namespace ClaudeOverview.Models;

/// <summary>
/// Subscription usage pulled from the Claude /api/oauth/usage endpoint.
/// Percentages are 0–100.
/// </summary>
public sealed class UsageInfo
{
    /// <summary>Length of the rolling session-limit block (the API's "five_hour" bucket).</summary>
    public static readonly TimeSpan SessionWindow = TimeSpan.FromHours(5);

    public double SessionPercent { get; set; }
    public DateTime? SessionResetsAt { get; set; }

    /// <summary>UTC start of the current session-limit window (its reset time minus the 5-hour block).</summary>
    public DateTime? SessionWindowStartUtc =>
        SessionResetsAt is { } r ? r.ToUniversalTime() - SessionWindow : null;

    public double WeeklyPercent { get; set; }
    public DateTime? WeeklyResetsAt { get; set; }

    public string? Error { get; set; }
    public bool Ok => Error is null;

    /// <summary>True when the last fetch was rejected with HTTP 429 (rate limited).</summary>
    public bool RateLimited { get; set; }

    /// <summary>Server-suggested wait before retrying (from the Retry-After header), if any.</summary>
    public TimeSpan? RetryAfter { get; set; }

    public static string ResetsIn(DateTime? resetsAtUtc)
    {
        if (resetsAtUtc is null) return "";
        var span = resetsAtUtc.Value.ToUniversalTime() - DateTime.UtcNow;
        if (span <= TimeSpan.Zero) return "resetting…";
        if (span < TimeSpan.FromHours(1)) return $"resets in {(int)span.TotalMinutes}m";
        if (span < TimeSpan.FromDays(1)) return $"resets in {(int)span.TotalHours}h{span.Minutes:00}m";
        return $"resets in {(int)span.TotalDays}d{span.Hours}h";
    }
}