package dk.thoerup.webconfig;


import java.lang.reflect.Field;



abstract public class ConfigLoader {
	// TODO: should this class be enhanced with a saveConfig() and a setValue() ?? 


	public abstract String getValue(String paramName);

	public void loadConfig(Object configObject) {

		Field fields[] = configObject.getClass().getDeclaredFields();

		for(Field field : fields) {
			field.setAccessible(true);

			ConfigVariable anno = field.getAnnotation(ConfigVariable.class);
			if (anno == null)
				continue;

			String value = getValue( field.getName() );
			if (value == null) {
				//TODO: find another exception to throw here
				throw new RuntimeException("Could not find a value to this field: " + field.getName() );
			}

			setFieldValue(field,configObject,value);
		}

	}

	public static void setFieldValue(Field field, Object configObject, String value) {

		field.setAccessible(true);
		try {

			if (field.getType().getName().equals("int") ) {
				field.setInt(configObject, Integer.parseInt(value) );
			} else if (field.getType().getName().equals("boolean") ) {
				value = value.toLowerCase();
				if (! (value.equals("true") || value.equals("false"))) {
					//TODO: Find another exception to throw here
					throw new RuntimeException("Only 'true' or 'false' as values for boolean field");
				}
				field.setBoolean(configObject, Boolean.parseBoolean(value) );
			} else if (field.getType().getName().equals("long") ) {
				field.setLong(configObject, Long.parseLong(value) );
			} else if (field.getType().getName().equals("short") ) {
				field.setShort(configObject, Short.parseShort(value) );
			} else if (field.getType().getName().equals("double") ) {
				field.setDouble(configObject, Double.parseDouble(value) );
			} else if (field.getType().getName().equals("float") ) {
				field.setFloat(configObject, Float.parseFloat(value) );
			} else if (field.getType().getName().equals("char") ) {
				field.setFloat(configObject, value.charAt(0) );
			} else {
				field.set(configObject, value );
			}
		} catch (IllegalAccessException e) {
			//this should never happen since we already have called setAccessible(true)
			throw new RuntimeException("How did we get here?", e);
		}
	}

}