random-stuff/computercraft/chat-ethics-monitor.lua

local monitor = peripheral.wrap "front"
local sensor = peripheral.wrap "right"
local laser = peripheral.wrap "left"
local get_ethics = require "/ethics"
local modem = peripheral.find "modem"

local targets = {}

local function scan()
    local nearby = sensor.sense()
    local ret = {}
    for k, v in pairs(nearby) do
        v.s = vector.new(v.x, v.y, v.z)
        v.v = vector.new(v.motionX, v.motionY, v.motionZ)
        v.distance = v.s:length()
        if v.displayName == v.name then ret[v.name] = v end
    end
    return ret
end

local function enable_lasing(player)
    targets[player] = os.epoch "utc"
    modem.transmit(55, 55, { "lase", player })
end

local function calc_yaw_pitch(v)
	local x, y, z = v.x, v.y, v.z
    local pitch = -math.atan2(y, math.sqrt(x * x + z * z))
    local yaw = math.atan2(-x, z)
    return math.deg(yaw), math.deg(pitch)
end

local function vector_sqlength(self)
	return self.x * self.x + self.y * self.y + self.z * self.z
end

local function project(line_start, line_dir, point)
	local t = (point - line_start):dot(line_dir) / vector_sqlength(line_dir)
	return line_start + line_dir * t, t
end

local function angles_to_axis(yaw, pitch)
    return vector.new(
        -math.sin(math.rad(yaw)) * math.cos(math.rad(pitch)),
        -math.sin(math.rad(pitch)),
        math.cos(math.rad(yaw)) * math.cos(math.rad(pitch))
    )
end

local laser_origin = vector.new(0, 0, 0)

local function would_hit(beam_line, player, target_position)
    local point, t = project(laser_origin, beam_line, player.s)
    return t > 0 and (point - player.s):length() < 1.5 and player.s:length() < target_position:length()
end

local function lase(entity, others)
	local target_location = entity.s - vector.new(0, 1, 0)
	for i = 1, 5 do
		target_location = entity.s + entity.v * (target_location:length() / 1.5)
	end
	local y, p = calc_yaw_pitch(target_location)
    local line = angles_to_axis(y, p)
    for _, other in pairs(others) do
        if would_hit(line, other, target_location) then
            --print("would hit", other.name)
            return false
        end
    end
    laser.fire(y, p, 1)
end

local function laser_defense()
    while true do
       local entities = scan()
       local safe_entities = {}
       local now = os.epoch "utc"
       for _, entity in pairs(entities) do
           local targeted_at = targets[entity.name]
           if not targeted_at or targeted_at <= (now - 60000) then
               table.insert(safe_entities, entity)
           end
       end
       
       local action_taken = false
       for _, entity in pairs(entities) do
           local targeted_at = targets[entity.name]
           if targeted_at and targeted_at > (now - 60000) then
                lase(entity, safe_entities)
                action_taken = true
           end
       end
       if not action_taken then sleep(0.5) end
    end
end

local function laser_commands()
    modem.open(55)
    while true do
        local _, _, c, rc, m = os.pullEvent "modem_message"
        if c == 55 and type(m) == "table" and m[1] == "lase" and type(m[2]) == "string" then
            targets[m[2]] = os.epoch "utc"
        end
    end
end

term.redirect(monitor)
term.setCursorPos(1, 1)
term.setBackgroundColor(colors.black)
term.clear()

local function writeline(color, ...)
    term.setTextColor(color)
    print(...)
end

local function chat_listen()
    while true do
        local _, user, message, obj = os.pullEvent "chat"
        local ethics_level = get_ethics(message)
        local color = colors.white
        if ethics_level < -2 then
            color = colors.red
        elseif ethics_level > 2 then
            color = colors.lime
        end
        writeline(color, user, ethics_level)
        modem.transmit(56, 56, { user, ethics_level, message })
        local nearby = scan()
        if nearby[user] and nearby[user].distance < 8 and ethics_level < -3 then
            writeline(colors.red, "Countermeasures initiated.")
            chatbox.tell(user, ("Hi %s and welcome to the GTech(tm) Apiaristics Division! Your recent message has an unacceptable ethics level of %d. The PIERB has preemptively approved countermeasures. Have a nice day!"):format(user, ethics_level))
            enable_lasing(user)
        end
    end
end

parallel.waitForAll(laser_defense, chat_listen, laser_commands)