import SwiftUI

struct CustomLightSequenceAnimation: View {
    // 核心循环序列：按"123321123321"规律定义基础单元
    private let baseSequence: [Int] = [1, 2, 3, 3, 2, 1, 1, 2, 3, 3, 2, 1]
    @State private var currentLight: Int = 1  // 当前显示的图片序号
    @State private var sequenceIndex: Int = 0  // 当前在序列中的索引
    
    // 淡入淡出透明度控制（确保切换丝滑）
    @State private var currentOpacity: CGFloat = 1.0
    @State private var nextOpacity: CGFloat = 0.0
    
    // 尺寸参数（适配正方形卡片）
    private let screenWidth = UIScreen.main.bounds.width
    private let squareSize: CGFloat
    private let imageSize: CGFloat
    
    init() {
        self.squareSize = screenWidth * 1.8  // 正方形背景尺寸
        self.imageSize = squareSize / 3      // 光束卡片尺寸（1/3背景大小）
    }

// MARK: - SwiftUI 背景重绘（方形版本）
private struct CardBlindBackground: View {
    var body: some View {
        GeometryReader { geo in
            let w = geo.size.width
            let h = geo.size.height
            ZStack {
                // 主背景卡片（方形）
                RoundedRectangle(cornerRadius: 28)
                    .fill(
                        LinearGradient(
                            colors: [Color.white, Color.white.opacity(0.96)],
                            startPoint: .topLeading,
                            endPoint: .bottomTrailing
                        )
                    )
                    .shadow(color: Color.black.opacity(0.06), radius: 16, x: 0, y: 8)
                    .frame(width: w * 0.88, height: h * 0.88)
                    .position(x: w / 2, y: h / 2)

                // 左上光斑
                Circle()
                    .fill(Color.themePrimary.opacity(0.18))
                    .blur(radius: 40)
                    .frame(width: min(w, h) * 0.35, height: min(w, h) * 0.35)
                    .position(x: w * 0.25, y: h * 0.25)

                // 右下光斑
                Circle()
                    .fill(Color.orange.opacity(0.14))
                    .blur(radius: 50)
                    .frame(width: min(w, h) * 0.40, height: min(w, h) * 0.40)
                    .position(x: w * 0.75, y: h * 0.75)

                // 中央高光描边
                RoundedRectangle(cornerRadius: 28)
                    .stroke(Color.white.opacity(0.35), lineWidth: 1)
                    .frame(width: w * 0.88, height: h * 0.88)
                    .position(x: w / 2, y: h / 2)
                    .blendMode(.overlay)
                    .opacity(0.7)
            }
        }
    }
}
    
    // 卡片中心位置（固定，确保摆正居中）
    private var centerPosition: CGPoint {
        CGPoint(x: screenWidth / 2, y: squareSize * 0.325)
    }
    
    var body: some View {
        ZStack {
            // 底部背景（正方形，SwiftUI 重绘）
            CardBlindBackground()
                .frame(width: squareSize, height: squareSize)
                .position(centerPosition)
        }
    }
    
}

// 预览
struct CustomLightSequenceAnimation_Previews: PreviewProvider {
    static var previews: some View {
        CustomLightSequenceAnimation()
    }
}