package store

import (
	core "agent-system-core"
)

// searchKnowledgePG：PG 档知识检索（设计 D16）。
// 单查询混合：tsvector（'simple' 配置，词级）OR trigram LIKE 子串（中文兜底；
// LIKE 由 pg_trgm GIN 索引加速）。排序：ts_rank 优先，命中时间次之。
func (s *Store) searchKnowledgePG(owner string, q core.RetrievalQuery) ([]core.RetrievalHit, error) {
	topK := q.TopK
	if topK <= 0 {
		topK = 5
	}
	text := q.Text
	rows, err := s.db.Query(s.q(`
		SELECT k.id,k.owner,k.project_id,k.source,k.title,k.ref,k.chunk,k.created_at,
		       ts_rank(k.tsv, websearch_to_tsquery('simple', ?)) AS r
		FROM knowledge k
		WHERE (k.owner=? OR k.owner='')
		  AND (? = '' OR k.tsv @@ websearch_to_tsquery('simple', ?) OR k.chunk LIKE ? OR k.title LIKE ?)
		ORDER BY r DESC, k.created_at DESC
		LIMIT ?`), text, owner, text, text, "%"+text+"%", "%"+text+"%", topK*2)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []core.RetrievalHit
	for rows.Next() {
		var d core.KnowledgeDoc
		var own, ca string
		var rank float64
		if err := rows.Scan(&d.ID, &own, &d.ProjectID, &d.Source, &d.Title, &d.Ref, &d.Chunk, &ca, &rank); err != nil {
			return nil, err
		}
		d.Owner = own
		d.CreatedAt, _ = parseTime(ca)
		if !knowledgeVisible(owner, q, d) {
			continue
		}
		score := rank
		if score == 0 {
			score = 0.5 // 纯子串命中（trigram/中文兜底）给保底分
		}
		out = append(out, core.RetrievalHit{Doc: d, Score: score, Kind: "fulltext"})
		if len(out) >= topK {
			break
		}
	}
	return out, rows.Err()
}