var app = getApp()
var drawChart = require("../../utils/chart").drawChart

var COLORS = ["#e53e3e", "#3182ce", "#38a169", "#d69e2e", "#805ad5", "#dd6b20", "#319795", "#d53f8c"]

Page({
  data: {
    persons: [],
    currentPersonName: "",
    items: [],
    filterItems: [],
    viewMode: "month",
    filterMonth: "",
    filterYear: "",
    customStart: "",
    customEnd: "",
    hasData: false,
    colors: COLORS
  },

  onLoad: function () {
    var today = this.formatDate(new Date(), "day")
    var month = today.slice(0, 7)
    var year = today.slice(0, 4)
    var items = app.getCurrentData().items
    var person = app.getCurrentPerson()
    this.setData({
      persons: app.globalData.persons,
      currentPersonName: person ? person.name : "",
      items: items,
      filterItems: items.slice(),
      filterMonth: month,
      filterYear: year,
      customStart: month,
      customEnd: month
    })
  },

  onReady: function () {
    this._initCanvas()
  },

  onShow: function () {
    var items = app.getCurrentData().items
    var person = app.getCurrentPerson()
    this.setData({
      persons: app.globalData.persons,
      currentPersonName: person ? person.name : ""
    })
    if (items.length !== this.data.items.length ||
        items.some(function (v, i) { return v !== this.data.items[i] }, this)) {
      this.setData({ items: items })
      var newFilter = items.filter(function (i) { return this.data.items.indexOf(i) === -1 }, this)
      if (newFilter.length > 0) {
        this.setData({ filterItems: this.data.filterItems.concat(newFilter) })
      }
    }
    if (this._canvasReady) {
      this.refreshChart()
    }
  },

  _initCanvas: function () {
    var that = this
    wx.createSelectorQuery().in(this)
      .select("#trendCanvas")
      .boundingClientRect(function (rect) {
        if (!rect || rect.width <= 0) return
        var dpr = wx.getWindowInfo().pixelRatio
        that._canvasW = rect.width
        that._canvasH = rect.height
        that.canvasCtx = wx.createCanvasContext('trendCanvas', that)
        that.canvasCtx.scale(dpr, dpr)
        that._canvasReady = true
        that.refreshChart()
      })
      .exec()
  },

  getDateRange: function () {
    var viewMode = this.data.viewMode
    var filterMonth = this.data.filterMonth
    var filterYear = this.data.filterYear
    var customStart = this.data.customStart
    var customEnd = this.data.customEnd
    var start, end, parts, y, m, sy, sm, ey, em

    if (viewMode === "month") {
      parts = filterMonth.split("-")
      y = Number(parts[0])
      m = Number(parts[1])
      start = new Date(y, m - 1, 1)
      end = new Date(y, m, 0)
    } else if (viewMode === "year") {
      y = parseInt(filterYear)
      start = new Date(y, 0, 1)
      end = new Date(y, 11, 31)
    } else {
      parts = customStart.split("-")
      sy = Number(parts[0])
      sm = Number(parts[1])
      parts = customEnd.split("-")
      ey = Number(parts[0])
      em = Number(parts[1])
      start = new Date(sy, sm - 1, 1)
      end = new Date(ey, em, 0)
    }
    return { start: start, end: end }
  },

  refreshChart: function () {
    var records = app.getCurrentData().records
    var filterItems = this.data.filterItems
    var range = this.getDateRange()
    var start = range.start
    var end = range.end

    var inRange = function (r) {
      var d = new Date(r.date + "T00:00:00")
      return d >= start && d <= end
    }

    var filtered = records.filter(function (r) {
      return inRange(r) && filterItems.indexOf(r.item) > -1
    })

    if (filtered.length === 0) {
      this.setData({ hasData: false })
      return
    }

    var dateMap = {}
    filtered.forEach(function (r) {
      if (!dateMap[r.date]) dateMap[r.date] = {}
      if (!dateMap[r.date][r.item]) {
        dateMap[r.date][r.item] = { sum: 0, count: 0 }
      }
      dateMap[r.date][r.item].sum += r.value
      dateMap[r.date][r.item].count += 1
    })

    var dates = Object.keys(dateMap).sort()
    var xLabels = dates.map(function (d) { return d.slice(5) })
    var series = filterItems.map(function (fi) {
      return {
        name: fi,
        data: dates.map(function (d) {
          var entry = dateMap[d][fi]
          if (!entry) return null
          return Math.round((entry.sum / entry.count) * 100) / 100
        })
      }
    })

    this._chartData = { xLabels: xLabels, series: series }
    var that = this
    this.setData({ hasData: true }, function () { that.drawChart() })
  },

  drawChart: function () {
    if (!this.canvasCtx || !this._canvasW || !this._canvasH) return
    var chartData = this._chartData
    if (!chartData || !chartData.xLabels.length) return
    var filterItems = this.data.filterItems
    var items = this.data.items
    var colors = this.data.colors
    var that = this
    drawChart(this.canvasCtx, this._canvasW, this._canvasH, {
      xLabels: chartData.xLabels,
      series: chartData.series,
      colors: filterItems.map(function (fi) {
        return colors[items.indexOf(fi) % colors.length]
      })
    })
  },

  onSwitchMode: function (e) {
    var that = this
    this.setData({ viewMode: e.currentTarget.dataset.mode }, function () { that.refreshChart() })
  },

  onMonthChange: function (e) {
    var that = this
    this.setData({ filterMonth: e.detail.value }, function () { that.refreshChart() })
  },

  onYearChange: function (e) {
    var that = this
    this.setData({ filterYear: e.detail.value }, function () { that.refreshChart() })
  },

  onCustomStartChange: function (e) {
    var that = this
    this.setData({ customStart: e.detail.value }, function () { that.refreshChart() })
  },

  onCustomEndChange: function (e) {
    var that = this
    this.setData({ customEnd: e.detail.value }, function () { that.refreshChart() })
  },

  onToggleItem: function (e) {
    var item = e.currentTarget.dataset.item
    var filterItems = this.data.filterItems.slice()
    var idx = filterItems.indexOf(item)
    var that = this
    if (idx > -1) {
      if (filterItems.length <= 1) {
        wx.showToast({ title: "至少保留一个项目", icon: "none" })
        return
      }
      filterItems.splice(idx, 1)
    } else {
      filterItems.push(item)
    }
    this.setData({ filterItems: filterItems }, function () { that.refreshChart() })
  },

  formatDate: function (d, mode) {
    var y = d.getFullYear()
    var m = String(d.getMonth() + 1)
    if (m.length === 1) m = "0" + m
    var day = String(d.getDate())
    if (day.length === 1) day = "0" + day
    if (mode === "year") return String(y)
    if (mode === "month") return y + "-" + m
    return y + "-" + m + "-" + day
  }
})