CellLayout.swift

import SwiftUI

// MARK: - Basic

public struct CellLayout<Icon: View, Content: View, Accessory: View>: View {

    @State var cellHeight: CGFloat = 0

    var horizontalGap: CGFloat
    var verticalGap: CGFloat
    let iconView: Icon
    let contentView: Content
    let accessoryView: Accessory

    public init(horizontalGap: CGFloat = 8, verticalGap: CGFloat = 4, @CellLayoutBuilder builder: () -> Self) where Accessory == EmptyView {
        self = builder()
        self.horizontalGap = horizontalGap
        self.verticalGap = verticalGap
    }

    init(iconView: Icon, contentView: Content) where Accessory == EmptyView {
        self.iconView = iconView
        self.contentView = contentView
        self.accessoryView = .init()
        self.horizontalGap = 8
        self.verticalGap = 4
    }

    init(base: CellLayout<Icon, Content, EmptyView>, accessory: Accessory) {
        self.iconView = base.iconView
        self.contentView = base.contentView
        self.accessoryView = accessory
        self.horizontalGap = base.horizontalGap
        self.verticalGap = base.verticalGap
    }

    public var body: some View {
        HStack(alignment: .top, spacing: horizontalGap) {
            iconView
            VStack(alignment: .leading, spacing: verticalGap) {
                contentView
            }
            .frame(maxWidth: .infinity, alignment: .leading)
            accessoryView
                .frame(height: cellHeight)
        }
        .background(GeometryReader { geometry in
            Color.clear
                .onChange(of: geometry.size.height) { height in cellHeight = height }
                .onAppear { cellHeight = geometry.size.height }
        })
    }
}

@resultBuilder
public struct CellLayoutBuilder {

    public static func buildBlock<V1>(_ v1: V1) -> (V1) where V1: View {
        (v1)
    }

    public static func buildBlock<V1, V2>(_ v1: V1, _ v2: V2) -> (V1, V2) where V1: View, V2: View {
        (v1, v2)
    }

    public static func buildBlock<V1, V2, V3>(_ v1: V1, _ v2: V2, _ v3: V3) -> (V1, V2, V3) where V1: View, V2: View, V3: View {
        (v1, v2, v3)
    }

    public static func buildBlock<V1, V2, V3, V4>(_ v1: V1, _ v2: V2, _ v3: V3, _ v4: V4) -> (V1, V2, V3, V4) where V1: View, V2: View, V3: View, V4: View {
        (v1, v2, v3, v4)
    }

    public static func buildBlock<V1, V2, V3, V4, V5>(_ v1: V1, _ v2: V2, _ v3: V3, _ v4: V4, _ v5: V5) -> (V1, V2, V3, V4, V5) where V1: View, V2: View, V3: View, V4: View, V5: View {
        (v1, v2, v3, v4, v5)
    }

    public static func buildIf<V>(_ view: (V)?) -> V? where V: View {
        view
    }

    public static func buildEither<T, F>(first component: T) -> _ConditionalContent<T, F> where T: View, F: View {
        ViewBuilder.buildEither(first: component)
    }

    public static func buildEither<T, F>(second component: F) -> _ConditionalContent<T, F> where T: View, F: View {
        ViewBuilder.buildEither(second: component)
    }

    public static func buildFinalResult<V1>(_ c: (V1)) -> CellLayout<V1, EmptyView, EmptyView> where V1: View {
        .init(
            iconView: c,
            contentView: .init()
        )
    }

    public static func buildFinalResult<V1, V2>(_ c: (V1, V2)) -> CellLayout<V1, V2, EmptyView> where V1: View, V2: View {
        .init(
            iconView: c.0,
            contentView: c.1
        )
    }

    public static func buildFinalResult<V1, V2, V3>(_ c: (V1, V2, V3)) -> CellLayout<V1, TupleView<(V2, V3)>, EmptyView> where V1: View, V2: View, V3: View {
        .init(
            iconView: c.0,
            contentView: TupleView((c.1, c.2))
        )
    }

    public static func buildFinalResult<V1, V2, V3, V4>(_ c: (V1, V2, V3, V4)) -> CellLayout<V1, TupleView<(V2, V3, V4)>, EmptyView> where V1: View, V2: View, V3: View, V4: View {
        .init(
            iconView: c.0,
            contentView: TupleView((c.1, c.2, c.3))
        )
    }

    public static func buildFinalResult<V1, V2, V3, V4, V5>(_ c: (V1, V2, V3, V4, V5)) -> CellLayout<V1, TupleView<(V2, V3, V4, V5)>, EmptyView> where V1: View, V2: View, V3: View, V4: View, V5: View {
        .init(
            iconView: c.0,
            contentView: TupleView((c.1, c.2, c.3, c.4))
        )
    }
}

// MARK: - Accessory

extension CellLayout {

    public func accessory<V>(alignment: VerticalAlignment = .center, @ViewBuilder content: @escaping () -> V) -> CellLayout<Icon, Content, some View> where V: View, Accessory == EmptyView {
        .init(base: self, accessory: CellAccessoryView(base: content(), alignment: alignment))
    }

    public func accessory<V>(alignment: VerticalAlignment = .center, _ view: V) -> CellLayout<Icon, Content, some View> where V: View, Accessory == EmptyView {
        .init(base: self, accessory: CellAccessoryView(base: view, alignment: alignment))
    }
}

private struct CellAccessoryView<BaseAccessory>: View where BaseAccessory: View {

    let base: BaseAccessory
    let alignment: VerticalAlignment

    var body: some View {
        base
            .frame(idealWidth: 0, maxHeight: .infinity, alignment: .init(horizontal: .center, vertical: alignment))
    }
}