-- MCP computer server: reacts to sandbox gateway requests.
--
-- No longer owns a websocket. It registers `exec-lua` / `write-file` handlers on the
-- sandbox daemon's event bus (apis/libsandbox.serve), so requests arrive over the one
-- gateway connection owned by servers/sandbox.lua and replies are sent back through it.
-- It only handles requests while a sandbox is configured, so exec stays gated behind
-- the same trusted, authenticated connection as the rest of the gateway.

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

local URL_SETTING = 'sandbox.url';

local url = settings.get(URL_SETTING);
if type(url) ~= 'string' or url == '' then
  print('mcp-computer-server: ' .. URL_SETTING .. ' not set, exec/write handlers inactive.');
  return;
end

local el = _G.bootEventLoop;
if not el then
  print('mcp-computer-server: no boot eventloop, handlers inactive.');
  return;
end

local sandbox = createSandbox();
local mcp = createMcpComputer();

-- A code error or a failed file write is a *successful* round-trip that carries an
-- ok:false result (so captured output survives the reply); only a thrown handler or
-- a dropped connection becomes a transport-level failure.
sandbox.serve('exec-lua', function(payload)
  local result = mcp.executeLua(payload and payload.code);
  return true, {
    ok = result.ok,
    returns = result.returns or {},
    output = result.output or '',
    error = result.error,
  };
end, { eventloop = el });

sandbox.serve('write-file', function(payload)
  local result = mcp.writeFile(payload and payload.path, payload and payload.content);
  return true, {
    ok = result.ok,
    path = result.path,
    bytes = result.bytes,
    error = result.error,
  };
end, { eventloop = el });

print('mcp-computer-server v' .. createVersion().forSelf()
  .. ' started (serving exec-lua/write-file over sandbox).');