import SwiftUI

struct ExpandableTextView: View {
    let text: String
    let lineLimit: Int
    let moreTitle: String
    let collapseTitle: String
    let font: SodaTypography
    let foregroundColor: Color

    @State private var isExpanded = false
    @State private var fullTextHeight: CGFloat = 0
    @State private var limitedTextHeight: CGFloat = 0

    init(
        text: String,
        lineLimit: Int = 3,
        moreTitle: String = I18n.HomeRecommendation.more,
        collapseTitle: String = I18n.HomeRecommendation.collapse,
        font: SodaTypography = .body3,
        foregroundColor: Color = Color.gray500
    ) {
        self.text = text
        self.lineLimit = lineLimit
        self.moreTitle = moreTitle
        self.collapseTitle = collapseTitle
        self.font = font
        self.foregroundColor = foregroundColor
    }

    var body: some View {
        VStack(alignment: .leading, spacing: SodaSpacing.s8) {
            Text(text)
                .appFont(font)
                .foregroundColor(foregroundColor)
                .lineLimit(isExpanded ? nil : lineLimit)
                .background(measuringText(lineLimit: nil, height: $fullTextHeight))
                .background(measuringText(lineLimit: lineLimit, height: $limitedTextHeight))

            if shouldShowToggle {
                Button {
                    isExpanded.toggle()
                } label: {
                    Text(isExpanded ? collapseTitle : moreTitle)
                        .appFont(.body5)
                        .foregroundColor(.white)
                }
                .buttonStyle(.plain)
            }
        }
    }

    private var shouldShowToggle: Bool {
        fullTextHeight > limitedTextHeight + 1
    }

    private func measuringText(lineLimit: Int?, height: Binding<CGFloat>) -> some View {
        Text(text)
            .appFont(font)
            .lineLimit(lineLimit)
            .fixedSize(horizontal: false, vertical: true)
            .hidden()
            .background(
                GeometryReader { proxy in
                    Color.clear
                        .onAppear { height.wrappedValue = proxy.size.height }
                        .onChange(of: proxy.size.height) { newHeight in height.wrappedValue = newHeight }
                        .onChange(of: text) { _ in height.wrappedValue = proxy.size.height }
                }
            )
    }
}

struct ExpandableTextView_Previews: PreviewProvider {
    static var previews: some View {
        ExpandableTextView(text: "긴 사업자 정보 텍스트가 들어가는 영역입니다. 세 줄을 넘어가면 더보기 버튼이 표시되고, 더보기 버튼을 누르면 전체 문구가 표시됩니다.")
            .padding(SodaSpacing.s20)
            .background(Color.black)
            .previewLayout(.sizeThatFits)
    }
}