extends Control

@export var item_pages: Array[Control]
@export var stage_page_scroller: ScrollContainer

const ITEM_BUTTON = preload("uid://d3xjfxwe3w16v")

const PAGE_COUNT = 5
const PAGE_WIDTH = 1080
const DRAG_TOLERANCE = 360
const SWIPE_DURATION: float = 2
const SWIPE_DELAY = 2000 # msec

@onready var g_entity_descriptions: Array = [
    $StageRows/PageScroller/HBoxContainer/ForcePage/Description,
    $StageRows/PageScroller/HBoxContainer/ResourcePage/Description,
    $StageRows/PageScroller/HBoxContainer/StarPage/Description,
    $StageRows/PageScroller/HBoxContainer/StructurePage/Description,
    $StageRows/PageScroller/HBoxContainer/LifePage/Description
]

@onready var g_top_menu: TopMenu = $StageRows/TopMenu


var g_tween: Tween = null
var g_dragged_start: Vector2 = Vector2.ZERO
var g_scroll_start: int = 0
var g_current_page: int = 0

var g_last_scroll_updated: int = 0

var f_check_swipe: bool = false
var g_swipe_time_delta: float = 0

var g_counters: Dictionary[String, Counter] = {
        "swipe": Counter.new(),
    }

var ActiveEntities: Dictionary = {}

var owniverse = Owniverse.new()


func entity_activated(entity: OwniverseEntity) -> void:
    _control_page(entity)
    _set_description(entity)

func _set_description(entity: OwniverseEntity) -> void:
    var description: String = "[b]" \
        + Global.get_localized_item_description(entity.entity_name, "label") \
        + "[/b]" \
        + "\n" \
        + Global.get_localized_item_description(entity.entity_name, "description")
    var desc_page = clamp(entity.entity_page, 0, 4)
    g_entity_descriptions[desc_page].text = description
    pass

func _control_page(entity: OwniverseEntity) -> void:
    if !ActiveEntities.has(entity.entity_page):
        ActiveEntities[entity.entity_page] = null
        
    var current_entity:OwniverseEntity = ActiveEntities[entity.entity_page]
    if current_entity == entity:
        return
    
    ActiveEntities[entity.entity_page] = entity
    
    if current_entity != null and current_entity.entity_page == entity.entity_page:
        current_entity.set_selection(false)

    entity.set_selection(true)

    # subpages
    if entity.sub_page != -1:
        item_pages[entity.sub_page].visible = true

    if current_entity == null \
            or current_entity.sub_page == -1 \
            or current_entity.sub_page == entity.sub_page:
        return
    item_pages[current_entity.sub_page].visible = false


func _init_entities() -> bool:
    for e_id in Global.Entities:
        var entity_properties: Dictionary = Global.Entities[e_id]
        var entity: OwniverseEntity = ITEM_BUTTON.instantiate()
        if !entity_properties.has("page"):
            printerr("Entity `", e_id, "` has no `page` key.")
            return false
        var page: int = int(entity_properties.page)
        item_pages[page].add_child(entity)
        entity.init_button(entity_properties)
        entity.entity_activated.connect(entity_activated)

    return false
    

func _check_counters(delta: float) -> Array:
    var actions: Array = []
    for k in g_counters:
        var cnt: Counter = g_counters[k]
        if not cnt.is_active:
            continue
            
        cnt.value += delta
        if cnt.value >= cnt.sec:
            actions.append(k)
            cnt.value = 0
            cnt.is_active = false
        
    return actions

func _do_actions(actions: Array) -> void:
    for action: String in actions:
        match action:
            "swipe": 
                _swipe_to_nearest_page()


#region Swipe


func _swipe_to_nearest_page() -> void:
    if stage_page_scroller.scroll_horizontal % PAGE_WIDTH == 0: return
    
    var new_page: int = round(1.0 * stage_page_scroller.scroll_horizontal / PAGE_WIDTH)

    if g_tween != null:
        if g_tween.is_running():
            return

    g_tween = stage_page_scroller.get_tree().create_tween()
    g_tween.tween_property(stage_page_scroller, "scroll_horizontal", 
        new_page * PAGE_WIDTH, SWIPE_DURATION).set_trans(Tween.TRANS_CUBIC).set_ease(Tween.EASE_OUT)


func _input(event: InputEvent) -> void:

    if event is InputEventScreenDrag:
        stage_page_scroller.scroll_horizontal = clamp(
                stage_page_scroller.scroll_horizontal - PAGE_COUNT * event.screen_relative.x,
                0, PAGE_WIDTH * (PAGE_COUNT - 1))
        g_counters.swipe.is_active = true
        g_counters.swipe.value = 0
    elif event is InputEventPanGesture:
        g_counters.swipe.is_active = true
        g_counters.swipe.value = 0
    elif event is InputEventScreenTouch:
        pass
#endregion


func _ready() -> void:
    _init_entities()
    
func _process(delta: float) -> void:
    # Update date
    var dt: float = owniverse.add_time_delta(delta)
    if owniverse.g_speed > 1:
        dt = round(dt)
    else:
        dt = snapped(dt, 0.1)
        
    g_top_menu.set_datetime(str(dt))
    
    
    var actions = _check_counters(delta)
    _do_actions(actions)