local function is_valid_mining_drill(entity)
    return entity and entity.valid and entity.type == "mining-drill"
end

local function get_drill_quality(drill)
    if drill.prototype.quality then
        return drill.prototype.quality
    end

    if drill.supports_quality and drill.quality then
        return drill.quality
    end


    return 1
end


local function update_inventory_quality(inventory, quality)
    if not (inventory and inventory.valid) then return false end

    local changed = false
    for i = 1, #inventory do
        local stack = inventory[i]
        if stack and stack.valid_for_read then
            local item_proto = game.item_prototypes[stack.name]
            if item_proto and item_proto.has_quality then
                if not stack.quality or stack.quality ~= quality then
                    local new_stack = {
                        name = stack.name,
                        count = stack.count,
                        quality = quality
                    }
                    inventory.remove(stack)
                    inventory.insert(new_stack)
                    changed = true
                end
            end
        end
    end
    return changed
end

local function update_mining_drills()
    if not settings.global["qmsa-enable-mod"].value then return end

    for _, surface in pairs(game.surfaces) do
        local drills = surface.find_entities_filtered { type = "mining-drill" }

        for _, drill in ipairs(drills) do
            if not is_valid_mining_drill(drill) then goto continue end

            if drill.name == "big-mining-drill" and not settings.global["qmsa-affect-big-drills"].value then
                goto continue
            end

            if drill.status == defines.entity_status.mining or drill.status == defines.entity_status.working then
                local drill_quality = get_drill_quality(drill)

                update_inventory_quality(drill.output_inventory, drill_quality)

                if drill.get_output_inventories then
                    for _, inv in pairs(drill.get_output_inventories()) do
                        update_inventory_quality(inv, drill_quality)
                    end
                end
            end

            ::continue::
        end
    end
end

script.on_init(function()
end)

script.on_configuration_changed(function(data)
    if data.mod_changes and data.mod_changes["quality-mining-space-age"] then
    end
end)

script.on_nth_tick(settings.global["qmsa-check-interval"].value or 60, function()
    pcall(update_mining_drills)
end)

script.on_event(defines.events.on_runtime_mod_setting_changed, function(event)
    if event.setting:find("qmsa%-") then
        pcall(update_mining_drills)
    end
end)