import { useEffect } from "react";
import { useSearchParams } from "react-router";
import { type AgentRunGroup, runGroup, useAgentRun } from "~/api/agent.ts";

// 智能体页面的导航状态(纯函数 + 模块级记忆,单测覆盖):
// - 分栏「对话 / 自动巡检」:URL 的 ?tab= 优先,其次当前会话所在分栏,再次上次看的分栏;
// - 会话链接、列表页链接的拼法(保留演示开关);
// - 页面会话列表的筛选与各分栏滚动位置(列表页 ↔ 会话页之间保留,刷新页面才清)。

export const TAB_PARAM = "tab";

/** URL 里的分栏;没写或写错时为 null */
export function groupFromSearch(search: string | URLSearchParams): AgentRunGroup | null {
  const v = (typeof search === "string" ? new URLSearchParams(search) : search).get(TAB_PARAM);
  return v === "auto" || v === "conversation" ? v : null;
}

/** 分栏取值:URL 显式指定 > 当前会话所在分栏 > 上次看的分栏 > 对话 */
export function resolveGroup(o: {
  fromUrl: AgentRunGroup | null;
  activeRun?: AgentRunGroup | null;
  remembered?: AgentRunGroup | null;
}): AgentRunGroup {
  return o.fromUrl ?? o.activeRun ?? o.remembered ?? "conversation";
}

function withQuery(path: string, q: Record<string, string | null>): string {
  const p = new URLSearchParams();
  for (const [k, v] of Object.entries(q)) if (v) p.set(k, v);
  const s = p.toString();
  return s ? `${path}?${s}` : path;
}

/** 会话页链接:分栏由会话本身决定,不带 tab */
export function agentRunHref(id: string, mock = false): string {
  return withQuery(`/console/agent/${id}`, { mock: mock ? "1" : null });
}

/** 列表页链接:「对话」是缺省,不写进 URL */
export function agentListHref(group: AgentRunGroup = "conversation", mock = false): string {
  return withQuery("/console/agent", { [TAB_PARAM]: group === "auto" ? "auto" : null, mock: mock ? "1" : null });
}

/** 页面会话列表的记忆:上次看的分栏、搜索与筛选、各分栏的滚动位置 */
export type ListMemory = {
  group: AgentRunGroup;
  q: string;
  view: "all" | "pending" | "failed";
  scroll: Record<AgentRunGroup, number>;
};
export const newListMemory = (): ListMemory => ({
  group: "conversation",
  q: "",
  view: "all",
  scroll: { conversation: 0, auto: 0 },
});
export const pageListMemory: ListMemory = newListMemory();

/**
 * 当前项要不要滚进可见区:完全看不见才滚,只滚到刚好露出(nearest),返回新的 scrollTop;不用滚时为 null。
 * top / height 是当前项相对滚动内容顶部的位置。
 */
export function revealScrollTop(
  item: { top: number; height: number },
  viewport: { scrollTop: number; height: number },
): number | null {
  const bottom = item.top + item.height;
  const viewBottom = viewport.scrollTop + viewport.height;
  if (item.top >= viewport.scrollTop && bottom <= viewBottom) return null;
  if (item.top < viewport.scrollTop) return Math.max(0, item.top);
  return Math.max(0, bottom - viewport.height);
}

/** 会话所在分栏(子会话按父会话);快照没到之前为 null */
export function useRunGroup(runId: string | undefined): AgentRunGroup | null {
  const run = useAgentRun(runId);
  const r = run.data?.run;
  const parentId = r?.trigger === "subagent" ? (r.parentRunId ?? undefined) : undefined;
  const parent = useAgentRun(parentId);
  if (!r) return null;
  if (parentId && !parent.data) return null;
  return runGroup(r, parent.data?.run ?? null);
}

/**
 * 页面会话列表的分栏:URL 的 ?tab= 优先;会话页再按当前会话所在分栏,快照没到时沿用上次的分栏(避免闪一下)。
 * 列表页没有 tab 就是「对话」,URL 与选中项一致。切换分栏只改 URL(replace,不进历史)。
 */
export function usePageListGroup(activeRun?: AgentRunGroup | null): [AgentRunGroup, (g: AgentRunGroup) => void] {
  const [params, setParams] = useSearchParams();
  const onRunPage = activeRun !== undefined;
  const group = resolveGroup({
    fromUrl: groupFromSearch(params),
    activeRun: onRunPage ? activeRun : null,
    remembered: onRunPage ? pageListMemory.group : null,
  });
  useEffect(() => {
    pageListMemory.group = group;
  }, [group]);
  const change = (g: AgentRunGroup) =>
    setParams(
      (prev) => {
        const next = new URLSearchParams(prev);
        next.set(TAB_PARAM, g);
        return next;
      },
      { replace: true, preventScrollReset: true },
    );
  return [group, change];
}