factorio-scenario-ExpCluster/exp_legacy/module/modules/addons/damage-popups.lua

--- Displays the amount of dmg that is done by players to entities;
-- also shows player health when a player is attacked
-- @addon Damage-Popups

local FlyingText = require("modules/exp_util/flying_text")
local Event = require("modules/exp_legacy/utils/event") --- @dep utils.event
local config = require("modules.exp_legacy.config.popup_messages") --- @dep config.popup_messages

Event.add(defines.events.on_entity_damaged, function(event)
    local entity = event.entity
    local cause = event.cause
    local damage = math.floor(event.original_damage_amount)
    local health = math.floor(entity.health)
    local health_percentage = entity.get_health_ratio()
    local text_colour = { r = 1 - health_percentage, g = health_percentage, b = 0 }

    -- Gets the location of the text
    local size = entity.get_radius()
    if size < 1 then size = 1 end
    local r = (math.random() - 0.5) * size * config.damage_location_variance
    local p = entity.position
    local position = { x = p.x + r, y = p.y - size }

    -- Sets the message
    local message
    if entity.name == "character" and config.show_player_health then
        message = { "damage-popup.player-health", health }
    elseif entity.name ~= "character" and cause and cause.name == "character" and config.show_player_damage then
        message = { "damage-popup.player-damage", damage }
    end

    -- Outputs the message as floating text
    if message then
        FlyingText.create{
            text = message,
            position = position,
            color = text_colour,
        }
    end
end)