ComfyFactorio/modules/towny/building.lua

local Public = {}

local connection_radius = 7

local entity_type_whitelist = {
    ['accumulator'] = true,
    ['ammo-turret'] = true,
    ['arithmetic-combinator'] = true,
    ['artillery-turret'] = true,
    ['assembling-machine'] = true,
    ['boiler'] = true,
    ['constant-combinator'] = true,
    ['container'] = true,
    ['curved-rail'] = true,
    ['decider-combinator'] = true,
    ['electric-pole'] = true,
    ['electric-turret'] = true,
    ['fluid-turret'] = true,
    ['furnace'] = true,
    ['gate'] = true,
    ['generator'] = true,
    ['heat-interface'] = true,
    ['heat-pipe'] = true,
    ['infinity-container'] = true,
    ['infinity-pipe'] = true,
    ['inserter'] = true,
    ['lamp'] = true,
    ['land-mine'] = true,
    ['loader'] = true,
    ['logistic-container'] = true,
    ['market'] = true,
    ['mining-drill'] = true,
    ['offshore-pump'] = true,
    ['pipe'] = true,
    ['pipe-to-ground'] = true,
    ['programmable-speaker'] = true,
    ['pump'] = true,
    ['radar'] = true,
    ['rail-chain-signal'] = true,
    ['rail-signal'] = true,
    ['reactor'] = true,
    ['roboport'] = true,
    ['rocket-silo'] = true,
    ['solar-panel'] = true,
    ['splitter'] = true,
    ['storage-tank'] = true,
    ['straight-rail'] = true,
    ['train-stop'] = true,
    ['transport-belt'] = true,
    ['underground-belt'] = true,
    ['wall'] = true
}

local function is_position_isolated(surface, force, position)
    local position_x = position.x
    local position_y = position.y
    local area = {{position_x - connection_radius, position_y - connection_radius}, {position_x + connection_radius, position_y + connection_radius}}
    local count = 0

    for _, e in pairs(surface.find_entities_filtered({area = area, force = force.name})) do
        if entity_type_whitelist[e.type] then
            count = count + 1
            if count > 1 then
                return
            end
        end
    end

    return true
end

local function refund_item(event, item_name)
    if event.player_index then
        game.players[event.player_index].insert({name = item_name, count = 1})
        return
    end

    if event.robot then
        local inventory = event.robot.get_inventory(defines.inventory.robot_cargo)
        inventory.insert({name = item_name, count = 1})
        return
    end
end

local function error_floaty(surface, position, msg)
    surface.create_entity(
        {
            name = 'flying-text',
            position = position,
            text = msg,
            color = {r = 0.77, g = 0.0, b = 0.0}
        }
    )
end

local function is_town_market_nearby(entity)
    local area = {{entity.position.x - 48, entity.position.y - 48}, {entity.position.x + 48, entity.position.y + 48}}
    local markets = entity.surface.find_entities_filtered({name = 'market', area = area})
    if not markets[1] then
        return false
    end
    for _, market in pairs(markets) do
        if market.force.index > 3 then
            return true
        end
    end
    return false
end

function Public.prevent_isolation(event)
    local entity = event.created_entity
    if not entity.valid then
        return
    end
    if entity.force.index == 1 then
        return
    end
    if not entity_type_whitelist[entity.type] then
        return
    end
    local surface = event.created_entity.surface

    if is_position_isolated(surface, entity.force, entity.position) then
        error_floaty(surface, entity.position, {'modules_towny.message_error_building'})
        refund_item(event, event.stack.name)
        entity.destroy()
        return true
    end
end

function Public.prevent_isolation_landfill(event)
    if event.item.name ~= 'landfill' then
        return
    end
    local surface = game.surfaces[event.surface_index]
    local tiles = event.tiles

    local force
    if event.player_index then
        force = game.players[event.player_index].force
    else
        force = event.robot.force
    end

    for _, placed_tile in pairs(tiles) do
        local position = placed_tile.position
        if is_position_isolated(surface, force, position) then
            error_floaty(surface, position, {'modules_towny.message_error_tile'})
            surface.set_tiles({{name = 'water', position = position}}, true)
            refund_item(event, 'landfill')
        end
    end
end

local square_min_distance_to_spawn = 80 ^ 2

function Public.restrictions(event)
    local entity = event.created_entity
    if not entity.valid then
        return
    end

    if entity.force.index == 1 then
        if is_town_market_nearby(entity) then
            refund_item(event, event.stack.name)
            error_floaty(entity.surface, entity.position, {'modules_towny.message_error_close_town'})
            entity.destroy()
        end
        return
    end

    if not entity_type_whitelist[entity.type] then
        return
    end
    if entity.position.x ^ 2 + entity.position.y ^ 2 > square_min_distance_to_spawn then
        return
    end
    refund_item(event, event.stack.name)
    error_floaty(entity.surface, entity.position, {'modules_towny.message_error_close_spawn'})
    entity.destroy()
end

return Public