/**
 * Integer cents → display format utilities
 * All backend prices now stored as Integer cents (1元 = 100)
 * All backend rates stored as Integer bps (100% = 10000)
 * All backend scores stored as Integer percentile (5.00 = 500)
 */

/**
 * Format cents to yuan string (no symbol)
 * 9900 → '99.00'
 */
export function formatPrice (cents) {
  if (cents === null || cents === undefined) return '0.00'
  return (Number(cents) / 100).toFixed(2)
}

/**
 * Format cents to yuan with ¥ symbol
 * 9900 → '¥99.00'
 */
export function formatPriceWithSymbol (cents) {
  return '¥' + formatPrice(cents)
}

/**
 * Format bps to percentage string
 * 235 → '2.35%'   1000 → '10.00%'
 */
export function formatRate (bps) {
  if (bps === null || bps === undefined) return '0.00%'
  return (Number(bps) / 100).toFixed(2) + '%'
}

/**
 * Format percentile score to decimal display
 * 500 → '5.00'   435 → '4.35'
 */
export function formatScore (percentile) {
  if (percentile === null || percentile === undefined) return '0.00'
  return (Number(percentile) / 100).toFixed(2)
}


/**
 * Format ISO datetime string to Chinese style: 'yyyy-MM-dd HH:mm:ss' -> 'yyyy年MM月dd日 HH:mm:ss'
 * Handles: null/undefined -> '-', already-formatted strings -> idempotent passthrough
 */
export function formatDateTime (t) {
  if (t === null || t === undefined || t === '') return '-'
  const s = String(t).replace('T', ' ').trim()
  const m = s.match(/^(\d{4})-(\d{2})-(\d{2})(.*)$/)
  if (!m) return s
  const timePart = m[4] ? ' ' + m[4].trim().substring(0, 8) : ''
  return m[1] + '年' + m[2] + '月' + m[3] + '日' + timePart
}

/**
 * Format ISO datetime string to Chinese date only: 'yyyy-MM-dd HH:mm:ss' -> 'yyyy年MM月dd日'
 */
export function formatDate (t) {
  if (t === null || t === undefined || t === '') return '-'
  const dt = formatDateTime(t)
  if (dt === '-') return '-'
  return dt.indexOf(' ') >= 0 ? dt.substring(0, dt.indexOf(' ')) : dt
}