SampleUsage.swift

// ASCollectionView. Created by Apptek Studios 2019

import ASCollectionView
import SwiftUI

struct SingleSectionExampleView: View
{
	@State var dataExample = (0 ..< 21).map { $0 }

	var body: some View
	{
		ASCollectionView(data: dataExample, dataID: \.self)
		{ item, _ in
			Color.blue
				.overlay(Text("\(item)"))
		}
		.layout
		{
			.grid(
				layoutMode: .adaptive(withMinItemSize: 100),
				itemSpacing: 5,
				lineSpacing: 5,
				itemSize: .absolute(50))
		}
	}
}

struct ExampleView: View
{
	@State var dataExampleA = (0 ..< 21).map { $0 }
	@State var dataExampleB = (0 ..< 15).map { "ITEM \($0)" }

	var body: some View
	{
		ASCollectionView
		{
			ASSection<Int>(
				id: 0,
				data: dataExampleA,
				dataID: \.self)
			{ item, _ in
				Color.blue
					.overlay(
						Text("\(item)")
					)
			}
			ASSection<Int>(
				id: 1,
				data: dataExampleB,
				dataID: \.self)
			{ item, _ in
				Color.green
					.overlay(
						Text("Complex layout - \(item)")
					)
			}
			.sectionHeader
			{
				Text("Section header")
					.padding()
					.frame(maxWidth: .infinity, alignment: .leading)
					.background(Color.yellow)
			}
			.sectionFooter
			{
				Text("This is a section footer!")
					.padding()
			}
		}
		.layout
		{ sectionID in
			switch sectionID
			{
			case 0:
				return .grid(
					layoutMode: .adaptive(withMinItemSize: 100),
					itemSpacing: 5,
					lineSpacing: 5,
					itemSize: .absolute(50))
			default:
				return ASCollectionLayoutSection
				{ environment in
					let isWide = environment.container.effectiveContentSize.width > 500
					let gridBlockSize = environment.container.effectiveContentSize.width / (isWide ? 5 : 3)
					let gridItemInsets = NSDirectionalEdgeInsets(top: 5, leading: 5, bottom: 5, trailing: 5)
					let itemSize = NSCollectionLayoutSize(widthDimension: .absolute(gridBlockSize), heightDimension: .absolute(gridBlockSize))
					let item = NSCollectionLayoutItem(layoutSize: itemSize)
					item.contentInsets = gridItemInsets
					let verticalGroupSize = NSCollectionLayoutSize(widthDimension: .absolute(gridBlockSize), heightDimension: .absolute(gridBlockSize * 2))
					let verticalGroup = NSCollectionLayoutGroup.vertical(layoutSize: verticalGroupSize, subitem: item, count: 2)

					let featureItemSize = NSCollectionLayoutSize(widthDimension: .absolute(gridBlockSize * 2), heightDimension: .absolute(gridBlockSize * 2))
					let featureItem = NSCollectionLayoutItem(layoutSize: featureItemSize)
					featureItem.contentInsets = gridItemInsets

					let verticalAndFeatureGroupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .absolute(gridBlockSize * 2))
					let verticalAndFeatureGroupA = NSCollectionLayoutGroup.horizontal(layoutSize: verticalAndFeatureGroupSize, subitems: isWide ? [verticalGroup, verticalGroup, featureItem, verticalGroup] : [verticalGroup, featureItem])
					let verticalAndFeatureGroupB = NSCollectionLayoutGroup.horizontal(layoutSize: verticalAndFeatureGroupSize, subitems: isWide ? [verticalGroup, featureItem, verticalGroup, verticalGroup] : [featureItem, verticalGroup])

					let rowGroupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .absolute(gridBlockSize))
					let rowGroup = NSCollectionLayoutGroup.horizontal(layoutSize: rowGroupSize, subitem: item, count: isWide ? 5 : 3)

					let outerGroupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .absolute(gridBlockSize * 6))
					let outerGroup = NSCollectionLayoutGroup.vertical(layoutSize: outerGroupSize, subitems: [verticalAndFeatureGroupA, rowGroup, verticalAndFeatureGroupB, rowGroup])

					let section = NSCollectionLayoutSection(group: outerGroup)

					let supplementarySize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .estimated(50))
					let headerSupplementary = NSCollectionLayoutBoundarySupplementaryItem(
						layoutSize: supplementarySize,
						elementKind: UICollectionView.elementKindSectionHeader,
						alignment: .top)
					let footerSupplementary = NSCollectionLayoutBoundarySupplementaryItem(
						layoutSize: supplementarySize,
						elementKind: UICollectionView.elementKindSectionFooter,
						alignment: .bottom)
					section.boundarySupplementaryItems = [headerSupplementary, footerSupplementary]
					return section
				}
			}
		}
	}
}