Salesforce Visualforce Development - touches SalesforceCPQ

Visualforce page development. This is an easy project for someone with VF dev experience. Please be experienced in this area. There is a likelihood of other projects in the future if this one goes well. Would prefer someone who has done VF, Apex, and triggers in Salesforce as future projects will include those also. Summary: The development of Visualforce pages that does field update and subsequently launches another already existing Visualforce page. Your page will be launched from a Quote detail page, the field update is done to that Quote, then you run an existing Visualforce page with the context of that Quote so that page knows it is also operating on that particular Quote record. Because of security for the customer, you will not have access to the customer Salesforce system. You will develop in your sandbox, provide me with the resources and I will retest in their sandbox. I realize that this is a hassle and will add some time. You may or may not need to setup Salesforce CPQ for this project. Given the simplicity of the changes, you may be able to mockup the object name and field names in a sandbox without doing that. Background: 1. The customer is using Salesforce's CPQ addon which enhances Quotes with an object SBQQ__Quote__c 2. On the Quote Detail page there is a button "GenerateDocument" which launches a Visualforce page "SBQQ_GenerateDocument" This VF page is managed code and so we don't have access to modify it. 4. We want to change the functionality so that when a button is pushed by the user that a field update will occur and then the existing SBQQ_GenerateDocument page will be called. Ideally we would have access to the existing VF code and could just add the field update into that. Because it is managed code, we want you to create the field update in a new VF page. So to summarize in a picture: Currently: Button -> VF SBQQ_GenerateDocument New desired functionality: Button2 -> [VF Field Update to Expires_OnCustom__c] -> VF SBQQ_GenerateDocument 5. Pseudocode: Notes: Expires_OnCustom__c is a Date Field Market_Segment__c is a Picklist a. Check SBQQ__Quote__c.Expires_OnCustom__c and if is NOT NULL then skip all of this and go to (d) b. If SBQQ__Quote__c.Market_Segment__c == "AERO/DEF" then update Expires_OnCustom__c = today + 90 days c. If SBQQ__Quote__c.Market_Segment__c != "AERO/DEF" then update Expires_OnCustom__c = today + 30 days d. Launch page SBQQ_GenerateDocument