package org.warp.cowdb;

import org.apache.commons.lang3.NotImplementedException;
import org.apache.commons.lang3.reflect.MethodUtils;
import org.warp.cowdb.database.EnhancedObjectFullInfo;
import org.warp.jcwdb.ann.DBClass;
import org.warp.jcwdb.ann.DBDataType;
import org.warp.jcwdb.ann.DBPropertyGetter;
import org.warp.jcwdb.ann.DBPropertySetter;

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

public abstract class EnhancedObject {
	protected final int version;
	protected IDatabaseTools databaseTools;
	private Field[] fields;
	private DBDataType[] fieldTypes;
	private long[] fieldReferences;
	private Method[] propertyGetters;
	private Method[] propertySetters;
	private DBDataType[] propertyTypes;
	private long[] propertyReferences;
	private boolean[] loadedProperties;
	private Object[] loadedPropertyValues;
	private Map<String, DBPropertySetter> setterMethods;
	private Map<String, DBPropertyGetter> getterMethods;

	public EnhancedObject() {
		version = getClassVersion();
	}

	public EnhancedObject(IDatabaseTools databaseTools) throws IOException {
		this.databaseTools = databaseTools;
		version = getClassVersion();
		databaseTools.initializeEnhancedObject(this);
	}

	public void setFields(Field[] fields, DBDataType[] fieldTypes, long[] fieldReferences) {
		this.fields = fields;
		this.fieldTypes = fieldTypes;
		this.fieldReferences = fieldReferences;
	}

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

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

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

	public EnhancedObjectFullInfo getAllInfo() {
		return new EnhancedObjectFullInfo(version, fieldReferences, fieldTypes, fields, propertyReferences, propertyTypes, loadedPropertyValues);
	}


	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);
		}
	}

	@SuppressWarnings("unchecked")
	private <T> T getProperty(int propertyId) throws IOException {
		if (!loadedProperties[propertyId]) {
			long propertyUID = propertyReferences[propertyId];
			databaseTools.getObjectsIO().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(), value);
	}

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

	private int getClassVersion() {
		DBClass classAnnotation = this.getClass().getAnnotation(DBClass.class);
		return classAnnotation == null ? 0 : classAnnotation.version();
	}

	/**
	 * Called when an unloaded class is older than the actual version
	 * @param oldObjectVersion
	 * @param enhancedObjectUpgrader
	 * @throws IOException
	 */
	public void onUpgrade(int oldObjectVersion, EnhancedObjectUpgrader enhancedObjectUpgrader) throws IOException {
		throw new NotImplementedException("Method onUpgrade() is not implemented for class " + this.getClass().getSimpleName());
	}

	public IDatabaseTools getDatabaseTools() {
		return databaseTools;
	}

	public void setDatabaseTools(IDatabaseTools databaseTools) {
		this.databaseTools = databaseTools;
	}
}