pricing.js

// Load pricing data from JSON – edit pricing.json to add/update models
const _raw = require('./pricing.json');
const MODEL_PRICING = Object.fromEntries(
  Object.entries(_raw).filter(([k]) => !k.startsWith('_'))
);

// Normalize a model identifier to match pricing keys
// Handles versioned names like "claude-sonnet-4-20250514", "gpt-4o-2024-08-06", etc.
function normalizeModelName(name) {
  if (!name) return null;
  let n = name.toLowerCase().trim();

  // Strip leading provider prefixes (e.g. "anthropic/claude-..." or "openai/gpt-...")
  const slashIdx = n.lastIndexOf('/');
  if (slashIdx !== -1) n = n.substring(slashIdx + 1);

  // Strip dot-delimited provider prefixes (e.g. "us.anthropic.claude-sonnet-4-6")
  // Only strip if all prefix segments are simple words (no dashes), to avoid
  // splitting version dots like "claude-4.6-opus"
  const dotParts = n.split('.');
  if (dotParts.length > 1) {
    const prefixes = dotParts.slice(0, -1);
    const last = dotParts[dotParts.length - 1];
    if (last.includes('-') && prefixes.every(p => !p.includes('-'))) n = last;
  }

  // Handle MODEL_CLAUDE_* / MODEL_GPT_* enum constants
  if (n.startsWith('model_')) {
    n = n.substring(6).replace(/_/g, '-');
  }

  // Build candidate list: original + dots→dashes + reversed claude names
  const candidates = [n];
  if (n.includes('.')) candidates.push(n.replace(/\./g, '-'));

  // Rearrange reversed claude names: "claude-4-6-opus-..." → "claude-opus-4-6"
  // Run on all candidates so dots→dashes variant is also checked
  for (const c of [...candidates]) {
    const rev = c.match(/^(claude)-(\d+)-(\d+)-(opus|sonnet|haiku)/);
    if (rev) candidates.push(`${rev[1]}-${rev[4]}-${rev[2]}-${rev[3]}`);
  }

  // Pass 1: exact and precise matches across ALL candidates first
  for (const c of candidates) {
    if (MODEL_PRICING[c]) return c;
  }
  for (const c of candidates) {
    const withoutDate = c.replace(/-\d{4}-?\d{2}-?\d{2}$/, '');
    if (MODEL_PRICING[withoutDate]) return withoutDate;
    const withoutTag = c.replace(/:(latest|thinking)$/, '');
    if (MODEL_PRICING[withoutTag]) return withoutTag;
    const withoutQual = c.replace(/-(thinking|high|xhigh|preview|latest)(-thinking|-high|-xhigh|-preview)*/g, '');
    if (withoutQual !== c && MODEL_PRICING[withoutQual]) return withoutQual;
  }

  // Pass 2: fuzzy startsWith (longest key match wins)
  const keys = Object.keys(MODEL_PRICING);
  for (const c of candidates) {
    let best = null;
    for (const key of keys) {
      if (c.startsWith(key) && (!best || key.length > best.length)) best = key;
    }
    if (best) return best;
  }

  return null;
}

function getModelPricing(modelName) {
  const key = normalizeModelName(modelName);
  return key ? MODEL_PRICING[key] : null;
}

// Calculate cost for a set of token counts and a model
// Returns cost in USD or null if model is unknown
function calculateCost(modelName, inputTokens, outputTokens, cacheRead, cacheWrite) {
  const pricing = getModelPricing(modelName);
  if (!pricing) return null;

  const input = ((inputTokens || 0) / 1_000_000) * pricing.input;
  const output = ((outputTokens || 0) / 1_000_000) * pricing.output;
  const cr = ((cacheRead || 0) / 1_000_000) * pricing.cacheRead;
  const cw = ((cacheWrite || 0) / 1_000_000) * pricing.cacheWrite;

  return input + output + cr + cw;
}

module.exports = { MODEL_PRICING, normalizeModelName, getModelPricing, calculateCost };