import type { AgentFamilyUsage, AgentRunNode } from "@umt/contracts";
import { ChevronRight, CornerLeftUp, GitBranch } from "lucide-react";
import { createContext, type ReactNode, useContext, useState } from "react";
import { Link } from "react-router";
import { agentMockEnabled, type RunSnapshot } from "~/api/agent.ts";
import { formatTokens } from "~/lib/tokens.ts";
import { cn } from "~/lib/utils.ts";
import { RunStatusBadge } from "./agent-conversation.tsx";
import { shortGoalTitle } from "./agent-store.ts";

// 子代理(agent.spawn):会话页显示父会话链接 + 继承信息,以及子会话树(可展开、可跳转)与会话树合计用量。
// 未派生过子会话、也不是子会话时不渲染(不显示空的多 Agent 看板)。

const tokens = (n: number | undefined) => formatTokens(n);

export function usageLine(u: { toolCalls: number; totalTokens?: number; costUsd?: number }) {
  const parts = [`${u.toolCalls} 次调用`, `${tokens(u.totalTokens)} token`];
  if (u.costUsd) parts.push(`$${u.costUsd.toFixed(3)}`);
  return parts.join(" · ");
}

const href = (id: string) => `/console/agent/${id}${agentMockEnabled() ? "?mock=1" : ""}`;

/** 抽屉里提供:点父/子会话在抽屉内打开,不跳页 */
export const AgentRunOpenContext = createContext<((runId: string) => void) | null>(null);

const LINK_CLASS =
  "line-clamp-2 cursor-pointer rounded-tight text-left text-caption break-words text-foreground outline-none hover:underline focus-visible:ring-2 focus-visible:ring-ring";

function RunLink({ id, children }: { id: string; children: ReactNode }) {
  const open = useContext(AgentRunOpenContext);
  if (open)
    return (
      <button type="button" onClick={() => open(id)} className={LINK_CLASS}>
        {children}
      </button>
    );
  return (
    <Link to={href(id)} className={LINK_CLASS}>
      {children}
    </Link>
  );
}

function budgetText(b: Record<string, number | undefined>) {
  const parts: string[] = [];
  if (b.maxToolCalls !== undefined) parts.push(`${b.maxToolCalls} 次调用`);
  if (b.maxTokens !== undefined) parts.push(`${tokens(b.maxTokens)} token`);
  if (b.maxDurationSec !== undefined) parts.push(`${b.maxDurationSec}s`);
  if (b.maxCostUsd !== undefined) parts.push(`$${b.maxCostUsd}`);
  return parts.length ? parts.join(" · ") : "沿用设置";
}

function Node({ node, byParent, depth }: { node: AgentRunNode; byParent: Map<string, AgentRunNode[]>; depth: number }) {
  const kids = byParent.get(node.id) ?? [];
  const [open, setOpen] = useState(true);
  return (
    <li>
      <div className="flex min-w-0 items-start gap-1.5 rounded-lg px-1.5 py-1 hover:bg-foreground/[0.04]">
        {kids.length ? (
          <button
            type="button"
            aria-expanded={open}
            aria-label={open ? "收起子会话" : "展开子会话"}
            onClick={() => setOpen(!open)}
            className="mt-0.5 cursor-pointer rounded-tight text-muted-foreground outline-none focus-visible:ring-2 focus-visible:ring-ring"
          >
            <ChevronRight className={cn("size-4 transition-transform duration-micro", open && "rotate-90")} />
          </button>
        ) : (
          <span className="mt-0.5 size-4 shrink-0" aria-hidden />
        )}
        <div className="min-w-0 flex-1">
          <RunLink id={node.id}>{shortGoalTitle(node.goal)}</RunLink>
          <div className="mt-0.5 flex flex-wrap items-center gap-1.5">
            <RunStatusBadge status={node.status} />
            <span className="text-meta text-muted-foreground tabular-nums">
              {usageLine({
                toolCalls: node.toolCallCount,
                totalTokens: node.usage.totalTokens,
                costUsd: node.usage.costUsd,
              })}
            </span>
          </div>
          {node.spawnReason ? (
            <p className="mt-0.5 truncate text-meta text-muted-foreground">理由：{node.spawnReason}</p>
          ) : null}
        </div>
      </div>
      {kids.length && open ? (
        <ul className={cn("ml-3 border-l border-border/70 pl-2", depth > 2 && "ml-1")}>
          {kids.map((k) => (
            <Node key={k.id} node={k} byParent={byParent} depth={depth + 1} />
          ))}
        </ul>
      ) : null}
    </li>
  );
}

/** 子会话树 + 父会话链接;两者都没有时返回 null */
export function SubagentTree({ snapshot, className }: { snapshot: RunSnapshot; className?: string }) {
  const { run, parent, children = [], familyUsage } = snapshot;
  if (!parent && children.length === 0) return null;
  const byParent = new Map<string, AgentRunNode[]>();
  for (const c of children) {
    const k = c.parentRunId ?? "";
    byParent.set(k, [...(byParent.get(k) ?? []), c]);
  }
  const direct = byParent.get(run.id) ?? [];
  const caps = ((run.scope as { capabilities?: string[] }).capabilities ?? []).length;
  return (
    <section aria-label="子会话" className={cn("space-y-2 rounded-xl border border-border/70 p-3", className)}>
      {parent ? (
        <div className="space-y-1">
          <p className="flex items-center gap-1.5 text-meta text-muted-foreground">
            <CornerLeftUp aria-hidden className="size-3.5" />
            父会话
          </p>
          <RunLink id={parent.id}>{shortGoalTitle(parent.goal)}</RunLink>
          <p className="text-meta text-muted-foreground">
            第 {run.depth} 层子会话 · 继承父会话的发起人与授权上限 · 能力 {caps} 项（⊆ 父会话）· 划拨预算{" "}
            {budgetText(run.budget as Record<string, number | undefined>)}
            {run.spawnReason ? ` · 理由：${run.spawnReason}` : ""}
          </p>
        </div>
      ) : null}
      {direct.length ? (
        <div className="space-y-1">
          <p className="flex flex-wrap items-center gap-1.5 text-meta text-muted-foreground">
            <GitBranch aria-hidden className="size-3.5" />
            子会话 {children.length} 个{familyUsage ? <FamilyUsage usage={familyUsage} /> : null}
          </p>
          <ul className="space-y-0.5">
            {direct.map((c) => (
              <Node key={c.id} node={c} byParent={byParent} depth={1} />
            ))}
          </ul>
        </div>
      ) : null}
    </section>
  );
}

function FamilyUsage({ usage }: { usage: AgentFamilyUsage }) {
  return <span className="ml-auto tabular-nums">会话树合计 {usageLine(usage)}</span>;
}