float decay_half_life_days;

float time_weight;

float min_weight;

ScoringConfig(float half_life = 30.0f, float weight = 0.3f, float min = 0.0f)

: decay_half_life_days(half_life), time_weight(weight), min_weight(min) {}

static float calculate_score(float distance, const Metadata& meta, const ScoringConfig& config, double now_ts) {

// Convert distance to similarity (0-1)

// For L2 distance, similarity = 1 / (1 + distance)

float similarity = 1.0f / (1.0f + distance);

// Temporal decay (exponential)

double age_seconds = now_ts - static_cast<double>(meta.timestamp);

if (age_seconds < 0) age_seconds = 0;

double age_days = age_seconds / 86400.0;

float recency = std::pow(0.5f, static_cast<float>(age_days / config.decay_half_life_days));

// Apply min_weight floor if needed

if (recency < config.min_weight) recency = config.min_weight;

// Combined score

float final_score = ((1.0f - config.time_weight) * similarity + config.time_weight * recency) * meta.importance;

return final_score;

}