// A digital phantom: a cloud of spins, each with a position (metres) and
// tissue properties. Matches the fields of a KomaMRI `.phantom` file
// (see ../KomaMRI.jl Phantom.jl): position group x/y/z, contrast group
// rho/T1/T2/T2s/dw.

export interface Phantom {
  name: string
  /** Number of spins */
  ns: number
  /** Spin x position, metres */
  x: Float32Array
  /** Spin y position, metres */
  y: Float32Array
  /** Spin z position, metres */
  z: Float32Array
  /** Proton density (equilibrium magnetisation), arbitrary units */
  rho: Float32Array
  /** Longitudinal relaxation time, seconds */
  t1: Float32Array
  /** Transverse relaxation time, seconds */
  t2: Float32Array
  /** T2* relaxation time, seconds */
  t2s: Float32Array
  /** Off-resonance, rad/s */
  dw: Float32Array
}

/** Axis-aligned bounding box of a phantom's spins, metres. */
export interface PhantomExtent {
  min: [number, number, number]
  max: [number, number, number]
}

export function phantomExtent(p: Phantom): PhantomExtent {
  const min: [number, number, number] = [Infinity, Infinity, Infinity]
  const max: [number, number, number] = [-Infinity, -Infinity, -Infinity]
  const axes = [p.x, p.y, p.z]
  for (let a = 0; a < 3; a++) {
    const arr = axes[a]
    for (let i = 0; i < arr.length; i++) {
      if (arr[i] < min[a]) min[a] = arr[i]
      if (arr[i] > max[a]) max[a] = arr[i]
    }
  }
  return { min, max }
}