Statistics: Average waiting time (per item)

[snailcato]

User stories

As a User I want to know how long I can expect to wait before I can lend an item.
As an Owner I want to know how long a user has to wait until they can lend my item in order to consider buying another copy, when there is enough interest.

Dependencies

Depends on:

• Model for statistics #138

UI Mockup

• to be designed

Context

We define waiting time as the time a user has to wait until he can request an item. (The first person who lends an item has an waiting time of 0s).
waiting time = lend-request-time - waitlist-join-time

Acceptance Criteria

• compute the average waiting time per item
• log timestamps of lend requests
• log timestamps of joining the waitlist
• visualization of waiting time should be designed and captured in Figma prototype in item view, PO should accept design decision
• display waiting time