SAlesforce Problem solving

Problem

Consider the following problem: Our sales organization uses Salesforce. It also frequently uses an external system (call it “Foobar”) in which the sales reps search for specific contacts. Once they have assembled a list of contacts, they request Foobar to inject these contacts into Salesforce as Leads. Foobar uses the sales rep’s credentials via OAUTH to authenticate to Salesforce and injects the Leads via the Salesforce API. The list may be as short as one Lead or as long as several hundred Leads.

Our Marketing team wants these leads to be grouped via Salesforce Campaign records. That is, all the leads injected as a list by the sales rep from Foobar in a short period should be grouped, even if they arrive in more than one batch.

Instructions

Please set up a Salesforce instance (a Trailhead playground or a standard developer org) where you implement this using Apex and give us access to this instance.

Your code should:

Respond to insertions of Leads.
Recognize leads injected by Foobar based on LeadSource = “Foobar”.
Whenever the sales rep requests Foobar to inject one or more leads into Salesforce, recognize that a new list is being inserted and create a new Campaign to group them. Leads inserted within a short period should be part of the same campaign. The campaign should have a name that includes the string “Foobar”, the sales rep’s name, and a representation of the time the list was injected. All the Leads in the list should be associated with the Campaign via CampaignMember records.
Be covered by unit tests.
Follow Apex developer best practices.

As this is a proof-of-concept, you are not expected to solve all possible operational and scaling issues now. However, please note in the code why you decided to take a shortcut or how it can be addressed in the future as a TODO item for the code reviewer. You will also be asked for a plan to address these concerns in your delivered project .

Decide which abstractions are essential and which can be added later to meet these time constraints. It is also perfectly acceptable to submit a partial solution. Of course, the more complete the implementation, the better the advantage over partial ones.

I will need explanation for each code and also a video Q&A Session afterwards to explain the solution.