import Vue from 'vue';

Vue.directive('dialogDrag', {
    bind(el, binding, vnode, oldVnode) {
        // 弹框可拉伸最小宽高
        const minWidth = 400;
        const minHeight = 300;
        // 初始非全屏 
        let isFullScreen = false;
        // 当前宽高 
        let nowWidth = 0;
        let nowHight = 0;
        // 当前顶部高度 
        let nowMarginTop = 0;
        // 获取弹框头部（这部分可双击全屏） 
        const dialogHeaderEl = el.querySelector('.el-dialog__header');
        // 弹窗 
        const dragDom = el.querySelector('.el-dialog');
        // 全屏按钮 
        dialogHeaderEl.insertAdjacentHTML('beforeEnd', '<div class="bigbtn"><div class="changeBig"></div><div class="changeSmall"></div></div>');
        // const bigBtn = el.querySelector('.bigbtn');
        const changeBig = el.querySelector('.changeBig');
        const changeSmall = el.querySelector('.changeSmall');
        // 给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog； 
        dragDom.style.overflow = 'auto';
        // 清除选择头部文字效果 
        // dialogHeaderEl.onselectstart = new Function("return false"); 
        // 头部加上可拖动cursor 
        dialogHeaderEl.style.cursor = 'move';
        // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null); 
        const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);
        const moveDown = e => {
            // 鼠标按下，计算当前元素距离可视区的距离 
            const disX = e.clientX - dialogHeaderEl.offsetLeft;
            const disY = e.clientY - dialogHeaderEl.offsetTop;
            // 获取到的值带px 正则匹配替换 
            let styL;
            let styT;
            // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px 
            if (sty.left.includes('%')) {
                styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100);
                styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100);
            } else {
                styL = +sty.left.replace(/\px/g, '');
                styT = +sty.top.replace(/\px/g, '');
            }
            document.onmousemove = e => {
                // 通过事件委托，计算移动的距离
                const l = e.clientX - disX;
                const t = e.clientY - disY;
                // 移动当前元素
                dragDom.style.left = `${l + styL}px`;
                dragDom.style.top = `${t + styT}px`;
                // 将此时的位置传出去
                // binding.value({x:e.pageX,y:e.pageY})
            };
            document.onmouseup = e => {
                document.onmousemove = null;
                document.onmouseup = null;
            };
        };
        dialogHeaderEl.onmousedown = moveDown;
        // 双击头部全屏效果
        dialogHeaderEl.ondblclick = e => {
            if (isFullScreen === false) {
                changeBig.style.display = 'none';
                changeSmall.style.display = 'block';
                nowHight = dragDom.clientHeight;
                nowWidth = dragDom.clientWidth;
                nowMarginTop = dragDom.style.marginTop;
                dragDom.style.left = 0;
                dragDom.style.top = 0;
                dragDom.style.height = '100VH';
                dragDom.style.width = '100VW';
                dragDom.style.marginTop = 0;
                isFullScreen = true;
                dialogHeaderEl.style.cursor = 'initial';
                dialogHeaderEl.onmousedown = null;
            } else {
                changeBig.style.display = 'block';
                changeSmall.style.display = 'none';
                dragDom.style.height = 'auto';
                dragDom.style.width = `${nowWidth}px`;
                dragDom.style.marginTop = nowMarginTop;
                isFullScreen = false;
                dialogHeaderEl.style.cursor = 'move';
                dialogHeaderEl.onmousedown = moveDown;
            }
        };
        dragDom.onmousemove = e => {
            if (e.clientX > dragDom.offsetLeft + dragDom.clientWidth - 10) {
                dragDom.style.cursor = 'e-resize';
            } else if (dragDom.offsetLeft + 10 > e.clientX) {
                dragDom.style.cursor = 'w-resize';
            } else if (el.scrollTop + e.clientY > dragDom.offsetTop + dragDom.clientHeight - 10) {
                dragDom.style.cursor = 's-resize';
            } else {
                dragDom.style.cursor = 'default';
                dragDom.onmousedown = null;
            }
            dragDom.onmousedown = e => {
                const { clientX } = e;
                const { clientY } = e;
                const elW = dragDom.clientWidth;
                const elH = dragDom.clientHeight;
                const EloffsetLeft = dragDom.offsetLeft;
                const EloffsetTop = dragDom.offsetTop;
                dragDom.style.userSelect = 'none';
                const ELscrollTop = el.scrollTop;
                // 判断点击的位置是不是为头部
                if (clientX > EloffsetLeft && clientX < EloffsetLeft + elW && clientY > EloffsetTop && clientY < EloffsetTop + 100) {
                    // 如果是头部在此就不做任何动作，以上有绑定dialogHeaderEl.onmousedown = moveDown;
                } else {
                    document.onmousemove = e => {
                        e.preventDefault(); // 移动时禁用默认事件
                        // 左侧鼠标拖拽位置
                        if (clientX > EloffsetLeft && clientX < EloffsetLeft + 10) {
                            // 往左拖拽
                            if (clientX > e.clientX) {
                                dragDom.style.width = `${elW + (clientX - e.clientX) * 2}px`;
                            }
                            // 往右拖拽
                            if (clientX < e.clientX) {
                                if (dragDom.clientWidth < minWidth) {
                                    return;
                                }
                                dragDom.style.width = `${elW - (e.clientX - clientX) * 2}px`;
                            }
                        }
                        // 右侧鼠标拖拽位置
                        if (clientX > EloffsetLeft + elW - 10 && clientX < EloffsetLeft + elW) {
                            // 往左拖拽
                            if (clientX > e.clientX) {
                                if (dragDom.clientWidth < minWidth) {
                                    return;
                                }
                                dragDom.style.width = `${elW - (clientX - e.clientX) * 2}px`;
                            }
                            // 往右拖拽
                            if (clientX < e.clientX) {
                                dragDom.style.width = `${elW + (e.clientX - clientX) * 2}px`;
                            }
                        }
                        // 底部鼠标拖拽位置
                        if (ELscrollTop + clientY > EloffsetTop + elH - 20 && ELscrollTop + clientY < EloffsetTop + elH) {
                            // 往上拖拽
                            if (clientY > e.clientY) {
                                if (dragDom.clientHeight < minHeight) {
                                    return;
                                }
                                dragDom.style.height = `${elH - (clientY - e.clientY) * 2}px`;
                            }
                            // 往下拖拽
                            if (clientY < e.clientY) {
                                dragDom.style.height = `${elH + (e.clientY - clientY) * 2}px`;
                            }
                        }
                    };
                    // 拉伸结束 
                    document.onmouseup = e => {
                        document.onmousemove = null;
                        document.onmouseup = null;
                    };
                }
            };
        };
    }
});