package com.theoryinpractise.halbuilder.json;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.theoryinpractise.halbuilder.api.ReadableRepresentation;
import com.theoryinpractise.halbuilder.api.RepresentationException;
import com.theoryinpractise.halbuilder.api.RepresentationFactory;
import com.theoryinpractise.halbuilder.api.RepresentationReader;
import com.theoryinpractise.halbuilder.impl.api.Support;
import com.theoryinpractise.halbuilder.impl.representations.MutableRepresentation;
import java.io.Reader;
import java.util.Iterator;
import java.util.Map;
import static com.theoryinpractise.halbuilder.impl.api.Support.CURIES;
import static com.theoryinpractise.halbuilder.impl.api.Support.EMBEDDED;
import static com.theoryinpractise.halbuilder.impl.api.Support.HREF;
import static com.theoryinpractise.halbuilder.impl.api.Support.HREFLANG;
import static com.theoryinpractise.halbuilder.impl.api.Support.LINKS;
import static com.theoryinpractise.halbuilder.impl.api.Support.NAME;
import static com.theoryinpractise.halbuilder.impl.api.Support.PROFILE;
import static com.theoryinpractise.halbuilder.impl.api.Support.TITLE;
public class JsonRepresentationReader implements RepresentationReader {
private RepresentationFactory representationFactory;
public JsonRepresentationReader(RepresentationFactory representationFactory) {
this.representationFactory = representationFactory;
}
public ReadableRepresentation read(Reader reader) {
try {
ObjectMapper mapper = new ObjectMapper();
JsonNode rootNode = mapper.readValue(reader, JsonNode.class);
MutableRepresentation resource = readResource(rootNode);
return resource.toImmutableResource();
} catch (Exception e) {
throw new RepresentationException(e);
}
}
private MutableRepresentation readResource(JsonNode rootNode) {
MutableRepresentation resource = new MutableRepresentation(representationFactory);
readNamespaces(resource, rootNode);
readLinks(resource, rootNode);
readProperties(resource, rootNode);
readResources(resource, rootNode);
return resource;
}
private void readNamespaces(MutableRepresentation resource, JsonNode rootNode) {
if (rootNode.has(LINKS)) {
JsonNode linksNode = rootNode.get(LINKS);
if (linksNode.has(CURIES)) {
JsonNode curieNode = linksNode.get(CURIES);
if (curieNode.isArray()) {
Iterator<JsonNode> values = curieNode.elements();
while (values.hasNext()) {
JsonNode valueNode = values.next();
resource.withNamespace(valueNode.get(NAME).asText(), valueNode.get(HREF).asText());
}
} else {
resource.withNamespace(curieNode.get(NAME).asText(), curieNode.get(HREF).asText());
}
}
}
}
private void readLinks(MutableRepresentation resource, JsonNode rootNode) {
if (rootNode.has(LINKS)) {
Iterator<Map.Entry<String, JsonNode>> fields = rootNode.get(LINKS).fields();
while (fields.hasNext()) {
Map.Entry<String, JsonNode> keyNode = fields.next();
if (!CURIES.equals((keyNode.getKey()))) {
if (keyNode.getValue().isArray()) {
Iterator<JsonNode> values = keyNode.getValue().elements();
while (values.hasNext()) {
JsonNode valueNode = values.next();
withJsonLink(resource, keyNode, valueNode);
}
} else {
withJsonLink(resource, keyNode, keyNode.getValue());
}
}
}
}
}
private void withJsonLink(MutableRepresentation resource, Map.Entry<String, JsonNode> keyNode, JsonNode valueNode) {
String rel = keyNode.getKey();
String href = valueNode.get(HREF).asText();
String name = optionalNodeValueAsText(valueNode, NAME);
String title = optionalNodeValueAsText(valueNode, TITLE);
String hreflang = optionalNodeValueAsText(valueNode, HREFLANG);
String profile = optionalNodeValueAsText(valueNode, PROFILE);
resource.withLink(rel, href, name, title, hreflang, profile);
}
String optionalNodeValueAsText(JsonNode node, String key) {
JsonNode value = node.get(key);
return value != null ? value.asText() : null;
}
private void readProperties(MutableRepresentation resource, JsonNode rootNode) {
Iterator<String> fieldNames = rootNode.fieldNames();
while (fieldNames.hasNext()) {
String fieldName = fieldNames.next();
if (!Support.RESERVED_JSON_PROPERTIES.contains(fieldName)) {
JsonNode field = rootNode.get(fieldName);
resource.withProperty(fieldName, field.isNull() ? null : field.asText());
}
}
}
private void readResources(MutableRepresentation resource, JsonNode rootNode) {
if (rootNode.has(EMBEDDED)) {
Iterator<Map.Entry<String, JsonNode>> fields = rootNode.get(EMBEDDED).fields();
while (fields.hasNext()) {
Map.Entry<String, JsonNode> keyNode = fields.next();
if (keyNode.getValue().isArray()) {
Iterator<JsonNode> values = keyNode.getValue().elements();
while (values.hasNext()) {
JsonNode valueNode = values.next();
resource.withRepresentation(keyNode.getKey(), readResource(valueNode));
}
} else {
resource.withRepresentation(keyNode.getKey(), readResource(keyNode.getValue()));
}
}
}
}
}