import { useMemo } from "react";
import { useConsole } from "../../context";
import { ChatList, ChatInput } from "../../components/chat/Chat";
import { traceEntryToChatMessage, type ChatMessage } from "../../components/chat/mapTrace";
import { TRACE_TERMINAL } from "../../api/types";

// Continue chat: same ChatList/ChatBubble/ChatInput as the trace timeline.
// Preferred source is GET /chat-history (server-merged true alternating
// history: prompt + persisted continues + followups + trace, in
// timestamp order). Only when that endpoint is unavailable (old server)
// fall back to the previous view: prompt + message-kind trace entries
// + followups appended after — that fallback cannot interleave exactly
// and cannot show pre-persistence continues, and it says so nowhere
// else, so the fallback path is kept only as a compatibility shim.
// Sending uses only live APIs: terminal tasks -> POST /tasks/:id/continue
// (the server now persists that message in the same transaction),
// queued/running tasks -> POST /tasks/:id/followups (direct).
export default function ContinuePanel() {
  const ctx = useConsole();
  const t = ctx.currentTask;
  const messages = useMemo<ChatMessage[]>(() => {
    if (!t) return [];
    if (ctx.chatHistory) {
      return ctx.chatHistory.messages.map((m) => ({
        id: m.id, role: m.role, text: m.text, label: m.label,
      }));
    }
    const head: ChatMessage[] = t.prompt ? [{ id: "task-prompt", role: "user", text: t.prompt }] : [];
    const assistant = ctx.traceEntries.filter((e) => e.kind === "message").map((e, i) => traceEntryToChatMessage(e, i));
    const followups: ChatMessage[] = ctx.followups.map((f, i) => ({
      id: "followup-" + i, role: "user" as const, text: String(f.body || ""), label: "后续消息",
    }));
    return [...head, ...assistant, ...followups];
  }, [t, ctx.chatHistory, ctx.traceEntries, ctx.followups]);
  if (!t) return <div className="muted">点任务行查看详情后，这里显示继续会话</div>;
  const terminal = TRACE_TERMINAL.includes(t.status);
  const running = ["queued", "running"].includes(t.status);
  const canSend = terminal || running;
  const hint = terminal
    ? "终态任务：发送走继续接口（同一会话再跑一轮）"
    : running
      ? "运行中/排队中：发送走后续消息直接发送（跑完当前轮后优先执行）"
      : "merged/merge-failed 任务不可继续，也不可发后续消息";
  const legacy = ctx.chatHistory ? (ctx.chatHistory.legacy_continue_count ?? null) : null;
  return (
    <div className="chat-column">
      {legacy !== null && legacy > 0 ? (
        <div className="muted">此前有 {legacy} 条继续消息发生在持久化之前，未入库，上面历史不完整；部署后新发的继续消息会正常显示。</div>
      ) : null}
      {ctx.chatHistory && ctx.chatHistory.trace_note ? (
        <div className="muted">{ctx.chatHistory.trace_note}</div>
      ) : null}
      <ChatList messages={messages} empty="（暂无会话消息）" />
      <ChatInput
        disabled={!canSend}
        placeholder="消息"
        onSend={(text) => void ctx.sendChatMessage(text)}
      />
      <div className="muted">{hint}。{ctx.chatMsg}</div>
    </div>
  );
}