using Fleet.Core;

namespace Monitor.Backend.Application;

public sealed record CreateJoinTokenRequest(string? Note, IReadOnlyList<string>? Labels, bool AutoApprove, int MaxUses, int ExpiresInHours);

public sealed record CreatedJoinToken(JoinTokenInfo Info, string Plaintext, string InstallCommand);

/// <summary>加入令牌：明文只在创建时返回一次，服务端只保存 SHA-256。</summary>
public sealed class JoinTokenService
{
    private readonly IJoinTokenStore _store;
    private readonly BackendOptions _options;
    private readonly TimeProvider _time;

    public JoinTokenService(IJoinTokenStore store, BackendOptions options, TimeProvider time)
    {
        _store = store;
        _options = options;
        _time = time;
    }

    public async ValueTask<Result<CreatedJoinToken>> CreateAsync(CreateJoinTokenRequest request, string? requestBaseUrl, CancellationToken ct)
    {
        var errors = new Dictionary<string, string>();
        if (request.MaxUses is < 1 or > 1000)
        {
            errors["max_uses"] = "must be between 1 and 1000";
        }

        if (request.ExpiresInHours is < 1 or > 24 * 365)
        {
            errors["expires_in_hours"] = "must be between 1 and 8760";
        }

        if (request.Labels is { } labels && (labels.Count > 16 || labels.Any(l => l.Length is 0 or > 32)))
        {
            errors["labels"] = "at most 16 labels of 1-32 characters";
        }

        if (request.Note is { Length: > 200 })
        {
            errors["note"] = "must be at most 200 characters";
        }

        if (errors.Count > 0)
        {
            return ValidationError.Fail<CreatedJoinToken>(errors);
        }

        string plaintext = TokenHash.NewToken("jt");
        long now = _time.GetUtcNow().ToUnixTimeMilliseconds();
        JoinTokenInfo info = await _store.CreateAsync(
            Ulid.NewPrefixed("jtk", _time), TokenHash.Sha256(plaintext), request.Note, request.Labels ?? [], request.AutoApprove,
            request.MaxUses, now + (request.ExpiresInHours * 3_600_000L), now, ct);

        string baseUrl = (_options.PublicUrl ?? requestBaseUrl ?? "https://panel.example.com").TrimEnd('/');
        string command = $"curl -fsSL {baseUrl}/install.sh | sh -s -- --join {plaintext} --name <node-name>";
        return Result<CreatedJoinToken>.Ok(new CreatedJoinToken(info, plaintext, command));
    }

    public ValueTask<IReadOnlyList<JoinTokenInfo>> ListAsync(CancellationToken ct) => _store.ListAsync(ct);

    public ValueTask<bool> RevokeAsync(string id, CancellationToken ct) => _store.RevokeAsync(id, _time.GetUtcNow().ToUnixTimeMilliseconds(), ct);
}