coroutine useless fun

local meta={}
local co=setmetatable({},meta)
_G.co=co

local costack=setmetatable({},{__index={
    push=function(tbl,val)
        table.insert(tbl,val)
    end,
    pop=function(tbl)
        return table.remove(tbl)
    end,
    current=function(tbl)
        return tbl[#tbl]
    end,

}})



co._re=function(thread,...)
    local status = coroutine.status(thread)
    if status=="running" then
        Msg"[CO] Running??? "print(thread)

    elseif status=="dead" then
        Msg"[CO] Dead "print(thread)

    elseif status=="suspended" then

    else
        error"invalid status?"
    end

    costack:push(thread)
    local ok,t,val = coroutine.resume(thread,...)
    costack:pop(thread)

    if not ok then
        ErrorNoHalt("Coroutine: "..tostring(t)..'\n')
    end

    if t=="sleep" then
        Msg"[CO] Sleep "print(val)
        timer.Simple(val,function()
            co._re(thread,"wait")
        end)
    elseif t=="cb" then
        Msg"[CO] wait for callback "print(val)
        return
    elseif t=="END" then
        Msg"[CO] END "print("OK")
    else
        Msg"[CO] Unhandled "print(t,val)
    end
end

function meta:__call(func)
    local thread = coroutine.create(function(...)
        func(...)
        return "END"
    end)
    co._re(thread)
end

function co.wait(delay)
    local ret = coroutine.yield("sleep",tonumber(delay) or 0)
    Msg"[CO] End wait "print(ret)
end
co.sleep=co.wait

function co.newcb()
    local thread = costack:current()

    if not thread then error"wot" end

    Msg"[CO] Created cb for thread "print(thread)
    local CB CB = function(...)
        Msg("[CO] Callback called for thread ",thread," with params ")print(...)
        co._re(thread,"cbret",CB,...)
    end
    return CB
end

function co.waitcb(cbobj)
    local function wrap(cbret,CB,...)
        Msg"[CO] WaitCB " print(cbret=="cbret" and "OKRET" or ("WOT"..tostring(cbret)),(not cbobj or CB==cbobj) and "right cb" or "wtf cb?!?!?")
        Msg"[CO] WaitCB Params " print(...)
        return ...
    end
    return wrap(coroutine.yield("cb",cbobj))
end

-- TESTING --

co(function()

    print"hello"
    co.wait(1)
    print"world"
    co.wait(1)
    print"!"

    local cb = co.newcb()

    timer.Simple(1,function()
        cb("callback","returning")
    end)
    local a,b,c,d=co.waitcb(cb)
    print("HTTP",b,c,d)
    co.wait(1)
    print"BYE"

end)