fix: Calculate Tax properly

[divyamtayal]

Fixes #7835

Short description of what this resolves:

If we buy paid tickets of more than one type, the tax on orders page shows 0.00 for all tickets. There is probably some calculation issue in tax system.

Checklist

• I have read the Contribution & Best practices Guide.
• My branch is up-to-date with the Upstream development branch.
• The acceptance, integration, unit tests and linter pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

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[codecov]

Codecov Report

Merging #7843 (42a3824) into development (cd012e9) will increase coverage by 0.02%.
The diff coverage is 0.00%.

❗ Current head 42a3824 differs from pull request most recent head 421017f. Consider uploading reports for the commit 421017f to get more accurate results

@@               Coverage Diff               @@
##           development    #7843      +/-   ##
===============================================
+ Coverage        18.56%   18.59%   +0.02%     
===============================================
  Files              613      614       +1     
  Lines             7201     7206       +5     
  Branches           149      149              
===============================================
+ Hits              1337     1340       +3     
- Misses            5837     5839       +2     
  Partials            27       27              

Impacted Files	Coverage Δ
app/models/order.js	0.00% <0.00%> (ø)
app/components/tabbed-navigation.js	53.33% <0.00%> (+20.00%)	⬆️

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[maze-runnar]

Can you share thoght process behind this.

[divyamtayal]

Let x be amount without taxIncluded
So we need to calculate tax which will can be calculated by totalAmount = x + x*taxRate/100;
where x * taxRate / 100 is tax added on top of it which is given by

totalAmount / ( 1 + taxRate / 100 ) * ( taxRate / 100 )  which gives
(taxRate * totalAmount) / (100 + taxRate)

here both if else statement means same, so I'll change that.

@maze-runnar pls have a look

[maze-runnar]

ok, so if my ticket price is 100, and the tax rate is 50%. And I have selected tax is included in the price, it is showing 33.33 tax amount price.

[divyamtayal]

ok, so if my ticket price is 100, and the tax rate is 50%. And I have selected tax is included in the price, it is showing 33.33 tax amount price.

@maze-runnar it is correct because 100 is ticket price inlcuding tax so actual ticket is of 66.66 + 33.33(tax) which gives 100
and if tax would be on top than total would be 100 + 50 = 150

[maze-runnar]

ok, so if my ticket price is 100, and the tax rate is 50%. And I have selected tax is included in the price, it is showing 33.33 tax amount price.

@maze-runnar it is correct because 100 is ticket price inlcuding tax so actual ticket is of 66.66 + 33.33(tax) which gives 100

yes, it is 🔥. good work.

[mariobehling]

This did not solve the issue. Tax is still not showing up e.g. compare here https://test.eventyay.com/e/554ef820

[divyamtayal]

@mariobehling This porblem is not showing on localsystem.
I think there is some problem in new changes been merges not properly deplying or maybe not deployed to
https://eventyay.com/

bcz the changes made in PR #3820 is also not showing (below ScreenShot).

I think the problem is in deployment and same goes with this PR.
@maze-runnar pls have a look at this problem

[mariobehling]

@daretobedifferent18 We are not deploying on live server. The server with the latest changes of the dev branch is https://test.eventyay.com.

[divyamtayal]

@mariobehling ok let me see what is the problem