/**
 * @file AgentDetails.tsx
 * @description What the chat shows of a subagent, like Claude Desktop: an
 * Agent/Task call's facts (type, model, status, time, tokens, tool calls),
 * the task it was given and the report it returned — read off the call, its
 * result (`tool_result.agent`) and, for a background agent, the
 * `<task-notification>` that closed it — and, one click further, the
 * subagent's own conversation as a small chat right there in the step, every
 * step of it. The chat's owner (ConversationView) supplies the links through
 * `AgentContext`: which agent transcript a call launched, the notifications
 * seen, and how to render one agent's conversation (a nested
 * ConversationView — passed in, so this module never imports it back).
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { createContext, useContext, useState } from "react";
import { useTranslation } from "react-i18next";
import { CheckCircle2, ChevronRight, CircleSlash, Loader2, XCircle } from "lucide-react";
import type { TranscriptContent, TranscriptMessage } from "../../lib/types";
import { fmt, formatModelName, formatMs } from "../../lib/format";
import { MarkdownContent } from "./MarkdownContent";

export type AgentStatus = "running" | "done" | "error" | "stopped";

/** One subagent as the chat knows it from the call that launched it. */
export interface AgentRef {
  /** The Agent/Task `tool_use` id. */
  toolUseId: string;
  /** Its own transcript's `agent_id`; null while nothing names it yet. */
  agentId: string | null;
  type: string;
  description: string;
  model: string | null;
  status: AgentStatus;
  background: boolean;
  prompt: string | null;
  report: string | null;
  durationMs: number | null;
  tokens: number | null;
  toolUses: number | null;
}

/** What a `<task-notification>` said about a background agent. */
export interface AgentNotice {
  status: string;
  result: string | null;
  durationMs: number | null;
  tokens: number | null;
  toolUses: number | null;
}

export interface AgentLinks {
  /** tool_use id → agent transcript id, from the session's transcript list. */
  ids: Map<string, string>;
  /** tool_use id → the notification that closed that background agent. */
  notices: Map<string, AgentNotice>;
  /** The session runs in a pane: a call with no result yet still works. */
  live: boolean;
  /** One agent's own conversation, as a chat that fills its box. */
  render?: (agent: AgentRef) => React.ReactNode;
}

export const AgentContext = createContext<AgentLinks>({
  ids: new Map(),
  notices: new Map(),
  live: false,
});

const AGENT_TOOLS = new Set(["Agent", "Task"]);
export const isAgentCall = (b: TranscriptContent) =>
  b.type === "tool_use" && AGENT_TOOLS.has(b.name ?? "");

// The result names the agent's own transcript (`agent-<id>.jsonl`).
const AGENT_ID = /agentId:\s*([\w-]+)/;
const USAGE = /<usage>([\s\S]*?)<\/usage>/;

const tag = (text: string, name: string) =>
  text.match(new RegExp(`<${name}>([\\s\\S]*?)</${name}>`))?.[1]?.trim() ?? null;

/** The time, tokens and tool calls of a `<usage>` block, in either form
 *  Claude Code writes it: `<total_tokens>N</…>` tags or `total_tokens: N`. */
export function parseUsage(text: string): Pick<AgentNotice, "durationMs" | "tokens" | "toolUses"> {
  const body = text.match(USAGE)?.[1] ?? "";
  const num = (...names: string[]) => {
    for (const n of names) {
      const v = body.match(new RegExp(`${n}(?:>|:\\s*)(\\d+)`))?.[1];
      if (v) return Number(v);
    }
    return null;
  };
  return {
    durationMs: num("duration_ms"),
    tokens: num("subagent_tokens", "total_tokens"),
    toolUses: num("tool_uses"),
  };
}

/** Each `<task-notification>` in the transcript, by the call it closes. */
export function agentNotices(messages: TranscriptMessage[]): Map<string, AgentNotice> {
  const out = new Map<string, AgentNotice>();
  for (const msg of messages) {
    if (msg.type !== "user") continue;
    for (const c of msg.content) {
      if (c.type !== "text" || !c.text?.includes("<task-notification>")) continue;
      for (const part of c.text.split("<task-notification>").slice(1)) {
        const id = tag(part, "tool-use-id");
        if (!id) continue;
        out.set(id, {
          status: tag(part, "status") ?? "completed",
          result: tag(part, "result"),
          ...parseUsage(part),
        });
      }
    }
  }
  return out;
}

/** A report without the footer Claude Code appends for the orchestrator. */
function stripFooter(text: string): string {
  return text
    .replace(USAGE, "")
    .replace(/^agentId:.*$/m, "")
    .trim();
}

/** Everything the chat can say about the subagent `block` launched. */
export function agentRef(
  block: TranscriptContent,
  result: TranscriptContent | null | undefined,
  links: AgentLinks
): AgentRef {
  const raw = block.input as Record<string, unknown> | undefined;
  const input = raw && !("_truncated" in raw) ? raw : {};
  const str = (v: unknown) => (typeof v === "string" && v ? v : null);
  const id = block.id ?? "";
  const facts = result?.agent;
  const output = result?.output ?? "";
  const background = facts?.status === "async_launched" || output.includes("Async agent launched");
  const notice = background ? links.notices.get(id) : undefined;
  const usage = !background && output ? parseUsage(output) : null;

  let status: AgentStatus;
  if (result?.is_error) status = "error";
  else if (!result || (background && !notice)) status = links.live ? "running" : "stopped";
  else if (notice && notice.status !== "completed")
    status = notice.status === "failed" ? "error" : "stopped";
  else status = "done";

  return {
    toolUseId: id,
    agentId: facts?.id ?? output.match(AGENT_ID)?.[1] ?? links.ids.get(id) ?? null,
    type: str(input.subagent_type) ?? "Agent",
    description: str(input.description) ?? "",
    model: facts?.model ?? str(input.model),
    status,
    background,
    prompt: str(input.prompt),
    report: background ? (notice?.result ?? null) : output ? stripFooter(output) || null : null,
    durationMs: facts?.duration_ms ?? notice?.durationMs ?? usage?.durationMs ?? null,
    tokens: facts?.tokens ?? notice?.tokens ?? usage?.tokens ?? null,
    toolUses: facts?.tool_uses ?? notice?.toolUses ?? usage?.toolUses ?? null,
  };
}

const STATUS_ICON: Record<AgentStatus, React.ReactNode> = {
  running: <Loader2 className="h-3.5 w-3.5 flex-shrink-0 animate-spin text-accent" />,
  done: <CheckCircle2 className="h-3.5 w-3.5 flex-shrink-0 text-status-success" />,
  error: <XCircle className="h-3.5 w-3.5 flex-shrink-0 text-status-danger" />,
  stopped: <CircleSlash className="h-3.5 w-3.5 flex-shrink-0 text-fg-muted" />,
};

/** One muted line: its status as an icon, then type · model · time ·
 *  tokens · tool calls, as far as they are known. */
export function AgentFacts({ agent }: { agent: AgentRef }) {
  const { t } = useTranslation("sessions");
  const parts = [
    agent.type,
    agent.model && formatModelName(agent.model),
    agent.background && t("conversation.agent.background"),
    agent.durationMs != null && formatMs(agent.durationMs),
    agent.tokens != null && t("conversation.agentContext", { tokens: fmt(agent.tokens) }),
    agent.toolUses != null && t("conversation.agent.toolUses", { count: agent.toolUses }),
  ].filter(Boolean);
  return (
    <div
      data-testid="agent-facts"
      title={t(`conversation.agent.status.${agent.status}`)}
      className="flex min-w-0 items-center gap-1.5 text-xs text-fg-muted"
    >
      {STATUS_ICON[agent.status]}
      <span className="sr-only">{t(`conversation.agent.status.${agent.status}`)}</span>
      <span className="truncate">{parts.join(" · ")}</span>
    </div>
  );
}

const linkClass =
  "inline-flex items-center gap-0.5 text-xs text-fg-muted transition-colors hover:text-fg-secondary";

/** The subagent's own conversation, a thread hung under its step by a line
 *  on the left — as tall as it is, up to 24rem, then it scrolls. */
export function AgentChatBox({ agent }: { agent: AgentRef }) {
  const links = useContext(AgentContext);
  return (
    <div data-testid="agent-chat" className="mt-2 border-l-2 border-border pl-3">
      {links.render?.(agent)}
    </div>
  );
}

/** An Agent/Task step opened in the chat: one line of facts, its report as
 *  prose, and "View conversation ›", which puts the agent's own thread (its
 *  task, every step, its reply) in the report's place. With no transcript
 *  to show, the task it was given opens on its own instead. */
export function AgentStepBody({
  block,
  result,
}: {
  block: TranscriptContent;
  result: TranscriptContent | null;
}) {
  const { t } = useTranslation("sessions");
  const links = useContext(AgentContext);
  const agent = agentRef(block, result, links);
  const canOpen = !!agent.agentId && !!links.render;
  const [thread, setThread] = useState(false);
  const [task, setTask] = useState(false);
  return (
    <div data-testid="agent-step" className="space-y-1.5">
      <AgentFacts agent={agent} />
      {thread ? (
        <AgentChatBox agent={agent} />
      ) : (
        <>
          {!canOpen && agent.prompt && task && (
            <div className="max-h-60 overflow-auto border-l-2 border-border pl-3 text-fg-secondary">
              <MarkdownContent text={agent.prompt} dense />
            </div>
          )}
          {agent.report && (
            <div
              className={`max-h-60 overflow-auto ${agent.status === "error" ? "text-status-danger" : "text-fg-secondary"}`}
            >
              <MarkdownContent text={agent.report} dense />
            </div>
          )}
        </>
      )}
      {canOpen ? (
        <button
          type="button"
          data-testid="agent-open"
          aria-expanded={thread}
          onClick={() => setThread(!thread)}
          className={linkClass}
        >
          {t(thread ? "conversation.agent.hide" : "conversation.agent.open")}
          <ChevronRight className={`h-3 w-3 transition-transform ${thread ? "-rotate-90" : ""}`} />
        </button>
      ) : (
        agent.prompt && (
          <button
            type="button"
            aria-expanded={task}
            onClick={() => setTask(!task)}
            className={linkClass}
          >
            {t("conversation.agent.prompt")}
            <ChevronRight className={`h-3 w-3 transition-transform ${task ? "rotate-90" : ""}`} />
          </button>
        )
      )}
    </div>
  );
}