using System.Net;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting.Server;
using Microsoft.AspNetCore.Hosting.Server.Features;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using WebDrop.Core;
using WebDrop.FileApi;
using WebDrop.FileProtocol;
using static WebDrop.Api.Tests.ServerFixture;

namespace WebDrop.Api.Tests;

/// <summary>文件服务把新增的帧同步到外部存储(WebDAV):增量、可重试、删除后保留一段时间再清理。</summary>
public sealed class FileSyncTests : IAsyncLifetime
{
    private const string Secret = "sync-test-secret-0123456789abcdef-xyz-0123";
    private readonly string _dir = Path.Combine(Path.GetTempPath(), "webdrop-sync-" + Guid.NewGuid().ToString("N"));
    private readonly FakeWebDav _dav = new();
    private WebApplication _files = null!;
    private HttpClient _http = null!;
    private string _channel = "", _channelId = "";

    public async Task InitializeAsync()
    {
        await _dav.StartAsync();
        _files = FileApiApp.Build([], b =>
        {
            b.Configuration["FileApi:DataDir"] = _dir;
            b.Configuration["FileApi:Secret"] = Secret;
            b.Configuration["FileApi:Backup:Enabled"] = "false"; // 定时任务不在测试里跑,测试手动触发
            b.Configuration["FileApi:Backup:RetainDays"] = "30";
            b.Configuration["FileApi:Backup:WebDav:Url"] = _dav.Url;
            b.Configuration["FileApi:Backup:WebDav:Username"] = FakeWebDav.User;
            b.Configuration["FileApi:Backup:WebDav:Password"] = FakeWebDav.Password;
            b.Configuration["FileApi:Backup:WebDav:BasePath"] = "webdrop";
            b.Configuration["urls"] = "http://127.0.0.1:0";
            b.Logging.ClearProviders();
        });
        await _files.StartAsync();
        _http = new HttpClient { BaseAddress = new Uri(_files.Services.GetRequiredService<IServer>().Features.Get<IServerAddressesFeature>()!.Addresses.First()) };
        _channelId = NewId();
        _channel = Hex(_channelId);
    }

    public async Task DisposeAsync()
    {
        _http.Dispose();
        await _files.StopAsync(); await _files.DisposeAsync(); await _dav.DisposeAsync();
        try { Directory.Delete(_dir, recursive: true); } catch (IOException) { }
    }

    private static string Hex(string id) { Codec.TryDecodeExact(id, 16, out var b); return Convert.ToHexStringLower(b); }

    private string Admin() => FileTokens.Sign(System.Text.Encoding.UTF8.GetBytes(Secret), new FileTicket(FileOp.Admin, "*", "*", 0, DateTimeOffset.UtcNow.AddMinutes(5).ToUnixTimeMilliseconds()));

    private async Task<byte[]> PutAsync(string item, uint index, byte fill)
    {
        var frame = Frame(item, index, GatedEnc, EncPayload, fill);
        using var request = new HttpRequestMessage(HttpMethod.Put, $"/f/{_channel}/{Hex(item)}/{index}") { Content = new ByteArrayContent(frame) };
        request.Headers.Add("X-WD-Ticket", Admin());
        using var response = await _http.SendAsync(request);
        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
        return frame;
    }

    private SyncWorker Worker => _files.Services.GetRequiredService<SyncWorker>();
    private string Remote(string item, uint index) => $"webdrop/files/{_channel}/{Hex(item)}/{index:D10}";

    [Fact]
    public async Task NewFramesAreUploadedOnceAndTheRestResumesAfterAnOutage()
    {
        string a = NewId(), b = NewId();
        var frames = new[] { await PutAsync(a, 0, 1), await PutAsync(a, 1, 2), await PutAsync(a, 2, 3), await PutAsync(b, 0, 4) };

        // 外部存储暂时连不上:不会标记已同步,下次接着来
        _dav.Down = true;
        var down = await Worker.RunOnceAsync(CancellationToken.None);
        Assert.Equal(0, down.Uploaded); Assert.True(down.Failed > 0);
        Assert.Empty(_dav.Files);

        _dav.Down = false;
        var first = await Worker.RunOnceAsync(CancellationToken.None);
        Assert.Equal(4, first.Uploaded);
        Assert.Equal(frames[0], _dav.Files[Remote(a, 0)]);
        Assert.Equal(frames[2], _dav.Files[Remote(a, 2)]);
        Assert.Equal(frames[3], _dav.Files[Remote(b, 0)]);

        // 增量:没有新内容就什么也不传;新来的帧只传新的
        Assert.Equal(0, (await Worker.RunOnceAsync(CancellationToken.None)).Uploaded);
        var more = await PutAsync(a, 3, 5);
        var second = await Worker.RunOnceAsync(CancellationToken.None);
        Assert.Equal(1, second.Uploaded);
        Assert.Equal(more, _dav.Files[Remote(a, 3)]);
    }

    [Fact]
    public async Task DeletedContentStaysInTheBackupUntilTheRetentionPeriodPasses()
    {
        string a = NewId(), b = NewId();
        await PutAsync(a, 0, 1); await PutAsync(b, 0, 2);
        await Worker.RunOnceAsync(CancellationToken.None);
        Assert.True(_dav.Files.ContainsKey(Remote(a, 0)));

        // 在文件服务上删掉 a:本地没了,外部备份里还在(误删可以找回)
        using (var delete = new HttpRequestMessage(HttpMethod.Delete, $"/internal/prefix?p={_channel}/{Hex(a)}"))
        {
            delete.Headers.Add("X-WD-Ticket", Admin());
            using var response = await _http.SendAsync(delete);
            Assert.Equal(HttpStatusCode.NoContent, response.StatusCode);
        }
        var early = await Worker.RunOnceAsync(CancellationToken.None);
        Assert.Equal(0, early.Purged);
        Assert.True(_dav.Files.ContainsKey(Remote(a, 0)));
        Assert.True(_dav.Files.ContainsKey(Remote(b, 0)));

        // 删除记录满 30 天后,下一次同步才把外部备份里的也清掉(没删的 b 不受影响)
        var log = Path.Combine(_dir, "sync", "deleted.log");
        long old = DateTimeOffset.UtcNow.AddDays(-31).ToUnixTimeMilliseconds();
        File.WriteAllLines(log, File.ReadAllLines(log).Select(l => l.Split('\t')[0] + "\t" + old));
        var late = await Worker.RunOnceAsync(CancellationToken.None);
        Assert.Equal(1, late.Purged);
        Assert.False(_dav.Files.ContainsKey(Remote(a, 0)));
        Assert.True(_dav.Files.ContainsKey(Remote(b, 0)));
        Assert.Empty(File.ReadAllLines(log));
    }

    [Fact]
    public async Task ContentDeletedBeforeItWasEverSyncedLeavesNothingToPurge()
    {
        string a = NewId();
        await PutAsync(a, 0, 1);
        using (var delete = new HttpRequestMessage(HttpMethod.Delete, $"/internal/prefix?p={_channel}/{Hex(a)}"))
        {
            delete.Headers.Add("X-WD-Ticket", Admin());
            using var response = await _http.SendAsync(delete);
            Assert.Equal(HttpStatusCode.NoContent, response.StatusCode);
        }
        var run = await Worker.RunOnceAsync(CancellationToken.None);
        Assert.Equal(0, run.Uploaded);
        Assert.Empty(_dav.Files);
        Assert.False(File.Exists(Path.Combine(_dir, "sync", "deleted.log")));
    }
}