// Formatting helpers shared by the viewer components.

/** Gyromagnetic ratio of 1H, Hz/T — used to express gradients in mT/m. */
export const GAMMA = 42.576e6

/** Format a time in seconds with an adaptive unit. */
export function formatTime(t: number, digits = 4): string {
  const a = Math.abs(t)
  if (a >= 1) return `${t.toFixed(digits)} s`
  if (a >= 1e-3) return `${(t * 1e3).toPrecision(digits)} ms`
  if (a === 0) return '0'
  return `${(t * 1e6).toPrecision(digits)} µs`
}

/** Tick label for a time axis where the tick spacing is `step` seconds. */
export function formatTick(t: number, step: number): string {
  if (step >= 0.1) return `${trimZeros(t.toFixed(2))} s`
  if (step >= 1e-4) return `${trimZeros((t * 1e3).toFixed(3))} ms`
  return `${trimZeros((t * 1e6).toFixed(2))} µs`
}

function trimZeros(s: string): string {
  return s.includes('.') ? s.replace(/\.?0+$/, '') : s
}

/** Gradient amplitude, Hz/m -> compact display in both unit systems. */
export function formatGrad(hzPerM: number): string {
  const mTm = (hzPerM / GAMMA) * 1e3
  return `${(hzPerM / 1e3).toFixed(1)} kHz/m (${mTm.toFixed(2)} mT/m)`
}

/** Slew rate, Hz/m/s -> display in T/m/s. */
export function formatSlew(hzPerMPerS: number): string {
  return `${(hzPerMPerS / GAMMA).toFixed(1)} T/m/s`
}

export function formatNumber(v: number, digits = 6): string {
  if (Number.isInteger(v)) return String(v)
  return String(Number(v.toPrecision(digits)))
}