open-swe/packages/shared/src/caching.ts

import { CacheMetrics, ModelTokenData } from "./open-swe/types.js";

export function calculateCostSavings(metrics: CacheMetrics): {
  totalSavings: number;
  totalCost: number;
  totalTokens: number;
  totalInputTokens: number;
  totalOutputTokens: number;
  totalOutputTokensCost: number;
} {
  const SONNET_4_BASE_RATE = 3.0 / 1_000_000; // $3 per MTok
  const SONNET_4_OUTPUT_RATE = 15.0 / 1_000_000; // $15 per MTok

  const CACHE_WRITE_MULTIPLIER = 1.25;
  const CACHE_READ_MULTIPLIER = 0.1;

  const cacheWriteCost =
    metrics.cacheCreationInputTokens *
    SONNET_4_BASE_RATE *
    CACHE_WRITE_MULTIPLIER;

  const cacheReadCost =
    metrics.cacheReadInputTokens * SONNET_4_BASE_RATE * CACHE_READ_MULTIPLIER;

  const regularInputCost = metrics.inputTokens * SONNET_4_BASE_RATE;

  const totalOutputTokensCost = metrics.outputTokens * SONNET_4_OUTPUT_RATE;

  // Cost without caching (all tokens at base rate)
  const totalInputTokens =
    metrics.cacheCreationInputTokens +
    metrics.cacheReadInputTokens +
    metrics.inputTokens;
  const totalTokens = totalInputTokens + metrics.outputTokens;
  const costWithoutCaching = totalInputTokens * SONNET_4_BASE_RATE;

  // Actual cost with caching
  const actualCost = cacheWriteCost + cacheReadCost + regularInputCost;

  return {
    totalSavings: costWithoutCaching - actualCost,
    totalCost: actualCost,
    totalTokens,
    totalInputTokens,
    totalOutputTokens: metrics.outputTokens,
    totalOutputTokensCost,
  };
}

export function tokenDataReducer(
  state: ModelTokenData[] | undefined,
  update: ModelTokenData[],
): ModelTokenData[] {
  if (!state) {
    return update;
  }

  // Create a map to merge data by model
  const modelMap = new Map<string, ModelTokenData>();

  // Add existing state data to the map
  for (const data of state) {
    modelMap.set(data.model, { ...data });
  }

  // Merge update data with existing data
  for (const data of update) {
    const existing = modelMap.get(data.model);
    if (existing) {
      // Merge the metrics for the same model
      modelMap.set(data.model, {
        model: data.model,
        cacheCreationInputTokens:
          existing.cacheCreationInputTokens + data.cacheCreationInputTokens,
        cacheReadInputTokens:
          existing.cacheReadInputTokens + data.cacheReadInputTokens,
        inputTokens: existing.inputTokens + data.inputTokens,
        outputTokens: existing.outputTokens + data.outputTokens,
      });
    } else {
      // Add new model data
      modelMap.set(data.model, { ...data });
    }
  }

  // Convert map back to array
  return Array.from(modelMap.values());
}