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package org.scijava.options;

import org.scijava.command.DynamicCommand;
import org.scijava.event.EventService;
import org.scijava.module.ModuleItem;
import org.scijava.module.ModuleService;
import org.scijava.options.event.OptionsEvent;
import org.scijava.plugin.Parameter;
import org.scijava.plugin.SingletonPlugin;
import org.scijava.prefs.PrefService;

// TODO - outline for how to address issues with options (initializing, aggregating into 1 dialog)

// 1. iterate over all inputs: array of CommandModuleItem?
//     - or, split common logic into ParameterHelper class?
// 2. for each input, call loadValue
// 3. if loaded value is null, ignore; else set parameter to equal loaded value
// This should solve IJ2<->IJ1 initialization problem
// All IJ2 options will be set always, when asked using OptionsService
// Legacy layer just needs to query OptionsService.getOption(Class, String) for values

// Other issue is tabbed options dialog
// can get all OptionsPlugins from the OptionsService
// can iterate over all values of OptionsPlugin?
// 1. Remove all menu parameters from Plugin annotations
// 2. Create Options plugin, extends DynamicCommand
//    - Aggregates inputs from all OptionsPlugins from OptionsService & PluginService
//    - assigns "group" field matching name of OptionsPlugin
//    - Would iterate over options: one tab per OptionsPlugin class?
//    - One widget per field of that class -- reuse InputWidget logic
//    - List<CommandInfo<OptionsPlugin>> infos = pluginService.getCommands(OptionsPlugin.class)
//      from those, can get name & label (for use setting group name, which we'll use for tab name)
// "Best" approach: a "grouped" set of inputs rendered as tabs by input harvester
// that get rendered as tabs by Swing, but potentially something else in other UIs
// Then InputHarvester can "just handle" the Options special plugin

/**
 * Base class for all options-oriented plugins.
 * 
 * @author Barry DeZonia
 * @author Curtis Rueden
 */
public abstract class OptionsPlugin extends DynamicCommand implements
	SingletonPlugin
{

	// -- Parameters --

	@Parameter
	protected EventService eventService;

	@Parameter
	private PrefService prefService;

	@Parameter
	private ModuleService moduleService;

	// -- OptionsPlugin methods --

	/** Loads option values from persistent storage. */
	public void load() {
		for (final ModuleItem<?> input : getInfo().inputs()) {
			loadInput(input);
		}
	}

	/** Saves option values to persistent storage. */
	public void save() {
		for (final ModuleItem<?> input : getInfo().inputs()) {
			saveInput(input);
		}
	}

	/** Clears option values from persistent storage. */
	public void reset() {
		prefService.clear(getClass());
	}

	// -- Module methods --

	@Override
	public void cancel() {
		resetState();
	}

	// -- Runnable methods --

	@Override
	public void run() {
		save();
		eventService.publish(new OptionsEvent(this));
		resetState();
	}

	// -- Helper methods --

	private <T> void loadInput(final ModuleItem<T> input) {
		final T value = moduleService.load(input);
		if (value != null) input.setValue(this, value);
	}

	private <T> void saveInput(final ModuleItem<T> input) {
		final T value = input.getValue(this);
		moduleService.save(input, value);
	}

	private void resetState() {
		// NB: Clear "resolved" status of all inputs.
		// Otherwise, no inputs are harvested on next run.
		for (final ModuleItem<?> input : getInfo().inputs()) {
			unresolveInput(input.getName());
		}

		// NB: Clear "canceled" status.
		// Otherwise, the command cannot run again.
		uncancel();
	}
}
