feat: Integrate Bitget for Rate Fetching & Median Calculation Across Multiple Providers

[sundayonah]

Description

This PR integrates Bitget as a source for fetching rates for all supported currencies (e.g., NGN, KES, GHS). It enhances the rate calculation system by retrieving data from multiple providers (Quidax, Binance, and Bitget) and computing the median rate for improved accuracy and reliability.

References

Closes #423
Bitget API Documentation

Testing

• Fetching exchange rates from Bitget, Binance, and Quidax.
• Median calculation logic across multiple price sources.
• Handling API failures and missing data scenarios.

Checklist

• I have added documentation and tests for new/changed functionality in this PR
• All active GitHub checks for tests, formatting, and security are passing
• The correct base branch is being used, if not main

By submitting a PR, I agree to Paycrest's Contributor Code of Conduct and Contribution Guide.

[onahprosper]

@sundayonah there are conflicts

[onahprosper]

Please can you share the direct link to the query advList, when i test the endpoint i am getting:

{
    "status": "error",
    "message": "Failed to fetch rates",
    "data": "FetchBitgetRates: failed to parse response: invalid character '<' looking for beginning of value"
}

[onahprosper]

This check is not enough.
The first check should includes what we have here

if currency == "NGN" || currency == "KES" || currency == "GHS"
// get market price from each Bitget, Binance, and Quidax
// calculate the median

[sundayonah]

This check is not enough. The first check should includes what we have here

if currency == "NGN" || currency == "KES" || currency == "GHS"
// get market price from each Bitget, Binance, and Quidax
// calculate the median

based on this part:

GIVEN the currency is NGN
WHEN fetching rates for USDT/NGN
THEN the system should fetch rates from Quidax and Bitget

GIVEN the currency is not NGN
WHEN fetching rates for USDT/
THEN the system should fetch rates from Binance and Bitget

if currency == NGN use FetchQuidaxRates and FetchBitgetRates
else if currency is ... use FetchBinanceRates and FetchBitgetRates

         if currency == "NGN" {
		quidaxRate, err := FetchQuidaxRates(currency)
		if err == nil {
			prices = append(prices, quidaxRate)
		}
	} else {
		binanceRates, err := FetchBinanceRates(currency)
		if err == nil {
			prices = append(prices, binanceRates...)
		}
	}

	// Fetch Bitget rates for all supported currencies
	bitgetRates, err := FetchBitgetRates(currency)
	if err == nil {
		prices = append(prices, bitgetRates...)
	}
	```

[sundayonah]

Please can you share the direct link to the query advList, when i test the endpoint i am getting:

{
    "status": "error",
    "message": "Failed to fetch rates",
    "data": "FetchBitgetRates: failed to parse response: invalid character '<' looking for beginning of value"
}

https://www.bitget.com/v1/p2p/pub/adv/queryAdvList

body Params
{ "side": 2, "pageNo": 1, "pageSize": 10, "coinCode": "USDT", "fiatCode": "NGN", "languageType": 0 }

[onahprosper]

Please can you share the direct link to the query advList, when i test the endpoint i am getting:

{
    "status": "error",
    "message": "Failed to fetch rates",
    "data": "FetchBitgetRates: failed to parse response: invalid character '<' looking for beginning of value"
}

https://www.bitget.com/v1/p2p/pub/adv/queryAdvList

body Params { "side": 2, "pageNo": 1, "pageSize": 10, "coinCode": "USDT", "fiatCode": "NGN", "languageType": 0 }

What are the inputs?

[sundayonah]

Please can you share the direct link to the query advList, when i test the endpoint i am getting:

{
    "status": "error",
    "message": "Failed to fetch rates",
    "data": "FetchBitgetRates: failed to parse response: invalid character '<' looking for beginning of value"
}

https://www.bitget.com/v1/p2p/pub/adv/queryAdvList
body Params { "side": 2, "pageNo": 1, "pageSize": 10, "coinCode": "USDT", "fiatCode": "NGN", "languageType": 0 }

What are the inputs?

body Params

{
 "side": 2, 
 "pageNo": 1,
 "pageSize": 10, 
 "coinCode": "USDT", 
 "fiatCode": "NGN", 
 "languageType": 0 
 }

[onahprosper]

in your controller/index.go file, kindly add this after running the aggregator locally to reproduce

// GetBitgetRates fetches USDT exchange rates from Bitget P2P listings
func (ctrl *Controller) GetBitgetRates(ctx *gin.Context) {
    currency := ctx.Param("currency")
    if currency == "" {
        u.APIResponse(ctx, http.StatusBadRequest, "error", "Currency code is required", nil)
        return
    }

    rates, err := u.FetchBitgetRates(currency)
    if err != nil {
        fmt.Println("Bitget rates error:")
        u.APIResponse(ctx, http.StatusInternalServerError, "error", "Failed to fetch rates", err.Error())
        return
    }

    u.APIResponse(ctx, http.StatusOK, "success", "Rates fetched successfully", rates)
}

and you can register the route in your router file

v1.GET("bitget/:currency", ctrl.GetBitgetRates)

test with postman