/**
 * num 小于0，左缩进num*2个空格； 大于0，右缩进num*2个空格。
 * @param {string} str 代码
 * @param {number} num 缩进次数
 * @param {number} len 【可选】缩进单位，空格数
 */
export function indent(str, num, len = 2) {
  if (num === 0) return str
  const isLeft = num < 0; const result = []; let reg; let
    spaces = ''
  if (isLeft) {
    num *= -1
    reg = new RegExp(`(^\\s{0,${num * len}})`, 'g')
  } else {
    for (let i = 0; i < num * len; i++) spaces += ' '
  }

  str.split('\n').forEach(line => {
    line = isLeft ? line.replace(reg, '') : spaces + line
    result.push(line)
  })
  return result.join('\n')
}

// 首字母大小
export function titleCase(str) {
  return str.replace(/( |^)[a-z]/g, L => L.toUpperCase())
}

// 下划转驼峰
export function camelCase(str) {
  return str.replace(/-[a-z]/g, str1 => str1.substr(-1).toUpperCase())
}

export function isNumberStr(str) {
  return /^[+-]?(0|([1-9]\d*))(\.\d+)?$/g.test(str)
}

export const exportDefault = 'export default '

export const beautifierConf = {
  html: {
    indent_size: '2',
    indent_char: ' ',
    max_preserve_newlines: '-1',
    preserve_newlines: false,
    keep_array_indentation: false,
    break_chained_methods: false,
    indent_scripts: 'separate',
    brace_style: 'end-expand',
    space_before_conditional: true,
    unescape_strings: false,
    jslint_happy: false,
    end_with_newline: true,
    wrap_line_length: '110',
    indent_inner_html: true,
    comma_first: false,
    e4x: true,
    indent_empty_lines: true
  },
  js: {
    indent_size: '2',
    indent_char: ' ',
    max_preserve_newlines: '-1',
    preserve_newlines: false,
    keep_array_indentation: false,
    break_chained_methods: false,
    indent_scripts: 'normal',
    brace_style: 'end-expand',
    space_before_conditional: true,
    unescape_strings: false,
    jslint_happy: true,
    end_with_newline: true,
    wrap_line_length: '110',
    indent_inner_html: true,
    comma_first: false,
    e4x: true,
    indent_empty_lines: true
  }
}

function stringify(obj) {
  return JSON.stringify(obj, (key, val) => {
    if (typeof val === 'function') {
      return `${val}`
    }
    return val
  })
}

function parse(str) {
  JSON.parse(str, (k, v) => {
    if (v.indexOf && v.indexOf('function') > -1) {
      return eval(`(${v})`)
    }
    return v
  })
}

export function jsonClone(obj) {
  return parse(stringify(obj))
}