using FileService.Application.Ports;
using FileService.Application.StorageContracts;
using FileService.Domain.ValueObjects;
using IM.Commons;
using IM.InitCommon;
using Microsoft.Extensions.Options;
using StackExchange.Redis;

namespace FileService.Infrastructure.Storage
{
    public class LocalStorageAdapter(IStorageRedisCache redis, IOptions<StorageOptions> options) : IObjectStoragePort, ILocalChunkStorage
    {
        private readonly IStorageRedisCache redis = redis;
        private readonly IOptions<StorageOptions> options = options;
        private readonly StorageProviderOptions providerOptions = options.Value.Providers[options.Value.DefaultProviderCode];

        public string ProviderCode => "Local";

        /// <summary>
        /// 单次直传：直接写入 LocalRootPath/{bucket}/{objectKey}。
        /// bucket 传公开桶名即落到公开目录，可被静态托管直链访问。
        /// </summary>
        public async Task<StorageLocation> PutObjectAsync(PutObjectCommand command, CancellationToken token)
        {
            var fullPath = Path.Combine(providerOptions.LocalRootPath!, command.Bucket, command.ObjectKey);
            Directory.CreateDirectory(Path.GetDirectoryName(fullPath)!);

            await using (var fs = new FileStream(fullPath, FileMode.Create))
            {
                await command.Content.CopyToAsync(fs, token);
                await fs.FlushAsync(token);
            }

            return new StorageLocation(
                storageProvider: ProviderCode,
                bucket: command.Bucket,
                objectKey: command.ObjectKey,
                region: providerOptions.Region);
        }

        /// <summary>
        /// 公开桶文件返回静态托管直链；私有文件返回 null。
        /// </summary>
        public string? GetPublicUrl(StorageLocation location)
        {
            if (string.IsNullOrEmpty(providerOptions.PublicBucket) ||
                !string.Equals(location.Bucket, providerOptions.PublicBucket, StringComparison.OrdinalIgnoreCase))
            {
                return null;
            }

            var baseUrl = (providerOptions.PublicBaseUrl ?? providerOptions.LocalUploadApiBaseUrl ?? string.Empty)
                .TrimEnd('/');
            var key = location.ObjectKey.Replace('\\', '/').TrimStart('/');
            return $"{baseUrl}/static/{key}";
        }

        /// <summary>
        /// 打开本地文件读取流：LocalRootPath/{bucket}/{objectKey}。
        /// </summary>
        public Task<Stream> OpenReadAsync(StorageLocation location, CancellationToken token)
        {
            var fullPath = Path.Combine(providerOptions.LocalRootPath!, location.Bucket, location.ObjectKey);
            if (!File.Exists(fullPath))
            {
                throw new FileNotFoundException(fullPath);
            }

            Stream stream = new FileStream(fullPath, FileMode.Open, FileAccess.Read, FileShare.Read);
            return Task.FromResult(stream);
        }

        public async Task<CompleteUploadResult> CompleteUploadAsync(CompleteUploadCommand command, CancellationToken token)
        {
            var res = await MergeAsync(command.UploadSessionId, command.ObjectKey, command.Parts);
            return new CompleteUploadResult(new StorageLocation(
                    storageProvider: command.ProviderCode,
                    bucket: command.Bucket,
                    objectKey: command.ObjectKey,
                    region: command.Region
                ), null, command.Parts.Sum(x => x.Size).Value);
        }
        public async Task<Result<object>> MergeAsync(string sessionId, string objectKey, IReadOnlyList<UploadPart> parts)
        {
            var rootPath = options.Value.Providers[options.Value.DefaultProviderCode].LocalRootPath;
            var tempPath = Path.Combine(rootPath, sessionId, "parts"); // 项目根目录下 uploads                                                                               // 最终文件存储路径（这里可以用你之前 ObjectNameGenerator 生成的名字）
            var finalPath = Path.Combine(rootPath, objectKey);
            var finalDir = Path.GetDirectoryName(finalPath);
            Directory.CreateDirectory(finalDir);

            var storageCache = await redis.GetAsync(sessionId);
            var totalChunks = storageCache.TotalPartCount;
            try
            {
                using (var finalStream = new FileStream(finalPath, FileMode.Create))
                {
                    for (var i = 1; i <= totalChunks; i++)
                    {
                        var progress = (i * 100.0 / totalChunks);
                        if (i % 5 == 0 || i == totalChunks)
                        {
                            //await _redis.HashSetAsync(RedisKeys.MergeStatus(taskId), new HashEntry[]
                            //{
                            //    new("status", "processing"),
                            //    new("progress", progress.ToString("F2"))
                            //});
                        }
                        var chunkPath = Path.Combine(tempPath, $"{i}.part");
                        if (!File.Exists(chunkPath))
                            return Result.Fail(ResultCode.CHUNK_NOT_FOUND);
                        using (var chunkStream = new FileStream(chunkPath, FileMode.Open))
                        {
                            await chunkStream.CopyToAsync(finalStream);
                        }
                    }
                    Directory.Delete(tempPath, true);
                    await redis.DeleteAsync(sessionId);
                }

                return Result.Success();
            }
            catch (Exception e)
            {
                //_logger.LogError(e, e.Message);
                throw;

            }
        }

        public async Task<PresignedUrl> GenerateUploadUrlAsync(GenerateUploadUrlCommand command, CancellationToken token)
        {
            var baseUrl = options.Value.Providers[options.Value.DefaultProviderCode].LocalUploadApiBaseUrl;
            return new PresignedUrl(
                baseUrl + $"local/parts/upload?sessionId={command.UploadSessionId}&partNumber={command.PartNumber}",
                new Dictionary<string, string>(),
                ExpiresAt: DateTimeOffset.Now.Add(options.Value.Providers[options.Value.DefaultProviderCode].UploadUrlExpiresIn)
                );
        }

        public async Task<InitiateUploadResult> InitUploadAsync(InitiateUploadCommand command, CancellationToken token)
        {
            var sessionId = Guid.NewGuid();
            var location = new StorageLocation();
            return new InitiateUploadResult(sessionId.ToString(),location);
        }

        public async Task SavePartAsync(SaveLocalPartCommand command)
        {
            var path = BuildPartPath(
       command.UploadSessionId,
       command.PartNumber);

            Directory.CreateDirectory(
                Path.GetDirectoryName(path)!);

            await using var fs = File.Create(path);

            await command.Stream.CopyToAsync(fs);

            await fs.FlushAsync();
        }
        private string BuildPartPath(
    string uploadSessionId,
    int partNumber)
        {
            return Path.Combine(
                providerOptions.LocalRootPath,
                uploadSessionId,
                "parts",
                $"{partNumber}.part");
        }
    }
}