local vars = {}

local additionalChars = {".", ",", "!", ":", ";"}

function fileExists(name)
    local f=io.open(name,"r")
    if f~=nil then io.close(f) return true else return false end
end

local function countWords()
    local rawText = pandoc.pipe("pdftotext", {"output.pdf", "-"}, "")
    return pandoc.pipe("wc", {"-w"}, rawText)
end

local function getVars(meta)
    for k, v in pairs(meta) do
        if v.t == 'MetaInlines' then
            local var_key = "$" .. k .. "$"
            local var_value = table.unpack(v)["c"]
            vars[var_key] = var_value
            for _, char in pairs(additionalChars) do
                vars[var_key .. char] = var_value .. char
                vars[char .. var_key] = char .. var_value
            end
        end
    end
end

return {
    {
        Meta = function(meta)
            getVars(meta)
            if fileExists("output.pdf") then
                meta["wordcount"] = countWords()
                meta["secondpass"] = true
            end
            return meta
        end,
    },
    {
        Str = function (el)
            if vars[el.text] then
                return pandoc.Span(vars[el.text])
            else
                return el
            end
        end
    }
}