Create pricing.py

core/pricing.py

@@ -0,0 +1,32 @@
+from dataclasses import asdict
+from typing import Dict, Any
+from .config import ModelRate
+
+def cost_from_tokens(rate: ModelRate, tokens: Dict[str, int]) -> Dict[str, Any]:
+    """
+    tokens fields supported:
+      prompt_tokens, completion_tokens, cached_prompt_tokens, reasoning_tokens
+    """
+    prompt = int(tokens.get("prompt_tokens", 0))
+    completion = int(tokens.get("completion_tokens", 0))
+    cached = int(tokens.get("cached_prompt_tokens", 0))
+    reasoning = int(tokens.get("reasoning_tokens", 0))
+
+    # per-token costs
+    inp = (prompt / 1_000_000.0) * rate.input_per_1m
+    out = (completion / 1_000_000.0) * rate.output_per_1m
+    cache = (cached / 1_000_000.0) * rate.cached_input_per_1m
+    reas = (reasoning / 1_000_000.0) * rate.reasoning_per_1m
+
+    total = inp + out + cache + reas
+
+    return {
+        "usd": round(total, 8),
+        "breakdown": {
+            "input": round(inp, 8),
+            "output": round(out, 8),
+            "cached_input": round(cache, 8),
+            "reasoning": round(reas, 8),
+        },
+        "rate": asdict(rate),
+    }