/**
 * @class Ext.chart.series.Cartesian
 * @extends Ext.chart.series.Series
 *
 * Common base class for series implementations which plot values using x/y coordinates.
 */
Ext.define('Ext.chart.series.Cartesian', {

    /* Begin Definitions */

    extend: 'Ext.chart.series.Series',

    alternateClassName: ['Ext.chart.CartesianSeries', 'Ext.chart.CartesianChart'],

    /* End Definitions */

    /**
     * The field used to access the x axis value from the items from the data
     * source.
     *
     * @cfg xField
     * @type String
     */
    xField: null,

    /**
     * The field used to access the y-axis value from the items from the data
     * source.
     *
     * @cfg yField
     * @type String
     */
    yField: null,

    /**
     * @cfg {String} axis
     * The position of the axis to bind the values to. Possible values are 'left', 'bottom', 'top' and 'right'.
     * You must explicitly set this value to bind the values of the line series to the ones in the axis, otherwise a
     * relative scale will be used.
     */
    axis: 'left',

    getLegendLabels: function() {
        var me = this,
            labels = [],
            combinations = me.combinations;

        Ext.each([].concat(me.yField), function(yField, i) {
            var title = me.title;
            // Use the 'title' config if present, otherwise use the raw yField name
            labels.push((Ext.isArray(title) ? title[i] : title) || yField);
        });

        // Handle yFields combined via legend drag-drop
        if (combinations) {
            Ext.each(combinations, function(combo) {
                var label0 = labels[combo[0]],
                    label1 = labels[combo[1]];
                labels[combo[1]] = label0 + ' & ' + label1;
                labels.splice(combo[0], 1);
            });
        }

        return labels;
    },

    /**
     * @protected Iterates over a given record's values for each of this series's yFields,
     * executing a given function for each value. Any yFields that have been combined
     * via legend drag-drop will be treated as a single value.
     * @param {Ext.data.Model} record
     * @param {Function} fn
     * @param {Object} scope
     */
    eachYValue: function(record, fn, scope) {
        Ext.each(this.getYValueAccessors(), function(accessor, i) {
            fn.call(scope, accessor(record), i);
        });
    },

    /**
     * @protected Returns the number of yField values, taking into account fields combined
     * via legend drag-drop.
     * @return {Number}
     */
    getYValueCount: function() {
        return this.getYValueAccessors().length;
    },

    combine: function(index1, index2) {
        var me = this,
            accessors = me.getYValueAccessors(),
            accessor1 = accessors[index1],
            accessor2 = accessors[index2];

        // Combine the yValue accessors for the two indexes into a single accessor that returns their sum
        accessors[index2] = function(record) {
            return accessor1(record) + accessor2(record);
        };
        accessors.splice(index1, 1);

        me.callParent([index1, index2]);
    },

    clearCombinations: function() {
        // Clear combined accessors, they'll get regenerated on next call to getYValueAccessors
        delete this.yValueAccessors;
        this.callParent();
    },

    /**
     * @protected Returns an array of functions, each of which returns the value of the yField
     * corresponding to function's index in the array, for a given record (each function takes the
     * record as its only argument.) If yFields have been combined by the user via legend drag-drop,
     * this list of accessors will be kept in sync with those combinations.
     * @return {Array} array of accessor functions
     */
    getYValueAccessors: function() {
        var me = this,
            accessors = me.yValueAccessors;
        if (!accessors) {
            accessors = me.yValueAccessors = [];
            Ext.each([].concat(me.yField), function(yField) {
                accessors.push(function(record) {
                    return record.get(yField);
                });
            });
        }
        return accessors;
    },

    /**
     * Calculate the min and max values for this series's xField.
     * @return {Array} [min, max]
     */
    getMinMaxXValues: function() {
        var me = this,
            min, max,
            xField = me.xField;

        if (me.getRecordCount() > 0) {
            min = Infinity;
            max = -min;
            me.eachRecord(function(record) {
                var xValue = record.get(xField);
                if (xValue > max) {
                    max = xValue;
                }
                if (xValue < min) {
                    min = xValue;
                }
            });
        } else {
            min = max = 0;
        }
        return [min, max];
    },

    /**
     * Calculate the min and max values for this series's yField(s). Takes into account yField
     * combinations, exclusions, and stacking.
     * @return {Array} [min, max]
     */
    getMinMaxYValues: function() {
        var me = this,
            stacked = me.stacked,
            min, max,
            positiveTotal, negativeTotal;

        function eachYValueStacked(yValue, i) {
            if (!me.isExcluded(i)) {
                if (yValue < 0) {
                    negativeTotal += yValue;
                } else {
                    positiveTotal += yValue;
                }
            }
        }

        function eachYValue(yValue, i) {
            if (!me.isExcluded(i)) {
                if (yValue > max) {
                    max = yValue;
                }
                if (yValue < min) {
                    min = yValue;
                }
            }
        }

        if (me.getRecordCount() > 0) {
            min = Infinity;
            max = -min;
            me.eachRecord(function(record) {
                if (stacked) {
                    positiveTotal = 0;
                    negativeTotal = 0;
                    me.eachYValue(record, eachYValueStacked);
                    if (positiveTotal > max) {
                        max = positiveTotal;
                    }
                    if (negativeTotal < min) {
                        min = negativeTotal;
                    }
                } else {
                    me.eachYValue(record, eachYValue);
                }
            });
        } else {
            min = max = 0;
        }
        return [min, max];
    },

    getAxesForXAndYFields: function() {
        var me = this,
            axes = me.chart.axes,
            axis = [].concat(me.axis),
            xAxis, yAxis;

        if (Ext.Array.indexOf(axis, 'top') > -1) {
            xAxis = 'top';
        } else if (Ext.Array.indexOf(axis, 'bottom') > -1) {
            xAxis = 'bottom';
        } else {
            if (axes.get('top')) {
                xAxis = 'top';
            } else if (axes.get('bottom')) {
                xAxis = 'bottom';
            }
        }

        if (Ext.Array.indexOf(axis, 'left') > -1) {
            yAxis = 'left';
        } else if (Ext.Array.indexOf(axis, 'right') > -1) {
            yAxis = 'right';
        } else {
            if (axes.get('left')) {
                yAxis = 'left';
            } else if (axes.get('right')) {
                yAxis = 'right';
            }
        }

        return {
            xAxis: xAxis,
            yAxis: yAxis
        };
    }


});