package wave

import (
	"context"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
)

// Only currently visible activity is a social signal. A hidden profile never contributes
// its listening history, and self feedback/recent plays retain precedence.
func (h *Handler) friendCandidates(ctx context.Context, user uuid.UUID, exclude []string) ([]string, error) {
	rows, e := h.pool.Query(ctx, `SELECT a.track_id::text FROM listening_activity a
 JOIN users friend ON friend.id=a.user_id AND NOT friend.is_blocked AND friend.activity_visibility IN ('friends','everyone')
 JOIN users own ON own.id=$1 AND own.friends_recommendations
 JOIN friendships f ON f.low_id=LEAST($1::uuid,a.user_id) AND f.high_id=GREATEST($1::uuid,a.user_id) AND f.accepted
 JOIN tracks t ON t.id=a.track_id JOIN media_files mf ON mf.id=t.primary_file_id AND mf.missing_since IS NULL
 JOIN library_sources src ON src.id=mf.source_id AND src.status='mounted'
 WHERE a.updated_at>now()-interval '90 seconds' AND NOT(a.track_id::text=ANY($2::text[]))
 AND NOT EXISTS(SELECT 1 FROM social_blocks b WHERE (b.user_id=$1 AND b.peer_id=a.user_id) OR (b.user_id=a.user_id AND b.peer_id=$1))
 AND NOT EXISTS(SELECT 1 FROM track_reactions r WHERE r.user_id=$1 AND r.track_id=a.track_id AND r.reaction='dislike')
 AND NOT EXISTS(SELECT 1 FROM play_events e WHERE e.user_id=$1 AND e.track_id=a.track_id AND e.type='play_start' AND e.occurred_at>now()-interval '3 hours')
 GROUP BY a.track_id ORDER BY count(DISTINCT a.user_id) DESC,max(a.updated_at) DESC LIMIT 30`, user, exclude)
	if e != nil {
		return nil, e
	}
	defer rows.Close()
	return pgx.CollectRows(rows, pgx.RowTo[string])
}
func blendFriendPick(picks []Pick, ids []string) []Pick {
	if len(ids) == 0 || len(picks) < 3 {
		return picks
	}
	for _, id := range ids {
		exists := false
		for _, p := range picks {
			if p.ID == id {
				exists = true
				break
			}
		}
		if !exists {
			out := append([]Pick(nil), picks...)
			out[len(out)-1] = Pick{ID: id, Source: "friends", Score: 0.1}
			return out
		}
	}
	return picks
}