package org.warp.jcwdb.ann;

import org.apache.commons.lang3.reflect.MethodUtils;

import java.io.IOError;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.LinkedHashMap;
import java.util.Map;

public abstract class DBObject {
	protected JCWDatabase database;
	private Field[] fields;
	private DBDataType[] fieldTypes;
	private long[] fieldUIDs;

	private Method[] propertyGetters;
	private Method[] propertySetters;
	private DBDataType[] propertyTypes;
	private long[] propertyUIDs;
	private boolean[] loadedProperties;
	private Object[] loadedPropertyValues;
	private Map<String, DBPropertySetter> setterMethods;
	private Map<String, DBPropertyGetter> getterMethods;
	private final Object fieldsAccessLock = new Object();
	private final Object propertiesAccessLock = new Object();

	public DBObject() {

	}

	public DBObject(JCWDatabase database) throws IOException {
		this.database = database;
		database.initializeDBObject(this);
	}

	public abstract void initialize() throws IOException;


	public <T> T getProperty() {
		StackWalker walker = StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE);
		StackWalker.StackFrame stackFrame = walker.walk(f -> f.skip(1).findFirst().orElse(null));
		try {
			int propertyId = stackFrame.getDeclaringClass().getDeclaredMethod(stackFrame.getMethodName()).getAnnotation(DBPropertyGetter.class).id();
			return getProperty(propertyId);
		} catch (IOException | NoSuchMethodException e) {
			throw new RuntimeException(e);
		}
	}

	<T> void setLoadedProperty(int propertyId, T value) {
		loadedPropertyValues[propertyId] = value;
		loadedProperties[propertyId] = true;
	}

	@SuppressWarnings("unchecked")
	private <T> T getProperty(int propertyId) throws IOException {
		synchronized (propertiesAccessLock) {
			if (!loadedProperties[propertyId]) {
				long propertyUID = propertyUIDs[propertyId];
				database.getDataLoader().loadProperty(this, propertyId, propertyGetters[propertyId], propertyTypes[propertyId], propertyUID);
			}
			return (T) loadedPropertyValues[propertyId];
		}
	}

	public <T> void setProperty(T value) {
		StackWalker walker = StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE);
		StackWalker.StackFrame stackFrame = walker.walk(f -> f.skip(1).findFirst().orElse(null));
		DBPropertySetter propertyAnnotation = setterMethods.get(stackFrame.getMethodName());
		setProperty(propertyAnnotation.id(), propertyAnnotation.type(), value);
	}

	public <T> void setProperty(int propertyId, DBDataType propertyType, T value) {
		synchronized (propertiesAccessLock) {
			loadedPropertyValues[propertyId] = value;
			loadedProperties[propertyId] = true;
		}
	}

	public void writeToDisk(long uid) {
		//System.err.println("Saving object " + uid + ":" + this);
		try {
			synchronized (propertiesAccessLock) {
				synchronized (fieldsAccessLock) {
					database.getDataLoader().writeObjectInfo(uid, fieldUIDs, propertyUIDs);
				}
			}
			synchronized (fieldsAccessLock) {
				for (int i = 0; i < fieldUIDs.length; i++) {
					try {
						database.getDataLoader().writeObjectProperty(fieldUIDs[i], fieldTypes[i], fields[i].get(this));
					} catch (IllegalAccessException e) {
						throw new IOError(e);
					}
				}
			}
			synchronized (propertiesAccessLock) {
				for (int i = 0; i < propertyUIDs.length; i++) {
					database.getDataLoader().writeObjectProperty(propertyUIDs[i], propertyTypes[i], loadedPropertyValues[i]);
				}
			}
		} catch (IOException e) {
			throw new IOError(e);
		}
	}

	public final void setFields(Field[] fields, DBDataType[] fieldTypes, long[] fieldUIDs) {
		synchronized (fieldsAccessLock) {
			this.fields = fields;
			this.fieldTypes = fieldTypes;
			this.fieldUIDs = fieldUIDs;
		}
	}

	public final void setProperties(Method[] propertyGetters, Method[] propertySetters, DBDataType[] propertyTypes, long[] propertyUIDs, Map<String, DBPropertySetter> setterMethods, Map<String, DBPropertyGetter> getterMethods) {
		synchronized (propertiesAccessLock) {
			this.propertyGetters = propertyGetters;
			this.propertySetters = propertySetters;
			this.propertyTypes = propertyTypes;
			this.propertyUIDs = propertyUIDs;
			this.loadedProperties = new boolean[this.propertyUIDs.length];
			this.loadedPropertyValues = new Object[this.propertyUIDs.length];
			this.setterMethods = setterMethods;
			this.getterMethods = getterMethods;
		}
	}

	Method[] getPropertyGetters() {
		return MethodUtils.getMethodsWithAnnotation(this.getClass(), DBPropertyGetter.class);
	}

	public Method[] getPropertySetters() {
		return MethodUtils.getMethodsWithAnnotation(this.getClass(), DBPropertySetter.class);
	}
}