import clickhouse from 'lib/clickhouse';
import { CLICKHOUSE, PRISMA, runQuery } from 'lib/db';
import prisma from 'lib/prisma';
import { EVENT_TYPE } from 'lib/constants';
import { loadWebsite } from 'lib/load';
import { maxDate } from 'lib/date';

export interface PageviewStatsCriteria {
  startDate: Date;
  endDate: Date;
  timezone?: string;
  unit?: string;
  count?: string;
  filters: object;
  sessionKey?: string;
}

export async function getPageviewStats(
  ...args: [websiteId: string, criteria: PageviewStatsCriteria]
) {
  return runQuery({
    [PRISMA]: () => relationalQuery(...args),
    [CLICKHOUSE]: () => clickhouseQuery(...args),
  });
}

async function relationalQuery(websiteId: string, criteria: PageviewStatsCriteria) {
  const {
    startDate,
    endDate,
    timezone = 'utc',
    unit = 'day',
    count = '*',
    filters = {},
    sessionKey = 'session_id',
  } = criteria;
  const { getDateQuery, parseFilters, rawQuery } = prisma;
  const website = await loadWebsite(websiteId);
  const { filterQuery, joinSession } = parseFilters(filters);

  return rawQuery(
    `
    select
      ${getDateQuery('website_event.created_at', unit, timezone)} x,
      count(${count !== '*' ? `${count}${sessionKey}` : count}) y
    from website_event
      ${joinSession}
    where website_event.website_id = {{websiteId::uuid}}
      and website_event.created_at between {{startDate}} and {{endDate}}
      and event_type = {{eventType}}
      ${filterQuery}
    group by 1
    `,
    {
      websiteId,
      startDate: maxDate(startDate, website.resetAt),
      endDate,
      eventType: EVENT_TYPE.pageView,
      ...filters,
    },
  );
}

async function clickhouseQuery(websiteId: string, criteria: PageviewStatsCriteria) {
  const {
    startDate,
    endDate,
    timezone = 'UTC',
    unit = 'day',
    count = '*',
    filters = {},
  } = criteria;
  const { parseFilters, rawQuery, getDateStringQuery, getDateQuery } = clickhouse;
  const website = await loadWebsite(websiteId);
  const { filterQuery } = parseFilters(filters);

  return rawQuery(
    `
    select
      ${getDateStringQuery('g.t', unit)} as x, 
      g.y as y
    from (
      select 
        ${getDateQuery('created_at', unit, timezone)} as t,
        count(${count !== '*' ? 'distinct session_id' : count}) as y
      from website_event
      where website_id = {websiteId:UUID}
        and created_at between {startDate:DateTime} and {endDate:DateTime}
        and event_type = {eventType:UInt32}
        ${filterQuery}
      group by t
    ) as g
    order by t
    `,
    {
      ...filters,
      websiteId,
      startDate: maxDate(startDate, website.resetAt),
      endDate,
      eventType: EVENT_TYPE.pageView,
    },
  );
}