import { _decorator, Node, Button, Label, ScrollView, instantiate, UITransform } from 'cc';
import { BaseView } from 'db://assets/scripts/core/BaseView';
import { ViewManager } from 'db://assets/scripts/core/ViewManager';
import { CompletedLevelsManager } from 'db://assets/scripts/utils/CompletedLevelsManager';
import { PreviewLevelItem } from './PreviewLevelItem';
const { ccclass, property } = _decorator;

/**
 * 预览试卷页面
 * 垂直滚动展示用户在 PageWriteLevels 中选中的 6 个关卡
 * 每个关卡展示：封面图、线索1、线索2、线索3、答案
 *
 * 节点结构（仅 ScrollView 侧需要固定）:
 *   PagePreviewLevels
 *     ├── ScrollView / view / content   ← listContent 容器
 *     └── ListTpl                       ← listTemplate 模板根节点
 *                                         (挂 PreviewLevelItem 组件，字段由编辑器拖拽绑定)
 *
 * item 内部节点层级/命名对本文件透明：所有引用都来自 PreviewLevelItem 的 @property。
 */

/** 布局配置 — 垂直列表 */
const LAYOUT = {
    /** 关卡项高度（与 ListTpl UITransform 高度一致） */
    ITEM_HEIGHT: 300,
    /** 关卡项之间的垂直间距 */
    SPACING_Y: 30,
    /** 列表顶部内边距 */
    PADDING_TOP: 20,
};

@ccclass('PagePreviewLevels')
export class PagePreviewLevels extends BaseView {
    @property({ type: Node, tooltip: '返回按钮(左上角)' })
    backBtn: Node | null = null;

    @property({ type: Node, tooltip: 'ScrollView 节点' })
    scrollView: Node | null = null;

    @property({ type: Node, tooltip: '列表 content 节点' })
    listContent: Node | null = null;

    @property({ type: Node, tooltip: '关卡模板节点' })
    listTemplate: Node | null = null;

    @property({ type: Node, tooltip: '底部返回按钮' })
    backButton: Node | null = null;

    @property({ type: Node, tooltip: '标题Label节点' })
    pkTitle: Node | null = null;

    /** 已创建的 item 节点列表 */
    private _itemNodes: Node[] = [];

    // ─── 生命周期 ───────────────────────────────────────

    onViewLoad(): void {
        console.log('[PagePreviewLevels] onViewLoad');
        this._initButtons();
        this._initScrollView();
    }

    onViewShow(): void {
        console.log('[PagePreviewLevels] onViewShow');
        this._buildList();
    }

    onViewHide(): void {
        console.log('[PagePreviewLevels] onViewHide');
    }

    onViewDestroy(): void {
        console.log('[PagePreviewLevels] onViewDestroy');
        this._offButtons();
        this._clearList();
    }

    // ─── 初始化 ─────────────────────────────────────────

    private _initButtons(): void {
        if (this.backBtn) {
            this.backBtn.on(Button.EventType.CLICK, this._onBackClick, this);
        }
        if (this.backButton) {
            this.backButton.on(Button.EventType.CLICK, this._onBackClick, this);
        }
    }

    private _offButtons(): void {
        if (this.backBtn) {
            this.backBtn.off(Button.EventType.CLICK, this._onBackClick, this);
        }
        if (this.backButton) {
            this.backButton.off(Button.EventType.CLICK, this._onBackClick, this);
        }
    }

    private _initScrollView(): void {
        if (!this.listContent) return;
        const contentTransform = this.listContent.getComponent(UITransform);
        if (contentTransform) {
            contentTransform.setAnchorPoint(0.5, 1);
        }
    }

    // ─── 列表构建 ───────────────────────────────────────

    private _buildList(): void {
        this._clearList();

        const params = this.getParams();
        if (!params || !params.selectedIndices || params.selectedIndices.length === 0) {
            console.warn('[PagePreviewLevels] 未传入选中关卡数据');
            return;
        }

        // 显示用户输入的标题
        if (this.pkTitle) {
            const label = this.pkTitle.getComponent(Label);
            if (label) {
                label.string = params.shareTitle || '挑战';
            }
        }

        const indices: number[] = params.selectedIndices;
        console.log('[PagePreviewLevels] 选中关卡索引:', indices);

        // 更新 content 高度
        this._updateContentSize(indices.length);

        // 创建每个关卡 item
        for (let i = 0; i < indices.length; i++) {
            const levelIndex = indices[i];
            const itemNode = this._createItem(i);
            if (itemNode) {
                this.listContent!.addChild(itemNode);
                this._itemNodes.push(itemNode);
                this._loadLevelData(itemNode, levelIndex, i);
            }
        }

        // 滚动到顶部
        const scrollComp = this.scrollView?.getComponent(ScrollView);
        if (scrollComp) {
            scrollComp.scrollToTop(0);
        }
    }

    private _clearList(): void {
        for (const node of this._itemNodes) {
            if (node && node.isValid) {
                node.destroy();
            }
        }
        this._itemNodes = [];
    }

    private _updateContentSize(count: number): void {
        if (!this.listContent) return;
        const contentTransform = this.listContent.getComponent(UITransform);
        if (!contentTransform) return;

        const totalHeight = LAYOUT.PADDING_TOP
            + count * LAYOUT.ITEM_HEIGHT
            + (count > 0 ? (count - 1) * LAYOUT.SPACING_Y : 0)
            + LAYOUT.PADDING_TOP;

        contentTransform.setContentSize(contentTransform.contentSize.width, totalHeight);
    }

    /**
     * 创建单个关卡展示项
     * content anchor=(0.5, 1)，y 轴负向下
     */
    private _createItem(displayIndex: number): Node | null {
        if (!this.listTemplate) return null;

        const item = instantiate(this.listTemplate);
        item.active = true;
        item.name = `preview_item_${displayIndex}`;

        // 垂直居中排列：x=0（水平居中于 content），y 负向下
        const y = -(LAYOUT.PADDING_TOP + displayIndex * (LAYOUT.ITEM_HEIGHT + LAYOUT.SPACING_Y) + LAYOUT.ITEM_HEIGHT / 2);
        item.setPosition(0, y, 0);

        return item;
    }

    /**
     * 异步加载关卡数据并填充到 item 节点
     */
    private async _loadLevelData(item: Node, levelIndex: number, displayIndex: number): Promise<void> {
        const level = CompletedLevelsManager.instance.getByIndex(levelIndex);
        if (!level || !item.isValid) return;

        const view = item.getComponent(PreviewLevelItem);
        if (!view) {
            console.warn('[PagePreviewLevels] listTemplate 缺少 PreviewLevelItem 组件');
            return;
        }

        view.setTexts({
            answer: level.answer || '',
            hint1: level.hint1 || '',
            hint2: level.hint2 || '',
            hint3: level.hint3 || '',
        });

        // 异步加载封面图（通常已由 WriteLevels 预热到缓存）
        const spriteFrame = await CompletedLevelsManager.instance.loadImage(level.image1Url);
        if (!spriteFrame || !item.isValid) return;
        view.setCover(spriteFrame);
    }

    // ─── 事件处理 ───────────────────────────────────────

    private _onBackClick(): void {
        console.log('[PagePreviewLevels] 返回');
        ViewManager.instance.back();
    }
}