/* ========================================================================
 * Copyright (c) 2005-2025 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * The complete license agreement can be found here:
 * http://opcfoundation.org/License/MIT/1.00/
 * ======================================================================*/

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

namespace Opc.Ua.Gds.Client
{
    public class LocalDiscoveryServerClient : ILocalDiscoveryServerClient
    {
        /// <summary>
        /// Create local discovery client
        /// </summary>
        /// <param name="configuration">Application configuration to use</param>
        /// <param name="diagnosticsMasks">The return diagnostics for all discovery requests</param>
        public LocalDiscoveryServerClient(
            ApplicationConfiguration configuration,
            DiagnosticsMasks diagnosticsMasks = DiagnosticsMasks.None)
        {
            ApplicationConfiguration = configuration ?? throw new ArgumentNullException(nameof(configuration));
            DiagnosticsMasks = diagnosticsMasks;
            MessageContext = configuration.CreateMessageContext();

            // set some defaults for the preferred locales.
            System.Globalization.CultureInfo culture = System.Globalization.CultureInfo
                .CurrentUICulture;

            var locales = new List<string> { culture.Name };

            culture = System.Globalization.CultureInfo.CurrentCulture;

            if (!locales.Contains(culture.Name))
            {
                locales.Add(culture.Name);
            }

            if (!locales.Contains("en-US"))
            {
                locales.Add("en-US");
            }

            PreferredLocales = [.. locales];
        }

        public ApplicationConfiguration ApplicationConfiguration { get; }
        public DiagnosticsMasks DiagnosticsMasks { get; }
        public IServiceMessageContext MessageContext { get; }

        public ArrayOf<string> PreferredLocales { get; set; }

        public int DefaultOperationTimeout { get; set; }

        public ValueTask<ArrayOf<ApplicationDescription>> FindServersAsync(
            CancellationToken ct = default)
        {
            return FindServersAsync(null, null, ct);
        }

        public async ValueTask<ArrayOf<ApplicationDescription>> FindServersAsync(
            string? endpointUrl,
            string? endpointTransportProfileUri,
            CancellationToken ct = default)
        {
            DiscoveryClient client = await CreateClientAsync(
                endpointUrl,
                endpointTransportProfileUri,
                ct).ConfigureAwait(false);

            FindServersResponse response = await client.FindServersAsync(
                null,
                endpointUrl,
                PreferredLocales,
                default,
                ct).ConfigureAwait(false);

            return response.Servers;
        }

        public ValueTask<ArrayOf<EndpointDescription>> GetEndpointsAsync(string endpointUrl, CancellationToken ct = default)
        {
            return GetEndpointsAsync(endpointUrl, null, ct);
        }

        public async ValueTask<ArrayOf<EndpointDescription>> GetEndpointsAsync(
            string endpointUrl,
            string? endpointTransportProfileUri,
            CancellationToken ct = default)
        {
            DiscoveryClient client = await CreateClientAsync(endpointUrl, endpointTransportProfileUri, ct).ConfigureAwait(false);

            GetEndpointsResponse response = await client.GetEndpointsAsync(
                null,
                endpointUrl,
                PreferredLocales,
                default,
                ct)
                .ConfigureAwait(false);

            return response.Endpoints;
        }

        public ValueTask<(ArrayOf<ServerOnNetwork>, DateTimeUtc lastCounterResetTime)> FindServersOnNetworkAsync(
            uint startingRecordId,
            uint maxRecordsToReturn,
            CancellationToken ct = default)
        {
            return FindServersOnNetworkAsync(
                null,
                null,
                startingRecordId,
                maxRecordsToReturn,
                default,
                ct);
        }

        public async ValueTask<(ArrayOf<ServerOnNetwork>, DateTimeUtc lastCounterResetTime)> FindServersOnNetworkAsync(
            string? endpointUrl,
            string? endpointTransportProfileUri,
            uint startingRecordId,
            uint maxRecordsToReturn,
            ArrayOf<string> serverCapabilityFilters,
            CancellationToken ct = default)
        {
            DiscoveryClient client = await CreateClientAsync(endpointUrl, endpointTransportProfileUri, ct).ConfigureAwait(false);

            FindServersOnNetworkResponse response = await client.FindServersOnNetworkAsync(
                null,
                startingRecordId,
                maxRecordsToReturn,
                serverCapabilityFilters,
                ct).ConfigureAwait(false);

            return (response.Servers, response.LastCounterResetTime);
        }

        protected virtual Task<DiscoveryClient> CreateClientAsync(
            string? endpointUrl,
            string? endpointTransportProfileUri,
            CancellationToken ct = default)
        {
            if (string.IsNullOrEmpty(endpointUrl))
            {
                endpointUrl = kDefaultUrl;
            }

            if (!Uri.IsWellFormedUriString(endpointUrl, UriKind.Absolute))
            {
                throw new ArgumentException("Not a valid URL.", nameof(endpointUrl));
            }

            var configuration = EndpointConfiguration.Create(ApplicationConfiguration);

            if (DefaultOperationTimeout != 0)
            {
                configuration.OperationTimeout = DefaultOperationTimeout;
            }

            return DiscoveryClient.CreateAsync(
                ApplicationConfiguration,
                new Uri(endpointUrl),
                configuration,
                DiagnosticsMasks,
                ct);
        }

        /// <inheritdoc/>
        public async ValueTask DisposeAsync()
        {
            if (m_disposed)
            {
                return;
            }
            m_disposed = true;
            try
            {
                await m_disposeCts.CancelAsync().ConfigureAwait(false);
            }
            catch (ObjectDisposedException)
            {
            }
            m_disposeCts.Dispose();
            GC.SuppressFinalize(this);
        }

        private readonly CancellationTokenSource m_disposeCts = new();
        private bool m_disposed;
        private const string kDefaultUrl = "opc.tcp://localhost:4840";
    }
}