'use strict'
var utils = require('./utils')

var noop = utils.noop
var assign = utils.assign
var isString = utils.isString

function RouteNode (options) {
  options = options || {}
  this._children = Object.create(null)
  this._regExs = Object.create(null)
}

assign(RouteNode.prototype, {
  handler: null,

  add: function add(parts, handler, context) {
    parts = parts || []
    handler = handler || noop
    context = context || null

    if (parts.length === 0) {
      this.handler = handler
      this.context = context
      return this
    }
    var part = parts.shift()
    var node = null

    if (isString(part)) {
      node = this._children[part]
    } else {
      this._regExs[part] = part
    }

    if (node == null) {
      node = new RouteNode()
      this._children[part] = node
    }
    return node.add(parts, handler, context)
  },

  get: function get(parts, args, done) {
    parts = parts || []
    args = args || []

    if (parts.length === 0) {
      return done(null, this.handler, this.context, args)
    }
    var part = parts.shift()
    var childNode = this._children[part]
    if (childNode) {
      return childNode.get(parts, args, done)
    } else {
      var results = this._getRegexChild(part)
      if (results && results.node) {
        return results.node.get(parts, args.concat(results.args), done)
      } else {
        return done(new Error('not found'))
      }
    }
  },

  _getRegexChild: function _getRegexChild(part) {
    var childKey = null
    var args = []
    var self = this

    Object.keys(this._regExs).forEach(function checkRegex(key) {
      if (childKey) {
        return
      }
      var regex = self._regExs[key]
      var results = regex.exec(part)
      var lastIndex = null
      if (results) {
        childKey = key
      }
      while (results && results.index !== lastIndex) {
        args = args.concat(results[0])
        lastIndex = results.index
        results = regex.exec(part)
      }
    })

    if (childKey) {
      return {
        args: args,
        key: childKey,
        node: this._children[childKey]
      }
    } else {
      return null
    }
  }

})

module.exports = RouteNode