import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import {
  cursorPage,
  type FeedHealth,
  FeedSource,
  type FeedSourceCreate,
  type FeedSourceUpdate,
  Id,
  Observation,
} from "@umt/contracts";
import { z } from "zod";
import { TTL_SECOND } from "~/lib/api.ts";
import { apiMutate, apiParsed, cleanParams, fetchAllCursorPages } from "./parse.ts";

// Feed 来源(W2-B:/feed-sources)

const FeedPage = cursorPage(FeedSource);

export const feedKeys = {
  all: ["feeds"] as const,
  list: (f: { siteId?: string; health?: FeedHealth }) => ["feeds", "list", f] as const,
};

export function useFeeds(f: { siteId?: string; health?: FeedHealth } = {}) {
  return useQuery({
    queryKey: feedKeys.list(f),
    queryFn: ({ signal }) =>
      fetchAllCursorPages((cursor) =>
        apiParsed(FeedPage, "/api/v1/feed-sources", { params: cleanParams({ ...f, limit: 200, cursor }), signal }),
      ),
    refetchInterval: 30 * TTL_SECOND,
  });
}

/** 单个 Feed;poll 为真时每 2 秒刷新(站点内添加后等首抓结果) */
export function useFeed(id: string | null, poll = false) {
  return useQuery({
    queryKey: [...feedKeys.all, "one", id] as const,
    enabled: !!id,
    queryFn: ({ signal }) =>
      apiParsed(FeedSource, "/api/v1/feed-sources/:id", { pathParams: { id: id ?? "" }, signal }),
    refetchInterval: poll ? 2 * TTL_SECOND : false,
  });
}

const ObservationPage = cursorPage(Observation);

/** RSS 最近条目(观察记录,新的在前);只在详情打开时请求 */
export function useFeedObservations(feedId: string | null, limit = 20) {
  return useQuery({
    queryKey: [...feedKeys.all, "observations", feedId, limit] as const,
    enabled: !!feedId,
    queryFn: ({ signal }) =>
      apiParsed(ObservationPage, "/api/v1/observations", { params: { feedId: feedId ?? "", limit }, signal }),
  });
}

/** 同站判定的主机键(与服务端 feedDefaultsForSite 一致):去 www.,取最后两级;IP 原样 */
export function feedHostKey(u: string): string | null {
  try {
    const host = new URL(u).hostname.toLowerCase().replace(/^www\./, "");
    if (/^[\d.]+$/.test(host) || host.includes(":")) return host;
    return host.split(".").slice(-2).join(".");
  } catch {
    return null;
  }
}

/** 游标窗口里的条目数(最近一次成功抓取的 Feed 条目数);没抓过为 null */
export function feedWindowCount(f: FeedSource): number | null {
  const w = f.cursor.window as { lastGuidSet?: unknown[] } | undefined;
  return Array.isArray(w?.lastGuidSet) ? w.lastGuidSet.length : null;
}

export function useCreateFeed() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: (body: FeedSourceCreate) =>
      apiMutate("/api/v1/feed-sources", { body }).then((d) => FeedSource.parse(d)),
    onSuccess: () => qc.invalidateQueries({ queryKey: feedKeys.all }),
  });
}

export function useUpdateFeed() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: ({ id, body }: { id: string; body: FeedSourceUpdate }) =>
      apiMutate("/api/v1/feed-sources/:id", { method: "PATCH", pathParams: { id }, body }).then((d) =>
        FeedSource.parse(d),
      ),
    onSuccess: () => qc.invalidateQueries({ queryKey: feedKeys.all }),
  });
}

/** 启停 / 熔断复位 */
export function useFeedAction() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: ({ id, action }: { id: string; action: "enable" | "disable" | "reset" }) =>
      apiMutate(`/api/v1/feed-sources/:id/${action}`, { pathParams: { id } }).then((d) => FeedSource.parse(d)),
    onSuccess: () => qc.invalidateQueries({ queryKey: feedKeys.all }),
  });
}

/** 立即抓取(仍受站点限流),返回任务 ID */
export function useFetchFeedNow() {
  const qc = useQueryClient();
  return useMutation({
    mutationFn: (id: string) =>
      apiMutate("/api/v1/feed-sources/:id/fetch", { pathParams: { id } }).then((d) =>
        z.object({ taskId: Id }).parse(d),
      ),
    onSuccess: () => qc.invalidateQueries({ queryKey: feedKeys.all }),
  });
}

/**
 * 疑似缺口:服务端在 Feed 窗口与上次零重叠时写 possibleGap 并排站点补漏;下一次抓取衔接上后清空。
 * 没有服务端标记但"距上次成功超过 3 个周期"时,只作推断提示(标"可能")。
 */
export function feedGapHint(f: FeedSource, now = Date.now()): string | null {
  if (f.possibleGap) {
    const at = new Date(f.possibleGap.detectedAt).toLocaleString("zh-CN", { hour12: false });
    return `疑似缺口（${at} 检测，${f.possibleGap.backfillQueued ? "已排补漏" : "RSS 未关联站点，无法自动补漏"}）`;
  }
  if (!f.enabled || !f.lastSuccessAt) return null;
  const gapMs = now - new Date(f.lastSuccessAt).getTime();
  if (gapMs > f.pollIntervalSec * 1000 * 3) return "距上次成功已超过 3 个周期，可能漏项";
  return null;
}