import 'package:ducafe_ui_core/ducafe_ui_core.dart';
import 'package:flutter/material.dart';

import 'package:pj_supermarket_cloud/common/models/plugs/face_recognition_session_models.dart';
import 'package:pj_supermarket_cloud/common/style/xfj_design_tokens.dart';
import 'package:pj_supermarket_cloud/common/widgets/face/face_recognition_preview_layer.dart';

/// 人脸摄像头画面组件，只负责 Texture、人脸框、摄像头状态和空画面提示。
class FaceCameraPreview extends StatelessWidget {
  /// 创建一个不持有识别会话和插件资源的摄像头展示区域。
  const FaceCameraPreview({
    super.key,
    required this.texture,
    required this.event,
    required this.status,
    this.statusText,
    this.statusColor,
    this.scale = 1,
  });

  /// 原生创建的预览纹理；为空时展示摄像头准备状态。
  final FaceRecognitionPreviewTexture? texture;

  /// 最近一次原生识别事件，用于绘制人脸框和方向信息。
  final FaceRecognitionSessionEvent? event;

  /// 当前识别状态，用于展示文字和非颜色状态标识。
  final FaceRecognitionSessionStatus status;

  /// 业务页面覆盖的摄像头状态文案；为空时沿用原生会话状态文案。
  final String? statusText;

  /// 业务页面覆盖的摄像头状态颜色；为空时沿用原生会话状态颜色。
  final Color? statusColor;

  /// 宿主 Engine 提供的尺寸缩放系数，副屏不得依赖主屏 ScreenUtil 全局状态。
  final double scale;

  /// 构建固定比例的摄像头画面和状态浮层。
  @override
  Widget build(BuildContext context) {
    return ColoredBox(
      color: const Color(0xFF102635),
      child: <Widget>[
        if (texture != null)
          FaceRecognitionPreviewLayer(
            texture: texture!,
            event: event,
            labelScale: scale,
          )
        else
          _FaceCameraEmptyState(status: status, scale: scale),
        _FaceCameraStatusPill(
          status: status,
          text: statusText,
          color: statusColor,
          scale: scale,
        ).positioned(
          left: 18 * scale,
          top: 18 * scale,
        ),
        _FaceCameraResolutionLabel(
          texture: texture,
          scale: scale,
        ).positioned(
          right: 18 * scale,
          bottom: 16 * scale,
        ),
      ].toStack(fit: StackFit.expand),
    );
  }
}

/// 摄像头 Texture 尚未创建时的明确等待或失败提示。
class _FaceCameraEmptyState extends StatelessWidget {
  /// 创建与当前识别状态匹配的空画面。
  const _FaceCameraEmptyState({required this.status, required this.scale});

  /// 决定展示加载反馈还是设备异常提示的会话状态。
  final FaceRecognitionSessionStatus status;

  /// 宿主页面计算的尺寸缩放系数。
  final double scale;

  /// 构建不会造成画面尺寸跳变的居中状态。
  @override
  Widget build(BuildContext context) {
    final failed = status == FaceRecognitionSessionStatus.failed;
    return <Widget>[
      if (failed)
        Icon(
          Icons.videocam_off_rounded,
          color: Colors.white,
          size: 42 * scale,
        )
      else
        SizedBox(
          width: 36 * scale,
          height: 36 * scale,
          child: const CircularProgressIndicator(
            color: Colors.white,
            strokeWidth: 3,
          ),
        ),
      SizedBox(height: 12 * scale),
      Text(
        failed ? '摄像头画面暂不可用' : '正在准备摄像头画面',
        style: TextStyle(
          color: Colors.white,
          fontSize: 16 * scale,
          fontWeight: FontWeight.w700,
        ),
      ),
    ].toColumn(mainAxisSize: MainAxisSize.min).center();
  }
}

/// 摄像头左上角的文字状态标识，确保状态不只依赖红绿颜色表达。
class _FaceCameraStatusPill extends StatelessWidget {
  /// 创建当前识别阶段的状态标识。
  const _FaceCameraStatusPill({
    required this.status,
    required this.text,
    required this.color,
    required this.scale,
  });

  /// 当前原生识别会话状态。
  final FaceRecognitionSessionStatus status;

  /// 业务页面提供的可选状态文案。
  final String? text;

  /// 业务页面提供的可选语义颜色。
  final Color? color;

  /// 宿主页面计算的尺寸缩放系数。
  final double scale;

  /// 构建包含状态点和文字的高对比标签。
  @override
  Widget build(BuildContext context) {
    final resolvedText = text ??
        switch (status) {
          FaceRecognitionSessionStatus.initializing => '初始化中',
          FaceRecognitionSessionStatus.success => '已识别',
          FaceRecognitionSessionStatus.failed => '需要重试',
          FaceRecognitionSessionStatus.cancelled => '已取消',
          _ => '识别中',
        };
    final resolvedColor = color ??
        switch (status) {
          FaceRecognitionSessionStatus.failed ||
          FaceRecognitionSessionStatus.cancelled =>
            XfjDesignTokens.danger,
          FaceRecognitionSessionStatus.initializing => XfjDesignTokens.warning,
          _ => XfjDesignTokens.success,
        };
    return <Widget>[
      DecoratedBox(
        decoration: BoxDecoration(
          color: resolvedColor,
          shape: BoxShape.circle,
        ),
      ).width(10 * scale).height(10 * scale),
      SizedBox(width: 8 * scale),
      Text(
        resolvedText,
        style: TextStyle(
          color: Colors.white,
          fontSize: 14 * scale,
          fontWeight: FontWeight.w700,
        ),
      ),
    ]
        .toRow(mainAxisSize: MainAxisSize.min)
        .padding(horizontal: 14 * scale, vertical: 9 * scale)
        .decorated(
          color: Colors.black.withValues(alpha: 0.62),
          borderRadius: BorderRadius.circular(99),
        );
  }
}

/// 摄像头右下角的实际纹理分辨率标签。
class _FaceCameraResolutionLabel extends StatelessWidget {
  /// 创建分辨率说明；纹理未就绪时使用插件既有默认分辨率。
  const _FaceCameraResolutionLabel({
    required this.texture,
    required this.scale,
  });

  /// 当前预览纹理元数据。
  final FaceRecognitionPreviewTexture? texture;

  /// 宿主页面计算的尺寸缩放系数。
  final double scale;

  /// 构建不遮挡主要人脸区域的紧凑标签。
  @override
  Widget build(BuildContext context) {
    return Text(
      '彩色摄像头  ${texture?.width ?? 1280} x ${texture?.height ?? 720}',
      style: TextStyle(color: Colors.white, fontSize: 13 * scale),
    ).padding(horizontal: 12 * scale, vertical: 8 * scale).decorated(
          color: Colors.black.withValues(alpha: 0.62),
          borderRadius: BorderRadius.circular(10),
        );
  }
}