/**
 * 首页布局纯函数模块（docs/16 主线B §4.1/§4.5）。
 * 布局存 config_json.home_layout（零 DDL）：{version:1, blocks:[…]}；无该键 = 回落现状渲染（老站零迁移）。
 * 与后端契约对齐：type 白名单（article_list/ticker/gallery/links/quick_links/notice_bar）、size 1~20、
 * title/subtitle ≤100 字、quick_links items ≤12 项（name ≤20 字、url 须 http(s):// 或 / 开头）、
 * notice_bar text 必填 ≤200 字、level ∈ {info,warn}；
 * 服务端 SiteService.validateHomeLayout 强校验，本模块做编辑端同语义校验与往返装拆。
 * vitest 单测对象：homeLayout.spec.ts，不依赖组件挂载基建。
 */
import { CategoryTreeNode } from "@/types/cms";

/** 区块类型白名单（与后端 SiteService HOME_LAYOUT_BLOCK_TYPES 一致；docs/20 D 新增后 12 种） */
export type BlockType =
    | "article_list" | "ticker" | "gallery" | "links" | "quick_links" | "notice_bar"
    // docs/20 D-1~D-9
    | "stats_band" | "featured_topics" | "video_tour" | "events" | "people" | "badges";

/** quick_links 单个入口（v2 手册 §2.8；D-2 加可选 icon 内置图标标识符） */
export interface QuickLinkItem {
    name: string;
    url: string;
    icon?: string;
}

/** stats_band 单个统计项（D-1：数字计数带） */
export interface StatItem {
    label: string;
    value: string;
    unit?: string;
    icon?: string;
}

/** featured_topics 单张专题卡（D-3） */
export interface TopicItem {
    title: string;
    description?: string;
    image: string;
    ctaText?: string;
    ctaUrl?: string;
}

/** badges 单个徽章（D-9） */
export interface BadgeItem {
    label: string;
    desc?: string;
    image: string;
}

/** article_list 展示形态（与后端渲染端 style 分支及主题 fragment 对应） */
export const LIST_STYLES: { value: string; label: string }[] = [
    { value: "card", label: "默认卡（头条+列表）" },
    { value: "news_grid", label: "双栏新闻卡" },
    { value: "media_focus", label: "媒体聚焦" },
    { value: "compact", label: "纯文字列表" },
    { value: "image_wall", label: "图片墙（有封面文章）" },
];

export function styleLabel(style: string | undefined): string {
    return LIST_STYLES.find(s => s.value === style)?.label || "默认卡（头条+列表）";
}

/** 布局区块（编辑器内存形态：含 visible 运行时键；序列化时仅落业务键） */
export interface LayoutBlock {
    id: string;
    type: BlockType;
    /** false = 保序下线（渲染端跳过） */
    visible: boolean;
    title?: string;
    /** gallery 英文副题 */
    subtitle?: string;
    /** article_list / ticker(source=category)：数据栏目（可多选，渲染端聚合子孙） */
    categoryIds?: number[];
    /** article_list 展示形态，缺省 card */
    style?: string;
    /** 条数（article_list 缺省 8、ticker 缺省 6；gallery 不设 = 全部） */
    size?: number;
    /** article_list news_grid 背景大图开关（取站点配置 news_bg_image 旧键） */
    background?: boolean;
    /** ticker 数据源：top=全站置顶（缺省）| category=指定栏目最新 */
    source?: string;
    /** links 分组名（空=全部分组） */
    group?: string;
    /** quick_links 入口列表（≤12 项；name ≤20 字、url 为 http(s):// 或站内 / 路径） */
    items?: QuickLinkItem[];
    /** notice_bar 公告正文（必填，≤200 字） */
    text?: string;
    /** notice_bar 跳转地址（可选） */
    url?: string;
    /** notice_bar 提示级别：info=一般（缺省）| warn=醒目 */
    level?: string;
    // ===== docs/20 D 组件库新增字段 =====
    /** gallery 布局（D-8）：grid 规整网格（缺省）| masonry 瀑布流 */
    layout?: string;
    /** quick_links 统一图标形状随主题参数，不落区块 */
    /** stats_band 统计项（D-1，1~8 项） */
    stats?: StatItem[];
    /** featured_topics 专题卡（D-3，编辑器模型；序列化键为 items，与后端契约对齐） */
    topicItems?: TopicItem[];
    /** video_tour（D-5） */
    cover?: string;
    /** people 数据栏目（D-7，可空 = 全部人物） */
    categoryId?: number;
    /** badges 徽章（D-9，1~8 项） */
    badgeItems?: BadgeItem[];
}

export interface HomeLayout {
    version: number;
    blocks: LayoutBlock[];
}

export const HOME_LAYOUT_VERSION = 1;

/** 服务端同款约束（SiteService §4.6 + v2 手册 §2.8 + docs/20 D） */
export const BLOCK_TYPES_ALLOWED: BlockType[] = [
    "article_list", "ticker", "gallery", "links", "quick_links", "notice_bar",
    "stats_band", "featured_topics", "video_tour", "events", "people", "badges",
];
export const SIZE_MIN = 1;
export const SIZE_MAX = 20;
export const TITLE_MAX = 100;
export const MAX_BLOCKS = 30;
export const QUICK_LINK_MAX = 12;
export const LINK_NAME_MAX = 20;
export const NOTICE_TEXT_MAX = 200;
export const NOTICE_LEVELS = ["info", "warn"];
// ===== docs/20 D 组件库约束（与后端 SiteService 同契约） =====
export const STATS_MAX = 8;
export const TOPICS_MAX = 6;
export const BADGES_MAX = 8;
export const GALLERY_LAYOUTS = ["grid", "masonry"];
/** 内置图标标识符（D-2：与门户骨架 icon fragment 同 key 集） */
export const ICON_KEY_PATTERN = /^[a-z0-9-]{1,30}$/;
export const ASSET_URL_PATTERN = /^(\/.+|https?:\/\/\S+)$/;
/** 入口/跳转地址：http(s):// 绝对地址或站内 / 路径（与后端 HOME_LAYOUT_LINK_PATTERN 同语义） */
const LINK_URL_PATTERN = /^(https?:\/\/\S+|\/.+)$/;

export function genBlockId(): string {
    return "b_" + Math.random().toString(36).slice(2, 8) + Date.now().toString(36).slice(-4);
}

function asObject(v: unknown): Record<string, unknown> | null {
    return v && typeof v === "object" && !Array.isArray(v) ? (v as Record<string, unknown>) : null;
}

/**
 * configJson → 布局（容错解析）：无键 / 非法 JSON / home_layout 非对象 / blocks 非数组 → null（=回落现状）。
 * 单块收敛为已知字段（未知键丢弃）；type 不在白名单的块跳过。
 */
export function parseHomeLayout(configJson: string | undefined | null): HomeLayout | null {
    if (!configJson || !configJson.trim()) {
        return null;
    }
    let root: Record<string, unknown> | null = null;
    try {
        root = asObject(JSON.parse(configJson));
    } catch {
        return null;
    }
    if (!root) {
        return null;
    }
    const hl = asObject(root["home_layout"]);
    if (!hl || !Array.isArray(hl["blocks"])) {
        return null;
    }
    const blocks: LayoutBlock[] = [];
    for (const raw of hl["blocks"] as unknown[]) {
        const obj = asObject(raw);
        const type = typeof obj?.["type"] === "string" ? (obj["type"] as string) : "";
        if (!BLOCK_TYPES_ALLOWED.includes(type as BlockType)) {
            continue;
        }
        blocks.push(normalizeBlock(obj as Record<string, unknown>, type as BlockType));
    }
    return { version: typeof hl["version"] === "number" ? hl["version"] : HOME_LAYOUT_VERSION, blocks };
}

function toIdList(v: unknown): number[] | undefined {
    if (!Array.isArray(v)) {
        return undefined;
    }
    const ids = v.filter((x): x is number => typeof x === "number" && Number.isFinite(x));
    return ids.length ? ids : undefined;
}

/** 入口列表容错还原：非对象项（字符串/数字/null）与非字符串 name/url 的脏行整行丢弃 */
function toLinkItems(v: unknown): QuickLinkItem[] | undefined {
    if (!Array.isArray(v)) {
        return undefined;
    }
    const items: QuickLinkItem[] = [];
    for (const raw of v as unknown[]) {
        const obj = asObject(raw);
        const name = typeof obj?.["name"] === "string" ? (obj["name"] as string).trim() : null;
        const url = typeof obj?.["url"] === "string" ? (obj["url"] as string).trim() : null;
        if (name === null || url === null) {
            continue;
        }
        const item: QuickLinkItem = { name, url };
        if (typeof obj?.["icon"] === "string" && ICON_KEY_PATTERN.test(obj["icon"] as string)) {
            item.icon = obj["icon"] as string;
        }
        items.push(item);
    }
    return items.length ? items : undefined;
}

/** stats_band 统计项容错还原（D-1） */
function toStatItems(v: unknown): StatItem[] | undefined {
    if (!Array.isArray(v)) return undefined;
    const items: StatItem[] = [];
    for (const raw of v as unknown[]) {
        const obj = asObject(raw);
        const label = typeof obj?.["label"] === "string" ? (obj["label"] as string).trim() : "";
        const value = typeof obj?.["value"] === "string" ? (obj["value"] as string).trim() : "";
        if (!label || !value) continue;
        const item: StatItem = { label, value };
        if (typeof obj?.["unit"] === "string" && (obj["unit"] as string).trim()) item.unit = (obj["unit"] as string).trim();
        if (typeof obj?.["icon"] === "string" && ICON_KEY_PATTERN.test(obj["icon"] as string)) item.icon = obj["icon"] as string;
        items.push(item);
    }
    return items.length ? items : undefined;
}

/** featured_topics 专题卡容错还原（D-3） */
function toTopicItems(v: unknown): TopicItem[] | undefined {
    if (!Array.isArray(v)) return undefined;
    const items: TopicItem[] = [];
    for (const raw of v as unknown[]) {
        const obj = asObject(raw);
        const title = typeof obj?.["title"] === "string" ? (obj["title"] as string).trim() : "";
        const image = typeof obj?.["image"] === "string" ? (obj["image"] as string).trim() : "";
        if (!title || !image) continue;
        const item: TopicItem = { title, image };
        if (typeof obj?.["description"] === "string" && (obj["description"] as string).trim()) item.description = (obj["description"] as string).trim();
        if (typeof obj?.["ctaText"] === "string" && (obj["ctaText"] as string).trim()) item.ctaText = (obj["ctaText"] as string).trim();
        if (typeof obj?.["ctaUrl"] === "string" && (obj["ctaUrl"] as string).trim()) item.ctaUrl = (obj["ctaUrl"] as string).trim();
        items.push(item);
    }
    return items.length ? items : undefined;
}

/** badges 徽章容错还原（D-9，序列化键 badgeItems 防与 featured_topics.items 语义混淆） */
function toBadgeItems(v: unknown): BadgeItem[] | undefined {
    if (!Array.isArray(v)) return undefined;
    const items: BadgeItem[] = [];
    for (const raw of v as unknown[]) {
        const obj = asObject(raw);
        const label = typeof obj?.["label"] === "string" ? (obj["label"] as string).trim() : "";
        const image = typeof obj?.["image"] === "string" ? (obj["image"] as string).trim() : "";
        if (!label || !image) continue;
        const item: BadgeItem = { label, image };
        if (typeof obj?.["desc"] === "string" && (obj["desc"] as string).trim()) item.desc = (obj["desc"] as string).trim();
        items.push(item);
    }
    return items.length ? items : undefined;
}

function normalizeBlock(obj: Record<string, unknown>, type: BlockType): LayoutBlock {
    const size = typeof obj["size"] === "number" ? Math.round(obj["size"]) : undefined;
    const block: LayoutBlock = {
        id: typeof obj["id"] === "string" && obj["id"] ? obj["id"] : genBlockId(),
        type,
        visible: obj["visible"] !== false,
    };
    if (typeof obj["title"] === "string") block.title = obj["title"];
    if (typeof obj["subtitle"] === "string") block.subtitle = obj["subtitle"];
    if (typeof obj["style"] === "string") block.style = obj["style"];
    if (size !== undefined) block.size = size;
    if (typeof obj["background"] === "boolean") block.background = obj["background"];
    if (typeof obj["source"] === "string") block.source = obj["source"];
    if (typeof obj["group"] === "string") block.group = obj["group"];
    if (type === "quick_links") {
        const items = toLinkItems(obj["items"]);
        if (items) block.items = items;
    }
    if (type === "notice_bar") {
        if (typeof obj["text"] === "string") block.text = obj["text"];
        if (typeof obj["url"] === "string") block.url = obj["url"];
        if (typeof obj["level"] === "string") block.level = obj["level"];
    }
    // ===== docs/20 D =====
    if (typeof obj["layout"] === "string") block.layout = obj["layout"];
    if (typeof obj["cover"] === "string") block.cover = obj["cover"];
    if (typeof obj["categoryId"] === "number" && Number.isFinite(obj["categoryId"]) && (obj["categoryId"] as number) > 0) {
        block.categoryId = obj["categoryId"] as number;
    }
    if (type === "stats_band") {
        const stats = toStatItems(obj["stats"]);
        if (stats) block.stats = stats;
    }
    if (type === "featured_topics") {
        const items = toTopicItems(obj["items"]);
        if (items) block.topicItems = items;
    }
    if (type === "badges") {
        const items = toBadgeItems(obj["badgeItems"]);
        if (items) block.badgeItems = items;
    }
    const ids = toIdList(obj["categoryIds"]);
    if (ids) block.categoryIds = ids;
    return block;
}

/** 单块 → 序列化对象：只写与类型相关的业务键（visible 仅 false 时写，size 仅显式设置时写） */
export function cleanBlock(block: LayoutBlock): Record<string, unknown> {
    const out: Record<string, unknown> = { id: block.id, type: block.type };
    if (block.visible === false) {
        out["visible"] = false;
    }
    const title = (block.title || "").trim();
    if (title) {
        out["title"] = title;
    }
    if (block.type === "article_list") {
        if (block.categoryIds && block.categoryIds.length) {
            out["categoryIds"] = block.categoryIds;
        }
        if (block.style && block.style !== "card") {
            out["style"] = block.style;
        }
        if (block.size != null) {
            out["size"] = block.size;
        }
        if (block.background) {
            out["background"] = true;
        }
    } else if (block.type === "ticker") {
        if (block.source && block.source !== "top") {
            out["source"] = block.source;
        }
        if (block.categoryIds && block.categoryIds.length) {
            out["categoryIds"] = block.categoryIds;
        }
        if (block.size != null) {
            out["size"] = block.size;
        }
    } else if (block.type === "gallery") {
        const subtitle = (block.subtitle || "").trim();
        if (subtitle) {
            out["subtitle"] = subtitle;
        }
        if (block.layout === "masonry") {
            out["layout"] = "masonry";
        }
    } else if (block.type === "links") {
        const group = (block.group || "").trim();
        if (group) {
            out["group"] = group;
        }
    } else if (block.type === "quick_links") {
        // 编辑期允许存在未填写的空行，提交前整行剔除（后端要求 name/url 齐备）；icon 可选随行
        const items = (block.items || [])
            .map(i => {
                const row: Record<string, string> = { name: (i.name || "").trim(), url: (i.url || "").trim() };
                if (i.icon && ICON_KEY_PATTERN.test(i.icon)) {
                    row["icon"] = i.icon;
                }
                return row;
            })
            .filter(i => i["name"] || i["url"]);
        if (items.length) {
            out["items"] = items;
        }
    } else if (block.type === "notice_bar") {
        const text = (block.text || "").trim();
        if (text) {
            out["text"] = text;
        }
        const url = (block.url || "").trim();
        if (url) {
            out["url"] = url;
        }
        if (block.level === "warn") {
            out["level"] = "warn";
        }
    } else if (block.type === "stats_band") {
        const stats = (block.stats || []).filter(st => st.label.trim() && st.value.trim());
        if (stats.length) {
            out["stats"] = stats;
        }
    } else if (block.type === "featured_topics") {
        const items = (block.topicItems || []).filter(t => t.title.trim() && t.image.trim());
        if (items.length) {
            out["items"] = items;
        }
    } else if (block.type === "video_tour") {
        const cover = (block.cover || "").trim();
        const url = (block.url || "").trim();
        if (cover) out["cover"] = cover;
        if (url) out["url"] = url;
    } else if (block.type === "people") {
        if (block.categoryId) {
            out["categoryId"] = block.categoryId;
        }
    } else if (block.type === "badges") {
        const items = (block.badgeItems || []).filter(b => b.label.trim() && b.image.trim());
        if (items.length) {
            out["badgeItems"] = items;
        }
    }
    return out;
}

/**
 * 布局写回 configJson（仅增删改 home_layout 键，其余键原样保留）。
 * layout=null = 清除自定义布局（删除键，回到回落态）；空 blocks = 显式空首页（写空数组，不删键）。
 */
export function serializeHomeLayout(configJson: string | undefined | null, layout: HomeLayout | null): string {
    let config: Record<string, unknown> = {};
    if (configJson && configJson.trim()) {
        try {
            const parsed = JSON.parse(configJson);
            if (parsed && typeof parsed === "object" && !Array.isArray(parsed)) {
                config = { ...parsed };
            }
        } catch {
            // 非法 JSON 按空配置处理（与后端 ExtJsonUtils.parse 语义一致）
        }
    }
    if (!layout) {
        delete config["home_layout"];
    } else {
        config["home_layout"] = {
            version: layout.version || HOME_LAYOUT_VERSION,
            blocks: layout.blocks.map(cleanBlock),
        };
    }
    return JSON.stringify(config);
}

/** 校验返回错误消息列表（空数组=通过；与后端 validateHomeLayout 同语义） */
export function validateHomeLayout(layout: HomeLayout | null): string[] {
    const errors: string[] = [];
    if (!layout) {
        return errors;
    }
    if (layout.blocks.length > MAX_BLOCKS) {
        errors.push(`区块数量不能超过 ${MAX_BLOCKS} 个`);
    }
    layout.blocks.forEach((b, i) => {
        const no = `第 ${i + 1} 个区块（${b.title || b.type}）`;
        if (!BLOCK_TYPES_ALLOWED.includes(b.type)) {
            errors.push(`${no}：类型不合法`);
        }
        if ((b.title || "").trim().length > TITLE_MAX || (b.subtitle || "").trim().length > TITLE_MAX) {
            errors.push(`${no}：标题/副题不能超过 ${TITLE_MAX} 字`);
        }
        if (b.size != null && (b.size < SIZE_MIN || b.size > SIZE_MAX)) {
            errors.push(`${no}：条数须在 ${SIZE_MIN}~${SIZE_MAX} 之间`);
        }
        if (b.type === "article_list" && !(b.categoryIds && b.categoryIds.length)) {
            errors.push(`${no}：请选择数据栏目`);
        }
        if (b.type === "ticker" && b.source === "category" && !(b.categoryIds && b.categoryIds.length)) {
            errors.push(`${no}：指定栏目模式请选择栏目`);
        }
        if (b.type === "quick_links") {
            const items = b.items || [];
            if (!items.length) {
                errors.push(`${no}：请至少填写 1 个入口`);
            } else if (items.length > QUICK_LINK_MAX) {
                errors.push(`${no}：入口数量不能超过 ${QUICK_LINK_MAX} 个`);
            }
            items.forEach(item => {
                const name = (item.name || "").trim();
                const linkUrl = (item.url || "").trim();
                if (!name) {
                    errors.push(`${no}：入口名称不能为空`);
                } else if (name.length > LINK_NAME_MAX) {
                    errors.push(`${no}：入口名称不能超过 ${LINK_NAME_MAX} 字`);
                }
                if (!LINK_URL_PATTERN.test(linkUrl)) {
                    errors.push(`${no}：入口「${name || linkUrl}」地址须为 http(s):// 开头或站内路径（/ 开头）`);
                }
            });
        }
        if (b.type === "notice_bar") {
            const text = (b.text || "").trim();
            if (!text) {
                errors.push(`${no}：请填写公告正文`);
            } else if (text.length > NOTICE_TEXT_MAX) {
                errors.push(`${no}：公告正文不能超过 ${NOTICE_TEXT_MAX} 字`);
            }
            const linkUrl = (b.url || "").trim();
            if (linkUrl && !LINK_URL_PATTERN.test(linkUrl)) {
                errors.push(`${no}：跳转地址须为 http(s):// 开头或站内路径（/ 开头）`);
            }
            if (b.level != null && !NOTICE_LEVELS.includes(b.level)) {
                errors.push(`${no}：提示级别只能是 info 或 warn`);
            }
        }
        // ===== docs/20 D 组件校验（与后端 SiteService 同语义） =====
        if (b.type === "gallery" && b.layout != null && !GALLERY_LAYOUTS.includes(b.layout)) {
            errors.push(`${no}：画廊布局只能是 grid 或 masonry`);
        }
        if (b.type === "stats_band") {
            const stats = b.stats || [];
            if (!stats.length) {
                errors.push(`${no}：请至少填写 1 个统计项`);
            } else if (stats.length > STATS_MAX) {
                errors.push(`${no}：统计项不能超过 ${STATS_MAX} 个`);
            }
            stats.forEach(st => {
                const label = (st.label || "").trim();
                const value = (st.value || "").trim();
                if (!label) {
                    errors.push(`${no}：统计项名称不能为空`);
                } else if (label.length > 20) {
                    errors.push(`${no}：统计项名称不能超过 20 字`);
                }
                if (!value) {
                    errors.push(`${no}：统计项数值不能为空`);
                } else if (value.length > 10) {
                    errors.push(`${no}：统计项数值不能超过 10 字`);
                }
                if ((st.unit || "").length > 10) {
                    errors.push(`${no}：统计项单位不能超过 10 字`);
                }
                if (st.icon && !ICON_KEY_PATTERN.test(st.icon)) {
                    errors.push(`${no}：统计项图标标识不合法`);
                }
            });
        }
        if (b.type === "featured_topics") {
            const items = b.topicItems || [];
            if (!items.length) {
                errors.push(`${no}：请至少填写 1 张专题卡`);
            } else if (items.length > TOPICS_MAX) {
                errors.push(`${no}：专题卡不能超过 ${TOPICS_MAX} 张`);
            }
            items.forEach(t => {
                const title = (t.title || "").trim();
                const image = (t.image || "").trim();
                if (!title) {
                    errors.push(`${no}：专题卡标题不能为空`);
                } else if (title.length > 50) {
                    errors.push(`${no}：专题卡标题不能超过 50 字`);
                }
                if ((t.description || "").length > 200) {
                    errors.push(`${no}：专题卡描述不能超过 200 字`);
                }
                if (!image) {
                    errors.push(`${no}：专题卡必须上传图片`);
                } else if (!ASSET_URL_PATTERN.test(image)) {
                    errors.push(`${no}：专题卡图片须为上传路径（/ 开头）或 http(s) 地址`);
                }
                if ((t.ctaText || "").length > 20) {
                    errors.push(`${no}：按钮文字不能超过 20 字`);
                }
                const ctaUrl = (t.ctaUrl || "").trim();
                if (ctaUrl && !LINK_URL_PATTERN.test(ctaUrl)) {
                    errors.push(`${no}：按钮地址须为 http(s):// 开头或站内路径（/ 开头）`);
                }
            });
        }
        if (b.type === "video_tour") {
            const cover = (b.cover || "").trim();
            const url = (b.url || "").trim();
            if (!cover) {
                errors.push(`${no}：请上传视频封面图`);
            } else if (!ASSET_URL_PATTERN.test(cover)) {
                errors.push(`${no}：封面图须为上传路径（/ 开头）或 http(s) 地址`);
            }
            if (!url) {
                errors.push(`${no}：请填写视频/VR 页面地址`);
            } else if (!LINK_URL_PATTERN.test(url)) {
                errors.push(`${no}：视频地址须为 http(s):// 开头或站内路径（/ 开头）`);
            }
        }
        if (b.type === "badges") {
            const items = b.badgeItems || [];
            if (!items.length) {
                errors.push(`${no}：请至少填写 1 个徽章`);
            } else if (items.length > BADGES_MAX) {
                errors.push(`${no}：徽章不能超过 ${BADGES_MAX} 个`);
            }
            items.forEach(bd => {
                const label = (bd.label || "").trim();
                const image = (bd.image || "").trim();
                if (!label) {
                    errors.push(`${no}：徽章名称不能为空`);
                } else if (label.length > 20) {
                    errors.push(`${no}：徽章名称不能超过 20 字`);
                }
                if ((bd.desc || "").length > 50) {
                    errors.push(`${no}：徽章说明不能超过 50 字`);
                }
                if (!image) {
                    errors.push(`${no}：徽章必须上传图片`);
                } else if (!ASSET_URL_PATTERN.test(image)) {
                    errors.push(`${no}：徽章图片须为上传路径（/ 开头）或 http(s) 地址`);
                }
            });
        }
    });
    return errors;
}

/** 树展开为可勾选的扁平列表（仅列表型栏目可作数据源；外链/单页排除） */
export interface FlatCategory {
    id: number;
    name: string;
    depth: number;
}

export function flattenListCategories(tree: CategoryTreeNode[], depth = 0, out: FlatCategory[] = []): FlatCategory[] {
    (tree || []).forEach(node => {
        if (node.type === 1) {
            out.push({ id: node.id as number, name: node.name, depth });
        }
        if (node.children && node.children.length) {
            flattenListCategories(node.children, depth + 1, out);
        }
    });
    return out;
}

/** 树内全部栏目 id（布局数据源合法性参考） */
export function allCategoryIds(tree: CategoryTreeNode[]): number[] {
    const ids: number[] = [];
    (tree || []).forEach(node => {
        if (node.id != null) {
            ids.push(node.id);
        }
        ids.push(...allCategoryIds(node.children || []));
    });
    return ids;
}

/**
 * 「从当前栏目一键生成」（docs/16 §4.3 首用救生索）：复刻渲染端 categoryBlocks 现状算法，
 * 生成与旧首页等价的初始序列（ticker → 各列表栏目区块（home_style→style、16/8 条）→ gallery），
 * 用户在此基础上删改，心智从「从零搭」变成「修剪」。
 */
export function genFromCategories(tree: CategoryTreeNode[], configJson: string | undefined | null): HomeLayout {
    let galleryTitle = "线上展厅";
    let gallerySubtitle = "Online Exhibition Hall";
    if (configJson && configJson.trim()) {
        try {
            const cfg = JSON.parse(configJson);
            if (cfg && typeof cfg === "object") {
                if (typeof cfg["gallery_title"] === "string" && cfg["gallery_title"].trim()) {
                    galleryTitle = cfg["gallery_title"];
                }
                if (typeof cfg["gallery_subtitle"] === "string" && cfg["gallery_subtitle"].trim()) {
                    gallerySubtitle = cfg["gallery_subtitle"];
                }
            }
        } catch {
            // 非法配置按缺省标题
        }
    }
    const blocks: LayoutBlock[] = [
        { id: genBlockId(), type: "ticker", visible: true, title: "要闻速递", source: "top", size: 6 },
    ];
    (tree || []).forEach(node => {
        if (node.type !== 1 || node.id == null) {
            return;
        }
        blocks.push({
            id: genBlockId(),
            type: "article_list",
            visible: true,
            title: node.name,
            categoryIds: [node.id],
            style: node.homeStyle || "card",
            size: node.homeStyle === "news_grid" ? 16 : 8,
        });
    });
    blocks.push({
        id: genBlockId(),
        type: "gallery",
        visible: true,
        title: galleryTitle,
        subtitle: gallerySubtitle,
    });
    return { version: HOME_LAYOUT_VERSION, blocks };
}