Upload openrouter.js

src/providers/openrouter.js

@@ -0,0 +1,84 @@
+import { config, ROUGH_PRICE_PER_1K } from '../config.js';
+
+// A process-wide spend counter. Good enough for a single-machine fleet;
+// swap for a shared store (redis/file) if you run true multi-process.
+let spentUsd = 0;
+
+function estimateCost(model, promptTokensApprox, completionTokensApprox) {
+  const rate = ROUGH_PRICE_PER_1K[model] ?? ROUGH_PRICE_PER_1K.default;
+  const totalTokens = promptTokensApprox + completionTokensApprox;
+  return (totalTokens / 1000) * rate;
+}
+
+function approxTokens(text) {
+  // ~4 chars per token is a fine rough estimate for budgeting purposes
+  return Math.ceil((text || '').length / 4);
+}
+
+/**
+ * Calls a model through OpenRouter's OpenAI-compatible chat completions API.
+ * @param {string} model - OpenRouter model slug, e.g. "google/gemini-flash-1.5"
+ * @param {string} systemPrompt
+ * @param {string} userPrompt
+ * @param {object} opts - { temperature, maxTokens, jsonMode }
+ */
+export async function callModel(model, systemPrompt, userPrompt, opts = {}) {
+  const { temperature = 0.9, maxTokens = 800, jsonMode = false } = opts;
+
+  const promptApprox = approxTokens(systemPrompt) + approxTokens(userPrompt);
+  const projectedCost = estimateCost(model, promptApprox, maxTokens);
+
+  if (spentUsd + projectedCost > config.maxSpendUsd) {
+    throw new Error(
+      `Spend guard tripped: estimated $${(spentUsd + projectedCost).toFixed(4)} ` +
+      `would exceed MAX_SPEND_USD=$${config.maxSpendUsd}. Stopping before the call.`
+    );
+  }
+
+  if (!config.openRouterKey) {
+    throw new Error('OPENROUTER_API_KEY is not set. Copy .env.example to .env and fill it in.');
+  }
+
+  const body = {
+    model,
+    temperature,
+    max_tokens: maxTokens,
+    messages: [
+      { role: 'system', content: systemPrompt },
+      { role: 'user', content: userPrompt },
+    ],
+  };
+  if (jsonMode) {
+    body.response_format = { type: 'json_object' };
+  }
+
+  const res = await fetch('https://openrouter.ai/api/v1/chat/completions', {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/json',
+      Authorization: `Bearer ${config.openRouterKey}`,
+    },
+    body: JSON.stringify(body),
+  });
+
+  if (!res.ok) {
+    const errText = await res.text();
+    throw new Error(`OpenRouter error ${res.status}: ${errText}`);
+  }
+
+  const data = await res.json();
+  const content = data?.choices?.[0]?.message?.content ?? '';
+
+  // Update running spend with actual usage if OpenRouter returns it, else fall back to estimate
+  const usage = data?.usage;
+  const actualCost = usage
+    ? estimateCost(model, usage.prompt_tokens ?? promptApprox, usage.completion_tokens ?? maxTokens)
+    : projectedCost;
+  spentUsd += actualCost;
+
+  return { content, spentUsd, callCostUsd: actualCost };
+}
+
+export function getSpentUsd() {
+  return spentUsd;
+}