import type { NormalizedBlock } from './types';

const NOISE_TOOLS = new Set([
  'TodoWrite',
  'TodoRead',
  'ToolSearch',
  'WebSearch',
  'AskUser',
  'ExitSpecMode',
  'GenerateDroid',
]);

const NOISE_STRINGS = [
  'Continue from where you left off.',
  'No response requested.',
  'IMPORTANT: TodoWrite was not called yet.',
];

const XML_WRAPPER_RE =
  /<(system-reminder|ide_opened_file|command-message|context-window-usage)[^>]*>[\s\S]*?<\/\1>/g;

const isNoiseUserBlock = (text: string): boolean => {
  const trimmed = text.trim();
  if (NOISE_STRINGS.some((s) => trimmed.includes(s))) return true;
  const stripped = trimmed.replace(XML_WRAPPER_RE, '').trim();
  return stripped.length === 0;
};

const cleanUserText = (text: string): string => text.replace(XML_WRAPPER_RE, '').trim();

export const filterNoise = (blocks: NormalizedBlock[]): NormalizedBlock[] => {
  const out: NormalizedBlock[] = [];
  for (const b of blocks) {
    if (b.kind === 'thinking') continue;
    if (b.kind === 'tool_call' && NOISE_TOOLS.has(b.name)) continue;
    if (b.kind === 'tool_result' && NOISE_TOOLS.has(b.name)) continue;
    if (b.kind === 'user') {
      if (isNoiseUserBlock(b.text)) continue;
      const cleaned = cleanUserText(b.text);
      if (!cleaned) continue;
      out.push({ kind: 'user', text: cleaned });
      continue;
    }
    out.push(b);
  }
  return out;
};