feat: API to fetch total order amount by passing tickets and discount code

[shreyanshdwivedi]

Fixes #6323

Changes proposed in this pull request:

• Adds an API to fetch total order amount by posting tickets, their amount, event and discount code
  Payload

           {
                "tickets": [
                	{"id": "32", "quantity": 2, "price": 100},
                	{"id": "31", "quantity": 3}
                ],
                "discount-code": "16"
            }

Response

{
    "tax_included": false,
    "tickets": [
        {
            "discount": {},
            "id": 32,
            "name": "donation",
            "price": 100,
            "quantity": 1,
            "sub_total": 110.5,
            "tax": {
                "amount": 10.5,
                "percent": 10.5
            },
            "ticket_fee": 0
        },
        {
            "discount": {
                "amount": 15,
                "code": "s1",
                "percent": 17.65
            },
            "id": 31,
            "name": "paid",
            "price": 85,
            "quantity": 1,
            "sub_total": 153.85,
            "tax": {
                "amount": 7.35,
                "percent": 10.5
            },
            "ticket_fee": 76.5
        }
    ],
    "total_amount": 264.35,
    "total_discount": 15,
    "total_tax": 17.85
}

Checklist

Ensure it works:

• with event including tax
• excluding tax,
• with discount code,
• without discount code,
• with donation ticket price
• without donation ticket price

[shreyanshdwivedi]

@uds5501 @kushthedude @mrsaicharan1 can you guys please test and review this PR?

[codecov]

Codecov Report

Merging #6366 into development will decrease coverage by 0.27%.
The diff coverage is 10%.

@@               Coverage Diff               @@
##           development    #6366      +/-   ##
===============================================
- Coverage        64.74%   64.47%   -0.28%     
===============================================
  Files              288      288              
  Lines            14966    15039      +73     
===============================================
+ Hits              9690     9696       +6     
- Misses            5276     5343      +67

Impacted Files	Coverage Δ
app/api/orders.py	27.15% <0%> (ø)	⬆️
app/api/helpers/ticketing.py	16.8% <10%> (-0.74%)	⬇️
app/api/helpers/order.py	23.96% <3.63%> (-16.95%)	⬇️
app/api/auth.py	24.3% <35.71%> (+0.26%)	⬆️

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[iamareebjamal]

Great job. Event key should support event ID as well

[iamareebjamal]

Secondly, create a function which takes tickets, event and discount_code as arguments and returns the computed dictionary so that it can be tested, and of course there will be several tests for this:

• with event including tax
• excluding tax,
• with discount code,
• without discount code,
• with donation ticket

so that we have confidence it is working and fidelity for future

[shreyanshdwivedi]

Sure. Will add functions and tests by tonight

[iamareebjamal]

Also, use marshmallow for validation

[iamareebjamal]

Actually, event ID should not be needed. It can be extracted from ticket. Just verify every ticket has same event ID

[shreyanshdwivedi]

Ok. Will make mentioned changes

[iamareebjamal]

Also, you can't just return the amount in JSON. You have to return a full object with price breakdown of individual tickets with tax and what not

[shreyanshdwivedi]

Also, you can't just return the amount in JSON. You have to return a full object with price breakdown of individual tickets with tax and what not

Yeah I was thinking about the same. Will return amount for each ticket, tax included in price or on the price, discount and overall total

[shreyanshdwivedi]

Currently, the response is -

{
    "grand_total": 270,
    "tickets": [
        {
            "discount_amount": 0,
            "discount_percent": 0,
            "exclusive_tax": 0,
            "id": 32,
            "inclusive_tax": 0,
            "price": 100,
            "quantity": 2,
            "sub_total": 200
        },
        {
            "discount_amount": 15,
            "discount_percent": 17.65,
            "exclusive_tax": 0,
            "id": 31,
            "inclusive_tax": 0,
            "price": 85,
            "quantity": 1,
            "sub_total": 70
        }
    ],
    "total_discount": 15,
    "total_tax": 0
}

If anyone wants anything else to be returned alongwith this info, please comment. Till then I'll test it out for different cases and add test to the order helper

[iamareebjamal]

OK, how price of 158 with inclusive tax of 9.87 and discount of 16.59 amount to sub_total of 282.82?

grand_total -> total_price
Add discount_percentage and discount_amount

Will add more recommendations on tax after seeing more examples

[shreyanshdwivedi]

For tax thing -> (158 - 16.59)*2
sub total includes multiplication with quantity too

About discount_percentage, so u need to calculate both % and amount for all cases of discount whether it is amount or percent type or not? Makes sense. Will help others to display on client directly.

[shreyanshdwivedi]

@iamareebjamal I've tested all the cases mentioned by you in PR description. Should I add test for these cases too? If yes, then what should I test, sub-total, by replicating calculation in the helper?

[iamareebjamal]

I think adding API documentation will serve both purposes, document it and also test the implementation

However, I will add more fields, so hold on to that

@anhanh11001 @liveHarshit, Please review the response and if it needs anything else

[liveHarshit]

@anhanh11001 @liveHarshit, Please review the response and if it needs anything else

How should I test it as it is not merged in development? I think @anhanh11001 has local setup for the server?

[shreyanshdwivedi]

Sub_total = (price + tax - discount)*quantity

Basically a user can get details of one ticket by adding tax to price (if tax is exclusive) and then subtract discount to get an effective price for a ticket

[shreyanshdwivedi]

Also we cannot have exclusive and inclusive tax at the same time for an event. I've made changes to local and will push it once we are have other's feedback too

[shreyanshdwivedi]

@uds5501 @mrsaicharan1 @CosmicCoder96 can you guys check this once? Please refer to the PR description for lastest request and response data format

[iamareebjamal]

Please remove the data section in request. It's unneeded

[iamareebjamal]

And discount should be null if not applied

[shreyanshdwivedi]

@iamareebjamal removed data from request and also now if discount code or tax is not applied the discount/tax key have null data

[shreyanshdwivedi]

@uds5501 @mrsaicharan1 @iamareebjamal please review this PR

[iamareebjamal]

Is the discount code ticket limit and maximum cutoff taken into account?

[shreyanshdwivedi]

@iamareebjamal currently they are being checked when we send a POST request to create order.

[iamareebjamal]

But the amount will be wrong if you don't check it here

[shreyanshdwivedi]

Agreed. Will apply checks here too

[shreyanshdwivedi]

Was caught up in finalizing work product and other high priority pending PRs. Will start to finalize this now

[shreyanshdwivedi]

@iamareebjamal I've included checks for overconsumption and service fees. Please have a look to updated response in the PR description
I checked for discount_code consumption. I set max discount tickets to be 1 and then tried for 2 tickets, error was produced as expected.
And the ticket service fee levied is 90% on INR with maximum_fee of 90. Please check

[iamareebjamal]

Error should not be produced. Discount code should only be applied to 1 ticket

[shreyanshdwivedi]

@iamareebjamal actually the current implementation while ordering tickets follow the same thing and produces error in case of overconsumption.
Can we handle this in a follow up issue?