feat(api): add listen report endpoint

src/reports/reports.service.ts

@@ -0,0 +1,73 @@
+import { Injectable } from "@nestjs/common";
+import {
+  eachDayOfInterval,
+  eachMonthOfInterval,
+  eachWeekOfInterval,
+  eachYearOfInterval,
+  formatISO,
+  Interval,
+  isSameDay,
+  isSameMonth,
+  isSameWeek,
+  isSameYear,
+  parseISO,
+} from "date-fns";
+import { ListensService } from "../listens/listens.service";
+import { GetListenReportDto } from "./dto/get-listen-report.dto";
+import { ListenReportDto } from "./dto/listen-report.dto";
+import { Timeframe } from "./timeframe.enum";
+
+const timeframeToDateFns: {
+  [x in Timeframe]: {
+    eachOfInterval: (interval: Interval) => Date[];
+    isSame: (dateLeft: Date, dateRight: Date) => boolean;
+  };
+} = {
+  [Timeframe.Day]: {
+    eachOfInterval: eachDayOfInterval,
+    isSame: isSameDay,
+  },
+  [Timeframe.Week]: {
+    eachOfInterval: eachWeekOfInterval,
+    isSame: isSameWeek,
+  },
+  [Timeframe.Month]: {
+    eachOfInterval: eachMonthOfInterval,
+    isSame: isSameMonth,
+  },
+  [Timeframe.Year]: {
+    eachOfInterval: eachYearOfInterval,
+    isSame: isSameYear,
+  },
+};
+
+@Injectable()
+export class ReportsService {
+  constructor(private readonly listensService: ListensService) {}
+
+  async getListens(options: GetListenReportDto): Promise<ListenReportDto> {
+    const { user, timeFrame, timeStart, timeEnd } = options;
+
+    const { items: listens } = await this.listensService.getListens({
+      user,
+      filter: { time: { start: timeStart, end: timeEnd } },
+      page: 1,
+      limit: 10000000,
+    });
+
+    const reportInterval: Interval = {
+      start: parseISO(timeStart),
+      end: parseISO(timeEnd),
+    };
+
+    const { eachOfInterval, isSame } = timeframeToDateFns[timeFrame];
+
+    const reportItems = eachOfInterval(reportInterval).map((date) => {
+      const count = listens.filter((listen) => isSame(date, listen.playedAt))
+        .length;
+      return { date: formatISO(date), count };
+    });
+
+    return { items: reportItems, timeStart, timeEnd, timeFrame };
+  }
+}