import type { Theme } from "@earendil-works/pi-coding-agent";
import { computeCacheHitPercent } from "./cache-math.js";
import type { CacheUsageTotals } from "./types.js";

/** Hit rates at or above this are considered healthy (green). */
const HIT_RATE_HEALTHY = 95;
/** Hit rates at or above this (but below healthy) need attention (yellow). */
const HIT_RATE_ATTENTION = 80;

/**
 * Colorizes a hit-rate value using pi's theme: green >= 95%, yellow 80-95%,
 * red < 80%. Callers should pad plain text *before* colorizing so ANSI codes
 * do not disturb column alignment.
 */
export function hitRateColor(theme: Theme, percent: number, text: string): string {
  if (percent >= HIT_RATE_HEALTHY) return theme.fg("success", text);
  if (percent >= HIT_RATE_ATTENTION) return theme.fg("warning", text);
  return theme.fg("error", text);
}

/**
 * Compact token formatting: 16,868,357 -> "16.9M". Always fits in 6 chars
 * for any practical token count, so fixed-width table columns never overflow.
 */
export function formatCompact(value: number): string {
  const abs = Math.abs(value);
  const fmt = (v: number, suffix: string): string =>
    v.toFixed(1).replace(/\.0$/, "") + suffix;
  if (abs >= 1_000_000_000) return fmt(value / 1_000_000_000, "B");
  if (abs >= 1_000_000) return fmt(value / 1_000_000, "M");
  if (abs >= 1_000) return fmt(value / 1_000, "k");
  return String(value);
}

export function formatPercent(value: number): string {
  return `${value.toFixed(1)}%`;
}

export function shortModelName(provider: string, model: string): string {
  return `${provider}/${model}`;
}

export function summarizeHitPercent(totals: CacheUsageTotals): number {
  return computeCacheHitPercent(totals.input, totals.cacheRead, totals.cacheWrite);
}