<script>
const facebook = uni.requireNativePlugin('sn-facebook');
var wv; //计划创建的webview
export default {
    data() {
        return {
            canBack: false
        };
    },
    onLoad() {},
    onBackPress() {
        if (wv && this.canBack) {
            wv.back();
            return true;
        }
        return false;
    },
    onReady() {
        // #ifdef APP-PLUS
        var self = this;
        var currentWebview = this.$scope.$getAppWebview(); //此对象相当于html5plus里的plus.webview.currentWebview()。在uni-app里vue页面直接使用plus.webview.currentWebview()无效，非v3编译模式使用this.$mp.page.$getAppWebview()
        setTimeout(function() {
            wv = currentWebview.children()[0];
            wv.addEventListener(
                'progressChanged',
                function(e) {
                    wv.canBack(function(e) {
                        self.canBack = e.canBack;
                    });
                },
                false
            );
        }, 500); //如果是页面初始化调用时，需要延时一下
        // #endif
    },
    methods: {
        onMessage({ detail }) {
            const data = detail.data[0];
            console.log('onMessage', data);
            if (data.action == 'login') {
                // 登录：自定义参数
                facebook.loginWithParams(
                    {
                        permissions: [
                            // 权限，更多权限请看 https://developers.facebook.com/docs/permissions/reference
                            'email',
                            'public_profile'
                        ],
                        // 返回字段，更多字段请查看 https://developers.facebook.com/docs/graph-api/reference/user/
                        fields: 'id, name, email'
                    },
                    e => {
                        console.log(e);
                        this.postMessage({ ...e, action: 'loginCallback' });
                    }
                );
            }
        },
        // postMessage to web
        postMessage(data) {
            if (wv) {
                wv.evalJS('window.postMessage(' + JSON.stringify(data) + ');');
            } else {
                uni.showToast({
                    icon: 'none',
                    title: 'webview不存在'
                });
            }
        }
    }
};
</script>