package store

import (
	"context"
	"errors"

	"github.com/jackc/pgx/v5/pgconn"
	"github.com/jackc/pgerrcode"
)

// AddContact creates a contact relation or returns ErrDuplicate if it exists.
func (s *Store) AddContact(ctx context.Context, ownerID, contactID int64) error {
	_, err := s.pool.Exec(ctx, `
       INSERT INTO contacts(owner_id, contact_id)
       VALUES($1, $2)
   `, ownerID, contactID)
	if err != nil {
		var pgErr *pgconn.PgError
		if errors.As(err, &pgErr) && pgErr.Code == pgerrcode.UniqueViolation {
			return ErrDuplicate
		}
	}
	return err
}

// RemoveContact deletes a contact relation; no error if not present.
func (s *Store) RemoveContact(ctx context.Context, ownerID, contactID int64) error {
	_, err := s.pool.Exec(ctx, `
       DELETE FROM contacts WHERE owner_id=$1 AND contact_id=$2
   `, ownerID, contactID)
	return err
}

// ListContacts returns all contacts for an owner ordered by created_at descending.
func (s *Store) ListContacts(ctx context.Context, ownerID int64) ([]Contact, error) {
	rows, err := s.pool.Query(ctx, `
       SELECT owner_id, contact_id, created_at
       FROM contacts WHERE owner_id=$1
       ORDER BY created_at DESC
   `, ownerID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var list []Contact
	for rows.Next() {
		var c Contact
		if err := rows.Scan(&c.OwnerID, &c.ContactID, &c.CreatedAt); err != nil {
			return nil, err
		}
		list = append(list, c)
	}
	return list, nil
}

// IsContact reports whether a contact relation exists.
func (s *Store) IsContact(ctx context.Context, ownerID, contactID int64) (bool, error) {
	var exists bool
	err := s.pool.QueryRow(ctx, `
       SELECT EXISTS(
           SELECT 1 FROM contacts WHERE owner_id=$1 AND contact_id=$2
       )
   `, ownerID, contactID).Scan(&exists)
	if err != nil {
		return false, err
	}
	return exists, nil
}