'use strict'

var own = {}.hasOwnProperty

module.exports = stringify

function stringify(value) {
  /* Nothing. */
  if (!value || typeof value !== 'object') {
    return null
  }

  /* Node. */
  if (own.call(value, 'position') || own.call(value, 'type')) {
    return position(value.position)
  }

  /* Position. */
  if (own.call(value, 'start') || own.call(value, 'end')) {
    return position(value)
  }

  /* Point. */
  if (own.call(value, 'line') || own.call(value, 'column')) {
    return point(value)
  }

  /* ? */
  return null
}

function point(point) {
  if (!point || typeof point !== 'object') {
    point = {}
  }

  return index(point.line) + ':' + index(point.column)
}

function position(pos) {
  if (!pos || typeof pos !== 'object') {
    pos = {}
  }

  return point(pos.start) + '-' + point(pos.end)
}

function index(value) {
  return value && typeof value === 'number' ? value : 1
}