Add a feature to apply discounts

[karlnyr]

As a user that does invoicing,
I want to easily apply discounts to specific samples automatically, and also in a particular quantity, without having to define a new application tag,
So that we can upon agreement with a customer give them a discount with a product without having to consider that when we are actively doing the invoicing step.

This is of peaking interest now that we are starting the PacBio 1000 genomes project, where a specific customer will need to have a discounted 1000 samples for the LWPBELB070 application tag.

Work impact

Answer the following questions:

• Is there currently a workaround for this issue? If so, what is it?
  • We can apply customer discounts manually when doing the invoicing, however, the people doing the invoicing are not necessarily the onces who has discussed the discounts with the customer, thus making it difficult to see when the discounts should be applied.
• How much time would be saved by implementing this feature on a weekly basis?
  • Difficult to say, but the impact of incorrect invoicing is high and it would take time and consideration every time we invoice would probably be an hour or so?
• How many users are affected by this issue?
  • 2 people are doing invoicing today, but those are @vwirta and @AnnaZetterlund, both of which are quite busy bees
• Are customers affected by this issue?
  • Yes, if incorrect discounts are applied the funds for projects may not be enough.

Acceptance Criteria

• There is a way to pre-define discounts for a specific service for a customer.
• The pre-defined discount should have the ability to be either infinite or finite

Clarification:

Clarification. Say that we want to give customer A a discount for TGA samples. Those TGA samples could for instance have the apptag PANKTTR020 or PANKTTR060 because they are tumor normal. I would want to give the customer a discount for 30 T/N pairs. Thus, I would want to discount 30 PANKTTR020 samples and PANKTTR060 respectively. Alternatively, I want to give one customer a permanent discount for PANKTTR020 and PANKTTR060.

Notes

• Additional information.
• Dependencies.
• Related user stories.

[Vince-janv]

The invoicing is part of cg is a mess. I think a discount system is a sound solution. From what I'm hearing @vwirta wants to change the entire invoicing logic during this year. I think a manual discount system is something we should consider then.

Will leave this open until the invoicing changes have been decided

[vwirta]

I think we need to use the discount model until we have time and resources to redesign the entire invoicing process.

The tricky part will be to remember what samples should receive discount, and I'd like to propose that we create new cust accounts for samples that will receive a discount. This will make it much more easy for us in the invoicing step.