func compare()

in AmplifyPlugins/DataStore/AWSDataStoreCategoryPlugin/Sync/Support/Model+Compare.swift [31:146]
104 lines of code
32 McCabe index (conditional complexity)

    func compare(_ model1: Model, _ model2: Model) -> Bool {
        let modelType1 = ModelRegistry.modelType(from: model1.modelName)
        let modelType2 = ModelRegistry.modelType(from: model2.modelName)
        if modelType1 != modelType2 {
            // no need to compare models as they have different type
            return false
        }

        for (fieldName, modelField) in fields {
            // read only fields or fields updated from the service are skipped for equality check
            // examples of such fields include `createdAt`, `updatedAt` and `coverId` in `Record`
            if modelField.isReadOnly || ModelSchema.serviceUpdatedFields.contains(modelField.name) {
                continue
            }

            let value1 = model1[fieldName] ?? nil
            let value2 = model2[fieldName] ?? nil

            // check equality for different `ModelFieldType`
            switch modelField.type {
            case .string:
                guard let value1Optional = value1 as? String?, let value2Optional = value2 as? String? else {
                    return false
                }
                if !compare(value1Optional, value2Optional) {
                    return false
                }
            case .int:
                guard let value1Optional = value1 as? Int?, let value2Optional = value2 as? Int? else {
                    return false
                }
                if !compare(value1Optional, value2Optional) {
                    return false
                }
            case .double:
                guard let value1Optional = value1 as? Double?, let value2Optional = value2 as? Double? else {
                    return false
                }
                if !compare(value1Optional, value2Optional) {
                    return false
                }
            case .date:
                guard let value1Optional = value1 as? Temporal.Date?,
                      let value2Optional = value2 as? Temporal.Date? else {
                    return false
                }
                if !compare(value1Optional, value2Optional) {
                    return false
                }
            case .dateTime:
                guard let value1Optional = value1 as? Temporal.DateTime?,
                      let value2Optional = value2 as? Temporal.DateTime? else {
                    return false
                }
                if !compare(value1Optional, value2Optional) {
                    return false
                }
            case .time:
                guard let value1Optional = value1 as? Temporal.Time?,
                      let value2Optional = value2 as? Temporal.Time? else {
                    return false
                }
                if !compare(value1Optional, value2Optional) {
                    return false
                }
            case .timestamp:
                guard let value1Optional = value1 as? String?, let value2Optional = value2 as? String? else {
                    return false
                }
                if !compare(value1Optional, value2Optional) {
                    return false
                }
            case .bool:
                guard let value1Optional = value1 as? Bool?, let value2Optional = value2 as? Bool? else {
                    return false
                }
                if !compare(value1Optional?.intValue, value2Optional?.intValue) {
                    return false
                }
            case .enum:
                guard case .some(Optional<Any>.some(let value1Optional)) = value1,
                      case .some(Optional<Any>.some(let value2Optional)) = value2 else {
                    if value1 == nil && value2 == nil {
                        continue
                    }
                    return false
                }
                let enumValue1Optional = (value1Optional as? EnumPersistable)?.rawValue
                let enumValue2Optional = (value2Optional as? EnumPersistable)?.rawValue
                if !compare(enumValue1Optional, enumValue2Optional) {
                    return false
                }
            case .embedded, .embeddedCollection:
                do {
                    if let encodable1 = value1 as? Encodable,
                       let encodable2 = value2 as? Encodable {
                        let json1 = try SQLiteModelValueConverter.toJSON(encodable1)
                        let json2 = try SQLiteModelValueConverter.toJSON(encodable2)
                        if !compare(json1, json2) {
                            return false
                        }
                    }
                } catch {
                    continue
                }
            // only the first level of data is used for comparison of models
            // and deeper levels(associated models/connections) are ignored
            // e.g. The graphql request contains only the information needed in the graphql variables which is sent to
            // the service. In such a case, the request model may have multiple levels of data while the response
            // model will have just one.
            case .model, .collection:
                continue
            }
        }
        return true
    }