**As** a project admin
**I want to** define the working days of the week for my OpenProject instance
**so that** weekends are correctly displayed and taken into account in all modules that involve dates (date picker, GANTT, team planner, calendar...).

Begin of the insertion###End of the insertion **Acceptance criteria**

* The icon for this entry is the existing "**icon-calendar**" (visible in the sidebar and on the overview pages).
* The page has a title: "Working days"
* There is an orange warning toast that is permanently visible:
* With icon 'warning'
* Text: "Changing which days of the week are considered working days can affect the start and finish days of all work packages in all projects in this instance."
* Text:
* **Define the working days of the week**
Non-working days are skipped when scheduling work packages and are excluded when calculating duration. This can be overriden at a work-package level.
* This is followed by the horizontal row of checkboxes, one for each day of the week.
* Monday–Friday are selected by default.
* Saturday and Sunday are unselected by default.
* **Mobile:** On smaller screens, the list become vertical, with only one element per line.
* A save button is present like on any settings page, except:
* If there was a change in the selection of working days (a new day checked or an old day unchecked), clicking on Save will display a modal dialogue:
* Header title: "Change working Begin of the insertiondays"End of the insertion Begin of the deletion days" End of the deletion
* with divider under header
* Modal Begin of the insertiontext:End of the insertion Begin of the deletion text: End of the deletion
* "Changing which days of the week are considered working days can affect the start and finish days of all work packages in all projects in this Begin of the insertioninstance.End of the insertion Begin of the deletion instance. 

End of the deletion Are you sure you want to to continue?"
* Primary button (danger): "Change working days" (same string as header)
* Secondary button (white): Cancel Begin of the insertion
End of the insertion Begin of the deletion



End of the deletion * Begin of the insertionThe user is freeEnd of the insertion Begin of the deletion When an admin makes a changeEnd of the deletion to Begin of the insertionenable/disable any of theEnd of the insertion Begin of the deletion which dates are considered non-workingEnd of the deletion days Begin of the insertionof the week as working days, as long as thereEnd of the insertion Begin of the deletion (checking or unchecking one or several days), they are warned that since thisEnd of the deletion is Begin of the insertionat least 1 day selected. _(Reason: removing days forces rescheduling based on next available day; unselecting all means there will be none, causingEnd of the insertion an Begin of the insertioninfinite loop)_
* If a user unchecksEnd of the insertion Begin of the deletion instance-level setting that might (and almost certainly will) affect the scheduling of work packages inEnd of the deletion all Begin of the insertioncheckboxes and clicksEnd of the insertion Begin of the deletion projects. This warning, although redundant with the warning toast alreadyEnd of the deletion on Begin of the insertionSave,End of the insertion Begin of the deletion the page, is important to make the potential consequences ofEnd of the deletion a Begin of the insertionred error toast will be displayed withEnd of the insertion Begin of the deletion change abundantly clear, sinceEnd of the deletion the Begin of the insertionwords: "At least one dayEnd of the insertion Begin of the deletion change is not easily undoable, and lotsEnd of the deletion of Begin of the insertionthe week must be defined asEnd of the insertion Begin of the deletion users are likely to suddently getEnd of the deletion a Begin of the insertionworking day". 
* Saving will not be possible until at least one day is selected.End of the insertion Begin of the deletion large number of notifications.End of the deletion

Begin of the insertion###End of the insertion **Visuals**

_Admin settings to configure working days of the week:_

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/38205/content">

_Modal dialogue askings users to confirm the change_

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/38206/content">

Begin of the insertion### Note

The settings here are instance-level and changes affect all work packages in all projects. An instance admin might not have the full context for scheduling in all projects in  that instance. 

Changes here should therefore be made sparingly. This is why there is redundancy in the warning (on the page + modal). 

Such a change is also likely to generate a large number of notifications for a large number of users (when start/finish dates of assigned/watched/accountable work packages change as a result). In future iterations, we can think consider finding a way to consolidate these notifications so as to not overwhelm the user.

###End of the insertion **Figma**

https://www.figma.com/file/SMzHAQWcY9k0PkTEKd5UQn/Duration-and-Non-Working-Days?node-id=1667%3A46400