import routes from "@/router/routes";

/**
 * 平台模块配置 → 前端内部路由的统一解析器（对齐 NoticeFront @/utils/menuRoute）。
 * 平台配置的 path 格式不可控（旧前缀 / index.html#/hash / 完整 URL / 配错），
 * 侧边栏跳转与高亮、登录后默认跳转都必须先经过这里，禁止手拼路由。
 */
const ROUTE_PATHS: string[] = routes
    .map((r: any) => (typeof r.redirect === "string" ? r.redirect : r.path))
    .filter((p: any): p is string => !!p && !String(p).includes(":"));

const ROUTE_BY_MODID = new Map<number, string>();
for (const r of routes as any[]) {
    const modId = r.meta?.modId as number | undefined;
    if (!modId || !r.path || String(r.path).includes(":") || r.redirect) continue;
    if (!ROUTE_BY_MODID.has(modId)) ROUTE_BY_MODID.set(modId, r.path);
}

const ROUTE_BY_TITLE = new Map<string, string>();
for (const r of routes as any[]) {
    if (r.redirect || !r.path || String(r.path).includes(":")) continue;
    const title = r.meta?.title as string | undefined;
    if (title && !ROUTE_BY_TITLE.has(title)) ROUTE_BY_TITLE.set(title, r.path);
}

/** 平台历史模块名 → 路由（旧菜单叫法与现页面标题不一致时的对照） */
const NAME_ALIASES: Record<string, string> = {
    学制设置: "/studySystemChoice",
    时段管理: "/itemSet",
    学校管理: "/schoolSetting",
    课程管理: "/subjectManForZy",
    学科设置: "/subjectSetzhi",
    班级列表: "/classManage",
    选修班: "/electiveClassManage",
    教师列表: "/teacherManage",
    学生列表: "/studentManage",
    日志查询: "/dailySearch",
};

/** 本应用历史上下文前缀（/bschclass、/userclass、/BschClassSystem）→ 去掉后比对 */
const LEGACY_PREFIXES = ["/bschclass", "/userclass", "/bschclasssystem"];

const EXTERNAL_RE = /^(https?:)?\/\//i;

function extractCandidate(raw: string): string {
    let p = raw.trim();
    try {
        p = decodeURIComponent(p);
    } catch {
        /* 非法编码保持原样 */
    }
    const hashIdx = p.indexOf("#");
    if (hashIdx >= 0) {
        p = p.slice(hashIdx + 1);
    } else if (EXTERNAL_RE.test(p)) {
        try {
            p = new URL(p, "http://placeholder.local").pathname;
        } catch {
            /* 保持原样 */
        }
    }
    const qIdx = p.indexOf("?");
    if (qIdx >= 0) p = p.slice(0, qIdx);
    p = p.replace(/index\.html?$/i, "");
    p = p.replace(/\/+$/, "");
    if (p && !p.startsWith("/")) p = "/" + p;
    return p;
}

function matchRoute(candidate: string): string | null {
    if (!candidate) return null;
    const lower = candidate.toLowerCase();
    const exact = ROUTE_PATHS.find((p: string) => p.toLowerCase() === lower);
    if (exact) return exact;
    for (const prefix of LEGACY_PREFIXES) {
        if (lower.startsWith(prefix + "/")) {
            const stripped = lower.slice(prefix.length);
            const hit = ROUTE_PATHS.find((p: string) => p.toLowerCase() === stripped);
            if (hit) return hit;
        }
    }
    return null;
}

function matchByName(name?: string | null): string | null {
    const n = String(name ?? "").trim();
    if (!n) return null;
    const byTitle = ROUTE_BY_TITLE.get(n);
    if (byTitle) return byTitle;
    const alias = NAME_ALIASES[n];
    if (alias) return alias;
    const hits = [...ROUTE_BY_TITLE.entries()].filter(
        ([title]) => title.length >= 2 && (n.includes(title) || title.includes(n))
    );
    return hits.length === 1 ? hits[0][1] : null;
}

function isAppEntryCandidate(candidate: string): boolean {
    if (!candidate || candidate === "/") return true;
    return LEGACY_PREFIXES.some(p => candidate === p);
}

export interface ResolvedMenuPage {
    path: string;
    external: boolean;
}

export const EMPTY_MENU_PAGE: ResolvedMenuPage = { path: "", external: false };

export function resolveMenuPage(
    page?: string | null,
    modId?: number | null,
    name?: string | null
): ResolvedMenuPage {
    const raw = String(page ?? "").trim();
    const byName = (): string | null => matchByName(name);
    const byModId = (): string | null => (modId != null ? ROUTE_BY_MODID.get(modId) ?? null : null);

    if (raw) {
        const candidate = extractCandidate(raw);
        const byPath = matchRoute(candidate);
        if (byPath) return { path: byPath, external: false };

        if (EXTERNAL_RE.test(raw) && !raw.includes("#")) {
            if (!isAppEntryCandidate(candidate)) {
                return { path: raw, external: true };
            }
        }

        const fallback = byName() ?? byModId();
        if (fallback) return { path: fallback, external: false };

        console.warn(
            "[menuRoute] 模块路径/名称/modId 均无法匹配前端路由，请检查基础平台模块配置:",
            raw,
            "modId =", modId,
            "name =", name
        );
        return EMPTY_MENU_PAGE;
    }

    const fallback = byName() ?? byModId();
    if (fallback) return { path: fallback, external: false };
    console.warn("[menuRoute] 模块未配置路径且名称/modId 无法识别:", name, "modId =", modId);
    return EMPTY_MENU_PAGE;
}