import type { Dispatch } from 'react';
import type { AppAction, SupportedLanguage } from '@/types';

const MAX_CODE_LENGTH = 10_000;

export function useCodeExecution(dispatch: Dispatch<AppAction>) {
  async function execute(language: SupportedLanguage, code: string): Promise<void> {
    if (code.trim().length === 0) return;

    if (code.length > MAX_CODE_LENGTH) {
      dispatch({ type: 'SET_ERROR', payload: 'Code exceeds the 10,000 character limit.' });
      return;
    }

    // HTML is handled by HtmlPreview client-side
    if (language === 'html') {
      return;
    }

    dispatch({ type: 'EXECUTE_START' });

    try {
      const res = await fetch('/api/execute', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ language, code }),
      });

      if (!res.ok) {
        const data = await res.json().catch(() => ({}));
        throw new Error(data.error ?? `Server error ${res.status}`);
      }

      const result = await res.json();
      dispatch({ type: 'EXECUTE_DONE', payload: result });
    } catch (err) {
      dispatch({
        type: 'EXECUTE_DONE',
        payload: {
          stdout: '',
          stderr: '',
          exitCode: -1,
          timedOut: false,
          error: err instanceof Error ? err.message : 'Execution failed',
        },
      });
    }
  }

  return { execute };
}