package auth

import (
	"context"
	"crypto/rand"
	"fmt"

	"github.com/jackc/pgx/v5/pgxpool"
)

// PostgresClientStore persists dynamically registered OAuth clients (RFC 7591) in PostgreSQL.
type PostgresClientStore struct {
	pool *pgxpool.Pool
}

func NewPostgresClientStore(pool *pgxpool.Pool) *PostgresClientStore {
	return &PostgresClientStore{pool: pool}
}

func (s *PostgresClientStore) Register(name string, redirectURIs []string) (DynamicClient, error) {
	b := make([]byte, 16)
	if _, err := rand.Read(b); err != nil {
		return DynamicClient{}, err
	}
	clientID := fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])

	var client DynamicClient
	row := s.pool.QueryRow(context.Background(), `
		insert into oauth_clients (client_id, client_name, redirect_uris)
		values ($1, $2, $3)
		returning client_id, client_name, redirect_uris, created_at
	`, clientID, name, redirectURIs)
	if err := row.Scan(&client.ClientID, &client.ClientName, &client.RedirectURIs, &client.CreatedAt); err != nil {
		return DynamicClient{}, fmt.Errorf("register oauth client: %w", err)
	}
	return client, nil
}

func (s *PostgresClientStore) Lookup(clientID string) (DynamicClient, bool) {
	var client DynamicClient
	row := s.pool.QueryRow(context.Background(), `
		select client_id, client_name, redirect_uris, created_at
		from oauth_clients
		where client_id = $1
	`, clientID)
	if err := row.Scan(&client.ClientID, &client.ClientName, &client.RedirectURIs, &client.CreatedAt); err != nil {
		return DynamicClient{}, false
	}
	return client, true
}