using System;
using System.IO;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using MySqlConnector;
using Serilog;
using SyncEngine.Configuration;
using SyncEngine.MySql;

namespace SyncEngine.Tests
{
    [TestClass]
    public class ShopSyncLogClientFallbackTests
    {
        private static ShopSyncLogEntry SampleEntry()
        {
            return new ShopSyncLogEntry
            {
                RunStartedAt = DateTime.UtcNow,
                RunFinishedAt = DateTime.UtcNow,
                Status = "failed",
                SourceReachable = false,
                ProductsUpserted = 0,
                ProductsWithdrawn = 0,
                Message = "MySQL down"
            };
        }

        [TestMethod]
        public void WriteLogWithFallback_MysqlSuccess_DoesNotCallApi()
        {
            var apiCalled = false;
            var options = new SyncOptions
            {
                ShopSyncApiUrl = "https://shop.example.com/api/shop-sync/log",
                ShopSyncApiKey = "secret"
            };
            var client = new ShopSyncLogClient(
                new LoggerConfiguration().CreateLogger(),
                options,
                new FakeApiClient(() => apiCalled = true));
            client.MySqlWriteForTests = (entry, factory) => { };

            client.WriteLogWithFallback(SampleEntry(), new MySqlConnectionFactory(options), options);

            Assert.IsFalse(apiCalled);
        }

        [TestMethod]
        public void WriteLogWithFallback_MysqlFails_UsesApiWhenConfigured()
        {
            var apiCalled = false;
            var options = new SyncOptions
            {
                ShopSyncApiUrl = "https://shop.example.com/api/shop-sync/log",
                ShopSyncApiKey = "secret"
            };
            var client = new ShopSyncLogClient(
                new LoggerConfiguration().CreateLogger(),
                options,
                new FakeApiClient(() => apiCalled = true));
            client.MySqlWriteForTests = (entry, factory) =>
            {
                throw new InvalidOperationException("connection failed");
            };

            client.WriteLogWithFallback(SampleEntry(), new MySqlConnectionFactory(options), options);

            Assert.IsTrue(apiCalled);
        }

        [TestMethod]
        public void WriteLogWithFallback_MysqlFailsWithoutApi_Rethrows()
        {
            var options = new SyncOptions();
            var client = new ShopSyncLogClient(new LoggerConfiguration().CreateLogger(), options, null);
            client.MySqlWriteForTests = (entry, factory) =>
            {
                throw new InvalidOperationException("connection failed");
            };

            try
            {
                client.WriteLogWithFallback(SampleEntry(), new MySqlConnectionFactory(options), options);
                Assert.Fail("Expected InvalidOperationException");
            }
            catch (InvalidOperationException)
            {
            }
        }

        [TestMethod]
        public void WriteLogWithFallback_BothFail_ThrowsAggregateException()
        {
            var options = new SyncOptions
            {
                ShopSyncApiUrl = "https://shop.example.com/api/shop-sync/log",
                ShopSyncApiKey = "secret"
            };
            var client = new ShopSyncLogClient(
                new LoggerConfiguration().CreateLogger(),
                options,
                new FakeApiClient(() => { throw new InvalidOperationException("API down"); }));
            client.MySqlWriteForTests = (entry, factory) =>
            {
                throw new InvalidOperationException("connection failed");
            };

            try
            {
                client.WriteLogWithFallback(SampleEntry(), new MySqlConnectionFactory(options), options);
                Assert.Fail("Expected AggregateException");
            }
            catch (AggregateException ex)
            {
                Assert.AreEqual(2, ex.InnerExceptions.Count);
            }

            var files = Directory.GetFiles(_tempDir, "shop-sync-log-failed-*.jsonl");
            Assert.AreEqual(1, files.Length);
        }

        private string _tempDir;

        [TestInitialize]
        public void FallbackSetUp()
        {
            _tempDir = Path.Combine(Path.GetTempPath(), "sync-coordinator-fallback-" + Guid.NewGuid().ToString("N"));
            Directory.CreateDirectory(_tempDir);
            ShopSyncLogLocalWriter.SetLogDirectoryProviderForTests(() => _tempDir);
        }

        [TestCleanup]
        public void FallbackTearDown()
        {
            ShopSyncLogLocalWriter.ResetLogDirectoryProviderForTests();
            if (Directory.Exists(_tempDir))
            {
                Directory.Delete(_tempDir, recursive: true);
            }
        }

        private sealed class FakeApiClient : IShopSyncLogApiClient
        {
            private readonly Action _onPost;

            public FakeApiClient(Action onPost)
            {
                _onPost = onPost;
            }

            public void PostLog(ShopSyncLogEntry entry)
            {
                _onPost();
            }
        }
    }
}