local alien = require("alien")

libzmq = alien.load("/usr/lib/libzmq.so")

local zmq_pollitem = alien.defstruct {
	{"socket", "pointer"},
	{"fd", "int"},
	{"events", "short"},
	{"revents", "short"}
}

local zmq_ctx_new = libzmq.zmq_ctx_new
zmq_ctx_new:types { ret = "pointer", abi="stdcall" }

local zmq_ctx_term = libzmq.zmq_ctx_term
zmq_ctx_term:types { ret = "int", abi="stdcall", "pointer" }

local zmq_bind = libzmq.zmq_bind
zmq_bind:types { ret = "int", abi="stdcall", "pointer", "string" }

local zmq_connect = libzmq.zmq_connect
zmq_connect:types { ret = "int", abi="stdcall", "pointer", "string" }

local zmq_close = libzmq.zmq_close
zmq_close:types { ret = "int", abi="stdcall", "pointer" }

local zmq_disconnect = libzmq.zmq_disconnect
zmq_disconnect:types { ret = "int", abi="stdcall", "pointer", "string" }

local zmq_setsockopt = libzmq.zmq_setsockopt
zmq_setsockopt:types { ret = "int", abi="stdcall", "pointer", "int", "pointer", "int" }

local zmq_errno = libzmq.zmq_errno
zmq_errno:types { ret = "int", abi="stdcall" }

local zmq_msg_close = libzmq.zmq_msg_close
zmq_msg_close:types { ret = "int", abi="stdcall", "pointer" }

local zmq_msg_data = libzmq.zmq_msg_data
zmq_msg_data:types { ret = "pointer", abi="stdcall", "pointer" }

local zmq_msg_get = libzmq.zmq_msg_get
zmq_msg_get:types { ret = "int", abi="stdcall", "pointer", "int" }

local zmq_msg_init_size = libzmq.zmq_msg_init_size
zmq_msg_init_size:types { ret = "int", abi="stdcall", "pointer", "int" }

local zmq_msg_init = libzmq.zmq_msg_init
zmq_msg_init:types { ret = "int", abi="stdcall", "pointer" }

local zmq_msg_more = libzmq.zmq_msg_more
zmq_msg_more:types { ret = "int", abi="stdcall", "pointer" }

local zmq_msg_recv = libzmq.zmq_msg_recv
zmq_msg_recv:types { ret = "int", abi="stdcall", "pointer", "pointer", "int" }

local zmq_msg_send = libzmq.zmq_msg_send
zmq_msg_send:types { ret = "int", abi="stdcall", "pointer", "pointer", "int" }

local zmq_msg_set = libzmq.zmq_msg_set
zmq_msg_set:types { ret = "int", abi="stdcall", "pointer", "int", "int" }

local zmq_msg_size = libzmq.zmq_msg_size
zmq_msg_size:types { ret = "int", abi="stdcall", "pointer" }

local zmq_poll = libzmq.zmq_poll
zmq_poll:types { ret = "int", abi="stdcall", "pointer", "int", "long" }

local zmq_recv = libzmq.zmq_recv
zmq_recv:types { ret = "int", abi="stdcall", "pointer", "pointer", "int", "int"}

local zmq_send = libzmq.zmq_send
zmq_send:types { ret = "int", abi="stdcall", "pointer", "pointer", "int", "int"}

local zmq_socket = libzmq.zmq_socket
zmq_socket:types { ret = "pointer", abi="stdcall", "pointer", "int"}

local zmq_version = libzmq.zmq_version
zmq_version:types { ret = "void", abi="stdcall", "ref int", "ref int", "ref int"}

local zmq_unbind = libzmq.zmq_unbind
zmq_unbind:types { ret = "int", abi="stdcall", "pointer", "string"}

local function zmq_msg_new()
	local buf = alien.buffer(64)
	return buf
end

local function zmq_msg_as_string(msg)
	return alien.tostring(zmq_msg_data(msg), zmq_msg_size(msg))
end

local ZMQ_PAIR = 0
local ZMQ_PUB = 1
local ZMQ_SUB = 2
local ZMQ_REQ = 3
local ZMQ_REP = 4
local ZMQ_DEALER = 5
local ZMQ_ROUTER = 6
local ZMQ_PULL = 7
local ZMQ_PUSH = 8
local ZMQ_XPUB = 9
local ZMQ_XSUB = 10
local ZMQ_STREAM = 11

local ZMQ_POLLIN = 1
local ZMQ_POLLOUT = 2
local ZMQ_POLLERR = 4

local ZMQ_SNDMORE = 2

local ZMQ_ROUTING_ID = 5
local ZMQ_LINGER = 17
local ZMQ_RCVTIMEO = 27
local ZMQ_SNDTIMEO = 28
local ZMQ_ROUTER_MANDATORY = 33

local function check_if_error(value, success_value, err_value)
    if value == err_value then
        return nil, zmq_errno()
    else
        return success_value, nil
    end
end

local function ctx_term(ctx)
    zmq_ctx_term(ctx.ctx)
end

local function socket_bind(socket, endpoint)
    return check_if_error(
        zmq_bind(socket.socket, endpoint), nil, -1)
end

local function socket_connect(socket, endpoint)
    return check_if_error(
        zmq_connect(socket.socket, endpoint), nil, -1)
end

local function socket_setsockopt_int(socket, option_name, value)
    local arr = alien.array("int", {value})
    return check_if_error(
        zmq_setsockopt(socket.socket, option_name, arr.buffer:topointer(), arr.size),
        nil, -1)
end

local function socket_setsockopt_str(socket, option_name, value)
    local arr = alien.buffer(value)
    return check_if_error(
        zmq_setsockopt(socket.socket, option_name, value, #arr - 1),
        nil, -1)
end

local function socket_close(socket)
    return check_if_error(
        zmq_close(socket.socket), nil, -1)
end

local function socket_disconnect(socket)
    return check_if_error(
        zmq_disconnect(socket.socket), nil, -1)
end

local function socket_send(socket, message)
    local rc = 0
    if #message > 1 then
        for i = 1, #message - 1 do
            rc = zmq_send(socket.socket, message[i], string.len(message[i]),
                          ZMQ_SNDMORE)
            if rc < 0 then
                print(rc)
                return nil, zmq_errno()
            end
        end
    end
    rc = zmq_send(socket.socket, message[#message], string.len(message[#message]), 0)
    if rc < 0 then
        return nil, zmq_errno()
    end
    return nil, nil
end

local function socket_recv(socket)

    local msg = {}
    local more = false
    repeat
        local part = zmq_msg_new()
        if not part then
            return nil, zmq_errno()
        end
        if not zmq_msg_init(part) then
            return nil, zmq_errno()
        end
        local rc = zmq_msg_recv(part, socket.socket, 0)
        if rc < 0 then
            return nil, zmq_errno()
        else
            local len = zmq_msg_size(part)
            local buf = alien.buffer(zmq_msg_data(part))
            msg[#msg + 1] = buf:tostring(len)
            more = (zmq_msg_more(part) == 0)
        end
        rc = zmq_msg_close(part)
        if rc == -1 then
            return nil, zmq_errno()
        end
    until more

    return msg, nil
end

local function poller_add_item(poller, sock, event)
    table.insert(poller.items, { sock = sock, event = event })
end

local function poller_poll(poller, timeout)
    local events_buffer = alien.buffer(zmq_pollitem.size * #poller.items)
    local ptr = 1
    for _, item in ipairs(poller.items) do
        local pollitem = zmq_pollitem:new(events_buffer:topointer(ptr))
        pollitem.socket = item.sock.socket
        pollitem.fd = 0
        pollitem.events = item.event
        pollitem.revents = 0
        ptr = ptr + zmq_pollitem.size
    end
    local rc = zmq_poll(events_buffer:topointer(), #poller.items, timeout)
    if rc < 0 then
        return nil, zmq_errno()
    end
    local result = {}
    local added = 0
    ptr = 1
    for i = 1, #poller.items do
        if added == rc then
            break
        end
        local pollitem = zmq_pollitem:new(events_buffer:topointer(ptr))
        if pollitem.revents ~= 0 then
            table.insert(result, poller.items[i])
            added = added + 1
        end
        ptr = ptr + zmq_pollitem.size
    end
    return result
end

local function mk_poller(ctx)
    local p = {
        ctx = ctx,
        items = {},
        add = poller_add_item,
        poll = poller_poll,
    }
    return p
end

local function mk_socket(ctx, socktype)
    local sock = zmq_socket(ctx.ctx, socktype)
    return check_if_error(sock,
                          {
                              ctx = ctx.ctx,
                              socket = sock,
                              bind = socket_bind,
                              connect = socket_connect,
                              close = socket_close,
                              disconnect = socket_disconnect,
                              send = socket_send,
                              recv = socket_recv,
                              setsockopt_int = socket_setsockopt_int,
                              setsockopt_str = socket_setsockopt_str,
                          }, nil)
end

local function ctx_new()
    local ctx = zmq_ctx_new()
    return check_if_error(ctx,
                          {
                              ctx = ctx,
                              term = ctx_term,
                              socket = mk_socket,
                              poller = mk_poller,
                          }, nil)
end

local P =
    {
        ctx_new = ctx_new,
        PUB = ZMQ_PUB,
        SUB = ZMQ_SUB,
        REQ = ZMQ_REQ,
        REP = ZMQ_REP,
        ROUTER = ZMQ_ROUTER,
        DEALER = ZMQ_DEALER,
        PAIR = ZMQ_PAIR,
        PULL = ZMQ_PULL,
        PUSH = ZMQ_PUSH,
        XPUB = ZMQ_XPUB,
        XSUB = ZMQ_XSUB,
        STREAM = ZMQ_STREAM,

        POLLIN = ZMQ_POLLIN,
        POLLOUT = ZMQ_POLLOUT,
        POLLERR = ZMQ_POLLERR,

        SOCKOPT_RCVTIMEO = ZMQ_RCVTIMEO,
        SOCKOPT_SNDTIMEO = ZMQ_SNDTIMEO,
        SOCKOPT_LINGER = ZMQ_LINGER,
        SOCKOPT_ROUTING_ID = ZMQ_ROUTING_ID,
        SOCKOPT_ROUTER_MANDATORY = ZMQ_ROUTER_MANDATORY,
    }

if _REQUIREDNAME == nil then
    zmq = P
else
    _G[_REQUIREDNAME] = P
end

return P