Refactor: Reduce Cognitive Complexity Reported by SonarQube on NF Discovery

[ReshmaJS]

This PR refactors the code to reduce cognitive complexity, improving maintainability and ensuring compliance with static analysis rules.

[Copilot]

Pull request overview

This PR refactors the NF Discovery implementation to reduce cognitive complexity (per SonarQube) by extracting validation and filter-building logic into smaller helper functions, aiming to improve maintainability without changing discovery behavior.

Changes:

• Extracted complexQuery validation into validateComplexQuery.
• Extracted profile sorting/decoding/fallback into sortNFProfiles, and BSF IP conversion into handleBSFIpConversion.
• Refactored buildFilter into many focused handle* helper functions.

Suppressed comments (2)

producer/nf_discovery.go:1792

• handleComplexQuery indexes queryParameters["complexQuery"][0] after only checking for nil. If the key exists with an empty (non-nil) slice, this panics. Use a length check before indexing.

	if queryParameters["complexQuery"] != nil {
		// translate raw data to complexQuery structure
		complexQuery := queryParameters["complexQuery"][0]
		complexQueryStruct := &models.ComplexQuery{}

producer/nf_discovery.go:1798

• The local variable name complexQueryFilter is the same as the function complexQueryFilter(...), which is easy to misread and makes debugging harder. Rename the variable to avoid shadowing/confusion.

		complexQueryFilter := complexQueryFilter(complexQueryStruct)
		filter["$and"] = append(filter["$and"].([]bson.M), complexQueryFilter)

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.