%D \module
%D   [       file=m-ipsum,
%D        version=2012.07.19,
%D          title=\CONTEXT\ Extra Modules,
%D       subtitle=Ipsum,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

%D After some discussing on the mailing list I made this example of
%D an implementation. Of course there can be alternatives as it's a
%D nice exercise in module writing.

\startluacode

local word         = lpeg.R("az","AZ")^1
local period       = lpeg.S(".")
local rest         = lpeg.P(1)
local whitespace   = lpeg.patterns.whitespace^1 / " "

local oneword      = lpeg.Cs(word / characters.lower)
local onesentence  = lpeg.Cs(word * (whitespace + word + (1-period))^0 * period)

local allwords     = lpeg.Ct((oneword     + rest)^1)
local allsentences = lpeg.Ct((onesentence + rest)^1)

local variables    = interfaces.variables

local v_paragraph  = variables.paragraph
local v_lines      = variables.lines
local v_words      = variables.words
local v_random     = variables.random

local ipsum = { } moduledata.ipsum = ipsum

local data = { }

local function getfiledata(settings)
    local filename = settings.filename or ""
    local filedata = data[filename]
    if not filedata then
        local text = resolvers.loadtexfile(filename) or ""
        filedata = {
            [v_paragraph] = { text or "" },
            [v_lines]     = lpeg.match(allsentences,text) or { },
            [v_words]     = lpeg.match(allwords,text) or { },
        }
        data[filename] = filedata
    end
    local d = filedata[settings.alternative or v_paragraph] or filedata[v_paragraph] or { }
    local n = settings.n
    if n ~= v_random then
        n = tonumber(n) or 0
        if n == 0 then
            n = #d
        end
    end
    return d, n
end

function moduledata.ipsum.typeset(settings)
    local d, n = getfiledata(settings)
    context(settings.before)
    if n == v_random then
        context(settings.left)
        context(d[math.random(1,#d)])
        context(settings.right)
    else
        for i=1,n do
            context(settings.left)
            context(d[i])
            context(settings.right)
            if i < n then
                context(settings.inbetween)
            end
        end
    end
    context(settings.after)
end

function moduledata.ipsum.direct(settings)
    local d, n = getfiledata(settings)
    if n == v_random then
        context(d[math.random(1,#d)])
    else
        for i=1,n do
            context(d[i])
            if i < n then
                context(settings.separator)
            end
        end
    end
end

\stopluacode

\unprotect

\installnamespace {ipsum}

\installcommandhandler \????ipsum {ipsum} \????ipsum

\setupipsum
  [\c!file=lorem,
   \c!alternative=\v!paragraph,
   \c!n=0,
   \c!left=,
   \c!right=,
   \c!before=,
   \c!after=,
   \c!separator=,
   \c!inbetween=]

\installactionhandler{ipsum} % grouped

\startsetups[handler:action:ipsum]
   \useipsumstyleandcolor\c!style\c!color
   \ctxlua{moduledata.ipsum.typeset {
      alternative = "\ipsumparameter\c!alternative",
      filename    = "\ipsumparameter\c!file",
      n           = "\ipsumparameter\c!n",
      left        = "\luaescapestring{\ipsumparameter\c!left}",
      right       = "\luaescapestring{\ipsumparameter\c!right}",
      before      = "\luaescapestring{\ipsumparameter\c!before}",
      after       = "\luaescapestring{\ipsumparameter\c!after}",
      inbetween   = "\luaescapestring{\ipsumparameter\c!inbetween}",
   }}
\stopsetups

\def\directipsum#1% only one argument, expanded
  {\ctxlua{moduledata.ipsum.typeset {
      alternative = "\namedipsumparameter{#1}\c!alternative",
      filename    = "\namedipsumparameter{#1}\c!file",
      n           = "\namedipsumparameter{#1}\c!n",
      separator   = "\luaescapestring{\ipsumparameter\c!separator}",
   }}
}

\protect

\continueifinputfile{m-ipsum.mkiv}

\setupbodyfont[dejavu,11pt]

\starttext

    \ipsum[alternative=paragraph,before=\blank,after=\blank]

    \ipsum[alternative=lines,n=2,right=\par,before=\blank,after=\blank]

    \ipsum[alternative=lines,n=random,before=\blank,after=\blank]

    \ipsum[alternative=lines,before=\startitemize,after=\stopitemize,left=\startitem,right=\stopitem]

    \ipsum[alternative=words,left=(,right=),inbetween=\space]

    \page

    \defineipsum
      [ward]
      [file=ward,
       before=\blank,
       after=\blank]

    \defineipsum
      [ward:itemize]
      [ward]
      [alternative=lines,
       before={\startitemize[packed]},
       after=\stopitemize,
       left=\startitem,
       right=\stopitem]

    \defineipsum
      [ward:title]
      [ward]
      [alternative=lines,
       n=random]

    \subject{\directipsum{ward:title}}

    \ipsum[ward]
    \ipsum[ward:itemize]

\stoptext