Firestore Value Flattening and unmarshalling

firestore_values.go

package firestore_type

import "encoding/json"

type Value struct {
	Value interface{}
}

func (v *Value) UnmarshalJSON(data []byte) error {
	var fsPayload map[string]interface{}

	if err := json.Unmarshal(data, &fsPayload); err != nil {
		return err
	}

	v.Value = DecodeValue(fsPayload)

	return nil
}

func (v Value) MarshalJSON() ([]byte, error) {
	return json.Marshal(v.Value)
}

func DecodeValue(fsPayload map[string]interface{}) interface{} {
	var value interface{}
	if fsPayload["integerValue"] != nil {
		value = fsPayload["integerValue"].(int64)
	} else if fsPayload["doubleValue"] != nil {
		value = fsPayload["doubleValue"].(float64)
	} else if fsPayload["timestampValue"] != nil {
		value = fsPayload["timestampValue"].(string)
	} else if fsPayload["stringValue"] != nil {
		value = fsPayload["stringValue"].(string)
	} else if fsPayload["booleanValue"] != nil {
		value = fsPayload["booleanValue"].(bool)
	} else if fsPayload["arrayValue"] != nil {
		value = DecodeValueArray(fsPayload["arrayValue"].(map[string]interface{}))
	} else if fsPayload["mapValue"] != nil {
		value = DecodeValueMap(fsPayload["mapValue"].(map[string]interface{}))
	} else {
		panic("Unrecognized Firestore value type")
	}

	return value
}

func DecodeValueArray(fsPayload map[string]interface{}) []interface{} {
	var values []interface{}
	if fsPayload["values"] != nil {
		for _, v := range fsPayload["values"].([]interface{}) {
			values = append(values, DecodeValue(v.(map[string]interface{})))
		}
	}
	return values
}

func DecodeValueMap(fsPayload map[string]interface{}) map[string]interface{} {
	var values = make(map[string]interface{})
	if fsPayload["fields"] != nil {
		for k, v := range fsPayload["fields"].(map[string]interface{}) {
			values[k] = DecodeValue(v.(map[string]interface{}))
		}
	}
	return values
}