let g:oldtail = oldtail
    "let g:rem2 = rem2
    "let g:keeper = keeper
    let regtype = getregtype('"')
    if oldtail == rem2 && col('.') + 1 == col('$')
        if oldhead =~# '^\s*$' && a:0 < 2
            "let keeper = substitute(keeper,'\n\s*','\n','')
            let keeper = substitute(keeper,oldhead.'\%$','','')
            let keeper = substitute(keeper,'\%^\n'.oldhead.'\(\s*.\{-\}\)\n\s*\%$','\1','')
        endif
        let pcmd = "p"
    else
        if oldhead == "" && a:0 < 2
            let keeper = substitute(keeper,'\%^\n\(.*\)\n\%$','\1','')
        endif
        let pcmd = "P"
    endif
    if line('.') < oldlnum && regtype == "V"
        let pcmd = "p"
    endif
    if removed =~ '\n$'
        let keeper = keeper."\n"
        let removed = substitute(removed,'\n$','','')
    endif
    " Originally was done twice on purpose
    "if removed =~ '\n'
        "let keeper = keeper . "\n"
        "let removed = substitute(removed,'\n','','')
    "endif
    "let g:removed = removed
    if newchar != ""
        let keeper = s:wrap(keeper,newchar,char == "p") . append
    endif
    let @@ = substitute(keeper,'\n\s+\n','\n\n','g')
    call setreg('"','','a'.regtype)
    silent exe "norm! ".(a:0 < 2 ? "" : "").pcmd.'`['
    call s:reindent()
    if getline('.') =~ '^\s\+$' && keeper =~ '^\s*\n'
        silent norm! cc
    endif
    let @@ = removed
endfunction " }}}1

function! s:changesurround() " {{{1
    let a = s:inputtarget()
    if a == ""
        return s:beep()
    endif
    let b = s:inputreplacement()
    if b == ""
        return s:beep()
    endif
    call s:dosurround(a,b)
endfunction " }}}1

function! s:opfunc(type) " {{{1
    let char = s:inputreplacement()
    if char == ""
        return s:beep()
    endif
    let sel_save = &selection
    let &selection = "inclusive"
    let reg_save = @@
    let linemode = (a:type == "line" || a:type == "V")
    if a:type == "char"
        silent norm! `[v`]y
    elseif a:type == "line"
        silent norm! '[V']y
    elseif a:type == "v" || a:type == "V"
        silent norm! gvy
    elseif a:type =~ '^\d\+$'
        silent exe 'norm! ^v'.a:type.'$hy'
    else
        let &selection = sel_save
        return s:beep()
    endif
    let keeper = @@
    let append = ""
    if linemode
        let append = matchstr(keeper,'\n*$')
        let keeper = substitute(keeper,'\n*$','','')
    else
        let append = matchstr(keeper,'\s*$')
        let keeper = substitute(keeper,'\s*$','','')
    endif
    let keeper = s:wrap(keeper,char,linemode) . append
    let @@ = keeper
    silent norm! gvp`[
    if linemode
        call s:reindent()
    endif
    let @@ = reg_save
    let &selection = sel_save
endfunction " }}}1

function! s:closematch()
    " Close an open (, {, [, or < on the command line.
    let tail = matchstr(getcmdline(),'.[^\[\](){}<>]*$')
    if tail =~ '^\[.\+'
        return "]"
    elseif tail =~ '^(.\+'
        return ")"
    elseif tail =~ '^{.\+'
        return "}"
    elseif tail =~ '^<.+'
        return ">"
    else
        return ""
    endif
endfunction

function! s:closedcmd()
    let cm = s:closematch()
    return getcmdline() . cm
endfunction

nnoremap <silent> <Plug>DSurround  :call <SID>dosurround(<SID>inputtarget())<CR>
nnoremap <silent> <Plug>CSurround  :call <SID>changesurround()<CR>
nnoremap <silent> <Plug>YSurround  :set opfunc=<SID>opfunc<CR>g@
nnoremap <silent> <Plug>YSSurround :<C-U>call <SID>opfunc(v:count1)<CR>
vnoremap <silent> <Plug>VSurround  :<C-U>call <SID>opfunc(visualmode())<CR>
inoremap <silent> <Plug>ISurround  <C-R>=<SID>insert()<CR>


nmap          ds   <Plug>DSurround
nmap          cs   <Plug>CSurround
nmap          ys   <Plug>YSurround
nmap          yss  <Plug>YSSurround
if !hasmapto("<Plug>VSurround","v")
    vmap      s    <Plug>VSurround
endif
if !hasmapto("<Plug>ISurround","i")
    imap     <C-S> <Plug>ISurround
endif


let &cpo = s:cpo_save