81 lines
2.6 KiB
C#
81 lines
2.6 KiB
C#
namespace AnchorCli.OpenRouter;
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/// <summary>
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/// Tracks token usage and calculates costs for the session.
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/// </summary>
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internal sealed class TokenTracker
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{
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public long SessionInputTokens { get; private set; }
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public long SessionOutputTokens { get; private set; }
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public int RequestCount { get; private set; }
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/// <summary>Maximum context window for the model (tokens). 0 = unknown.</summary>
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public int ContextLength { get; set; }
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/// <summary>Input tokens from the most recent API response — approximates current context size.</summary>
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public int LastInputTokens { get; private set; }
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/// <summary>USD per input token.</summary>
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public decimal InputPrice { get; set; }
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/// <summary>USD per output token.</summary>
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public decimal OutputPrice { get; set; }
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/// <summary>Fixed USD per API request.</summary>
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public decimal RequestPrice { get; set; }
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/// <summary>
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/// Record usage from one response (may span multiple LLM rounds).
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/// </summary>
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public void AddUsage(int inputTokens, int outputTokens)
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{
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SessionInputTokens += inputTokens;
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SessionOutputTokens += outputTokens;
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LastInputTokens = inputTokens;
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RequestCount++;
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}
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/// <summary>
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/// Returns true if the context is getting too large and should be compacted.
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/// Triggers at min(75% of model context, 150K tokens).
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/// </summary>
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public bool ShouldCompact()
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{
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if (LastInputTokens <= 0) return false;
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int threshold = ContextLength > 0
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? Math.Min((int)(ContextLength * 0.75), 150_000)
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: 150_000;
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return LastInputTokens >= threshold;
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}
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/// <summary>Context usage as a percentage (0-100). Returns -1 if context length is unknown.</summary>
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public double ContextUsagePercent =>
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ContextLength > 0 && LastInputTokens > 0
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? (double)LastInputTokens / ContextLength * 100.0
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: -1;
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/// <summary>
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/// Calculate cost for a single response.
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/// </summary>
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public decimal CalculateCost(int inputTokens, int outputTokens) =>
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inputTokens * InputPrice +
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outputTokens * OutputPrice +
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RequestPrice;
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/// <summary>
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/// Total session cost.
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/// </summary>
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public decimal SessionCost =>
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SessionInputTokens * InputPrice +
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SessionOutputTokens * OutputPrice +
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RequestCount * RequestPrice;
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public static string FormatTokens(long count) =>
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count >= 1_000 ? $"{count / 1_000.0:F1}k" : count.ToString("N0");
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public static string FormatCost(decimal cost) =>
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cost < 0.01m ? $"${cost:F4}" : $"${cost:F2}";
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}
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