"use strict"
define(["lib/helper"], function (Helper) {
  function streamElement(type, stream) {
    var el = document.createElement(type)
    el.destroy = stream.onValue(update)

    function update(d) {
      el.textContent = d
    }

    return el
  }

  function streamNode(stream) {
    var el = document.createTextNode("")
    el.destroy = stream.onValue(update)

    function update(d) {
      el.textContent = d
    }

    return el
  }

  function mkRow(table, label, stream) {
    var tr = document.createElement("tr")
    var th = document.createElement("th")
    var td = streamElement("td", stream)
    th.textContent = label
    tr.appendChild(th)
    tr.appendChild(td)
    table.appendChild(tr)

    tr.destroy = function () {
      td.destroy()
      table.removeChild(tr)
    }

    return tr
  }

  function mkTrafficRow(table, children, label, stream, selector) {
    var tr = document.createElement("tr")
    var th = document.createElement("th")
    var td = document.createElement("td")
    th.textContent = label

    var traffic = stream.slidingWindow(2, 2)
    var pkts = streamNode(traffic.map(deltaUptime(selector + ".packets")).map(prettyPackets))
    var bw = streamNode(traffic.map(deltaUptime(selector + ".bytes")).map(prettyBits))
    var bytes = streamNode(stream.map(selector).map(".bytes").map(prettyBytes))

    td.appendChild(pkts)
    td.appendChild(document.createElement("br"))
    td.appendChild(bw)
    td.appendChild(document.createElement("br"))
    td.appendChild(bytes)

    tr.appendChild(th)
    tr.appendChild(td)
    table.appendChild(tr)

    children.push(pkts)
    children.push(bw)
    children.push(bytes)
  }

  function mkMeshVPN(el, stream) {
    var children = {}
    var init = false
    var h = document.createElement("h3")
    h.textContent = "Mesh-VPN"

    var table = document.createElement("table")

    var unsubscribe = stream.onValue( function (d) {
      function addPeer(peer, path) {
        return { peer: peer, path: path }
      }

      function addPeers(d, path) {
        if (!("peers" in d))
          return []

        var peers = []

        for (var peer in d.peers)
          peers.push(addPeer(peer, path + ".peers." + peer))

        return peers
      }

      function addGroup(d, path) {
        var peers = []

        peers = peers.concat(addPeers(d, path))

        if ("groups" in d)
          for (var group in d.groups)
            peers = peers.concat(addGroup(d.groups[group], path + ".groups." + group))

        return peers
      }

      if (d === undefined)
        clear()

      else {
        if (!init) {
          init = true
          el.appendChild(h)
          el.appendChild(table)
        }

        var peers = addGroup(d, "")
        var paths = new Set(peers.map(function (d) { return d.path } ))

        for (var path in children)
          if (!paths.has(path)) {
            children[path].destroy()
            delete children[path]
          }

        peers.forEach( function (peer) {
          if (!(peer.path in children))
            children[peer.path] = mkRow(table, peer.peer,
                                        stream.startWith(d)
                                        .map(peer.path)
                                        .filter(function (d) { return d !== undefined })
                                        .map(prettyPeer))
        })
      }
    })

    function clear() {
      if (init) {
        init = false
        el.removeChild(h)
        el.removeChild(table)
      }

      for (var peer in children)
        children[peer].destroy()

      children = {}
    }

    function destroy() {
      unsubscribe()
      clear()
    }

    return { destroy: destroy }
  }

  function deltaUptime(selector) {
    return function (d) {
      var deltaTime = d[1].uptime - d[0].uptime
      var d0 = Helper.dictGet(d[0], selector.split(".").splice(1))
      var d1 = Helper.dictGet(d[1], selector.split(".").splice(1))

      return (d1 - d0) / deltaTime
    }
  }

  function prettyPeer(d) {
    if (d === null)
      return "nicht verbunden"
    else
      return "verbunden (" + prettyUptime(d.established) + ")"
  }

  function prettyPackets(d) {
    var v = new Intl.NumberFormat("de-DE", {maximumFractionDigits: 0}).format(d)
    return v + " Pakete/s"
  }

  function prettyPrefix(prefixes, step, d) {
    var prefix = 0

    while (d > step && prefix < 4) {
      d /= step
      prefix++
    }

    d = new Intl.NumberFormat("de-DE", {maximumSignificantDigits: 3}).format(d)
    return d + " " + prefixes[prefix]
  }

  function prettyBits(d) {
    return prettyPrefix([ "bps", "kbps", "Mbps", "Gbps" ], 1024, d * 8)
  }

  function prettyBytes(d) {
    return prettyPrefix([ "B", "kB", "MB", "GB" ], 1024, d)
  }

  function prettyUptime(seconds) {
    var minutes = Math.round(seconds / 60)

    var days = Math.floor(minutes / 1440)
    var hours = Math.floor((minutes % 1440) / 60)
    minutes = Math.floor(minutes % 60)

    var out = ""

    if (days === 1)
      out += "1 Tag, "
    else if (days > 1)
      out += days + " Tage, "

    out += hours + ":"

    if (minutes < 10)
      out += "0"

    out += minutes

    return out
  }

  function prettyNVRAM(usage) {
    return new Intl.NumberFormat("de-DE", {maximumSignificantDigits: 3}).format(usage * 100) + "% belegt"
  }

  function prettyLoad(load) {
    return new Intl.NumberFormat("de-DE", {maximumSignificantDigits: 3}).format(load)
  }

  function prettyRAM(memory) {
    var usage = 1 - (memory.free + memory.buffers + memory.cached) / memory.total
    return prettyNVRAM(usage)
  }

  return function (stream) {
    var children = []
    var el = document.createElement("div")
    var table = document.createElement("table")

    children.push(mkRow(table, "Laufzeit", stream.map(".uptime").map(prettyUptime)))
    children.push(mkRow(table, "Systemlast", stream.map(".loadavg").map(prettyLoad)))
    children.push(mkRow(table, "RAM", stream.map(".memory").map(prettyRAM)))
    children.push(mkRow(table, "NVRAM", stream.map(".rootfs_usage").map(prettyNVRAM)))
    children.push(mkRow(table, "Gateway", stream.map(".gateway")))
    children.push(mkRow(table, "Clients", stream.map(".clients.total")))

    el.appendChild(table)

    var h = document.createElement("h3")
    h.textContent = "Traffic"
    el.appendChild(h)

    table = document.createElement("table")

    mkTrafficRow(table, children, "Gesendet", stream, ".traffic.rx")
    mkTrafficRow(table, children, "Empfangen", stream, ".traffic.tx")
    mkTrafficRow(table, children, "Weitergeleitet", stream, ".traffic.forward")

    el.appendChild(table)

    children.push(mkMeshVPN(el, stream.map(".mesh_vpn")))

    function destroy() {
      children.forEach(function (d) {d.destroy()})
    }

    return { title: document.createTextNode("Statistik")
           , render: function (d) { d.appendChild(el) }
           , destroy: destroy
           }
  }
})