professor/components/chat/ChatPane.tsx

'use client';

import type { Dispatch } from 'react';
import type { AppState, AppAction, AppMode } from '@/types';
import TaskCard from './TaskCard';
import MessageList from './MessageList';
import ChatInput from './ChatInput';

interface Props {
  state: AppState;
  dispatch: Dispatch<AppAction>;
  onSendMessage: (text: string) => void;
  onSendClassroomMessage: (text: string) => void;
  onSubmit: () => void;
  onSetAppMode: (mode: AppMode) => void;
}

export default function ChatPane({ state, onSendMessage, onSendClassroomMessage, onSetAppMode }: Props) {
  const isClassroom = state.appMode === 'classroom';
  const isTaskLoading = state.phase === 'loading_task';

  // In classroom mode "busy" only covers classroom chat replies, not lesson generation
  const isBusy = isClassroom
    ? state.isStreaming && state.lessonContent !== null
    : state.isStreaming || state.phase === 'executing';

  const messages = isClassroom ? state.classroomMessages : state.messages;
  const handleSend = isClassroom ? onSendClassroomMessage : onSendMessage;

  const showChatStreaming = isClassroom
    ? state.isStreaming && state.lessonContent !== null
    : state.isStreaming && state.phase !== 'loading_task';
  const chatStreamingContent = showChatStreaming ? state.streamingContent : '';

  return (
    <div className="flex flex-col h-full bg-zinc-900">
      {/* Header */}
      <div className="flex items-center gap-2 border-b border-zinc-700 px-4 py-2">
        <div className="h-2 w-2 rounded-full bg-blue-400" />
        <span className="text-sm font-semibold text-zinc-200">Professor</span>

        {isBusy && (
          <div className="flex items-center gap-1.5 text-xs text-zinc-500">
            <div className="h-2 w-2 animate-pulse rounded-full bg-blue-400" />
            Thinking…
          </div>
        )}

        {/* Mode toggle */}
        <div className="ml-auto flex overflow-hidden rounded-lg border border-zinc-700">
          <button
            onClick={() => onSetAppMode('classroom')}
            className={`px-3 py-1 text-xs transition-colors ${
              isClassroom ? 'bg-zinc-700 text-zinc-100' : 'text-zinc-500 hover:bg-zinc-800 hover:text-zinc-300'
            }`}
          >
            Classroom
          </button>
          <button
            onClick={() => onSetAppMode('homework')}
            className={`border-l border-zinc-700 px-3 py-1 text-xs transition-colors ${
              !isClassroom ? 'bg-zinc-700 text-zinc-100' : 'text-zinc-500 hover:bg-zinc-800 hover:text-zinc-300'
            }`}
          >
            Homework
          </button>
        </div>
      </div>

      {/* Task card — homework only */}
      {!isClassroom && (
        <TaskCard
          task={state.task}
          isLoading={isTaskLoading}
          streamingContent={isTaskLoading ? state.streamingContent : ''}
        />
      )}

      {/* Error banner */}
      {state.error && (
        <div className="mx-3 mt-3 rounded-lg border border-red-800 bg-red-900/30 px-4 py-2.5 text-sm text-red-300">
          {state.error}
        </div>
      )}

      {/* Messages */}
      <MessageList
        messages={messages}
        isStreaming={showChatStreaming}
        streamingContent={chatStreamingContent}
        emptyText={
          isClassroom
            ? 'Ask me anything about this topic.'
            : 'Run your code or submit it for review — or ask me anything about the task.'
        }
      />

      {/* Input */}
      <ChatInput isDisabled={state.isStreaming} onSend={handleSend} />
    </div>
  );
}