import { useEffect, useRef, useState } from "react";
import { useOfficeStore } from "@/store/office-store";
import { resetChat, sendChat } from "@/gateway/live";

/**
 * Two-way chat with one project — each message runs headless and is stitched
 * to the previous with --resume. Shared by the side panel and the full-screen
 * overlay via the `variant` prop.
 */
export function ChatConversation({
  agentId,
  variant,
}: {
  agentId: string;
  variant: "panel" | "full";
}) {
  const thread = useOfficeStore((s) => s.chats.get(agentId));
  const setChatFullscreen = useOfficeStore((s) => s.setChatFullscreen);
  const isFull = useOfficeStore((s) => s.chatFullscreen);
  const [input, setInput] = useState("");
  const [fromProject, setFromProject] = useState(false);
  const listRef = useRef<HTMLDivElement>(null);

  const busy = thread?.busy ?? false;
  const messages = thread?.messages ?? [];
  const started = messages.length > 0;

  useEffect(() => {
    listRef.current?.scrollTo({ top: listRef.current.scrollHeight });
  }, [messages.length, busy]);

  const send = () => {
    const text = input.trim();
    if (!text || busy) return;
    sendChat(agentId, text, fromProject);
    setInput("");
  };

  return (
    <div className={`chat-panel ${variant === "full" ? "chat-panel-full" : ""}`}>
      <div className="chat-head">
        <h3>對話</h3>
        <div className="chat-head-actions">
          {started && (
            <button className="link-btn" onClick={() => resetChat(agentId)} disabled={busy}>
              🔄 新對話
            </button>
          )}
          <button
            className="link-btn"
            onClick={() => setChatFullscreen(!isFull)}
            title={isFull ? "縮回側邊面板" : "全螢幕對話"}
          >
            {isFull ? "⊟ 縮小" : "⛶ 全螢幕"}
          </button>
        </div>
      </div>

      {started && (
        <div className="chat-list" ref={listRef}>
          {messages.map((m, i) => (
            <div key={i} className={`chat-msg ${m.role}`}>
              {m.text}
            </div>
          ))}
          {busy && <div className="chat-msg pending">⋯ 執行中,過程看辦公室裡的小人</div>}
        </div>
      )}

      <textarea
        value={input}
        onChange={(e) => setInput(e.target.value)}
        placeholder={started ? "繼續對話…(Enter 送出)" : "跟這個專案的 Claude 對話…(Enter 送出)"}
        rows={variant === "full" ? 3 : 2}
        onKeyDown={(e) => {
          if (e.key === "Enter" && !e.shiftKey) {
            e.preventDefault();
            send();
          }
        }}
      />
      <div className="task-composer-row">
        {!started ? (
          <label
            className="tip"
            data-tip="第一句話從該專案最近一段「已結束」的 session 接續(--resume)。注意:無法插入正在終端機進行中的互動對話。"
          >
            <input
              type="checkbox"
              checked={fromProject}
              onChange={(e) => setFromProject(e.target.checked)}
            />
            接續專案最近 session
          </label>
        ) : (
          <span
            className="chat-hint tip"
            data-tip="辦公室對話有自己的 session,每則訊息自動以 --resume 延續,像 claudecodeui 一樣逐則接力。"
          >
            ✓ 對話自動延續
          </span>
        )}
        <button className="btn assign-btn" onClick={send} disabled={busy || !input.trim()}>
          {busy ? "執行中…" : "送出"}
        </button>
      </div>
    </div>
  );
}