using System.Text.RegularExpressions;

namespace WebDrop.Core.Tests;

/// <summary>
/// 权限规则只写在 ChannelPolicy 一处:别的地方只许调用,不许再各写一遍。
/// 这个测试扫描源码,发现在 ChannelPolicy 之外重新判断角色、读写授权就失败,防止重复实现长回来。
/// </summary>
public sealed class PolicySingleSourceTests
{
    private static string SourceRoot()
    {
        var dir = new DirectoryInfo(AppContext.BaseDirectory);
        while (dir is not null && !Directory.Exists(Path.Combine(dir.FullName, "src", "WebDrop.Core"))) dir = dir.Parent;
        return Path.Combine(dir?.FullName ?? throw new InvalidOperationException("找不到 server/src"), "src");
    }

    // 这些写法只能出现在 ChannelPolicy.cs(数据类的定义和令牌校验除外)
    private static readonly (string Name, Regex Pattern)[] Forbidden =
    [
        ("直接读频道访问授权的读写位", new Regex(@"\.(ChatRead|ChatWrite|FilesRead|FilesUpload)\b")),
        ("直接比较是不是所有者", new Regex(@"Role\s*[!=]=\s*Role\.Owner")),
        ("自己拼「所有者或创建者」", new Regex(@"AccountName\s*==\s*\w+\.CreatorAccount")),
    ];

    // 令牌校验(凭据层,不是授权规则)和数据定义,允许出现
    private static readonly string[] Allowed =
        ["ChannelPolicy.cs", "WorkspaceCrypto.cs", "RequestAuth.cs", "ShareService.cs"];

    [Fact]
    public void AuthorizationRulesAreWrittenOnlyInChannelPolicy()
    {
        var offenders = new List<string>();
        foreach (var file in Directory.EnumerateFiles(SourceRoot(), "*.cs", SearchOption.AllDirectories))
        {
            if (file.Contains(Path.DirectorySeparatorChar + "obj" + Path.DirectorySeparatorChar) || file.Contains(Path.DirectorySeparatorChar + "bin" + Path.DirectorySeparatorChar)) continue;
            if (Allowed.Contains(Path.GetFileName(file))) continue;
            var lines = File.ReadAllLines(file);
            for (int i = 0; i < lines.Length; i++)
            {
                if (lines[i].TrimStart().StartsWith("//") || lines[i].TrimStart().StartsWith("///")) continue;
                foreach (var (name, pattern) in Forbidden)
                    if (pattern.IsMatch(lines[i])) offenders.Add($"{Path.GetFileName(file)}:{i + 1} {name}: {lines[i].Trim()}");
            }
        }
        Assert.True(offenders.Count == 0, "这些地方在 ChannelPolicy 之外重新判断了权限,请改成调用 ChannelPolicy:\n" + string.Join("\n", offenders));
    }
}