var SavedQueryItemModel = require( './SavedQueryItemModel.js' ),
	SavedQueriesModel;

/**
 * View model for saved queries
 *
 * @class mw.rcfilters.dm.SavedQueriesModel
 * @mixins OO.EventEmitter
 * @mixins OO.EmitterList
 *
 * @constructor
 * @param {mw.rcfilters.dm.FiltersViewModel} filtersModel Filters model
 * @param {Object} [config] Configuration options
 * @cfg {string} [default] Default query ID
 */
SavedQueriesModel = function MwRcfiltersDmSavedQueriesModel( filtersModel, config ) {
	config = config || {};

	// Mixin constructor
	OO.EventEmitter.call( this );
	OO.EmitterList.call( this );

	this.default = config.default;
	this.filtersModel = filtersModel;
	this.converted = false;

	// Events
	this.aggregate( { update: 'itemUpdate' } );
};

/* Initialization */

OO.initClass( SavedQueriesModel );
OO.mixinClass( SavedQueriesModel, OO.EventEmitter );
OO.mixinClass( SavedQueriesModel, OO.EmitterList );

/* Events */

/**
 * @event initialize
 *
 * Model is initialized
 */

/**
 * @event itemUpdate
 * @param {mw.rcfilters.dm.SavedQueryItemModel} Changed item
 *
 * An item has changed
 */

/**
 * @event default
 * @param {string} New default ID
 *
 * The default has changed
 */

/* Methods */

/**
 * Initialize the saved queries model by reading it from the user's settings.
 * The structure of the saved queries is:
 * {
 *    version: (string) Version number; if version 2, the query represents
 *             parameters. Otherwise, the older version represented filters
 *             and needs to be readjusted,
 *    default: (string) Query ID
 *    queries:{
 *       query_id_1: {
 *          data:{
 *             filters: (Object) Minimal definition of the filters
 *             highlights: (Object) Definition of the highlights
 *          },
 *          label: (optional) Name of this query
 *       }
 *    }
 * }
 *
 * @param {Object} [savedQueries] An object with the saved queries with
 *  the above structure.
 * @fires initialize
 */
SavedQueriesModel.prototype.initialize = function ( savedQueries ) {
	var model = this;

	savedQueries = savedQueries || {};

	this.clearItems();
	this.default = null;
	this.converted = false;

	if ( savedQueries.version !== '2' ) {
		// Old version dealt with filter names. We need to migrate to the new structure
		// The new structure:
		// {
		//   version: (string) '2',
		//   default: (string) Query ID,
		//   queries: {
		//     query_id: {
		//       label: (string) Name of the query
		//       data: {
		//         params: (object) Representing all the parameter states
		//         highlights: (object) Representing all the filter highlight states
		//     }
		//   }
		// }
		// eslint-disable-next-line no-jquery/no-each-util
		$.each( savedQueries.queries || {}, function ( id, obj ) {
			if ( obj.data && obj.data.filters ) {
				obj.data = model.convertToParameters( obj.data );
			}
		} );

		this.converted = true;
		savedQueries.version = '2';
	}

	// Initialize the query items
	// eslint-disable-next-line no-jquery/no-each-util
	$.each( savedQueries.queries || {}, function ( id, obj ) {
		var normalizedData = obj.data,
			isDefault = String( savedQueries.default ) === String( id );

		if ( normalizedData && normalizedData.params ) {
			// Backwards-compat fix: Remove sticky parameters from
			// the given data, if they exist
			normalizedData.params = model.filtersModel.removeStickyParams( normalizedData.params );

			// Correct the invert state for effective selection
			if ( normalizedData.params.invert && !normalizedData.params.namespace ) {
				delete normalizedData.params.invert;
			}

			model.cleanupHighlights( normalizedData );

			id = String( id );

			// Skip the addNewQuery method because we don't want to unnecessarily manipulate
			// the given saved queries unless we literally intend to (like in backwards compat fixes)
			// And the addNewQuery method also uses a minimization routine that checks for the
			// validity of items and minimizes the query. This isn't necessary for queries loaded
			// from the backend, and has the risk of removing values if they're temporarily
			// invalid (example: if we temporarily removed a cssClass from a filter in the backend)
			model.addItems( [
				new SavedQueryItemModel(
					id,
					obj.label,
					normalizedData,
					{ default: isDefault }
				)
			] );

			if ( isDefault ) {
				model.default = id;
			}
		}
	} );

	this.emit( 'initialize' );
};

/**
 * Clean up highlight parameters.
 * 'highlight' used to be stored, it's not inferred based on the presence of absence of
 * filter colors.
 *
 * @param {Object} data Saved query data
 */
SavedQueriesModel.prototype.cleanupHighlights = function ( data ) {
	if (
		data.params.highlight === '0' &&
		data.highlights && Object.keys( data.highlights ).length
	) {
		data.highlights = {};
	}
	delete data.params.highlight;
};

/**
 * Convert from representation of filters to representation of parameters
 *
 * @param {Object} data Query data
 * @return {Object} New converted query data
 */
SavedQueriesModel.prototype.convertToParameters = function ( data ) {
	var newData = {},
		defaultFilters = this.filtersModel.getFiltersFromParameters( this.filtersModel.getDefaultParams() ),
		fullFilterRepresentation = $.extend( true, {}, defaultFilters, data.filters ),
		highlightEnabled = data.highlights.highlight;

	delete data.highlights.highlight;

	// Filters
	newData.params = this.filtersModel.getMinimizedParamRepresentation(
		this.filtersModel.getParametersFromFilters( fullFilterRepresentation )
	);

	// Highlights: appending _color to keys
	newData.highlights = {};
	// eslint-disable-next-line no-jquery/no-each-util
	$.each( data.highlights, function ( highlightedFilterName, value ) {
		if ( value ) {
			newData.highlights[ highlightedFilterName + '_color' ] = data.highlights[ highlightedFilterName ];
		}
	} );

	// Add highlight
	newData.params.highlight = String( Number( highlightEnabled || 0 ) );

	return newData;
};

/**
 * Add a query item
 *
 * @param {string} label Label for the new query
 * @param {Object} fulldata Full data representation for the new query, combining highlights and filters
 * @param {boolean} isDefault Item is default
 * @param {string} [id] Query ID, if exists. If this isn't given, a random
 *  new ID will be created.
 * @return {string} ID of the newly added query
 */
SavedQueriesModel.prototype.addNewQuery = function ( label, fulldata, isDefault, id ) {
	var normalizedData = { params: {}, highlights: {} },
		highlightParamNames = Object.keys( this.filtersModel.getEmptyHighlightParameters() ),
		randomID = String( id || Date.now() ),
		data = this.filtersModel.getMinimizedParamRepresentation( fulldata );

	// Split highlight/params
	// eslint-disable-next-line no-jquery/no-each-util
	$.each( data, function ( param, value ) {
		if ( param !== 'highlight' && highlightParamNames.indexOf( param ) > -1 ) {
			normalizedData.highlights[ param ] = value;
		} else {
			normalizedData.params[ param ] = value;
		}
	} );

	// Correct the invert state for effective selection
	if ( normalizedData.params.invert && !this.filtersModel.areNamespacesEffectivelyInverted() ) {
		delete normalizedData.params.invert;
	}

	// Add item
	this.addItems( [
		new SavedQueryItemModel(
			randomID,
			label,
			normalizedData,
			{ default: isDefault }
		)
	] );

	if ( isDefault ) {
		this.setDefault( randomID );
	}

	return randomID;
};

/**
 * Remove query from model
 *
 * @param {string} queryID Query ID
 */
SavedQueriesModel.prototype.removeQuery = function ( queryID ) {
	var query = this.getItemByID( queryID );

	if ( query ) {
		// Check if this item was the default
		if ( String( this.getDefault() ) === String( queryID ) ) {
			// Nulify the default
			this.setDefault( null );
		}

		this.removeItems( [ query ] );
	}
};

/**
 * Get an item that matches the requested query
 *
 * @param {Object} fullQueryComparison Object representing all filters and highlights to compare
 * @return {mw.rcfilters.dm.SavedQueryItemModel} Matching item model
 */
SavedQueriesModel.prototype.findMatchingQuery = function ( fullQueryComparison ) {
	// Minimize before comparison
	fullQueryComparison = this.filtersModel.getMinimizedParamRepresentation( fullQueryComparison );

	// Correct the invert state for effective selection
	if ( fullQueryComparison.invert && !this.filtersModel.areNamespacesEffectivelyInverted() ) {
		delete fullQueryComparison.invert;
	}

	return this.getItems().filter( function ( item ) {
		return OO.compare(
			item.getCombinedData(),
			fullQueryComparison
		);
	} )[ 0 ];
};

/**
 * Get query by its identifier
 *
 * @param {string} queryID Query identifier
 * @return {mw.rcfilters.dm.SavedQueryItemModel|undefined} Item matching
 *  the search. Undefined if not found.
 */
SavedQueriesModel.prototype.getItemByID = function ( queryID ) {
	return this.getItems().filter( function ( item ) {
		return item.getID() === queryID;
	} )[ 0 ];
};

/**
 * Get the full data representation of the default query, if it exists
 *
 * @return {Object|null} Representation of the default params if exists.
 *  Null if default doesn't exist or if the user is not logged in.
 */
SavedQueriesModel.prototype.getDefaultParams = function () {
	return ( !mw.user.isAnon() && this.getItemParams( this.getDefault() ) ) || {};
};

/**
 * Get a full parameter representation of an item data
 *
 * @param  {Object} queryID Query ID
 * @return {Object} Parameter representation
 */
SavedQueriesModel.prototype.getItemParams = function ( queryID ) {
	var item = this.getItemByID( queryID ),
		data = item ? item.getData() : {};

	return !$.isEmptyObject( data ) ? this.buildParamsFromData( data ) : {};
};

/**
 * Build a full parameter representation given item data and model sticky values state
 *
 * @param  {Object} data Item data
 * @return {Object} Full param representation
 */
SavedQueriesModel.prototype.buildParamsFromData = function ( data ) {
	data = data || {};
	// Return parameter representation
	return this.filtersModel.getMinimizedParamRepresentation( $.extend( true, {},
		data.params,
		data.highlights
	) );
};

/**
 * Get the object representing the state of the entire model and items
 *
 * @return {Object} Object representing the state of the model and items
 */
SavedQueriesModel.prototype.getState = function () {
	var obj = { queries: {}, version: '2' };

	// Translate the items to the saved object
	this.getItems().forEach( function ( item ) {
		obj.queries[ item.getID() ] = item.getState();
	} );

	if ( this.getDefault() ) {
		obj.default = this.getDefault();
	}

	return obj;
};

/**
 * Set a default query. Null to unset default.
 *
 * @param {string} itemID Query identifier
 * @fires default
 */
SavedQueriesModel.prototype.setDefault = function ( itemID ) {
	if ( this.default !== itemID ) {
		this.default = itemID;

		// Set for individual itens
		this.getItems().forEach( function ( item ) {
			item.toggleDefault( item.getID() === itemID );
		} );

		this.emit( 'default', itemID );
	}
};

/**
 * Get the default query ID
 *
 * @return {string} Default query identifier
 */
SavedQueriesModel.prototype.getDefault = function () {
	return this.default;
};

/**
 * Check if the saved queries were converted
 *
 * @return {boolean} Saved queries were converted from the previous
 *  version to the new version
 */
SavedQueriesModel.prototype.isConverted = function () {
	return this.converted;
};

module.exports = SavedQueriesModel;
