reactor_meltdown.lua

--Reactors melt down if:
--temperature is at 1000°C and health is 0 or reactor is picked up
--
--a reactors loses 2 damage per second at 1000°C

local Event = require 'utils.event'

global.reactors_enabled = false
global.wastelands = {}
global.reactors = {}
local wasteland_duration_seconds = 300

local function spawn_wasteland(surface, position)
    local positions = {
        {0, 0},
        {0, 12},
        {0, -12},
        {12, 0},
        {-12, 0},
        {-8.5, 8.5},
        {-8.5, -8.5},
        {8.5, -8.5},
        {8.5, 8.5},
        {4, 4},
        {-4, 4},
        {-4, -4},
        {4, -4},
        {13, 7.5},
        {-13, 7.5},
        {-13, -7.5},
        {13, -7.5},
        {7.5, 13},
        {-7.5, 13},
        {-7.5, -13},
        {7.5, -13},
        {0, 15},
        {-15, 0},
        {15, 0},
        {0, -15}
    }
    for _, rel_position in pairs(positions) do
        surface.create_entity {
            name = 'poison-capsule',
            position = position,
            target = {position.x + rel_position[1], position.y + rel_position[2]},
            speed = 0.4
        }
    end
end

local function entity_destroyed(event)
    if not global.reactors_enabled or not event.entity.valid or event.entity.name ~= 'nuclear-reactor' then
        return
    end

    local reactor = event.entity

    if reactor.temperature > 700 then
        reactor.surface.create_entity {name = 'atomic-rocket', position = reactor.position, target = reactor, speed = 1}
        spawn_wasteland(reactor.surface, reactor.position)
        global.wastelands[reactor.position.x .. '/' .. reactor.position.y] = {
            position = reactor.position,
            surface_id = reactor.surface.index,
            creation_time = game.tick
        }
    end
end

local function alert(reactor)
    for _, p in pairs(game.players) do
        p.add_custom_alert(
            reactor,
            {type = 'item', name = 'nuclear-reactor'},
            string.format('Reactor at %s°C', math.floor(reactor.temperature)),
            true
        )
    end
end

local function check_reactors()
    for _, surface in pairs(game.surfaces) do
        for i, reactor in pairs(global.reactors) do
            if reactor.valid then
                if reactor.temperature > 800 then
                    alert(reactor)
                end
                if reactor.temperature == 1000 then
                    reactor.force = 'enemy'
                    reactor.destructible = false
                    reactor.health = 0
                    reactor.surface.create_entity {
                        name = 'atomic-rocket',
                        position = reactor.position,
                        target = reactor,
                        speed = 1
                    }
                    spawn_wasteland(reactor.surface, reactor.position)
                    global.wastelands[reactor.position.x .. '/' .. reactor.position.y] = {
                        position = reactor.position,
                        surface_id = reactor.surface.index,
                        creation_time = game.tick
                    }
                    table.remove(global.reactors, i)
                else
                    reactor.health = 500 - (reactor.temperature - 800) * 2.5
                end
            else
                table.remove(global.reactors, i)
            end
        end
        global.last_reactor_warning = last_reactor_warning
    end
end

local function check_wastelands()
    for index, wl in pairs(global.wastelands) do
        local age = game.tick - wl.creation_time
        wl.last_checked = wl.last_checked or 0
        if (game.tick - wl.last_checked) > 899 then
            wl.last_checked = game.tick
            spawn_wasteland(game.surfaces[wl.surface_id], wl.position)
            if age > wasteland_duration_seconds * 60 - 1 then
                global.wastelands[index] = nil
                local reactors =
                    game.surfaces[wl.surface_id].find_entities_filtered {
                    position = wl.position,
                    name = 'nuclear-reactor'
                }
                if reactors[1] then
                    reactors[1].destroy()
                end
            end
        end
    end
end

local function on_tick()
    if global.reactors_enabled then
        check_wastelands()
        check_reactors()
    end
end

local function entity_build(event)
    if not event.created_entity.valid then
        return
    end
    if event.created_entity.name == 'nuclear-reactor' and event.created_entity.surface.name ~= "antigrief" then
        table.insert(global.reactors, event.created_entity)
    end
end

local function reactor_toggle()
    if not game.player or game.player.admin then
        global.reactors_enabled = not global.reactors_enabled
        if global.reactors_enabled then
            game.print('Reactor meltdown activated.')
        else
            game.print('Reactor meltdown deactivated.')
        end
    end
end

local function is_meltdown()
    if global.reactors_enabled then
        player_print('Reactor metldown is enabled.')
    else
        player_print('Reactor metldown is disabled.')
    end
end

commands.add_command('meltdown', 'Toggles if reactors blow up', reactor_toggle)
commands.add_command('is-meltdown', 'Prints if meltdown is enabled', is_meltdown)

Event.on_nth_tick(60, on_tick)
Event.add(defines.events.on_player_mined_entity, entity_destroyed)
Event.add(defines.events.on_robot_mined_entity, entity_destroyed)
Event.add(defines.events.on_entity_died, entity_destroyed)
Event.add(defines.events.on_built_entity, entity_build)
Event.add(defines.events.on_robot_built_entity, entity_build)