import { appSharePageMethods } from '../../base/pageMixin';
import { NAV_INNER_PX } from '../../utils/navMetrics';
import {
    parseMiniProgramUrl,
    stashPendingCategoryTabId,
} from '../../utils/index';
import {
    HOME_DAILY_CHECKIN_ITEMS,
    HOME_NOTICES,
    createEmptyHomeDataset,
    type HomeDisplayItem,
    type HomeDisplaySection,
    type HomeDisplayDataset,
} from './home.data';

type AgeBandKey = string;

type HomeTab = {
    id: string;
    name: string;
};

type HomeAgeBandView = {
    key: string;
    label: string;
    desc: string;
    path: string;
    icon: string;
};

type HomeDisplayItemView = HomeDisplayItem & {
    skeleton?: boolean;
};

type HomeDisplaySectionView = HomeDisplaySection & {
    anchorId: string;
    items: HomeDisplayItemView[];
};

const AGE_BAND_ICONS = ['🌱', '🚀', '🎓', '🧠', '🏆'] as const;

const SECTION_ANCHOR_PREFIX = 'section-';
const TAB_BAR_PATHS = new Set([
    '/pages/home/home',
    '/pages/category/category',
    '/pages/age/age',
    '/pages/favorites/favorites',
    '/pages/profile/profile',
]);

function toItemView(item: HomeDisplayItem): HomeDisplayItemView {
    return {
        ...item,
    };
}

function sortSectionsByTabs(
    tabs: readonly { id: string }[],
    sections: HomeDisplaySection[],
): HomeDisplaySectionView[] {
    const orderMap = tabs.reduce<Record<string, number>>((acc, tab, index) => {
        acc[tab.id] = index;
        return acc;
    }, {});

    return [...sections]
        .sort((a, b) => (orderMap[a.id] ?? 999) - (orderMap[b.id] ?? 999))
        .map((section) => ({
            ...section,
            anchorId: `${SECTION_ANCHOR_PREFIX}${section.id}`,
            items: section.items.map(toItemView),
        }));
}

let _navigating = false;

function releaseNavigateLock() {
    _navigating = false;
}

function navigateByPath(path?: string, fallbackTitle?: string) {
    if (_navigating) return;

    if (!path) {
        wx.showToast({
            title: fallbackTitle ? `${fallbackTitle} 即将上线` : '即将上线',
            icon: 'none',
        });
        return;
    }

    const { path: basePath, query } = parseMiniProgramUrl(path);

    if (TAB_BAR_PATHS.has(basePath)) {
        if (
            basePath === '/pages/category/category' &&
            query.id &&
            String(query.id).trim() !== ''
        ) {
            stashPendingCategoryTabId(String(query.id).trim());
        } else if (Object.keys(query).length > 0) {
            console.warn(
                '[navigateByPath] tabBar 不支持携带参数，已忽略 query:',
                basePath,
                query,
            );
        }
        _navigating = true;
        wx.switchTab({
            url: basePath,
            complete: releaseNavigateLock,
            fail: releaseNavigateLock,
        });
        return;
    }
    _navigating = true;
    wx.navigateTo({
        url: path,
        complete: releaseNavigateLock,
        fail: (err) => {
            console.error('navigateByPath error:', err);
            releaseNavigateLock();
        },
    });
}

// ── Skeleton data ──

function skeletonItem(id: string): HomeDisplayItemView {
    return {
        id,
        title: '\u00A0',
        subtitle: '\u00A0',
        category: 'math' as any,
        ageBand: '',
        difficulty: '基础',
        icon: '',
        path: '',
        available: false,
        skeleton: true,
    };
}

const SKELETON_FEATURED = Array.from({ length: 3 }, (_, i) =>
    skeletonItem(`skeleton-featured-${i}`),
);
const SKELETON_HOT = Array.from({ length: 3 }, (_, i) =>
    skeletonItem(`skeleton-hot-${i}`),
);

const win = wx.getWindowInfo();

// Page-level mutable state
let _homeData: HomeDisplayDataset | null = null;

function applyHomeData(data: HomeDisplayDataset) {
    _homeData = data;

    const sectionsWithItems = data.sections.filter(
        (section) => section.items.length > 0,
    );
    const sectionIdsWithItems = new Set(
        sectionsWithItems.map((section) => section.id),
    );

    const tabs: HomeTab[] = data.categoryTabs
        .filter((tab) => tab.id === 'all' || sectionIdsWithItems.has(tab.id))
        .map((tab) => ({
            id: tab.id,
            name: tab.name,
        }));

    const sections = sortSectionsByTabs(tabs, sectionsWithItems);
    const ageBands: HomeAgeBandView[] = data.ageBands.map((item, idx) => ({
        ...item,
        icon: AGE_BAND_ICONS[idx] || '🌟',
    }));

    return { tabs, sections, ageBands };
}

Page({
    data: {
        searchPlaceholder: '搜索你喜欢的练习册...',
        tabs: [] as HomeTab[],
        activeTab: 'all',
        ageBands: [] as HomeAgeBandView[],
        activeAgeBand: '3-4' as AgeBandKey,
        heroSwiperCurrent: 0,
        featuredItems: SKELETON_FEATURED,
        hotRecommends: SKELETON_HOT,
        dailyCheckinItems: HOME_DAILY_CHECKIN_ITEMS.map(toItemView),
        sections: [] as HomeDisplaySectionView[],
        notices: HOME_NOTICES,
        loading: true,
    },

    onLoad() {
        void this.initData();
    },

    async initData() {
        wx.showLoading({ title: '加载中', mask: false });

        const app = getApp<IAppOption>();
        const config = await app.getPageConfig();

        let homeData: HomeDisplayDataset;

        if (config?.home) {
            // Cloud config available — map to HomeDisplayDataset
            const raw = config.home as Record<string, any>;
            homeData = {
                searchPlaceholder:
                    raw.searchPlaceholder || '搜索你喜欢的练习册...',
                categoryTabs: raw.categoryTabs || [],
                ageBands: raw.ageBands || [],
                featured: (raw.featured || []) as HomeDisplayItem[],
                hot: (raw.hot || []) as HomeDisplayItem[],
                sections: (raw.sections || []) as HomeDisplaySection[],
            };
        } else {
            homeData = createEmptyHomeDataset();
        }

        const { tabs, sections, ageBands } = applyHomeData(homeData);

        this.setData({
            loading: false,
            searchPlaceholder: homeData.searchPlaceholder,
            tabs,
            ageBands,
            activeAgeBand: homeData.ageBands[0]?.key || '3-4',
            featuredItems: homeData.featured.map(toItemView),
            hotRecommends: homeData.hot.slice(0, 3).map(toItemView),
            sections,
        });

        wx.hideLoading();
    },

    // ── Tab & Navigation ──

    onHeroSwiperChange(e: WechatMiniprogram.SwiperChange) {
        this.setData({ heroSwiperCurrent: e.detail.current });
    },

    onTabChange(e: WechatMiniprogram.CustomEvent) {
        const id = e.detail.id as string | undefined;
        if (!id) return;

        this.setData({ activeTab: id });

        if (id === 'all') {
            wx.pageScrollTo({ scrollTop: 0, duration: 400 });
            return;
        }

        wx.pageScrollTo({
            selector: `#${SECTION_ANCHOR_PREFIX}${id}`,
            duration: 400,
            offsetTop: -(win.statusBarHeight + NAV_INNER_PX + 24),
        });
    },

    onTapAgeBand(e: WechatMiniprogram.TouchEvent) {
        const key = e.currentTarget.dataset.key as AgeBandKey | undefined;
        const path = e.currentTarget.dataset.path as string | undefined;
        if (!key) return;
        this.setData({ activeAgeBand: key });
        navigateByPath(path, '分龄内容');
    },

    onTapFeatured(e: WechatMiniprogram.TouchEvent) {
        const path = e.currentTarget.dataset.path as string | undefined;
        const title = e.currentTarget.dataset.title as string | undefined;
        navigateByPath(path, title);
    },

    onTapHotRecommend(e: WechatMiniprogram.TouchEvent) {
        const path = e.currentTarget.dataset.path as string | undefined;
        const title = e.currentTarget.dataset.title as string | undefined;
        navigateByPath(path, title);
    },

    onTapAgeMore() {
        wx.switchTab({ url: '/pages/age/age' });
    },

    onTapHotMore() {
        navigateByPath('/pages/category/category?id=hot');
    },

    onTapTrackMore(e: WechatMiniprogram.TouchEvent) {
        const path = e.currentTarget.dataset.path as string | undefined;
        const title = e.currentTarget.dataset.title as string | undefined;
        navigateByPath(path, title);
    },

    onTapNotice(e: WechatMiniprogram.TouchEvent) {
        const path = e.currentTarget.dataset.path as string | undefined;
        if (!path) return;
        navigateByPath(path);
    },

    onTapCard(e: WechatMiniprogram.CustomEvent) {
        const detail = (e.detail || {}) as { title?: string; path?: string };
        const path =
            detail.path || (e.currentTarget.dataset.path as string | undefined);
        const title =
            detail.title ||
            (e.currentTarget.dataset.title as string | undefined);
        navigateByPath(path, title);
    },

    ...appSharePageMethods,
});