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-- @SOCKETS MULTIPLAYER
-- PROTOCOL:
--   Transfer between 'packets' of data, each packed separated by '/'.
--   Each packet, also, starts with '(' and ends with ')'. These are arbitrarily
--   selected at design time, and will let us know if a packed arrived entirely.
--   If arrived entirely, process it, else, discard, unless it is the last received,
--   cause the last received probably been cutted, and receive the next part in the next
--   read. If this happens, should be executed correctly, else, discard.

coop = {
    status      = 0,
    connect     = false,
    socket      = nil,
    host        = "www.gcrew.es",
    port        = 8080,
    queue       = { },                                                                      -- Write queue.
    lastcmd     = os.clock(),
    linked      = false,
    linkmode    = 0,
    playing     = false,
    delay       = 1;
    send        = function(t)                                                               -- Enqueue data to send.
                if t then local s = coop.queue; table.insert(s,"("..t..")");
                coop.queue = s;
                end end,
    read        = function()                                                                -- Get data from socket.
                if coop.socket then local a,b = coop.socket:recv();                         --    Read data
                if a != "" then coop.lastcmd = os.clock(); return a, b; end                 --    Data and length if data found.
                return false, 0; end return false, 0;                                       --    false and 0 if error.
                end,
    flush       = function() coop.queue = { }; coop.playing = false;    -- Flush connection.
                coop.delay = 1;
                coop.linked = false; if coop.socket then                                    --    Clear vars, disconnect...
                coop.socket:send("QUIT\n"); coop.socket:free(); coop.socket = nil; end      --    ... prepare all for next
                coop.status = 0;                                                            --    connection.
                coop.lastcmd = os.clock(); end;                                             --    ....
    checkconn   = function()                                                                -- Check connection sanity.
    if not coop.connect then return true; end;                                              -- If no need of connection. get back.

    if coop.connect and not wlan.connected() then                                           -- If required connection and not wlan..
        coop.flush();                                                                       -- ... init wlan. retry.
        local c = wlan.init(0);
        if not c or c == 0 then coop.connect = false; end
        return true;
    end
    if coop.linked and not coop.connect then                                                -- If linked, but not asked to..
        coop.flush(); wlan.term(); return true;                                             -- flush(). retry
    end
    if not coop.socket then                                                                 -- If no socket...
        local a,b = socket.udp(coop.host,coop.port);                                        -- create socket...
        if a and b then coop.socket = a; return true; end                                   -- ... and return if ok.
    end
    if wlan.strength() < 40 then return true; end                                           -- Houston... signal... too weak...
    if not coop.socket then return true; end                                                -- If no socket. retry.
    coop.status = math.max(coop.status,1);
    return false;
    end,
    getall      = function()                                                                -- Get all avaiable data.
    local data, len = coop.read();                                                          -- Read from socket...
    if len > 0 then
        for cmd in data:gmatch("%b()") do
            coop.cmd(cmd:sub(2,-2));
        end
    end
    end,
    write       = function()                                                                -- Send queued data.
    if coop.queue[1] then                                                                   -- If pending data...
        local len;
        len = coop.socket:send(coop.queue[1].."\n",coop.host,coop.port);
        if (len > 0) then                                                                   -- If sent...
            table.remove(coop.queue,1);                                                     --    Remove from queue.
            return true;
        end
        return false;
    end
    return false; end,
    cmd         = function(rcvd)                                                            -- Process one command:
        local cmd = rcvd:explode(" ");                                                      -- Split by words.
        if (cmd[1] == "FLY") then
            local r = cmd[2]:explode(",");
            pla.x2, pla.y2, pla.z2, pla.RZ2 = tonumber(r[1]), tonumber(r[2]), tonumber(r[3]), tonumber(r[4]);
            coop.linked = true;
            coop.status = 2;
        end
    end,
    exec        = function()                                                                    -- For every cycle:
    if coop.checkconn() then return; end                                                        -- Check connection / connect.
    if os.clock() - coop.lastcmd > 10 and coop.linked then coop.connect = false; coop.flush(); end
    if os.clock() - coop.lastcmd > 60 and not coop.linked then coop.connect = false; coop.flush(); end
    coop.getall();                                                                              -- Check for avail. data.
    local written = coop.write();                                                               -- Send avail. data.
    if (os.clock() - coop.lastcmd) > coop.delay then                                                    -- While foreva' and waiting a bit...
        if coop.status == 0 then return end;
        if coop.status == 1 then coop.send("WPLAY"); return; end;
        if coop.status == 2 then
            coop.send(string.format("FLY %.2f,%.2f,%.2f,%.4f",pla.x,pla.y,pla.z,pla.RZ));       --   Refresh my position...
            return;
        end
    end
    screen.print(10,50,"Status: "..coop.status);
    end,
};