/**
 * The class of an unnamed release (REBUILD.md decision f; LOG.md (130)): what the headers say about its chance of a
 * name, from the pending ladder's own record. Size bucket × name shape × partial, 1..70, kept in step with
 * names.rs pending_class and the SQL pending_class() (migration 6800): the batch store sets it with the SQL, the
 * edge skips the classes a lease marks dropped.
 */

/** Size buckets: under 1 MB, 10 MB, 100 MB, 1 GB, and from 1 GB. */
export const SIZE_BUCKETS = [1_000_000, 10_000_000, 100_000_000, 1_000_000_000]
/** Name shapes, 1..7: hex, digits, base32, letters only, mixed letters and digits, with separators, other. */
export const SHAPES = [
  'hex',
  'digits',
  'base32',
  'letters',
  'alnum',
  'separators',
  'other',
] as const

export function sizeBucket(bytes: number): number {
  let i = 0
  while (i < SIZE_BUCKETS.length && bytes >= SIZE_BUCKETS[i]) i++
  return i
}

export function nameShape(name: string): number {
  const s = name.replace(/\.[A-Za-z0-9]{1,4}$/, '')
  if (/^[0-9a-fA-F]{16,}$/.test(s)) return 1
  if (/^[0-9]{6,}$/.test(s)) return 2
  if (/^[a-z2-7]{20,}$/.test(s) && /[2-7]/.test(s)) return 3
  if (/^[A-Za-z]+$/.test(s)) return 4
  if (/^[A-Za-z0-9]+$/.test(s)) return 5
  if (/^[A-Za-z0-9._-]+$/.test(s)) return 6
  return 7
}

/** 1..70: (size bucket × 7 + shape − 1) × 2 + partial + 1. */
export function pendingClass(name: string, bytes: number, partial: boolean): number {
  return sizeBucket(bytes) * 14 + (nameShape(name) - 1) * 2 + (partial ? 1 : 0) + 1
}

/** A class as droppedClasses lists it: "tool\tgroup\tklass". */
export function classKey(tool: string, group: string, klass: number): string {
  return `${tool}\t${group}\t${klass}`
}

/** A class in words ("10-100M hex partial"). */
export function describeClass(klass: number): string {
  const k = klass - 1
  const size = Math.floor(k / 14)
  const shape = SHAPES[Math.floor((k % 14) / 2)]
  const sizes = ['<1M', '1-10M', '10-100M', '100M-1G', '1G+']
  return `${sizes[size]} ${shape}${k % 2 ? ' partial' : ''}`
}