-- Taken from here: http://lua-users.org/wiki/LuaXml
local Parser = {}

function parseargs(s)
    local arg = {}
    string.gsub(s, "([%-%w]+)=([\"'])(.-)%2", function(w, _, a)
        arg[w] = a
    end)
    return arg
end

function Parser:collect(s)
    local stack = {}
    local top = {}
    table.insert(stack, top)
    local ni, c, label, xarg, empty
    local i, j = 1, 1
    while true do
        ni, j, c, label, xarg, empty = string.find(s,
                                                   "<(%/?)([%w:]+)(.-)(%/?)>", i)
        if not ni then
            break
        end
        local text = string.sub(s, i, ni - 1)
        if not string.find(text, "^%s*$") then
            table.insert(top, text)
        end
        if empty == "/" then -- empty element tag
            table.insert(top, {label = label, xarg = parseargs(xarg), empty = 1})
        elseif c == "" then -- start tag
            top = {label = label, xarg = parseargs(xarg)}
            table.insert(stack, top) -- new level
        else -- end tag
            local toclose = table.remove(stack) -- remove top
            top = stack[#stack]
            if #stack < 1 then
                error("nothing to close with " .. label)
            end
            if toclose.label ~= label then
                error("trying to close " .. toclose.label .. " with " .. label)
            end
            table.insert(top, toclose)
        end
        i = j + 1
    end
    local text = string.sub(s, i)
    if not string.find(text, "^%s*$") then
        table.insert(stack[#stack], text)
    end
    if #stack > 1 then
        error("unclosed " .. stack[#stack].label)
    end
    return stack[1]
end

return Parser