//
//  WaterHeartView.swift
//  SodaLive
//
//  Created by klaus on 11/5/25.
//

import SwiftUI

struct WaterHeartView: View {
    var progress: CGFloat = 0       // 0...1
    var show: Bool = false          // 하트 등장 여부
    var phase: CGFloat = 0          // 파도 위상 (애니메이션)
    
    var body: some View {
        GeometryReader { geo in
            let size = min(geo.size.width, geo.size.height)
            ZStack {
                // 하트 외곽선
                HeartShape()
                    .stroke(lineWidth: size * 0.03)
                    .foregroundStyle(Color(hex: "ff959a"))
                    .opacity(show ? 1 : 0)
                
                // 물 채우는 레이어들 (마스크로 하트 내부만 보이도록)
                ZStack {
                    // 아래 물(기본 채움)
                    Rectangle()
                        .fill(Color(hex: "ff959a"))
                        .frame(height: geo.size.height * progress)
                        .position(x: geo.size.width/2,
                                  y: geo.size.height - (geo.size.height * progress)/2)
                    
                    // 파도 라인 (상단에 얹히는 살짝 흔들리는 수면)
                    WaveShape(progress: progress,
                              phase: phase,
                              amplitude: max(2, size * 0.015))
                    .fill(Color(hex: "ff959a"))
                }
                .mask(HeartShape())
                .opacity(show ? 1 : 0)
                .animation(.easeInOut(duration: 0.2), value: show)
            }
        }
        .aspectRatio(4/3, contentMode: .fit)
    }
}

struct HeartShape: Shape {
    func path(in rect: CGRect) -> Path {
        let w = rect.width
        let h = rect.height
        let scale: CGFloat = 0.9 // 살짝 여백
        let cx = rect.midX
        let cy = rect.midY
        
        let r = min(w, h) * 0.5 * scale
        
        func pt(_ nx: CGFloat, _ ny: CGFloat) -> CGPoint {
            CGPoint(x: cx + nx * r, y: cy + ny * r)
        }
        
        var p = Path()
        // - notch: y ≈ -0.20
        // - shoulder 넓힘: (±1.20, 0.12) → (±1.25, 0.12)
        // - lobe top 하강: (±0.80, -0.95) → (±0.80, -0.85)
        p.move(to: pt(0, -0.20)) // top notch (shallow)
        // right lobe → bottom tip
        p.addCurve(
            to: pt(0, 1.0),
            control1: pt(0.80, -0.85), // right lobe top (lowered)
            control2: pt(1.25, 0.12)   // right shoulder (wider)
        )
        // left lobe → back to notch
        p.addCurve(
            to: pt(0, -0.20),
            control1: pt(-1.25, 0.12),  // left shoulder (wider)
            control2: pt(-0.80, -0.85)  // left lobe top (lowered)
        )
        p.closeSubpath()
        return p
    }
}

/// 물결 라인 (위로 채우는 면적의 상단을 살짝 흔들리게)
struct WaveShape: Shape {
    /// 0...1 채움 비율 (1이면 가득)
    var progress: CGFloat
    /// 파도 진행(위상)
    var phase: CGFloat
    /// 진폭
    var amplitude: CGFloat
    
    func path(in rect: CGRect) -> Path {
        let width = rect.width
        let height = rect.height
        
        // progress가 0이면 하단, 1이면 상단
        let waterLevel = height * (1 - progress)
        
        var path = Path()
        path.move(to: CGPoint(x: 0, y: waterLevel))
        
        // 부드러운 파형
        let wavelength = width / 1.2
        let step: CGFloat = 4
        
        for x in stride(from: 0, through: width, by: step) {
            let relative = x / wavelength
            let y = waterLevel + sin(relative * 2 * .pi + phase) * amplitude
            path.addLine(to: CGPoint(x: x, y: y))
        }
        
        // 바깥쪽 닫기 (아래쪽 영역 채움)
        path.addLine(to: CGPoint(x: width, y: height))
        path.addLine(to: CGPoint(x: 0, y: height))
        path.closeSubpath()
        
        return path
    }
    
    var animatableData: AnimatablePair<CGFloat, CGFloat> {
        get { AnimatablePair(progress, phase) }
        set {
            progress = newValue.first
            phase = newValue.second
        }
    }
}

#Preview {
    WaterHeartView()
}