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

using System.Globalization;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Net.Http.Headers;
using Squidex.Areas.Api.Controllers.Assets.Models;
using Squidex.Assets;
using Squidex.Domain.Apps.Core.Assets;
using Squidex.Domain.Apps.Entities;
using Squidex.Domain.Apps.Entities.Assets;
using Squidex.Infrastructure;
using Squidex.Infrastructure.Commands;
using Squidex.Web;

namespace Squidex.Areas.Api.Controllers.Assets
{
    /// <summary>
    /// Uploads and retrieves assets.
    /// </summary>
    [ApiExplorerSettings(GroupName = nameof(Assets))]
    public sealed class AssetContentController : ApiController
    {
        private readonly IAssetFileStore assetFileStore;
        private readonly IAssetQueryService assetQuery;
        private readonly IAssetLoader assetLoader;
        private readonly IAssetThumbnailGenerator assetThumbnailGenerator;

        public AssetContentController(
            ICommandBus commandBus,
            IAssetFileStore assetFileStore,
            IAssetQueryService assetQuery,
            IAssetLoader assetLoader,
            IAssetThumbnailGenerator assetThumbnailGenerator)
            : base(commandBus)
        {
            this.assetFileStore = assetFileStore;
            this.assetQuery = assetQuery;
            this.assetLoader = assetLoader;
            this.assetThumbnailGenerator = assetThumbnailGenerator;
        }

        /// <summary>
        /// Get the asset content.
        /// </summary>
        /// <param name="app">The name of the app.</param>
        /// <param name="idOrSlug">The id or slug of the asset.</param>
        /// <param name="request">The request parameters.</param>
        /// <param name="more">Optional suffix that can be used to seo-optimize the link to the image Has not effect.</param>
        /// <returns>
        /// 200 => Asset found and content or (resized) image returned.
        /// 404 => Asset or app not found.
        /// </returns>
        [HttpGet]
        [Route("assets/{app}/{idOrSlug}/{*more}")]
        [ProducesResponseType(typeof(FileResult), StatusCodes.Status200OK)]
        [ApiPermission]
        [ApiCosts(0.5)]
        [AllowAnonymous]
        public async Task<IActionResult> GetAssetContentBySlug(string app, string idOrSlug, AssetContentQueryDto request, string? more = null)
        {
            var requestContext = Context.Clone(b => b.WithoutAssetEnrichment());

            var asset = await assetQuery.FindAsync(requestContext, DomainId.Create(idOrSlug), ct: HttpContext.RequestAborted);

            if (asset == null)
            {
                asset = await assetQuery.FindBySlugAsync(requestContext, idOrSlug, HttpContext.RequestAborted);
            }

            return await DeliverAssetAsync(requestContext, asset, request);
        }

        /// <summary>
        /// Get the asset content.
        /// </summary>
        /// <param name="id">The id of the asset.</param>
        /// <param name="request">The request parameters.</param>
        /// <returns>
        /// 200 => Asset found and content or (resized) image returned.
        /// 404 => Asset or app not found.
        /// </returns>
        [HttpGet]
        [Route("assets/{id}/")]
        [ProducesResponseType(typeof(FileResult), StatusCodes.Status200OK)]
        [ApiPermission]
        [ApiCosts(0.5)]
        [AllowAnonymous]
        [Obsolete("Use overload with app name")]
        public async Task<IActionResult> GetAssetContent(DomainId id, AssetContentQueryDto request)
        {
            var requestContext = Context.Clone(b => b.WithoutAssetEnrichment());

            var asset = await assetQuery.FindGlobalAsync(requestContext, id, HttpContext.RequestAborted);

            return await DeliverAssetAsync(requestContext, asset, request);
        }

        private async Task<IActionResult> DeliverAssetAsync(Context context, IAssetEntity? asset, AssetContentQueryDto request)
        {
            request ??= new AssetContentQueryDto();

            if (asset == null)
            {
                return NotFound();
            }

            if (asset.IsProtected && !Resources.CanReadAssets)
            {
                Response.Headers[HeaderNames.CacheControl] = "public,max-age=0";

                return StatusCode(403);
            }

            if (asset != null && request.Version > EtagVersion.Any && asset.Version != request.Version)
            {
                if (context.App != null)
                {
                    asset = await assetQuery.FindAsync(context, asset.Id, request.Version, HttpContext.RequestAborted);
                }
                else
                {
                    // Fallback for old endpoint. Does not set the surrogate key.
                    asset = await assetLoader.GetAsync(asset.AppId.Id, asset.Id, request.Version);
                }
            }

            if (asset == null)
            {
                return NotFound();
            }

            Response.Headers[HeaderNames.ETag] = asset.FileVersion.ToString(CultureInfo.InvariantCulture);

            if (request.CacheDuration > 0)
            {
                Response.Headers[HeaderNames.CacheControl] = $"public,max-age={request.CacheDuration}";
            }

            var resizeOptions = request.ToResizeOptions(asset, HttpContext.Request);

            var contentLength = (long?)null;
            var contentCallback = (FileCallback?)null;
            var contentType = asset.MimeType;

            if (asset.Type == AssetType.Image && assetThumbnailGenerator.IsResizable(asset.MimeType, resizeOptions, out var destinationMimeType))
            {
                contentType = destinationMimeType!;

                contentCallback = async (body, range, ct) =>
                {
                    var suffix = resizeOptions.ToString();

                    if (request.Force)
                    {
                        using (Telemetry.Activities.StartActivity("Resize"))
                        {
                            await ResizeAsync(asset, suffix, body, resizeOptions, true, ct);
                        }
                    }
                    else
                    {
                        try
                        {
                            await DownloadAsync(asset, body, suffix, range, ct);
                        }
                        catch (AssetNotFoundException)
                        {
                            await ResizeAsync(asset, suffix, body, resizeOptions, false, ct);
                        }
                    }
                };
            }
            else
            {
                contentLength = asset.FileSize;

                contentCallback = async (body, range, ct) =>
                {
                    await DownloadAsync(asset, body, null, range, ct);
                };
            }

            return new FileCallbackResult(contentType, contentCallback)
            {
                EnableRangeProcessing = contentLength > 0,
                ErrorAs404 = true,
                FileDownloadName = asset.FileName,
                FileSize = contentLength,
                LastModified = asset.LastModified.ToDateTimeOffset(),
                SendInline = request.Download != 1
            };
        }

        private async Task DownloadAsync(IAssetEntity asset, Stream bodyStream, string? suffix, BytesRange range,
            CancellationToken ct)
        {
            await assetFileStore.DownloadAsync(asset.AppId.Id, asset.Id, asset.FileVersion, suffix, bodyStream, range, ct);
        }

        private async Task ResizeAsync(IAssetEntity asset, string suffix, Stream target, ResizeOptions resizeOptions, bool overwrite,
            CancellationToken ct)
        {
#pragma warning disable MA0040 // Flow the cancellation token
            using var activity = Telemetry.Activities.StartActivity("Resize");

            await using var assetOriginal = new TempAssetFile(asset.FileName, asset.MimeType, 0);
            await using var assetResized = new TempAssetFile(asset.FileName, asset.MimeType, 0);

            using (Telemetry.Activities.StartActivity("Read"))
            {
                await using (var originalStream = assetOriginal.OpenWrite())
                {
                    await assetFileStore.DownloadAsync(asset.AppId.Id, asset.Id, asset.FileVersion, null, originalStream);
                }
            }

            using (Telemetry.Activities.StartActivity("Resize"))
            {
                try
                {
                    await using (var originalStream = assetOriginal.OpenRead())
                    {
                        await using (var resizeStream = assetResized.OpenWrite())
                        {
                            await assetThumbnailGenerator.CreateThumbnailAsync(originalStream, asset.MimeType, resizeStream, resizeOptions);
                        }
                    }
                }
                catch
                {
                    await using (var originalStream = assetOriginal.OpenRead())
                    {
                        await using (var resizeStream = assetResized.OpenWrite())
                        {
                            await originalStream.CopyToAsync(resizeStream);
                        }
                    }
                }
            }

            using (Telemetry.Activities.StartActivity("Save"))
            {
                try
                {
                    await using (var resizeStream = assetResized.OpenRead())
                    {
                        await assetFileStore.UploadAsync(asset.AppId.Id, asset.Id, asset.FileVersion, suffix, resizeStream, overwrite);
                    }
                }
                catch (AssetAlreadyExistsException)
                {
                    return;
                }
            }

            using (Telemetry.Activities.StartActivity("Write"))
            {
                await using (var resizeStream = assetResized.OpenRead())
                {
                    await resizeStream.CopyToAsync(target, ct);
                }
            }
#pragma warning restore MA0040 // Flow the cancellation token
        }
    }
}