using System.Security.Cryptography;
using Microsoft.Extensions.Options;
using YD_Event.Application.Auth;
using YD_Event.Application.Common;
using YD_Event.Core.Options;

namespace YD_Event.Application.AppUpdate;

/// <summary>内部 Android 裁判端 APK 发布与升级检查。</summary>
[ApiDescriptionSettings("裁判端升级")]
[Route("api/app-updates")]
[Authorize]
public class AppUpdateController : IDynamicApiController
{
    private const string PackageName = "com.yd.event.yd_pattern_scoring_system";
    private const long MaxApkSize = 200L * 1024 * 1024;
    private readonly ISqlSugarRepository<JudgeAppRelease> _releases;
    private readonly AuthManager _auth;
    private readonly IIdGenerator _ids;
    private readonly FileService _files;
    private readonly IOptionsMonitor<OssConnectionOptions> _ossOptions;
    private readonly string _channel;

    public AppUpdateController(ISqlSugarRepository<JudgeAppRelease> releases,
        AuthManager auth, IIdGenerator ids, FileService files,
        IOptionsMonitor<OssConnectionOptions> ossOptions)
    {
        _releases = releases;
        _auth = auth;
        _ids = ids;
        _files = files;
        _ossOptions = ossOptions;
        _channel = Environment.GetEnvironmentVariable("APP_UPDATE_CHANNEL")?.Trim().ToLowerInvariant() ?? "production";
    }

    /// <summary>登录前即可查询当前环境的最新 APK。</summary>
    [HttpGet("latest")]
    [AllowAnonymous]
    public async Task<object> Latest()
    {
        var release = await _releases.AsQueryable()
            .Where(x => x.Channel == _channel && x.ReleaseStatus == 1 && x.PackageName == PackageName)
            .OrderByDescending(x => x.VersionCode).FirstAsync();
        return release == null ? new { available = false } : new
        {
            available = true, release.Id, release.PackageName, release.VersionCode,
            release.VersionName, release.NotesZh, release.NotesEn,
            release.IsMandatory, release.FileSize, release.Sha256,
            release.CertificateSha256, downloadUrl = DownloadUrlFor(release),
            release.PublishedTime
        };
    }

    /// <summary>OSS 已启用时直连阿里云/CDN；配置缺失或不安全时仍使用受控下载接口。</summary>
    private string DownloadUrlFor(JudgeAppRelease release)
    {
        var fallback = $"/api/app-updates/download/{release.Id}";
        // Direct delivery is opt-in: a private bucket without CDN/public-read
        // must continue using the existing server-side OSS stream.
        var cdn = Environment.GetEnvironmentVariable("APP_UPDATE_DIRECT_DOWNLOAD_BASE_URL");
        if (string.IsNullOrWhiteSpace(cdn)) return fallback;
        var oss = _ossOptions.CurrentValue;
        if (!oss.Enable || string.IsNullOrWhiteSpace(oss.Domain) ||
            !Uri.TryCreate(oss.Domain.TrimEnd('/') + "/", UriKind.Absolute, out var ossBase) ||
            ossBase.Scheme != Uri.UriSchemeHttps ||
            !Uri.TryCreate(release.FileUrl, UriKind.Absolute, out var fileUri) ||
            fileUri.Scheme != Uri.UriSchemeHttps ||
            !fileUri.AbsoluteUri.StartsWith(ossBase.AbsoluteUri, StringComparison.OrdinalIgnoreCase))
            return fallback;

        // FileUrl comes from the configured OSS domain at upload time. Never turn
        // an arbitrary stored URL into an untrusted redirect/download host.
        var objectKey = fileUri.AbsoluteUri[ossBase.AbsoluteUri.Length..];
        if (!objectKey.StartsWith($"app-releases/{_channel}/", StringComparison.Ordinal) ||
            objectKey.Contains("..", StringComparison.Ordinal) ||
            !objectKey.EndsWith(".apk", StringComparison.OrdinalIgnoreCase))
            return fallback;

        if (!Uri.TryCreate(cdn.TrimEnd('/') + "/", UriKind.Absolute, out var cdnBase) ||
            cdnBase.Scheme != Uri.UriSchemeHttps || !string.IsNullOrEmpty(cdnBase.UserInfo) ||
            !string.IsNullOrEmpty(cdnBase.Query) || !string.IsNullOrEmpty(cdnBase.Fragment))
            return fallback;
        return new Uri(cdnBase, objectKey).AbsoluteUri;
    }

    /// <summary>只允许下载当前环境已发布的版本，沿用现有文件服务流式返回。</summary>
    [HttpGet("download/{id:long}")]
    [AllowAnonymous]
    public async Task<IActionResult> Download(long id)
    {
        var release = await _releases.GetFirstAsync(x => x.Id == id && x.Channel == _channel &&
            x.PackageName == PackageName && x.ReleaseStatus == 1);
        if (release == null || string.IsNullOrWhiteSpace(release.FileUrl)) return new NotFoundResult();
        return _files.Download(release.FileUrl);
    }

    [HttpGet("admin/releases")]
    public async Task<object> Releases()
    {
        EnsureAdmin();
        return await _releases.AsQueryable().Where(x => x.Channel == _channel)
            .OrderByDescending(x => x.VersionCode).ToListAsync();
    }

    [HttpPost("admin/upload")]
    [DisplayName("上传裁判端 APK 草稿")]
    [RequestSizeLimit(MaxApkSize + 1024 * 1024)]
    [RequestFormLimits(MultipartBodyLengthLimit = MaxApkSize + 1024 * 1024)]
    public async Task<JudgeAppRelease> Upload([FromForm] IFormFile file,
        [FromForm] string versionName, [FromForm] int versionCode,
        [FromForm] string certificateSha256, [FromForm] string notesZh,
        [FromForm] string? notesEn = null,
        [FromForm] bool isMandatory = false)
    {
        EnsureAdmin();
        if (file == null || file.Length < 1024 || file.Length > MaxApkSize ||
            !string.Equals(Path.GetExtension(file.FileName), ".apk", StringComparison.OrdinalIgnoreCase))
            throw Oops.Bah("仅允许上传 1KB 至 200MB 的 APK");
        if (string.IsNullOrWhiteSpace(notesZh)) throw Oops.Bah("请填写中文更新说明");
        if (versionCode <= 0 || string.IsNullOrWhiteSpace(versionName) || versionName.Length > 64)
            throw Oops.Bah("请填写有效的版本名和正整数版本号");
        // 本阶段由超级管理员提供 build-info.json 中的元数据；后续再恢复 APK 内部解析与签名比对。
        // 文件哈希仍在服务端计算，平板安装前仍会核对真实 APK 的包名、版本和签名。
        var fingerprint = certificateSha256?.Trim().Replace(":", "").ToUpperInvariant();
        if (fingerprint == null || !Regex.IsMatch(fingerprint, "^[0-9A-F]{64}$"))
            throw Oops.Bah("请填写 64 位的公开签名证书 SHA-256 指纹");
        var existing = await _releases.GetFirstAsync(x => x.Channel == _channel &&
            x.PackageName == PackageName && x.VersionCode == versionCode);
        if (existing != null) throw Oops.Bah("该版本号已存在，请使用新的递增版本号");
        var temp = Path.Combine(Path.GetTempPath(), $"yd-app-release-{Guid.NewGuid():N}.apk");
        try
        {
            await using (var output = System.IO.File.Create(temp))
            await using (var source = file.OpenReadStream())
                await source.CopyToAsync(output);
            await using (var input = System.IO.File.OpenRead(temp))
            {
                var magic = new byte[4];
                if (await input.ReadAsync(magic) != 4 || magic[0] != 0x50 || magic[1] != 0x4B || magic[2] != 0x03 || magic[3] != 0x04)
                    throw Oops.Bah("文件不是有效的 APK/ZIP");
            }
            await using var hashStream = System.IO.File.OpenRead(temp);
            var sha = Convert.ToHexString(await SHA256.HashDataAsync(hashStream));
            await using var uploadStream = System.IO.File.OpenRead(temp);
            var release = new JudgeAppRelease
            {
                Id = _ids.NextId(), Channel = _channel, PackageName = PackageName,
                VersionCode = versionCode, VersionName = versionName.Trim(),
                NotesZh = notesZh?.Trim() ?? string.Empty, NotesEn = notesEn?.Trim() ?? string.Empty,
                IsMandatory = isMandatory, FileSize = uploadStream.Length,
                Sha256 = sha, CertificateSha256 = fingerprint,
                FileUrl = await _files.UploadFileStreamAsync($"app-releases/{_channel}/{Guid.NewGuid():N}.apk", uploadStream),
                ReleaseStatus = 0, CreatedUserId = _auth.UserId, CreatedTime = DateTime.UtcNow
            };
            await _releases.InsertAsync(release);
            return release;
        }
        finally { if (System.IO.File.Exists(temp)) System.IO.File.Delete(temp); }
    }

    [HttpPost("admin/{id:long}/publish")]
    public async Task<JudgeAppRelease> Publish(long id)
    {
        EnsureAdmin();
        var release = await FindOwn(id);
        if (release.ReleaseStatus != 0) throw Oops.Bah("只有草稿可以发布");
        var latest = await _releases.AsQueryable()
            .Where(x => x.Channel == _channel && x.PackageName == PackageName && x.ReleaseStatus != 0)
            .OrderByDescending(x => x.VersionCode).FirstAsync();
        if (latest != null && release.VersionCode <= latest.VersionCode)
            throw Oops.Bah("版本号必须高于当前已发布版本");
        release.ReleaseStatus = 1;
        release.PublishedUserId = _auth.UserId;
        release.PublishedTime = DateTime.UtcNow;
        await _releases.UpdateAsync(release);
        return release;
    }

    [HttpPost("admin/{id:long}/withdraw")]
    public async Task<JudgeAppRelease> Withdraw(long id)
    {
        EnsureAdmin();
        var release = await FindOwn(id);
        if (release.ReleaseStatus != 1) throw Oops.Bah("只有已发布版本可以撤回");
        release.ReleaseStatus = 2;
        release.WithdrawnUserId = _auth.UserId;
        release.WithdrawnTime = DateTime.UtcNow;
        await _releases.UpdateAsync(release);
        return release;
    }

    private void EnsureAdmin()
    {
        if (!_auth.IsSuperAdmin) throw Oops.Bah("仅超级管理员可管理裁判端版本");
    }

    private async Task<JudgeAppRelease> FindOwn(long id)
    {
        var release = await _releases.GetFirstAsync(x => x.Id == id && x.Channel == _channel);
        return release ?? throw Oops.Bah("版本不存在");
    }

}