EnderCC

-- JSON
local controls = {["\n"]="\\n", ["\r"]="\\r", ["\t"]="\\t", ["\b"]="\\b", ["\f"]="\\f", ["\""]="\\\"", ["\\"]="\\\\"}

local whites = {['\n']=true; ['r']=true; ['\t']=true; [' ']=true; [',']=true; [':']=true}
function removeWhite(str)
    while whites[str:sub(1, 1)] do
        str = str:sub(2)
    end
    return str
end

function parseBoolean(str)
    if str:sub(1, 4) == "true" then
        return true, removeWhite(str:sub(5))
    else
        return false, removeWhite(str:sub(6))
    end
end

function parseNull(str)
    return nil, removeWhite(str:sub(5))
end

local numChars = {['e']=true; ['E']=true; ['+']=true; ['-']=true; ['.']=true}
function parseNumber(str)
    local i = 1
    while numChars[str:sub(i, i)] or tonumber(str:sub(i, i)) do
        i = i + 1
    end
    local val = tonumber(str:sub(1, i - 1))
    str = removeWhite(str:sub(i))
    return val, str
end

function parseString(str)
    local i,j = str:find('[^\\]"')
    local s = str:sub(2, j - 1)

    for k,v in pairs(controls) do
        s = s:gsub(v, k)
    end
    str = removeWhite(str:sub(j + 1))
    return s, str
end

function parseArray(str)
    str = removeWhite(str:sub(2))

    local val = {}
    local i = 1
    while str:sub(1, 1) ~= "]" do
        local v = nil
        v, str = parseValue(str)
        val[i] = v
        i = i + 1
        str = removeWhite(str)
    end
    str = removeWhite(str:sub(2))
    return val, str
end

function parseObject(str)
    str = removeWhite(str:sub(2))

    local val = {}
    while str:sub(1, 1) ~= "}" do
        local k, v = nil, nil
        k, v, str = parseMember(str)
        val[k] = v
        str = removeWhite(str)
    end
    str = removeWhite(str:sub(2))
    return val, str
end

function parseMember(str)
    local k = nil
    k, str = parseValue(str)
    local val = nil
    val, str = parseValue(str)
    return k, val, str
end

function parseValue(str)
    local fchar = str:sub(1, 1)
    if fchar == "{" then
        return parseObject(str)
    elseif fchar == "[" then
        return parseArray(str)
    elseif tonumber(fchar) ~= nil or numChars[fchar] then
        return parseNumber(str)
    elseif str:sub(1, 4) == "true" or str:sub(1, 5) == "false" then
        return parseBoolean(str)
    elseif fchar == "\"" then
        return parseString(str)
    elseif str:sub(1, 4) == "null" then
        return parseNull(str)
    end
    return nil
end

function decode(str)
    str = removeWhite(str)
    t = parseValue(str)
    return t
end

-- Usage: decode(str) encode(val)

local url = "http://ender.fluidnode.com/"

function rawStart(chan)
    local res = http.get(url .. "start?channel=" .. chan)
    if res then
        local msg = decode(res.readAll())
        if msg then
            if msg.err then
                return false, msg.err
            end
            return true, msg.uuid, msg.name
        else
            return false
        end
    else
        return false
    end
end

function rawPoll(uuid)
    local res = http.get(url .. "poll?uuid=" .. uuid);
    if res then
        local msg = decode(res.readAll())
        if msg then
            if msg.err then
                return false, msg.err
            end
            if not msg.res then
                return false
            end
            return true, msg.res, msg.from
        else
            return false
        end
    else
        return false
    end
end

function rawSend(msg, uuid)
    local res = http.get(url .. "send?uuid=" .. uuid .. "&message=" .. textutils.urlEncode(msg));
    if res then
        local msg = decode(res.readAll())
        if msg then
            if msg.err then
                return false, msg.err
            end
            return true
        else
            return false
        end
    else
        return false
    end
end

function rawCheck(uuid)
    local res = http.get(url .. "check?uuid=" .. uuid)
    if res then
        return res.readAll() == "true"
    else
        return false
    end
end

local chans = {}

function connect(channel)
    if chans[channel] then
        if rawCheck(chans[channel]) then
            return chans[channel][1]
        else
            chans[channel] = nil
            return connect(channel)
        end
    else
        local res, uuid, name = rawStart(channel)
        if res then
            chans[channel] = {uuid, name}
            return uuid
        else
            return connect(channel)
        end
    end
end

function getName(channel)
    connect(channel)
    return chans[channel][2]
end

function send(channel, message)
    local uuid = connect(channel)
    return rawSend(message, uuid)
end

function receive(channel)
    local uuid = connect(channel)
    return rawPoll(uuid)
end