`Sales today`, `Order today`, `Product top` values don't handle browser timezones

[fijolekProjects]

What I'm trying to achieve

Hello. First of all thank you for all the great work that you're doing - Saleor is awesome! :fire:

It seems that stats available on a dashboard main page (Sales today, Order today, Product top) don't handle client/browser timezone correctly which results in odd values and confusion for an end user.

Steps to reproduce the problem

1. Go to the dashboard main page
2. Make sure that you have some orders fulfilled for a current day
3. See Sales today and Orders today and make sure that these are non-zero values
4. Change your timezone where there's next day already. Example: my timezone is GMT+1, local time: 23:52. I've changed my timezone using google chrome sensors tool (https://dev.to/aileenr/how-to-spoof-your-timezone-in-google-chrome-48ch#:~:text=Click%20the%20three%2C%20vertically%2Daligned,to%20manually%20enter%20a%20timezone) to Tokyo, GMT+9, local time: 7:52.
5. Refresh the page. Value of Sales today stays the same as it was before and value of Orders today is now 0.

What I expected to happen

Value of Sales today and Orders today should be calculated based on a browser timezone and exact date range for both values (mismatch between 0 in Orders today and some non-zero value in Sales today)

What is the cause of that behavior

• Sales today and Product top (wasn't mentioned in a reproduction steps) - both use TODAY enum as a graphql query param which is interpreted without any timezone info on a backend side as UTC time
• Order today - counts order based on browser date (without both time and timezone) which seems incorrect, because today is a date range filter (like datePeriod: {gte: "2021-11-09", lte: "2021-11-09"}) which is handled as UTC date on a backend side

Screenshots

Another reproduction for GMT+1 timezone is to go to https://demo.saleor.io/dashboard/ between 00:00 and 01:00

Http request and response from inspector

query:

query Home($channel: String!, $datePeriod: DateRangeInput!) {
  salesToday: ordersTotal(period: TODAY, channel: $channel) {
    gross {
      amount
      currency
      __typename
    }
    __typename
  }
  ordersToday: orders(filter: {created: $datePeriod}, channel: $channel){
    totalCount
    __typename
  }
}

variables:

{
  "channel": "default-channel", 
  "datePeriod": {"gte": "2021-11-09", "lte": "2021-11-09"}
}

run via https://demo.saleor.io/graphql/ few minutes after midnight GMT+1 result:

{
  "data": {
    "salesToday": {
      "gross": {
        "amount": 497.24,
        "currency": "USD",
        "__typename": "Money"
      },
      "__typename": "TaxedMoney"
    },
    "ordersToday": {
      "totalCount": 0,
      "__typename": "OrderCountableConnection"
    }
  }
}

System information

Saleor version:

• [x] dev (current main)
• [x] 3.0
• [ ] 2.11
• [ ] 2.10

Operating system:

• [ ] Windows
• [x] Linux
• [ ] MacOS
• [ ] Other

Browser:

• [ ] Safari
• [X] Chrome
• [ ] Edge
• [ ] Other

[michalina-graczyk]

Thx for a catch @fijolekProjects ! I am reporting it, we will try to fix it ASAP.