const SOURCE_QUALITY = {
  calendar: 0.95,
  chat: 0.85,
  meinput: 0.82,
  memory_v2: 0.78,
};

function parseMs(value) {
  if (!value) return null;
  const ms = new Date(value).getTime();
  return Number.isNaN(ms) ? null : ms;
}

function temporalMatch(item, plan) {
  const mode = plan.temporal_mode ?? 'AMBIGUOUS';
  const mentionStart = parseMs(plan.time?.mention_range?.start);
  const mentionEnd = parseMs(plan.time?.mention_range?.end);
  const eventStart = parseMs(plan.time?.event_range?.start);
  const eventEnd = parseMs(plan.time?.event_range?.end);
  const observed = parseMs(item.observed_time);
  const event = parseMs(item.event_time);

  const inMention =
    observed !== null && mentionStart !== null && mentionEnd !== null
      ? observed >= mentionStart && observed < mentionEnd
      : 0.5;
  const inEvent =
    event !== null && eventStart !== null && eventEnd !== null
      ? event >= eventStart && event < eventEnd
      : inMention;

  switch (mode) {
    case 'OCCURRED_IN':
      return event !== null ? (inEvent ? 1 : 0.2) : inMention * 0.85;
    case 'MENTIONED_IN':
    case 'CREATED_IN':
      return inMention ? 1 : 0.25;
    case 'PLANNED_IN':
    case 'DUE_IN':
      return event !== null ? (inEvent ? 1 : 0.3) : inMention * 0.7;
    default:
      return Math.max(inMention, inEvent * 0.9);
  }
}

function semanticMatch(item, expandedQueries = []) {
  if (!expandedQueries?.length) return 0.75;
  const text = `${item.title ?? ''} ${item.content ?? ''}`;
  let hits = 0;
  for (const q of expandedQueries) {
    if (q && text.includes(q)) hits += 1;
  }
  return Math.min(1, 0.45 + hits * 0.12);
}

/**
 * @param {object} item
 * @param {object} plan
 * @param {string[]} expandedQueries
 */
export function computeRecallScore(item, plan, expandedQueries = []) {
  const source_quality = SOURCE_QUALITY[item.source] ?? 0.7;
  const temporal_match = temporalMatch(item, plan);
  const semantic_match = semanticMatch(item, expandedQueries);
  const importance = Number(item.importance ?? 0.5);
  const confidence = Number(item.confidence ?? 0.8);
  const recall_score =
    source_quality * temporal_match * semantic_match * importance * confidence;
  return Number(Math.min(1, recall_score).toFixed(4));
}

/**
 * @param {object[]} items
 * @param {object} plan
 */
export function rankTimelineItems(items, plan) {
  const retrievalQueries = Object.fromEntries(
    (plan.retrievals ?? []).map((r) => [r.source, r.expanded_queries ?? []]),
  );
  return items
    .map((item) => ({
      ...item,
      recall_score: computeRecallScore(
        item,
        plan,
        retrievalQueries[item.source] ?? [],
      ),
    }))
    .filter((item) => item.recall_score >= (plan.filters?.importance_min ?? 0.35) * 0.55)
    .sort((a, b) => b.recall_score - a.recall_score);
}