class_name CourseBoardPanel
extends Control

# ============================================================================
# CourseBoardPanel.gd - Datawhale 课程看板
# ============================================================================
# 展示 Datawhale 学习中心课程列表，由打工区 VirtualWhaleRecruitmentBoard 打开。
# ============================================================================

const MOVEMENT_ACTIONS: Array[String] = ["move_left", "move_right", "move_up", "move_down"]
const NetworkConfig = preload("res://_Core/utils/NetworkConfig.gd")
const API_PATH: String = "/course-resources/datawhale"
const PANEL_SIZE: Vector2 = Vector2(1500, 1020)
const MIN_MARGIN: Vector2 = Vector2(24, 24)
const CARD_SIZE: Vector2 = Vector2(320, 348)
const COVER_HEIGHT: float = 171.0
const TEXT_COLOR: Color = Color(0.098, 0.140, 0.190)
const MUTED_COLOR: Color = Color(0.380, 0.450, 0.540)
const ACCENT_COLOR: Color = Color(0.000, 0.322, 0.851)
const SOFT_BLUE: Color = Color(0.925, 0.965, 1.0, 1.0)
const IMAGE_PLACEHOLDER: Color = Color(1.0, 0.965, 0.870, 1.0)

var _overlay: ColorRect
var _panel: Control
var _grid: GridContainer
var _statusLabel: Label
var _request: HTTPRequest
var _isOpen: bool = false
var _transitionTween: Tween

func _ready() -> void:
	visible = false
	mouse_filter = Control.MOUSE_FILTER_IGNORE
	set_process(false)
	_buildUi()

func _notification(what: int) -> void:
	if what == NOTIFICATION_RESIZED and is_instance_valid(_panel):
		_positionPanel()

func _input(event: InputEvent) -> void:
	if not _isOpen:
		return
	if event is InputEventKey:
		var keyEvent := event as InputEventKey
		if keyEvent.pressed and not keyEvent.echo and keyEvent.keycode == KEY_ESCAPE:
			hide_panel()
			get_viewport().set_input_as_handled()

func _process(_delta: float) -> void:
	if _isOpen:
		_releaseMovementActions()

func show_panel() -> void:
	if _isOpen:
		return
	_isOpen = true
	visible = true
	mouse_filter = Control.MOUSE_FILTER_STOP
	set_process(true)
	_releaseMovementInputState()
	_fetchCourses()
	_animatePanel(true)

func hide_panel() -> void:
	if not _isOpen:
		return
	_isOpen = false
	_releaseMovementInputState()
	_animatePanel(false)

func is_panel_open() -> bool:
	return _isOpen

func _buildUi() -> void:
	_overlay = ColorRect.new()
	_overlay.name = "courseBoardDimOverlay"
	_overlay.set_anchors_preset(Control.PRESET_FULL_RECT)
	_overlay.color = Color(0.020, 0.036, 0.060, 0.64)
	_overlay.mouse_filter = Control.MOUSE_FILTER_STOP
	_overlay.gui_input.connect(_onOverlayGuiInput)
	add_child(_overlay)

	_panel = Control.new()
	_panel.name = "courseBoardPanel"
	_panel.custom_minimum_size = PANEL_SIZE
	_panel.mouse_filter = Control.MOUSE_FILTER_STOP
	add_child(_panel)
	_positionPanel()

	var frame := PanelContainer.new()
	frame.set_anchors_preset(Control.PRESET_FULL_RECT)
	frame.add_theme_stylebox_override("panel", _createPanelStyle(Color(0.972, 0.988, 1.0, 1.0), 26, true))
	frame.mouse_filter = Control.MOUSE_FILTER_IGNORE
	_panel.add_child(frame)

	var margin := MarginContainer.new()
	margin.set_anchors_preset(Control.PRESET_FULL_RECT)
	margin.add_theme_constant_override("margin_left", 34)
	margin.add_theme_constant_override("margin_top", 28)
	margin.add_theme_constant_override("margin_right", 34)
	margin.add_theme_constant_override("margin_bottom", 28)
	_panel.add_child(margin)

	var root := VBoxContainer.new()
	root.add_theme_constant_override("separation", 18)
	margin.add_child(root)
	root.add_child(_buildHeader())
	root.add_child(_buildGridPanel())
	root.add_child(_buildFooter())

	_request = HTTPRequest.new()
	_request.timeout = 18.0
	_request.request_completed.connect(_onRequestCompleted)
	add_child(_request)
	_updatePanelAlpha(0.0, 0.0)

func _buildHeader() -> Control:
	var header := PanelContainer.new()
	header.custom_minimum_size = Vector2(0, 106)
	header.add_theme_stylebox_override("panel", _createPanelStyle(Color(0.000, 0.322, 0.851, 0.96), 24, false))

	var margin := MarginContainer.new()
	margin.add_theme_constant_override("margin_left", 28)
	margin.add_theme_constant_override("margin_top", 12)
	margin.add_theme_constant_override("margin_right", 20)
	margin.add_theme_constant_override("margin_bottom", 12)
	header.add_child(margin)

	var row := HBoxContainer.new()
	row.alignment = BoxContainer.ALIGNMENT_CENTER
	row.add_theme_constant_override("separation", 16)
	margin.add_child(row)

	var titleStack := VBoxContainer.new()
	titleStack.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	titleStack.add_theme_constant_override("separation", 4)
	row.add_child(titleStack)

	var title := Label.new()
	title.text = "Datawhale 课程看板"
	title.add_theme_font_size_override("font_size", 32)
	title.add_theme_color_override("font_color", Color.WHITE)
	titleStack.add_child(title)

	var subtitle := Label.new()
	subtitle.text = "AI学习中心最新课程"
	subtitle.add_theme_font_size_override("font_size", 18)
	subtitle.add_theme_color_override("font_color", Color(0.835, 0.925, 1.0, 1.0))
	titleStack.add_child(subtitle)

	var closeButton := Button.new()
	closeButton.text = "×"
	closeButton.custom_minimum_size = Vector2(54, 54)
	closeButton.focus_mode = Control.FOCUS_NONE
	closeButton.add_theme_font_size_override("font_size", 30)
	closeButton.add_theme_color_override("font_color", Color.WHITE)
	closeButton.add_theme_stylebox_override("normal", _createButtonStyle(Color(1.0, 1.0, 1.0, 0.12)))
	closeButton.add_theme_stylebox_override("hover", _createButtonStyle(Color(1.0, 1.0, 1.0, 0.22)))
	closeButton.add_theme_stylebox_override("pressed", _createButtonStyle(Color(1.0, 1.0, 1.0, 0.30)))
	closeButton.add_theme_stylebox_override("focus", StyleBoxEmpty.new())
	closeButton.pressed.connect(hide_panel)
	row.add_child(closeButton)
	return header

func _buildGridPanel() -> Control:
	var holder := PanelContainer.new()
	holder.size_flags_vertical = Control.SIZE_EXPAND_FILL
	holder.add_theme_stylebox_override("panel", _createPanelStyle(Color(0.948, 0.978, 1.0, 0.92), 20, false))

	var margin := MarginContainer.new()
	margin.add_theme_constant_override("margin_left", 18)
	margin.add_theme_constant_override("margin_top", 18)
	margin.add_theme_constant_override("margin_right", 18)
	margin.add_theme_constant_override("margin_bottom", 18)
	holder.add_child(margin)

	var scroll := ScrollContainer.new()
	scroll.horizontal_scroll_mode = ScrollContainer.SCROLL_MODE_DISABLED
	scroll.vertical_scroll_mode = ScrollContainer.SCROLL_MODE_AUTO
	scroll.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	scroll.size_flags_vertical = Control.SIZE_EXPAND_FILL
	margin.add_child(scroll)

	_grid = GridContainer.new()
	_grid.columns = 4
	_grid.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	_grid.add_theme_constant_override("h_separation", 24)
	_grid.add_theme_constant_override("v_separation", 24)
	scroll.add_child(_grid)
	return holder

func _buildFooter() -> Control:
	var footer := HBoxContainer.new()
	footer.custom_minimum_size = Vector2(0, 34)
	footer.alignment = BoxContainer.ALIGNMENT_CENTER

	_statusLabel = Label.new()
	_statusLabel.text = "靠近招募看板按 E 打开，点击课程卡片进入详情"
	_statusLabel.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	_statusLabel.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	_statusLabel.add_theme_font_size_override("font_size", 16)
	_statusLabel.add_theme_color_override("font_color", MUTED_COLOR)
	footer.add_child(_statusLabel)
	return footer

func _fetchCourses() -> void:
	_statusLabel.text = "正在同步 Datawhale 课程..."
	_clearChildren(_grid)
	var err := _request.request("%s%s" % [NetworkConfig.get_api_base_url(), API_PATH])
	if err != OK:
		_statusLabel.text = "课程加载失败：%s" % error_string(err)

func _onRequestCompleted(result: int, responseCode: int, _headers: PackedStringArray, body: PackedByteArray) -> void:
	if result != HTTPRequest.RESULT_SUCCESS or responseCode < 200 or responseCode >= 300:
		_statusLabel.text = "课程加载失败，请稍后再试"
		return

	var parsed: Variant = JSON.parse_string(body.get_string_from_utf8())
	if not parsed is Dictionary:
		_statusLabel.text = "课程数据解析失败"
		return

	var payload: Dictionary = parsed as Dictionary
	if not bool(payload.get("success", true)):
		_statusLabel.text = str(payload.get("message", "课程加载失败"))
		return

	var data: Variant = payload.get("data", {})
	if not data is Dictionary:
		_statusLabel.text = "课程数据为空"
		return

	var coursesVariant: Variant = (data as Dictionary).get("courses", [])
	if not coursesVariant is Array:
		_statusLabel.text = "课程数据为空"
		return

	var courses: Array = coursesVariant as Array
	_renderCourses(courses)
	_statusLabel.text = "已同步 %d 门课程" % courses.size()

func _renderCourses(rows: Array) -> void:
	_clearChildren(_grid)
	for row in rows:
		if row is Dictionary:
			_grid.add_child(_buildCourseCard(row as Dictionary))

func _buildCourseCard(course: Dictionary) -> Button:
	var card := Button.new()
	card.custom_minimum_size = CARD_SIZE
	card.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	card.focus_mode = Control.FOCUS_NONE
	card.clip_contents = true
	card.mouse_default_cursor_shape = Control.CURSOR_POINTING_HAND
	card.add_theme_stylebox_override("normal", _createCardStyle(false))
	card.add_theme_stylebox_override("hover", _createCardStyle(true))
	card.add_theme_stylebox_override("pressed", _createCardStyle(true))
	card.add_theme_stylebox_override("focus", StyleBoxEmpty.new())
	card.pressed.connect(_openCourse.bind(course))

	var root := VBoxContainer.new()
	root.set_anchors_preset(Control.PRESET_FULL_RECT)
	root.add_theme_constant_override("separation", 0)
	root.mouse_filter = Control.MOUSE_FILTER_IGNORE
	card.add_child(root)

	var coverPanel := Control.new()
	coverPanel.custom_minimum_size = Vector2(0, COVER_HEIGHT)
	coverPanel.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	coverPanel.clip_contents = true
	coverPanel.mouse_filter = Control.MOUSE_FILTER_IGNORE
	root.add_child(coverPanel)

	var coverBg := ColorRect.new()
	coverBg.set_anchors_preset(Control.PRESET_FULL_RECT)
	coverBg.color = IMAGE_PLACEHOLDER
	coverBg.mouse_filter = Control.MOUSE_FILTER_IGNORE
	coverPanel.add_child(coverBg)

	var coverImage := TextureRect.new()
	coverImage.set_anchors_preset(Control.PRESET_FULL_RECT)
	coverImage.expand_mode = TextureRect.EXPAND_IGNORE_SIZE
	coverImage.stretch_mode = TextureRect.STRETCH_KEEP_ASPECT_COVERED
	coverImage.mouse_filter = Control.MOUSE_FILTER_IGNORE
	coverPanel.add_child(coverImage)

	var coverText := Label.new()
	coverText.text = _shortTitle(str(course.get("title", "课程")))
	coverText.set_anchors_preset(Control.PRESET_FULL_RECT)
	coverText.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	coverText.vertical_alignment = VERTICAL_ALIGNMENT_CENTER
	coverText.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	coverText.add_theme_font_size_override("font_size", 22)
	coverText.add_theme_color_override("font_color", ACCENT_COLOR)
	coverText.mouse_filter = Control.MOUSE_FILTER_IGNORE
	coverPanel.add_child(coverText)
	_loadCoverImage(str(course.get("coverUrl", "")), coverImage, coverText)

	var bodyMargin := MarginContainer.new()
	bodyMargin.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	bodyMargin.size_flags_vertical = Control.SIZE_EXPAND_FILL
	bodyMargin.add_theme_constant_override("margin_left", 16)
	bodyMargin.add_theme_constant_override("margin_top", 16)
	bodyMargin.add_theme_constant_override("margin_right", 16)
	bodyMargin.add_theme_constant_override("margin_bottom", 30)
	bodyMargin.mouse_filter = Control.MOUSE_FILTER_IGNORE
	root.add_child(bodyMargin)

	var info := VBoxContainer.new()
	info.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	info.size_flags_vertical = Control.SIZE_EXPAND_FILL
	info.clip_contents = true
	info.add_theme_constant_override("separation", 6)
	info.mouse_filter = Control.MOUSE_FILTER_IGNORE
	bodyMargin.add_child(info)

	var title := Label.new()
	title.text = str(course.get("title", "未命名课程"))
	title.custom_minimum_size = Vector2(0, 46)
	title.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	title.vertical_alignment = VERTICAL_ALIGNMENT_CENTER
	title.text_overrun_behavior = TextServer.OVERRUN_TRIM_ELLIPSIS
	title.add_theme_font_size_override("font_size", 18)
	title.add_theme_color_override("font_color", TEXT_COLOR)
	title.mouse_filter = Control.MOUSE_FILTER_IGNORE
	info.add_child(title)

	var intro := Label.new()
	intro.text = str(course.get("intro", ""))
	intro.custom_minimum_size = Vector2(0, 58)
	intro.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	intro.text_overrun_behavior = TextServer.OVERRUN_TRIM_ELLIPSIS
	intro.add_theme_font_size_override("font_size", 13)
	intro.add_theme_color_override("font_color", MUTED_COLOR)
	intro.mouse_filter = Control.MOUSE_FILTER_IGNORE
	info.add_child(intro)

	var spacer := Control.new()
	spacer.size_flags_vertical = Control.SIZE_EXPAND_FILL
	info.add_child(spacer)

	var meta := HFlowContainer.new()
	meta.custom_minimum_size = Vector2(0, 34)
	meta.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	meta.add_theme_constant_override("h_separation", 6)
	meta.add_theme_constant_override("v_separation", 6)
	meta.mouse_filter = Control.MOUSE_FILTER_IGNORE
	info.add_child(meta)
	meta.add_child(_buildTag(str(course.get("difficultyLabel", "其他")), Color(0.918, 0.960, 1.0, 1.0), ACCENT_COLOR, 56.0))
	meta.add_child(_buildTag(str(course.get("categoryLabel", "其他")), Color(0.945, 0.950, 0.965, 1.0), MUTED_COLOR, 112.0))

	var views := int(course.get("viewCount", 0))
	if views > 0:
		meta.add_child(_buildTag(_formatViews(views), Color(0.950, 0.980, 0.965, 1.0), Color(0.160, 0.510, 0.340), 82.0))

	return card

func _buildTag(text: String, bgColor: Color, fontColor: Color, maxWidth: float) -> Label:
	var tag := Label.new()
	tag.text = text
	tag.custom_minimum_size = Vector2(maxWidth, 26)
	tag.clip_text = true
	tag.text_overrun_behavior = TextServer.OVERRUN_TRIM_ELLIPSIS
	tag.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	tag.vertical_alignment = VERTICAL_ALIGNMENT_CENTER
	tag.add_theme_font_size_override("font_size", 12)
	tag.add_theme_color_override("font_color", fontColor)
	tag.add_theme_stylebox_override("normal", _createPanelStyle(bgColor, 12, false))
	tag.mouse_filter = Control.MOUSE_FILTER_IGNORE
	return tag

func _loadCoverImage(url: String, textureRect: TextureRect, fallbackLabel: Label) -> void:
	var coverUrl := url.strip_edges()
	if coverUrl.is_empty():
		return

	var request := HTTPRequest.new()
	request.timeout = 12.0
	request.request_completed.connect(_onCoverRequestCompleted.bind(textureRect, fallbackLabel, request))
	add_child(request)
	var err := request.request(coverUrl)
	if err != OK:
		request.queue_free()

func _onCoverRequestCompleted(result: int, responseCode: int, _headers: PackedStringArray, body: PackedByteArray, textureRect: TextureRect, fallbackLabel: Label, request: HTTPRequest) -> void:
	if is_instance_valid(request):
		request.queue_free()
	if not is_instance_valid(textureRect):
		return
	if result != HTTPRequest.RESULT_SUCCESS or responseCode < 200 or responseCode >= 300:
		return

	var image := Image.new()
	var loadError := image.load_png_from_buffer(body)
	if loadError != OK:
		loadError = image.load_jpg_from_buffer(body)
	if loadError != OK:
		loadError = image.load_webp_from_buffer(body)
	if loadError != OK:
		return

	textureRect.texture = ImageTexture.create_from_image(image)
	if is_instance_valid(fallbackLabel):
		fallbackLabel.visible = false

func _openCourse(course: Dictionary) -> void:
	var detailUrl := str(course.get("detailUrl", "")).strip_edges()
	if detailUrl.is_empty():
		return
	OS.shell_open(detailUrl)

func _onOverlayGuiInput(event: InputEvent) -> void:
	if event is InputEventMouseButton:
		var mouseEvent := event as InputEventMouseButton
		if mouseEvent.pressed and mouseEvent.button_index == MOUSE_BUTTON_LEFT:
			hide_panel()

func _positionPanel() -> void:
	var viewportSize := get_viewport_rect().size
	var width := minf(PANEL_SIZE.x, maxf(980.0, viewportSize.x - MIN_MARGIN.x * 2.0))
	var height := minf(PANEL_SIZE.y, maxf(760.0, viewportSize.y - MIN_MARGIN.y * 2.0))
	_panel.position = (viewportSize - Vector2(width, height)) * 0.5
	_panel.size = Vector2(width, height)
	_panel.pivot_offset = _panel.size * 0.5

func _animatePanel(opening: bool) -> void:
	if is_instance_valid(_transitionTween):
		_transitionTween.kill()
	_transitionTween = create_tween()
	_transitionTween.set_parallel(true)
	if opening:
		_updatePanelAlpha(0.0, 0.0)
		_panel.scale = Vector2(0.985, 0.985)
		_transitionTween.tween_property(_overlay, "modulate:a", 1.0, 0.16)
		_transitionTween.tween_property(_panel, "modulate:a", 1.0, 0.18)
		_transitionTween.tween_property(_panel, "scale", Vector2.ONE, 0.18)
	else:
		_transitionTween.tween_property(_overlay, "modulate:a", 0.0, 0.12)
		_transitionTween.tween_property(_panel, "modulate:a", 0.0, 0.12)
		_transitionTween.tween_property(_panel, "scale", Vector2(0.985, 0.985), 0.12)
		_transitionTween.finished.connect(_onCloseAnimationFinished)

func _onCloseAnimationFinished() -> void:
	if _isOpen:
		return
	visible = false
	mouse_filter = Control.MOUSE_FILTER_IGNORE
	set_process(false)

func _updatePanelAlpha(overlayAlpha: float, panelAlpha: float) -> void:
	if is_instance_valid(_overlay):
		_overlay.modulate.a = overlayAlpha
	if is_instance_valid(_panel):
		_panel.modulate.a = panelAlpha

func _releaseMovementInputState() -> void:
	Input.flush_buffered_events()
	_releaseMovementActions()

func _releaseMovementActions() -> void:
	for action in MOVEMENT_ACTIONS:
		Input.action_release(action)

func _clearChildren(node: Node) -> void:
	for child in node.get_children():
		child.queue_free()

func _shortTitle(title: String) -> String:
	var trimmed := title.strip_edges()
	if trimmed.length() <= 8:
		return trimmed
	return trimmed.substr(0, 8)

func _formatViews(views: int) -> String:
	if views >= 10000:
		var wan := float(views) / 10000.0
		return "%.1f万看过" % wan
	return "%d人看过" % views

func _createPanelStyle(color: Color, radius: int, shadow: bool) -> StyleBoxFlat:
	var style := StyleBoxFlat.new()
	style.bg_color = color
	style.corner_radius_top_left = radius
	style.corner_radius_top_right = radius
	style.corner_radius_bottom_left = radius
	style.corner_radius_bottom_right = radius
	style.content_margin_left = 10
	style.content_margin_top = 7
	style.content_margin_right = 10
	style.content_margin_bottom = 7
	if shadow:
		style.shadow_color = Color(0.030, 0.120, 0.250, 0.18)
		style.shadow_size = 16
		style.shadow_offset = Vector2(0, 5)
	return style

func _createButtonStyle(color: Color) -> StyleBoxFlat:
	var style := _createPanelStyle(color, 18, false)
	style.content_margin_left = 0
	style.content_margin_top = 0
	style.content_margin_right = 0
	style.content_margin_bottom = 0
	return style

func _createCardStyle(hover: bool) -> StyleBoxFlat:
	var style := _createPanelStyle(Color.WHITE if not hover else Color(0.986, 0.996, 1.0, 1.0), 18, false)
	style.border_width_left = 2
	style.border_width_top = 2
	style.border_width_right = 2
	style.border_width_bottom = 2
	style.border_color = Color(0.815, 0.890, 0.960, 0.92) if not hover else Color(0.000, 0.322, 0.851, 0.72)
	style.shadow_color = Color(0.040, 0.150, 0.300, 0.08 if not hover else 0.14)
	style.shadow_size = 4 if not hover else 8
	style.shadow_offset = Vector2(0, 3)
	return style