local function getMetricsStorageData(entity)
    local unit = entity.unit_number
    storage.metrics[unit] = storage.metrics[unit] or {
        name = "",
        enabled = false,
    }
    return storage.metrics[unit]
end

function CreateMetricsEntry(event)
    if event.entity.name == "metrics-combinator"
        and event.entity.valid then
        ---@type LuaEntity
        local entity = event.entity
        storage.metrics[entity.unit_number] = storage.metrics[entity.unit_number] or {
            name = "",
            enabled = false
        }
    end
end

local function open_metrics_gui(player, entity)
    if player.gui.screen.metrics_frame then
        player.gui.screen.metrics_frame.destroy()
    end

    local frame = player.gui.screen.add {
        type = "frame",
        name = "metrics_frame",
        direction = "vertical"
    }

    -- Titelzeile mit Close-Button
    local titlebar = frame.add {
        type = "flow",
        direction = "horizontal"
    }

    titlebar.drag_target = frame

    titlebar.add {
        type = "label",
        caption = "Metrics Combinator",
        style = "frame_title"
    }

    local spacer = titlebar.add {
        type = "empty-widget",
        style = "draggable_space_header",
    }
    spacer.style.horizontally_stretchable = true
    spacer.drag_target = frame

    titlebar.add {
        type = "sprite-button",
        name = "metrics_close",
        sprite = "utility/close",
        style = "frame_action_button"
    }

    -- Inhalt
    frame.add {
        type = "textfield",
        name = "metrics_name",
        text = storage.metrics[entity.unit_number].name
    }

    frame.add {
        type = "checkbox",
        name = "metrics_enabled",
        caption = "Enabled",
        state = storage.metrics[entity.unit_number].enabled
    }

    frame.force_auto_center()
    frame.tags = { entity_unit_number = entity.unit_number }
    player.opened = frame
end

function onGuiClick(event)
    if event.element.name ~= "metrics_close" then return end

    local player = game.get_player(event.player_index)
    if not player then return end
    if player.gui.screen.metrics_frame then
        player.gui.screen.metrics_frame.destroy()
    end
end

function onGuiOpened(event)
    if event.gui_type ~= defines.gui_type.entity then return end
    if not (event.entity and event.entity.valid and event.entity.name == "metrics-combinator") then
        return
    end

    local player = game.get_player(event.player_index)

    -- SCHLÜSSELZEILE: Engine-GUI sofort schließen
    player.opened = nil

    open_metrics_gui(player, event.entity)
end

function onClosedCombinatorGui(event)
    if event.element and event.element.name == "metrics_frame" then
        event.element.destroy()
    end
end

function onGuiTextChanged(event)
    if event.element.name ~= "metrics_name" then return end

    local player = game.get_player(event.player_index)
    if not player then return end
    local entity = player.opened
    if not (entity and entity.valid) then return end

    local data = getMetricsStorageData(game.get_entity_by_unit_number(entity.tags.entity_unit_number))
    data.name = event.text
end

function onGuiCheckedState(event)
    if event.element.name ~= "metrics_enabled" then return end

    local player = game.get_player(event.player_index)
    if not player then return end
    local frame = player.opened
    if not (frame and frame.valid) then return end


    local data = getMetricsStorageData(game.get_entity_by_unit_number(frame.tags.entity_unit_number))
    data.enabled = event.element.state

    -- optional: echtes Abschalten
    --frame.active = data.enabled
end

function onMetricsCombinatorDied(event)
    if event.entity.name ~= "metrics-combinator" then return end
    storage.metrics[event.entity.unit_number] = nil
end

function onMetricsCombinatorMined(event)
    if event.entity.name ~= "metrics-combinator" then return end
    storage.metrics[event.entity.unit_number] = nil
end

function SendCombinatorMetrics()
    local netParts = {}
    netParts[#netParts + 1] = "---circuit-stats---\n"
    for unitNumber, combinatorFlags in pairs(storage.metrics) do
        if combinatorFlags.enabled then
            local entity = game.get_entity_by_unit_number(unitNumber)
            if entity and entity.valid then
                ---@type LuaCircuitNetwork?
                local redNet = entity.get_circuit_network(defines.wire_connector_id.circuit_red)
                ---@type LuaCircuitNetwork?
                local greenNet = entity.get_circuit_network(defines.wire_connector_id.circuit_green)
                if redNet then
                    for _, signal in pairs(redNet.signals) do
                        local quality = "-normal"
                        if signal.signal.quality then
                            quality = signal.signal.quality.name
                        end
                        netParts[#netParts + 1] = ("%s:red:%s:%d"):format(combinatorFlags.name,
                            signal.signal.name.."-"..quality, signal.count)
                    end
                end
                if greenNet then
                    for _, signal in pairs(greenNet.signals) do
                        netParts[#netParts + 1] = ("%s:green:%s:%d"):format(combinatorFlags.name,
                            signal.signal.name .. signal.signal.quality.name, signal.count)
                    end
                end
            end
        end
    end
    SendChunked(table.concat(netParts, "\n"))
end