-- biters gain strength scaling with player amount in the game -- by mewmew

local Event = require 'utils.event'

local function refresh_difficulty()
    global.connected_players = #game.connected_players
    if global.connected_players > 75 then
        global.connected_players = 75
    end

    local f = game.forces.enemy
    local m = #game.connected_players * 0.05

    f.set_ammo_damage_modifier('melee', m)
    f.set_ammo_damage_modifier('biological', m * 0.5)
    f.set_ammo_damage_modifier('artillery-shell', m * 0.5)
    f.set_ammo_damage_modifier('flamethrower', m * 0.5)
    f.set_ammo_damage_modifier('laser-turret', m * 0.5)
end

local function on_entity_damaged(event)
    if not event.entity.valid then
        return
    end
    if event.entity.type ~= 'unit' then
        return
    end
    if math.random(1, 100) >= global.connected_players then
        return
    end
    if event.final_damage_amount > event.entity.prototype.max_health then
        return
    end
    event.entity.health = event.entity.health + event.final_damage_amount
end

local function on_player_joined_game()
    refresh_difficulty()
end

local function on_player_left_game()
    refresh_difficulty()
end

Event.add(defines.events.on_player_left_game, on_player_left_game)
Event.add(defines.events.on_player_joined_game, on_player_joined_game)
Event.add(defines.events.on_entity_damaged, on_entity_damaged)