import uPlot from '../lib/uPlot.esm'

import { RelativeScale } from './scale'

import { formatNumber, formatTimestamp, isMobileBrowser } from './util'
import { uPlotTooltipPlugin } from './tooltip'

import { FAVORITE_SERVERS_STORAGE_KEY } from './favorites'

const HIDDEN_SERVERS_STORAGE_KEY = 'minetrack_hidden_servers'
const SHOW_FAVORITES_STORAGE_KEY = 'minetrack_show_favorites'

export class GraphDisplayManager {
  // Only emit graph data request if not on mobile due to graph data size
  isVisible = !isMobileBrowser()

  constructor (app) {
    this._app = app
    this._graphData = []
    this._graphTimestamps = []
    this._hasLoadedSettings = false
    this._initEventListenersOnce = false
    this._showOnlyFavorites = false
  }

  addGraphPoint (serverId, timestamp, playerCount) {
    if (!this._hasLoadedSettings) {
      // _hasLoadedSettings is controlled by #setGraphData
      // It will only be true once the context has been loaded and initial payload received
      // #addGraphPoint should not be called prior to that since it means the data is racing
      // and the application has received updates prior to the initial state
      return
    }

    // FIXME
  }

  loadLocalStorage () {
    if (typeof localStorage !== 'undefined') {
      const showOnlyFavorites = localStorage.getItem(SHOW_FAVORITES_STORAGE_KEY)
      if (showOnlyFavorites) {
        this._showOnlyFavorites = true
      }

      // If only favorites mode is active, use the stored favorite servers data instead
      let serverNames
      if (this._showOnlyFavorites) {
        serverNames = localStorage.getItem(FAVORITE_SERVERS_STORAGE_KEY)
      } else {
        serverNames = localStorage.getItem(HIDDEN_SERVERS_STORAGE_KEY)
      }

      if (serverNames) {
        serverNames = JSON.parse(serverNames)

        // Iterate over all active serverRegistrations
        // This merges saved state with current state to prevent desyncs
        for (const serverRegistration of this._app.serverRegistry.getServerRegistrations()) {
          // isVisible will be true if showOnlyFavorites && contained in FAVORITE_SERVERS_STORAGE_KEY
          // OR, if it is NOT contains within HIDDEN_SERVERS_STORAGE_KEY
          // Checks between FAVORITE/HIDDEN keys are mutually exclusive
          if (this._showOnlyFavorites) {
            serverRegistration.isVisible = serverNames.indexOf(serverRegistration.data.name) >= 0
          } else {
            serverRegistration.isVisible = serverNames.indexOf(serverRegistration.data.name) < 0
          }
        }
      }
    }
  }

  updateLocalStorage () {
    if (typeof localStorage !== 'undefined') {
      // Mutate the serverIds array into server names for storage use
      const serverNames = this._app.serverRegistry.getServerRegistrations()
        .filter(serverRegistration => !serverRegistration.isVisible)
        .map(serverRegistration => serverRegistration.data.name)

      // Only store if the array contains data, otherwise clear the item
      // If showOnlyFavorites is true, do NOT store serverNames since the state will be auto managed instead
      if (serverNames.length > 0 && !this._showOnlyFavorites) {
        localStorage.setItem(HIDDEN_SERVERS_STORAGE_KEY, JSON.stringify(serverNames))
      } else {
        localStorage.removeItem(HIDDEN_SERVERS_STORAGE_KEY)
      }

      // Only store SHOW_FAVORITES_STORAGE_KEY if true
      if (this._showOnlyFavorites) {
        localStorage.setItem(SHOW_FAVORITES_STORAGE_KEY, true)
      } else {
        localStorage.removeItem(SHOW_FAVORITES_STORAGE_KEY)
      }
    }
  }

  getVisibleGraphData () {
    return this._app.serverRegistry.getServerRegistrations()
      .filter(serverRegistration => serverRegistration.isVisible)
      .map(serverRegistration => this._graphData[serverRegistration.serverId])
  }

  getPlotSize () {
    return {
      width: Math.max(window.innerWidth, 800) * 0.9,
      height: 400
    }
  }

  buildPlotInstance (graphData) {
    // Lazy load settings from localStorage, if any and if enabled
    if (!this._hasLoadedSettings) {
      this._hasLoadedSettings = true

      this.loadLocalStorage()
    }

    // FIXME: timestamps are not shared!
    this._graphTimestamps = graphData[0].map(val => Math.floor(val[0] / 1000))
    this._graphData = Object.values(graphData).map(val => {
      return val.map(element => {
        // Safely handle null data points, they represent gaps in the graph
        return element === null ? null : element[1]
      })
    })

    const series = this._app.serverRegistry.getServerRegistrations().map(serverRegistration => {
      return {
        scale: 'Players',
        stroke: serverRegistration.data.color,
        width: 2,
        value: (_, raw) => formatNumber(raw) + ' Players',
        show: serverRegistration.isVisible
      }
    })

    const tickCount = 10

    // eslint-disable-next-line new-cap
    this._plotInstance = new uPlot({
      plugins: [
        uPlotTooltipPlugin((pos, id, plot) => {
          if (pos) {
            // FIXME
            let text = '<strong>' + formatTimestamp(this._graphTimestamps[id] * 1000) + '</strong><br><br>'

            for (let i = 1; i < plot.series.length; i++) {
              const serverRegistration = this._app.serverRegistry.getServerRegistration(i - 1)
              const serverGraphData = this._graphData[serverRegistration.serverId]

              let playerCount

              if (id >= serverGraphData.length || typeof serverGraphData[id] !== 'number') {
                playerCount = '-'
              } else {
                playerCount = formatNumber(serverGraphData[id])
              }

              text += serverRegistration.data.name + ': ' + playerCount + '<br>'
            }

            this._app.tooltip.set(pos.left, pos.top, 10, 10, text)
          } else {
            this._app.tooltip.hide()
          }
        })
      ],
      ...this.getPlotSize(),
      cursor: {
        y: false
      },
      series: [
        {
        },
        ...series
      ],
      axes: [
        {
          font: '14px "Open Sans", sans-serif',
          stroke: '#FFF',
          grid: {
            show: false
          },
          space: 60
        },
        {
          font: '14px "Open Sans", sans-serif',
          stroke: '#FFF',
          size: 60,
          grid: {
            stroke: '#333',
            width: 1
          },
          split: () => {
            const visibleGraphData = this.getVisibleGraphData()
            const [, max, scale] = RelativeScale.scaleMatrix(visibleGraphData, tickCount)
            const ticks = RelativeScale.generateTicks(0, max, scale)
            return ticks
          }
        }
      ],
      scales: {
        Players: {
          auto: false,
          range: () => {
            const visibleGraphData = this.getVisibleGraphData()
            const [, scaledMax] = RelativeScale.scaleMatrix(visibleGraphData, tickCount)
            return [0, scaledMax]
          }
        }
      },
      legend: {
        show: false
      }
    }, [
      this._graphTimestamps,
      ...this._graphData
    ], document.getElementById('big-graph'))

    // Show the settings-toggle element
    document.getElementById('settings-toggle').style.display = 'inline-block'
  }

  redraw = () => {
    // Use drawing as a hint to update settings
    // This may cause unnessecary localStorage updates, but its a rare and harmless outcome
    this.updateLocalStorage()

    // Copy application state into the series data used by uPlot
    for (const serverRegistration of this._app.serverRegistry.getServerRegistrations()) {
      this._plotInstance.series[serverRegistration.serverId + 1].show = serverRegistration.isVisible
    }

    this._plotInstance.redraw()
  }

  requestResize () {
    // Only resize when _plotInstance is defined
    // Set a timeout to resize after resize events have not been fired for some duration of time
    // This prevents burning CPU time for multiple, rapid resize events
    if (this._plotInstance) {
      if (this._resizeRequestTimeout) {
        clearTimeout(this._resizeRequestTimeout)
      }

      // Schedule new delayed resize call
      // This can be cancelled by #requestResize, #resize and #reset
      this._resizeRequestTimeout = setTimeout(this.resize, 200)
    }
  }

  resize = () => {
    this._plotInstance.setSize(this.getPlotSize())

    // undefine value so #clearTimeout is not called
    // This is safe even if #resize is manually called since it removes the pending work
    if (this._resizeRequestTimeout) {
      clearTimeout(this._resizeRequestTimeout)
    }

    this._resizeRequestTimeout = undefined
  }

  initEventListeners () {
    if (!this._initEventListenersOnce) {
      this._initEventListenersOnce = true

      // These listeners should only be init once since they attach to persistent elements
      document.getElementById('settings-toggle').addEventListener('click', this.handleSettingsToggle, false)

      document.querySelectorAll('.graph-controls-show').forEach((element) => {
        element.addEventListener('click', this.handleShowButtonClick, false)
      })
    }

    // These listeners should be bound each #initEventListeners call since they are for newly created elements
    document.querySelectorAll('.graph-control').forEach((element) => {
      element.addEventListener('click', this.handleServerButtonClick, false)
    })
  }

  handleServerButtonClick = (event) => {
    const serverId = parseInt(event.target.getAttribute('minetrack-server-id'))
    const serverRegistration = this._app.serverRegistry.getServerRegistration(serverId)

    if (serverRegistration.isVisible !== event.target.checked) {
      serverRegistration.isVisible = event.target.checked

      // Any manual changes automatically disables "Only Favorites" mode
      // Otherwise the auto management might overwrite their manual changes
      this._showOnlyFavorites = false

      this.redraw()
    }
  }

  handleShowButtonClick = (event) => {
    const showType = event.target.getAttribute('minetrack-show-type')

    // If set to "Only Favorites", set internal state so that
    // visible graphData is automatically updating when a ServerRegistration's #isVisible changes
    // This is also saved and loaded by #loadLocalStorage & #updateLocalStorage
    this._showOnlyFavorites = showType === 'favorites'

    let redraw = false

    this._app.serverRegistry.getServerRegistrations().forEach(function (serverRegistration) {
      let isVisible
      if (showType === 'all') {
        isVisible = true
      } else if (showType === 'none') {
        isVisible = false
      } else if (showType === 'favorites') {
        isVisible = serverRegistration.isFavorite
      }

      if (serverRegistration.isVisible !== isVisible) {
        serverRegistration.isVisible = isVisible
        redraw = true
      }
    })

    if (redraw) {
      this.redraw()
      this.updateCheckboxes()
    }
  }

  handleSettingsToggle = () => {
    const element = document.getElementById('big-graph-controls-drawer')

    if (element.style.display !== 'block') {
      element.style.display = 'block'
    } else {
      element.style.display = 'none'
    }
  }

  handleServerIsFavoriteUpdate = (serverRegistration) => {
    // When in "Only Favorites" mode, visibility is dependent on favorite status
    // Redraw and update elements as needed
    if (this._showOnlyFavorites && serverRegistration.isVisible !== serverRegistration.isFavorite) {
      serverRegistration.isVisible = serverRegistration.isFavorite

      this.redraw()
      this.updateCheckboxes()
    }
  }

  updateCheckboxes () {
    document.querySelectorAll('.graph-control').forEach((checkbox) => {
      const serverId = parseInt(checkbox.getAttribute('minetrack-server-id'))
      const serverRegistration = this._app.serverRegistry.getServerRegistration(serverId)

      checkbox.checked = serverRegistration.isVisible
    })
  }

  reset () {
    this._graphTimestamps = []
    this._graphData = []
    this._plotInstance = undefined
    this._hasLoadedSettings = false

    // Fire #clearTimeout if the timeout is currently defined
    if (this._resizeRequestTimeout) {
      clearTimeout(this._resizeRequestTimeout)

      this._resizeRequestTimeout = undefined
    }

    // Reset modified DOM structures
    document.getElementById('big-graph-checkboxes').innerHTML = ''
    document.getElementById('big-graph-controls').style.display = 'none'

    document.getElementById('settings-toggle').style.display = 'none'

    const graphElement = document.getElementById('big-graph')

    graphElement.innerHTML = ''
    graphElement.removeAttribute('style')
  }
}