import type { Adapter, RankedDoc, Session } from "../types.js";

interface GrepState {
  sessions: Session[];
}

function tokenize(s: string): string[] {
  return s
    .toLowerCase()
    .replace(/[^a-z0-9_]+/g, " ")
    .split(/\s+/)
    .filter((t) => t.length > 2);
}

export const grepAdapter: Adapter<GrepState> = {
  name: "grep",
  async init(sessions) {
    return { sessions };
  },
  async query(q, state, k) {
    const terms = tokenize(q);
    const scored: RankedDoc[] = [];
    for (const s of state.sessions) {
      const body = s.content.toLowerCase();
      let hits = 0;
      for (const t of terms) {
        if (body.includes(t)) hits += 1;
      }
      if (hits > 0) {
        scored.push({ sessionId: s.id, score: hits });
      }
    }
    scored.sort((a, b) => b.score - a.score);
    return scored.slice(0, k);
  },
};