import { makeArray } from "discourse-common/lib/helpers";
import { debounce, schedule } from "@ember/runloop";
import Component from "@ember/component";
import { number } from "discourse/lib/formatter";
import loadScript from "discourse/lib/load-script";

export default Component.extend({
  classNames: ["admin-report-chart"],
  limit: 8,
  total: 0,
  options: null,

  init() {
    this._super(...arguments);

    this.resizeHandler = () =>
      debounce(this, this._scheduleChartRendering, 500);
  },

  didInsertElement() {
    this._super(...arguments);

    $(window).on("resize.chart", this.resizeHandler);
  },

  willDestroyElement() {
    this._super(...arguments);

    $(window).off("resize.chart", this.resizeHandler);

    this._resetChart();
  },

  didReceiveAttrs() {
    this._super(...arguments);

    debounce(this, this._scheduleChartRendering, 100);
  },

  _scheduleChartRendering() {
    schedule("afterRender", () => {
      this._renderChart(
        this.model,
        this.element && this.element.querySelector(".chart-canvas")
      );
    });
  },

  _renderChart(model, chartCanvas) {
    if (!chartCanvas) return;

    const context = chartCanvas.getContext("2d");
    const chartData = this._applyChartGrouping(
      model,
      makeArray(model.get("chartData") || model.get("data"), "weekly"),
      this.options
    );
    const prevChartData = makeArray(
      model.get("prevChartData") || model.get("prev_data")
    );

    const labels = chartData.map(d => d.x);

    const data = {
      labels,
      datasets: [
        {
          data: chartData.map(d => Math.round(parseFloat(d.y))),
          backgroundColor: prevChartData.length
            ? "transparent"
            : model.secondary_color,
          borderColor: model.primary_color,
          pointRadius: 3,
          borderWidth: 1,
          pointBackgroundColor: model.primary_color,
          pointBorderColor: model.primary_color
        }
      ]
    };

    if (prevChartData.length) {
      data.datasets.push({
        data: prevChartData.map(d => Math.round(parseFloat(d.y))),
        borderColor: model.primary_color,
        borderDash: [5, 5],
        backgroundColor: "transparent",
        borderWidth: 1,
        pointRadius: 0
      });
    }

    loadScript("/javascripts/Chart.min.js").then(() => {
      this._resetChart();

      if (!this.element) {
        return;
      }

      this._chart = new window.Chart(
        context,
        this._buildChartConfig(data, this.options)
      );
    });
  },

  _buildChartConfig(data, options) {
    return {
      type: "line",
      data,
      options: {
        tooltips: {
          callbacks: {
            title: tooltipItem =>
              moment(tooltipItem[0].xLabel, "YYYY-MM-DD").format("LL")
          }
        },
        legend: {
          display: false
        },
        responsive: true,
        maintainAspectRatio: false,
        responsiveAnimationDuration: 0,
        animation: {
          duration: 0
        },
        layout: {
          padding: {
            left: 0,
            top: 0,
            right: 0,
            bottom: 0
          }
        },
        scales: {
          yAxes: [
            {
              display: true,
              ticks: {
                userCallback: label => {
                  if (Math.floor(label) === label) return label;
                },
                callback: label => number(label),
                sampleSize: 5,
                maxRotation: 25,
                minRotation: 25
              }
            }
          ],
          xAxes: [
            {
              display: true,
              gridLines: { display: false },
              type: "time",
              time: {
                unit: this._unitForGrouping(options)
              },
              ticks: {
                sampleSize: 5,
                maxRotation: 50,
                minRotation: 50
              }
            }
          ]
        }
      }
    };
  },

  _resetChart() {
    if (this._chart) {
      this._chart.destroy();
      this._chart = null;
    }
  },

  _applyChartGrouping(model, data, options) {
    if (!options.chartGrouping || options.chartGrouping === "daily") {
      return data;
    }

    if (
      options.chartGrouping === "weekly" ||
      options.chartGrouping === "monthly"
    ) {
      const isoKind = options.chartGrouping === "weekly" ? "isoWeek" : "month";
      const kind = options.chartGrouping === "weekly" ? "week" : "month";
      const startMoment = moment(model.start_date, "YYYY-MM-DD");

      let currentIndex = 0;
      let currentStart = startMoment.clone().startOf(isoKind);
      let currentEnd = startMoment.clone().endOf(isoKind);
      const transformedData = [
        {
          x: currentStart.format("YYYY-MM-DD"),
          y: 0
        }
      ];

      data.forEach(d => {
        let date = moment(d.x, "YYYY-MM-DD");

        if (!date.isBetween(currentStart, currentEnd)) {
          currentIndex += 1;
          currentStart = currentStart.add(1, kind).startOf(isoKind);
          currentEnd = currentEnd.add(1, kind).endOf(isoKind);
        }

        if (transformedData[currentIndex]) {
          transformedData[currentIndex].y += d.y;
        } else {
          transformedData[currentIndex] = {
            x: d.x,
            y: d.y
          };
        }
      });

      return transformedData;
    }

    // ensure we return something if grouping is unknown
    return data;
  },

  _unitForGrouping(options) {
    switch (options.chartGrouping) {
      case "monthly":
        return "month";
      case "weekly":
        return "week";
      default:
        return "day";
    }
  }
});