local Public = {}

local score_values = {
    ['small-spitter'] = 1,
    ['small-biter'] = 1,
    ['medium-spitter'] = 3,
    ['medium-biter'] = 3,
    ['big-spitter'] = 5,
    ['big-biter'] = 5,
    ['behemoth-spitter'] = 10,
    ['behemoth-biter'] = 10,
    ['small-worm-turret'] = 4,
    ['medium-worm-turret'] = 6,
    ['big-worm-turret'] = 8,
    ['behemoth-worm-turret'] = 10,
    ['biter-spawner'] = 16,
    ['spitter-spawner'] = 16
}

function Public.set_daytime_difficulty(surface)
    local daytime = surface.daytime
    if daytime < 0.30 then
        surface.peaceful_mode = true
    else
        surface.peaceful_mode = false
    end
end

function Public.set_biter_difficulty()
    local daytime = global.daytime

    local daytime_extra_life_modifier = (-0.30 + daytime) * 2
    if daytime_extra_life_modifier < 0 then
        daytime_extra_life_modifier = 0
    end

    local extra_lifes = global.map_score * 0.0001 * daytime + daytime_extra_life_modifier
    global.biter_reanimator.forces[2] = extra_lifes
end

function Public.add_score(entity)
    local value = score_values[entity.name]
    if not value then
        return
    end
    global.map_score = global.map_score + value
end

function Public.fleeing_biteys(entity, cause)
    local surface = entity.surface
    if not surface.peaceful_mode then
        return
    end

    if not cause then
        return
    end
    if not cause.valid then
        return
    end
    if entity.type ~= 'unit' then
        return
    end

    local unit_groups = {}
    local position = entity.position
    local units = surface.find_entities_filtered({type = 'unit', force = 'enemy', area = {{position.x - 16, position.y - 16}, {position.x + 16, position.y + 16}}})

    for _, unit in pairs(units) do
        local unit_group = unit.unit_group
        if unit_group then
            if unit_group.valid then
                if not unit_groups[unit_group.group_number] then
                    unit_groups[unit_group.group_number] = unit_group
                end
            end
        else
            unit.set_command(
                {
                    type = defines.command.flee,
                    from = cause,
                    distraction = defines.distraction.none
                }
            )
        end
    end

    for _, group in pairs(unit_groups) do
        group.set_command(
            {
                type = defines.command.flee,
                from = cause,
                distraction = defines.distraction.none
            }
        )
    end
end

return Public