// Author: Simon-Pierre Boucher
// Contact: contact@spboucher.ai
// Project: chat.spboucher.ai

import type { ORModelRaw } from "./schemas";
import type { ModelDefinition } from "./types";

function toNumber(v: string | number | null | undefined): number | undefined {
  if (v === null || v === undefined) return undefined;
  const n = typeof v === "number" ? v : parseFloat(v);
  return Number.isFinite(n) ? n : undefined;
}

/** Pricing values are USD per token (per request/image where applicable). */
export function derivePricing(raw: ORModelRaw): ModelDefinition["pricing"] {
  const p = raw.pricing ?? {};
  return {
    prompt: toNumber(p.prompt),
    completion: toNumber(p.completion),
    image: toNumber(p.image),
    request: toNumber(p.request),
  };
}

/** Estimated cost in USD from token counts and per-token prices. */
export function estimateCost(
  pricing: ModelDefinition["pricing"] | undefined,
  promptTokens: number | undefined,
  completionTokens: number | undefined
): number | undefined {
  if (!pricing) return undefined;
  const inCost = pricing.prompt !== undefined && promptTokens !== undefined ? pricing.prompt * promptTokens : undefined;
  const outCost =
    pricing.completion !== undefined && completionTokens !== undefined
      ? pricing.completion * completionTokens
      : undefined;
  if (inCost === undefined && outCost === undefined) return undefined;
  return (inCost ?? 0) + (outCost ?? 0);
}

/** Format a USD amount for display: $0.0042, $0.42, $4.20. */
export function formatUsd(v: number | undefined | null): string {
  if (v === undefined || v === null) return "—";
  if (v === 0) return "$0";
  if (v < 0.01) return `$${v.toFixed(4)}`;
  if (v < 1) return `$${v.toFixed(3)}`;
  return `$${v.toFixed(2)}`;
}

/** Price per 1M tokens for the model rail chip. */
export function perMillion(perToken: number | undefined): string {
  if (perToken === undefined) return "—";
  const v = perToken * 1_000_000;
  if (v === 0) return "free";
  if (v < 1) return `$${v.toFixed(2)}/M`;
  return `$${v.toFixed(v < 10 ? 2 : 0)}/M`;
}