using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using Cysharp.Threading.Tasks;

namespace ShrinkDataSaver.Tests
{
    /// <summary>
    /// 内存模拟存储，用于单元测试，无需文件 I/O。
    /// </summary>
    public class MockStorageProvider : IStorageProvider
    {
        private readonly Dictionary<string, byte[]> _store = new();

        public UniTask WriteAsync(string path, byte[] data, CancellationToken ct = default)
        {
            _store[NormalizePath(path)] = data;
            return UniTask.CompletedTask;
        }

        public UniTask<byte[]> ReadAsync(string path, CancellationToken ct = default)
        {
            var key = NormalizePath(path);
            if (!_store.TryGetValue(key, out var data))
                throw new FileNotFoundException($"MockStorage: {key}");
            return UniTask.FromResult(data);
        }

        public UniTask<bool> ExistsAsync(string path, CancellationToken ct = default)
            => UniTask.FromResult(_store.ContainsKey(NormalizePath(path)));

        public UniTask DeleteAsync(string path, CancellationToken ct = default)
        {
            _store.Remove(NormalizePath(path));
            return UniTask.CompletedTask;
        }

        public UniTask<string[]> ListAsync(string prefix = "", CancellationToken ct = default)
        {
            var norm = NormalizePath(prefix);
            var results = _store.Keys
                .Where(k => string.IsNullOrEmpty(norm) || k.StartsWith(norm))
                .ToArray();
            return UniTask.FromResult(results);
        }

        public void Clear() => _store.Clear();
        public int Count => _store.Count;

        private static string NormalizePath(string path)
            => path.Replace('\\', '/');
    }
}