LogEntriesGrid.swift

import SwiftUI

@available(macOS 13.0, iOS 16.0, tvOS 16.0, watchOS 9.0, *)
public struct LogEntriesGrid: View {
    var logEntries: [LogEntry]
    @Binding var highlight: String?

    private static let tableRowHorizontalPadding: CGFloat = 8
    private static let tableRowVerticalPadding: CGFloat = 4

    public init(logEntries: [LogEntry], highlight: Binding<String?>? = nil) {
        self.logEntries = logEntries
        if let binding = highlight {
            self._highlight = binding
        } else {
            var nirvana: String? = nil
            self._highlight = Binding(get: { nirvana }, set: { nirvana = $0 })
        }
    }

    public var body: some View {
        ScrollView(.vertical) {
            Grid(alignment: .leadingFirstTextBaseline, horizontalSpacing: 0, verticalSpacing: 0) {
                // Table header row
                GridRow {
                    Text("View")
                    Text("Proposal")
                    Text("Response")
                }
                .font(.headline)
                .padding(.vertical, Self.tableRowVerticalPadding)
                .padding(.horizontal, Self.tableRowHorizontalPadding)

                // Table header separator line
                Rectangle().fill(.secondary)
                    .frame(height: 1)
                    .gridCellUnsizedAxes(.horizontal)
                    .padding(.vertical, Self.tableRowVerticalPadding)
                    .padding(.horizontal, Self.tableRowHorizontalPadding)

                // Table rows
                ForEach(logEntries) { item in
                    let isSelected = highlight == item.label
                    GridRow {
                        HStack(spacing: 0) {
                            indentation(level: item.indent)
                            Text(item.label)
                                .font(.body)
                        }
                        .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .leading)

                        Text(item.proposal?.pretty ?? "…")
                            .monospacedDigit()
                            .fixedSize()
                            .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .leading)

                        Text(item.response?.pretty ?? "…")
                            .monospacedDigit()
                            .fixedSize()
                            .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .leading)
                    }
                    .font(.callout)
                    .padding(.vertical, Self.tableRowVerticalPadding)
                    .padding(.horizontal, Self.tableRowHorizontalPadding)
                    .foregroundColor(isSelected ? .white : nil)
                    .background(isSelected ? Color.accentColor : .clear)
                    .contentShape(Rectangle())
                    .onTapGesture {
                        highlight = isSelected ? nil : item.label
                    }
                }
            }
            .padding(.vertical, 8)
        }
        .background {
            #if os(macOS)
            Color(white: 0.8)
            #else
            Color(uiColor: .secondarySystemBackground)
            #endif
        }
    }

    private func indentation(level: Int) -> some View {
        ForEach(0 ..< level, id: \.self) { _ in
            Color.clear
                .frame(width: 16)
                .overlay(alignment: .leading) {
                    Rectangle()
                        .frame(width: 1)
                        .padding(.leading, 4)
                        // Compensate for cell padding, we want continuous vertical lines.
                        .padding(.vertical, -Self.tableRowVerticalPadding)
                }
        }
    }
}

@available(macOS 13.0, iOS 16.0, tvOS 16.0, watchOS 9.0, *)
struct LogEntriesGrid_Previews: PreviewProvider {
    static var previews: some View {
        LogEntriesGrid(logEntries: sampleLogEntries)
    }
}