local createMcpComputer = require('/apis/libmcpcomputer');
local createVersion = require('/apis/libversion');

local args = table.pack(...);
local command = args[1];

local function printUsage()
  print('mcp-computer usage:');
  print();
  print('  mcp-computer <ws-url>');
  print('  mcp-computer -url <ws-url>');
  print('  mcp-computer --version');
  print('  mcp-computer --help');
  print();
  print('examples:');
  print('  mcp-computer ws://192.168.1.20:3001');
  print('  mcp-computer -url ws://mcp-bridge.local:3001');
  print();
  print('with no URL, falls back to the mcp-computer.ws-url setting.');
end

local function fail(message)
  print(message);
  error('mcp-computer failed', 0);
end

local function decodeJson(text)
  return textutils.unserializeJSON(text);
end

local function sendJson(ws, value)
  ws.send(textutils.serializeJSON(value));
end

local function waitForHelloOk(ws)
  local message = ws.receive(5);
  if not message then
    return false, 'timed out waiting for hello-ok';
  end

  local frame = decodeJson(message);
  if type(frame) ~= 'table' or frame.type ~= 'hello-ok' then
    return false, 'unexpected hello response';
  end

  return true;
end

if command == '-help' or command == '--help' or command == 'help' then
  printUsage();
  return;
end

if command == '-version' or command == '--version' or command == 'version' then
  print('v' .. createVersion().forSelf());
  return;
end

local mcpComputer = createMcpComputer();
local config, err = mcpComputer.resolveUrl(args, settings);
if not config then
  print(err);
  print('use: mcp-computer -help');
  return;
end

if not http then
  fail('CC:Tweaked HTTP/WebSocket is unavailable: enable the http API.');
end

if not http.websocket then
  fail('CC:Tweaked WebSocket is unavailable: enable HTTP WebSocket support.');
end

local version = createVersion().forSelf();
print('mcp-computer v' .. version .. ' connecting to ' .. config.url);

local ws, connectErr = http.websocket(config.url);
if not ws then
  fail('websocket failed: ' .. tostring(connectErr));
end

local ok, runtimeErr = pcall(function()
  sendJson(ws, mcpComputer.hello(os));

  local helloOk, helloErr = waitForHelloOk(ws);
  if not helloOk then
    error(helloErr, 0);
  end

  print('linked as ' .. tostring(os.getComputerID())
    .. ' (Label: ' .. mcpComputer.formatLabel(os.getComputerLabel()) .. ')');
  print('waiting for requests... Press Ctrl+T to stop.');

  while true do
    local message = ws.receive();
    if not message then return; end

    local frame = decodeJson(message);
    local response = mcpComputer.handleRequest(frame, os);
    if response then
      sendJson(ws, response);
    end
  end
end);

pcall(function() ws.close(); end);

if not ok then
  if tostring(runtimeErr) == 'Terminated' then
    print('stopped.');
    return;
  end
  fail(tostring(runtimeErr));
end