Operator Card

-- Endless day: at dusk, set the world's time back to morning and clear the weather.
-- lua operator-daylight.lua &
--
-- The operator card's file runs a line written to it as a server command, as a command block
-- would, at once. A command that fails fails the write, and reading the file then says what the
-- server answered. The world's clock is the computer's (os.date's hours are the game's), so the
-- program looks once a minute of game time and sleeps in between.
local sys = require("sys")

local DUSK = 18          -- the hour (of the game's 24) after which it is time to act
local CHECK = 50         -- seconds between looks (a game hour is 50 seconds)
local COMMANDS = {"time set day", "weather clear"}

local card = assert(io.open("/dev/operator0", "w"))

while true do
  if os.date("*t").hour >= DUSK then
    for _, command in ipairs(COMMANDS) do
      card:write(command, "\n")
      local ok = card:flush()
      if not ok then
        local answer = io.open("/dev/operator0")
        io.stderr:write("daylight: ", command, ": ", answer:read("a"))
        answer:close()
      end
    end
  end
  sys.sleep(CHECK)
end

-- Run a file of server commands, a line each, and log how each went:
-- lua operator-script.lua setup.txt [log]
--
-- Blank lines and lines starting with # are skipped. Each command goes to the operator card's
-- command method (an ioctl on its file, /dev/operator0), which answers a table: success, result
-- (the command's value) and output (what the server said). The log gets a line per command; the
-- first command that fails stops the run, and the exit status is 1, so a shell script can tell.
local sys = require("sys")

local LOG = "/home/operator.log"  -- where the log goes, unless named

local script, logpath = arg[1], arg[2] or LOG
if not script then
  io.stderr:write("usage: operator-script.lua FILE [LOG]\n")
  os.exit(2)
end

local input = assert(io.open(script))
local log = assert(io.open(logpath, "a"))
local card = assert(sys.open("/dev/operator0"))

local status = 0
local number = 0
for line in input:lines() do
  number = number + 1
  local command = line:match("^%s*(.-)%s*$")
  if command ~= "" and command:sub(1, 1) ~= "#" then
    local answer, why = sys.ioctl(card, "command", command)
    if not answer then
      log:write(("%d: %s: error: %s\n"):format(number, command, why))
      status = 1
    else
      local said = answer.output:gsub("\n", " "):gsub("%s+$", "")
      log:write(("%d: %s: %s %d %s\n"):format(number, command, answer.success and "ok" or "FAILED", answer.result, said))
      if not answer.success then
        status = 1
      end
    end
    if status ~= 0 then
      io.stderr:write("operator-script: stopped at line ", number, "\n")
      break
    end
  end
end

sys.close(card)
input:close()
log:close()
os.exit(status)

-- Greet whoever steps on the pressure plate at the door, and keep a visitors' log.
-- lua operator-greeter.lua &
--
-- The plate's signal comes in on a redstone card (/dev/redstone0, a line a face: "face level
-- powered"); sys.poll waits for its change (PRI). On each step the program runs a server command
-- through the operator card's set method (as a line written to its file would: a command that
-- fails fails the call, with what the server said), then its get method gives what the command
-- said (who was shown the greeting), which goes in the log with the world's date and time.
local sys = require("sys")

local PLATE = "south"                  -- the face the plate's signal comes in on
-- The command run for each visitor: a title on the screens of the players within 5 blocks of the
-- card (a command runs at its block). The server answers "Showing new title for <player>".
local GREETING = 'title @a[distance=..5] title "Welcome home!"'
local LOG = "/home/visitors.log"

local redstone = assert(io.open("/dev/redstone0"))
local card = assert(sys.open("/dev/operator0"))
local watch = {[sys.fileno(redstone)] = {PRI = true}}

-- Whether the plate is pressed now: the file read again from its start.
local function pressed()
  redstone:seek("set", 0)
  return (tonumber(redstone:read("a"):match(PLATE .. " (%d+)")) or 0) > 0
end

local was = pressed()
while true do
  sys.poll(watch)  -- block until the redstone card changes
  local now = pressed()
  if now and not was then
    local done, why = sys.ioctl(card, "set", {command = GREETING})
    local log = assert(io.open(LOG, "a"))
    if done then
      log:write(os.date("%c"), " visitor: ", (sys.ioctl(card, "get"):gsub("\n$", "")), "\n")
    else
      log:write(os.date("%c"), " greeting failed: ", tostring(why), "\n")
    end
    log:close()
  end
  was = now
end