vexplor/frontend/components/messenger/MessageInput.tsx

"use client";

import { useState, useRef, useCallback, useEffect, KeyboardEvent, ChangeEvent } from "react";
import { Paperclip, Send, SmilePlus } from "lucide-react";
import { useSendMessage, useUploadFile, useCompanyUsers } from "@/hooks/useMessenger";

const QUICK_EMOJIS = ["\u{1F44D}", "\u{2764}\u{FE0F}", "\u{1F602}", "\u{1F44F}", "\u{1F64F}", "\u{1F525}", "\u{1F389}", "\u{1F914}"];

interface MessageInputProps {
  roomId: string;
  onTypingStart?: () => void;
  onTypingStop?: () => void;
}

export function MessageInput({ roomId, onTypingStart, onTypingStop }: MessageInputProps) {
  const [text, setText] = useState("");
  const [showEmoji, setShowEmoji] = useState(false);
  const [mentionQuery, setMentionQuery] = useState<string | null>(null);
  const [mentionIndex, setMentionIndex] = useState(0);
  const textareaRef = useRef<HTMLTextAreaElement>(null);
  const fileRef = useRef<HTMLInputElement>(null);
  const typingTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);

  const sendMessage = useSendMessage();
  const uploadFile = useUploadFile();
  const { data: users } = useCompanyUsers();

  const filteredMentionUsers = mentionQuery !== null && users
    ? users.filter((u) => u.userName.toLowerCase().includes(mentionQuery.toLowerCase())).slice(0, 5)
    : [];

  const adjustHeight = useCallback(() => {
    const el = textareaRef.current;
    if (el) {
      el.style.height = "auto";
      el.style.height = Math.min(el.scrollHeight, 120) + "px";
    }
  }, []);

  useEffect(() => {
    adjustHeight();
  }, [text, adjustHeight]);

  // Auto-focus when room changes
  useEffect(() => {
    if (roomId) {
      textareaRef.current?.focus();
    }
  }, [roomId]);

  const handleSend = useCallback(() => {
    const trimmed = text.trim();
    if (!trimmed) return;
    sendMessage.mutate({ roomId, content: trimmed });
    setText("");
    onTypingStop?.();
  }, [text, roomId, sendMessage, onTypingStop]);

  const handleKeyDown = (e: KeyboardEvent<HTMLTextAreaElement>) => {
    if (mentionQuery !== null && filteredMentionUsers.length > 0) {
      if (e.key === "ArrowDown") {
        e.preventDefault();
        setMentionIndex((p) => Math.min(p + 1, filteredMentionUsers.length - 1));
        return;
      }
      if (e.key === "ArrowUp") {
        e.preventDefault();
        setMentionIndex((p) => Math.max(p - 1, 0));
        return;
      }
      if (e.key === "Enter" || e.key === "Tab") {
        e.preventDefault();
        insertMention(filteredMentionUsers[mentionIndex]);
        return;
      }
      if (e.key === "Escape") {
        setMentionQuery(null);
        return;
      }
    }

    if (e.key === "Enter" && !e.shiftKey) {
      e.preventDefault();
      handleSend();
    }
  };

  const insertMention = (user: { userId: string; userName: string }) => {
    const el = textareaRef.current;
    if (!el) return;
    const val = el.value;
    const atIdx = val.lastIndexOf("@", el.selectionStart - 1);
    if (atIdx === -1) return;
    const before = val.slice(0, atIdx);
    const after = val.slice(el.selectionStart);
    setText(`${before}@${user.userName} ${after}`);
    setMentionQuery(null);
  };

  const handleChange = (e: ChangeEvent<HTMLTextAreaElement>) => {
    const val = e.target.value;
    setText(val);

    // Typing events
    onTypingStart?.();
    if (typingTimerRef.current) clearTimeout(typingTimerRef.current);
    typingTimerRef.current = setTimeout(() => onTypingStop?.(), 2000);

    // Mention detection
    const cursor = e.target.selectionStart;
    const textBeforeCursor = val.slice(0, cursor);
    const atMatch = textBeforeCursor.match(/@(\S*)$/);
    if (atMatch) {
      setMentionQuery(atMatch[1]);
      setMentionIndex(0);
    } else {
      setMentionQuery(null);
    }
  };

  const handleFileChange = async (e: ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (!file) return;
    try {
      const result = await uploadFile.mutateAsync(file);
      sendMessage.mutate({
        roomId,
        content: file.name,
        type: "file",
      });
    } catch {
      // upload failed silently
    }
    e.target.value = "";
  };

  return (
    <div className="border-t p-2 relative">
      {mentionQuery !== null && filteredMentionUsers.length > 0 && (
        <div className="absolute bottom-full left-2 right-2 bg-background border rounded-md shadow-md max-h-40 overflow-y-auto">
          {filteredMentionUsers.map((u, i) => (
            <button
              key={u.userId}
              onClick={() => insertMention(u)}
              className={`w-full text-left px-3 py-1.5 text-sm hover:bg-muted ${i === mentionIndex ? "bg-muted" : ""}`}
            >
              <span className="font-medium">{u.userName}</span>
              {u.deptName && <span className="text-muted-foreground ml-2">{u.deptName}</span>}
            </button>
          ))}
        </div>
      )}

      <div className="flex items-end gap-1">
        <button onClick={() => fileRef.current?.click()} className="p-1.5 hover:bg-muted rounded">
          <Paperclip className="h-4 w-4 text-muted-foreground" />
        </button>
        <input ref={fileRef} type="file" className="hidden" onChange={handleFileChange} />

        <div className="relative">
          <button onClick={() => setShowEmoji((p) => !p)} className="p-1.5 hover:bg-muted rounded">
            <SmilePlus className="h-4 w-4 text-muted-foreground" />
          </button>
          {showEmoji && (
            <div className="absolute bottom-full left-0 bg-background border rounded-md shadow-md p-1.5 flex flex-wrap gap-1 w-48 z-10">
              {QUICK_EMOJIS.map((emoji) => (
                <button
                  key={emoji}
                  onClick={() => {
                    setText((p) => p + emoji);
                    setShowEmoji(false);
                    textareaRef.current?.focus();
                  }}
                  className="hover:bg-muted rounded p-1 text-lg"
                >
                  {emoji}
                </button>
              ))}
            </div>
          )}
        </div>

        <textarea
          ref={textareaRef}
          value={text}
          onChange={handleChange}
          onKeyDown={handleKeyDown}
          placeholder="메시지를 입력하세요..."
          rows={1}
          className="flex-1 resize-none bg-transparent text-sm outline-none placeholder:text-muted-foreground py-1.5 px-2 max-h-[120px]"
        />

        <button
          onClick={handleSend}
          disabled={!text.trim()}
          className="p-1.5 hover:bg-muted rounded disabled:opacity-40"
        >
          <Send className="h-4 w-4 text-primary" />
        </button>
      </div>
    </div>
  );
}