import 'package:flutter/material.dart';
import 'package:ftrecruiter/comm/constants/color_constants.dart';
import 'package:ftrecruiter/comm/widget/my_load_image.dart';
import 'package:ftrecruiter/comm/widget/my_text_view.dart';
import 'package:get/get.dart';

///四种视图状态
enum LoadState { State_Success, State_Error, State_Loading, State_Empty }

///根据不同状态来展示不同的视图
class LoadStateLayout extends StatefulWidget {
  final LoadState state; //页面状态
  final Widget? successWidget; //成功视图
  final VoidCallback? errorRetry; //错误事件处理

  const LoadStateLayout(
      {Key? key,
      this.state = LoadState.State_Loading, //默认为加载状态
      this.successWidget,
      this.errorRetry})
      : super(key: key);

  @override
  _LoadStateLayoutState createState() => _LoadStateLayoutState();
}

class _LoadStateLayoutState extends State<LoadStateLayout> {
  @override
  Widget build(BuildContext context) {
    return Container(
      //宽高都充满屏幕剩余空间
      width: double.infinity,
      height: double.infinity,
      child: _buildWidget,
    );
  }

  ///根据不同状态来显示不同的视图
  Widget get _buildWidget {
    switch (widget.state) {
      case LoadState.State_Success:
        return widget.successWidget ?? const SizedBox();
      case LoadState.State_Error:
        return _errorView;
      case LoadState.State_Loading:
        return _loadingView;
      case LoadState.State_Empty:
        return _emptyView;
      default:
        return _loadingView;
    }
  }

  ///加载中视图
  Widget get _loadingView {
    return Container(
      width: double.infinity,
      height: double.infinity,
      alignment: Alignment.center,
      child: Column(
        mainAxisSize: MainAxisSize.max,
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          const CircularProgressIndicator(
            strokeWidth: 3,
            valueColor: AlwaysStoppedAnimation(ColorConstants.appBlue),
          ),
          MyTextView('loading'.tr, marginTop: 15, fontSize: 15.5)
        ],
      ),
    );
  }

  ///错误视图
  Widget get _errorView {
    return SizedBox(
        width: double.infinity,
        height: double.infinity,
        child: GestureDetector(
            onTap: widget.errorRetry,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.center,
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                const MyAssetImage('other/page_no_data.webp', width: 180, height: 180, fit: BoxFit.contain),
                MyTextView('load_error_try_again'.tr, marginTop: 10, fontSize: 15.5)
              ],
            )));
  }

  ///数据为空的视图
  Widget get _emptyView {
    return Container(
      width: double.infinity,
      height: double.infinity,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.center,
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          const MyAssetImage('other/page_no_data.webp', width: 180, height: 180, fit: BoxFit.contain),
          MyTextView('load_no_data'.tr, marginTop: 10, fontSize: 15.5)
        ],
      ),
    );
  }
}