/**
 * 多边形
 * @module zrender/shape/Polygon
 * @author Kener (@Kener-林峰, kener.linfeng@gmail.com)
 * @example
 *     var Polygon = require('zrender/shape/Polygon');
 *     var shape = new Polygon({
 *         style: {
 *             // 100x100的正方形
 *             pointList: [[0, 0], [100, 0], [100, 100], [0, 100]],
 *             color: 'blue'
 *         }
 *     });
 *     zr.addShape(shape);
 */

/**
 * @typedef {Object} IPolygonStyle
 * @property {string} pointList 多边形顶点数组
 * @property {string} [smooth=''] 是否做平滑插值, 平滑算法可以选择 bezier, spline
 * @property {number} [smoothConstraint] 平滑约束
 * @property {string} [brushType='fill']
 * @property {string} [color='#000000'] 填充颜色
 * @property {string} [strokeColor='#000000'] 描边颜色
 * @property {string} [lineCape='butt'] 线帽样式，可以是 butt, round, square
 * @property {number} [lineWidth=1] 描边宽度
 * @property {number} [opacity=1] 绘制透明度
 * @property {number} [shadowBlur=0] 阴影模糊度，大于0有效
 * @property {string} [shadowColor='#000000'] 阴影颜色
 * @property {number} [shadowOffsetX=0] 阴影横向偏移
 * @property {number} [shadowOffsetY=0] 阴影纵向偏移
 * @property {string} [text] 图形中的附加文本
 * @property {string} [textColor='#000000'] 文本颜色
 * @property {string} [textFont] 附加文本样式，eg:'bold 18px verdana'
 * @property {string} [textPosition='end'] 附加文本位置, 可以是 inside, left, right, top, bottom
 * @property {string} [textAlign] 默认根据textPosition自动设置，附加文本水平对齐。
 *                                可以是start, end, left, right, center
 * @property {string} [textBaseline] 默认根据textPosition自动设置，附加文本垂直对齐。
 *                                可以是top, bottom, middle, alphabetic, hanging, ideographic
 */
define(
    function (require) {
        var Base = require('./Base');
        var smoothSpline = require('./util/smoothSpline');
        var smoothBezier = require('./util/smoothBezier');
        var dashedLineTo = require('./util/dashedLineTo');

        /**
         * @alias module:zrender/shape/Polygon
         * @param {Object} options
         * @constructor
         * @extends module:zrender/shape/Base
         */
        var Polygon = function (options) {
            Base.call(this, options);
            /**
             * 多边形绘制样式
             * @name module:zrender/shape/Polygon#style
             * @type {module:zrender/shape/Polygon~IPolygonStyle}
             */
            /**
             * 多边形高亮绘制样式
             * @name module:zrender/shape/Polygon#highlightStyle
             * @type {module:zrender/shape/Polygon~IPolygonStyle}
             */
        };

        Polygon.prototype = {
            type: 'polygon',

            /**
             * 创建多边形路径
             * @param {CanvasRenderingContext2D} ctx
             * @param {module:zrender/shape/Polygon~IPolygonStyle} style
             */
            buildPath : function (ctx, style) {
                // 虽然能重用brokenLine，但底层图形基于性能考虑，重复代码减少调用吧
                var pointList = style.pointList;
                // 开始点和结束点重复
                /*
                var start = pointList[0];
                var end = pointList[pointList.length-1];

                if (start && end) {
                    if (start[0] == end[0] &&
                        start[1] == end[1]) {
                        // 移除最后一个点
                        pointList.pop();
                    }
                }
                */

                if (pointList.length < 2) {
                    // 少于2个点就不画了~
                    return;
                }

                if (style.smooth && style.smooth !== 'spline') {
                    var controlPoints = smoothBezier(
                        pointList, style.smooth, true, style.smoothConstraint
                    );

                    ctx.moveTo(pointList[0][0], pointList[0][1]);
                    var cp1;
                    var cp2;
                    var p;
                    var len = pointList.length;
                    for (var i = 0; i < len; i++) {
                        cp1 = controlPoints[i * 2];
                        cp2 = controlPoints[i * 2 + 1];
                        p = pointList[(i + 1) % len];
                        ctx.bezierCurveTo(
                            cp1[0], cp1[1], cp2[0], cp2[1], p[0], p[1]
                        );
                    }
                } 
                else {
                    if (style.smooth === 'spline') {
                        pointList = smoothSpline(pointList, true);
                    }

                    if (!style.lineType || style.lineType == 'solid') {
                        // 默认为实线
                        ctx.moveTo(pointList[0][0], pointList[0][1]);
                        for (var i = 1, l = pointList.length; i < l; i++) {
                            ctx.lineTo(pointList[i][0], pointList[i][1]);
                        }
                        ctx.lineTo(pointList[0][0], pointList[0][1]);
                    }
                    else if (style.lineType == 'dashed'
                            || style.lineType == 'dotted'
                    ) {
                        var dashLength = 
                            style._dashLength
                            || (style.lineWidth || 1) 
                               * (style.lineType == 'dashed' ? 5 : 1);
                        style._dashLength = dashLength;
                        ctx.moveTo(pointList[0][0], pointList[0][1]);
                        for (var i = 1, l = pointList.length; i < l; i++) {
                            dashedLineTo(
                                ctx,
                                pointList[i - 1][0], pointList[i - 1][1],
                                pointList[i][0], pointList[i][1],
                                dashLength
                            );
                        }
                        dashedLineTo(
                            ctx,
                            pointList[pointList.length - 1][0], 
                            pointList[pointList.length - 1][1],
                            pointList[0][0],
                            pointList[0][1],
                            dashLength
                        );
                    }
                }

                ctx.closePath();

            },

            /**
             * 计算返回多边形包围盒矩阵
             * @param {module:zrender/shape/Polygon~IPolygonStyle} style
             * @return {module:zrender/shape/Base~IBoundingRect}
             */
            getRect : function (style) {
                if (style.__rect) {
                    return style.__rect;
                }
                
                var minX =  Number.MAX_VALUE;
                var maxX =  Number.MIN_VALUE;
                var minY = Number.MAX_VALUE;
                var maxY = Number.MIN_VALUE;

                var pointList = style.pointList;
                for (var i = 0, l = pointList.length; i < l; i++) {
                    if (pointList[i][0] < minX) {
                        minX = pointList[i][0];
                    }
                    if (pointList[i][0] > maxX) {
                        maxX = pointList[i][0];
                    }
                    if (pointList[i][1] < minY) {
                        minY = pointList[i][1];
                    }
                    if (pointList[i][1] > maxY) {
                        maxY = pointList[i][1];
                    }
                }

                var lineWidth;
                if (style.brushType == 'stroke' || style.brushType == 'fill') {
                    lineWidth = style.lineWidth || 1;
                }
                else {
                    lineWidth = 0;
                }
                
                style.__rect = {
                    x : Math.round(minX - lineWidth / 2),
                    y : Math.round(minY - lineWidth / 2),
                    width : maxX - minX + lineWidth,
                    height : maxY - minY + lineWidth
                };
                return style.__rect;
            }
        };

        require('../tool/util').inherits(Polygon, Base);
        return Polygon;
    }
);

