refactor(connector): added amount conversion framework for klarna and change type of amount to MinorUnit for OrderDetailsWithAmount

[KiranKBR]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

• added amount conversion framework for klarna
• For struct OrderDetailsWithAmount, changed the type of amount from i64 to MinorUnit
• Made unit_price as Option, for TaxJar connector.

Additional Changes

• This PR modifies the API contract
• This PR modifies the database schema
• This PR modifies application configuration/environment variables

Motivation and Context

How did you test it?

1. Create Merchant Account
2. Create API Key
3. Create MCA for Klarna|

curl --location 'http://localhost:8080/account/merchant_1729494178/connectors' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: test_admin' \
--data '{
    "connector_type": "payment_processor",
    "connector_name": "klarna",
    "connector_account_details": {
        "auth_type": "BodyKey",
        "api_key": "___", 
        "key1":  "_____"   
        
    },
    "test_mode": true,
    "disabled": false,
    "payment_methods_enabled": [
        {
            "payment_method": "pay_later",
            "payment_method_types": [
                {
                    "minimum_amount": 1,
                    "maximum_amount": 68607706,
                    "recurring_enabled": true,
                    "installment_payment_enabled": true,
                    "payment_experience": "invoke_sdk_client",
                    "payment_method_type": "klarna"
                }
            ]
        }
    ],
    "metadata": {
        "klarna_region": "NorthAmerica"
    },
    "business_country": "US",
    "business_label": "food"
}
'

4. Create Tax Jar

curl --location 'http://localhost:8080/account/merchant_1729494178/connectors' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: test_admin' \
--data '{
    "connector_type": "tax_processor",
    "connector_name": "taxjar",
    "connector_account_details": {
        "auth_type": "HeaderKey",
        "api_key": "____" 
    },

    "test_mode": false,
    "disabled": false,

    "metadata": {
        "city": "NY",
        "unit": "245"
    },
    "business_country": "US",
    "business_label": "food"
}'

5. Create a Payment

curl --location 'http://localhost:8080/payments' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: _____' \
--data-raw '{
    "amount": 3000,
    "currency": "USD",
    "confirm": false,
    "capture_method": "manual",
    "capture_on": "2022-09-10T10:11:12Z",
    "customer_id": "StripeCustomer",
    "email": "guest@example.com",
    "name": "John Doe",
    "phone": "999999999",
    "phone_country_code": "+1",
    "description": "Its my first payment request",
    "authentication_type": "no_three_ds",
    "return_url": "https://google.com",
    "billing": {
        "address": {
            "line1": "1467",
            "line2": "Harrison Street",
            "line3": "Harrison Street",
            "city": "San Fransico",
            "state": "California",
            "zip": "94122",
            "country": "US",
            "first_name": "joseph",
            "last_name": "Doe"
        },
        "phone": {
            "number": "8056594427",
            "country_code": "+91"
        },
        "email": "swangi@gmail.com"
    },
    "order_details": [ 
        {
            "product_name": "Apple iphone 15",
            "quantity": 1,
            "amount": 1000,
            "product_tax_code": "23"
        },
        {
            "product_name": "Apple iphone 15",
            "quantity": 1,
            "amount": 2000,
            "minor_amount" : 2000,
            "product_tax_code": "23"
        }
    ],
    "statement_descriptor_name": "joseph",
    "statement_descriptor_suffix": "JS",
    "metadata": {
        "udf1": "value1",
        "new_customer": "true",
        "login_date": "2019-09-10T10:11:12Z"
    }
    
}'

6. Session Token

curl --location 'http://localhost:8080/payments/session_tokens' \
--header 'Content-Type: application/json' \
--header 'api-key: pk_dev_28ab740febb44c1eb1c3176698abd56f' \
--data '{
    "payment_id": "pay_PnNHfYis89QYkvY7sFcX",
    "wallets": [],
    "client_secret": "__"
}'

7. List Payment Methods for merchant

curl --location 'http://localhost:8080/account/payment_methods?client_secret=pay_PnNHfYis89QYkvY7sFcX_secret_drsmJqh2E2sZM7UuIVGd' \
--header 'Accept: application/json' \
--header 'api-key: ___'

8. Calculate Tax

curl --location 'http://localhost:8080/payments/pay_PnNHfYis89QYkvY7sFcX/calculate_tax' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: pk_dev_28ab740febb44c1eb1c3176698abd56f' \
--data-raw '{
    "client_secret": "pay_PnNHfYis89QYkvY7sFcX_secret_drsmJqh2E2sZM7UuIVGd",
    "shipping": {
        "address": {
            "line1": "1335",
            "line2": "E 103rd St",
            
            "city": "Los Angeles",
            "state": "California",
            "zip": "90002",
            "country": "US",
            "first_name": "Test",
            "last_name": "Person-us"
        },
        "phone": {
            "number": "5551234",
            "country_code": "+1"
        },
        "email": "generated_email_us+1715685671426@example.com"
    },
    "payment_method_type": "klarna",
    
    "session_id": "feb4fc0d-4196-6856-8d02-eb999d6b971a"
}
'

Response

{
    "payment_id": "pay_PnNHfYis89QYkvY7sFcX",
    "net_amount": 3190,
    "order_tax_amount": 190,
    "shipping_cost": null,
    "display_amount": {
        "net_amount": "31.90",
        "order_tax_amount": "1.90",
        "shipping_cost": null
    }
}

Note:

• To test end to end flow please test Klarna payments flow via sdk.
• We can not test TaxCalculation for Klarna via sdk as SessionUpdate flow for klarna is not yet implemented.

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible

[sahkal]

add is already there why is Sum needed?

[swangi-kumari]

.sum() function is required to accumulate the elements of an iterator for OrderDetails.