"use strict"

module.exports = function(string) {
	if (string === "" || string == null) return {}
	if (string.charAt(0) === "?") string = string.slice(1)

	var entries = string.split("&"), counters = {}, data = {}
	for (var i = 0; i < entries.length; i++) {
		var entry = entries[i].split("=")
		var key = decodeURIComponent(entry[0])
		var value = entry.length === 2 ? decodeURIComponent(entry[1]) : ""

		if (value === "true") value = true
		else if (value === "false") value = false

		var levels = key.split(/\]\[?|\[/)
		var cursor = data
		if (key.indexOf("[") > -1) levels.pop()
		for (var j = 0; j < levels.length; j++) {
			var level = levels[j], nextLevel = levels[j + 1]
			var isNumber = nextLevel == "" || !isNaN(parseInt(nextLevel, 10))
			var isValue = j === levels.length - 1
			if (level === "") {
				var key = levels.slice(0, j).join()
				if (counters[key] == null) {
					counters[key] = Array.isArray(cursor) ? cursor.length : 0
				}
				level = counters[key]++
			}
			// Disallow direct prototype pollution
			else if (level === "__proto__") break
			if (isValue) cursor[level] = value
			else {
				// Read own properties exclusively to disallow indirect
				// prototype pollution
				value = Object.getOwnPropertyDescriptor(cursor, level)
				if (value != null) value = value.value
				if (value == null) value = cursor[level] = isNumber ? [] : {}
			}
			cursor = value
		}
	}
	return data
}