// ==========================================================================
//  Squidex Headless CMS
// ==========================================================================
//  Copyright (c) Squidex UG (haftungsbeschraenkt)
//  All rights reserved. Licensed under the MIT license.
// ==========================================================================

using Microsoft.Azure.CognitiveServices.Vision.ComputerVision;
using Microsoft.Azure.CognitiveServices.Vision.ComputerVision.Models;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Squidex.Domain.Apps.Core.Assets;
using Squidex.Domain.Apps.Entities.Assets;
using Squidex.Domain.Apps.Entities.Assets.Commands;
using Squidex.Infrastructure.Json.Objects;

namespace Squidex.Extensions.Assets.Azure
{
    public sealed class AzureMetadataSource : IAssetMetadataSource
    {
        private const long MaxSize = 5 * 1025 * 1024;
        private readonly ILogger<AzureMetadataSource> log;
        private readonly ComputerVisionClient client;
        private readonly char[] trimChars =
        {
            ' ',
            '_',
            '-'
        };
        private readonly List<VisualFeatureTypes?> features = new List<VisualFeatureTypes?>
        {
            VisualFeatureTypes.Categories,
            VisualFeatureTypes.Description,
            VisualFeatureTypes.Color
        };

        public int Order => int.MaxValue;

        public AzureMetadataSource(IOptions<AzureMetadataSourceOptions> options,
            ILogger<AzureMetadataSource> log)
        {
            client = new ComputerVisionClient(new ApiKeyServiceClientCredentials(options.Value.ApiKey))
            {
                Endpoint = options.Value.Endpoint
            };

            this.log = log;
        }

        public async Task EnhanceAsync(UploadAssetCommand command,
            CancellationToken ct)
        {
            try
            {
                if (command.Type == AssetType.Image && command.File.FileSize <= MaxSize)
                {
                    await using (var stream = command.File.OpenRead())
                    {
                        var result = await client.AnalyzeImageInStreamAsync(stream, features, cancellationToken: ct);

                        command.Tags ??= new HashSet<string>();

                        if (result.Color?.DominantColorForeground != null)
                        {
                            command.Tags.Add($"color/{result.Color.DominantColorForeground.Trim(trimChars).ToLowerInvariant()}");
                        }

                        if (result.Categories != null)
                        {
                            foreach (var category in result.Categories.OrderByDescending(x => x.Score).Take(3))
                            {
                                command.Tags.Add($"category/{category.Name.Trim(trimChars).ToLowerInvariant()}");
                            }
                        }

                        var description = result.Description?.Captions.MaxBy(x => x.Confidence)?.Text;

                        if (description != null)
                        {
                            command.Metadata["caption"] = JsonValue.Create(description);
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                log.LogError(ex, "Failed to enrich asset.");
            }
        }

        public IEnumerable<string> Format(IAssetEntity asset)
        {
            yield break;
        }
    }
}