import { React, h, Box, Text, useInput, useApp, ChatSession } from './plugins.js';
import type { LanguageModelV3, ToolSet, IChatUsage } from './plugins.js';
import { MessageList } from './components.messagelist.js';
import { InputArea } from './components.inputarea.js';
import { StatusBar } from './components.statusbar.js';
import type { IChatMessage } from './components.message.js';

export interface IChatAppProps {
  model: LanguageModelV3;
  system?: string;
  tools?: ToolSet;
  maxSteps?: number;
  modelName?: string;
}

const emptyUsage: IChatUsage = { inputTokens: 0, outputTokens: 0, totalTokens: 0, turns: 0 };

export function ChatApp({ model, system, tools, maxSteps, modelName }: IChatAppProps): React.ReactElement {
  const { exit } = useApp();
  const [messages, setMessages] = React.useState<IChatMessage[]>([]);
  const [streamingText, setStreamingText] = React.useState('');
  const [busy, setBusy] = React.useState(false);
  const [usage, setUsage] = React.useState<IChatUsage>({ ...emptyUsage });

  const sessionRef = React.useRef<ChatSession | null>(null);

  if (!sessionRef.current) {
    sessionRef.current = new ChatSession(
      { model, system, tools, maxSteps: maxSteps ?? 20 },
      {
        onToken: (delta) => {
          setStreamingText((prev) => prev + delta);
        },
        onToolCall: (name, input) => {
          setMessages((prev) => [
            ...prev,
            {
              role: 'tool' as const,
              content: '',
              toolName: name,
              toolInput: typeof input === 'string' ? input : JSON.stringify(input),
            },
          ]);
        },
      },
    );
  }

  useInput((input, key) => {
    if (input === 'c' && key.ctrl) {
      exit();
    }
    if (input === 'l' && key.ctrl) {
      setMessages([]);
      setStreamingText('');
      sessionRef.current?.clear();
      setUsage({ ...emptyUsage });
    }
  });

  const handleSubmit = async (text: string) => {
    if (busy) return;

    if (text === '/clear') {
      setMessages([]);
      setStreamingText('');
      sessionRef.current?.clear();
      setUsage({ ...emptyUsage });
      return;
    }

    if (text === '/quit' || text === '/exit') {
      exit();
      return;
    }

    setMessages((prev) => [...prev, { role: 'user', content: text }]);
    setBusy(true);
    setStreamingText('');

    try {
      const result = await sessionRef.current!.send(text);
      setStreamingText('');
      setMessages((prev) => [...prev, { role: 'assistant', content: result.text }]);
      setUsage(sessionRef.current!.getUsage());
    } catch (error) {
      const errMsg = error instanceof Error ? error.message : String(error);
      setMessages((prev) => [...prev, { role: 'assistant', content: `Error: ${errMsg}` }]);
    } finally {
      setBusy(false);
    }
  };

  return h(Box, { flexDirection: 'column' as const },
    h(Box, { paddingX: 1 },
      h(Text, { bold: true, color: 'cyan' }, 'smartchat'),
      modelName ? h(Text, { dimColor: true }, ` \u2014 ${modelName}`) : null,
    ),
    h(MessageList, { messages, streamingText, busy }),
    h(InputArea, { disabled: busy, onSubmit: handleSubmit }),
    h(StatusBar, { modelName, usage, busy }),
  );
}