// The Example shows how to display two sections, each with 10 cells and a header.
//
// To use a data source there a certain requirements that have to be fulfilled:
// Every cell or header/footer view needs to conform against ModelDataSourceViewDisplayable. 
// They can be stored with their associated content (Model) in either a ModelItem or ModelDecorative
// which are contstrained to a specific view conforming against ModelDataSourceView (e.g. UITableView). 
// Each section is represented by a ModelSection holding ModelItems and ModelDecoratives.
//
// NOTE: The Example folder contains the full code.

var dataSource = TableViewDataSource()

// Setup the UITableViewView
let tableView = UITableView()
tableView.register(TableViewCell.self)
tableView.register(DecorativeView.self)
tableView.dataSource = dataSource

// Items to be displayed in each section-
let items: [ModelItem<UITableView>] = (1...10).map { index in
    return .init(model: .init(color: .gray, title: "cell # \(index)"), cell: TableViewCell.self)
}

// Build first section
let firstHeaderModel: DecorativeView.Model = .init(color: .darkGray, title: "Header 1")
let firstDecorative: ModelDecorative<UITableView> =  .init(model: firstHeaderModel, view: DecorativeView.self)
var firstSection: ModelSection<UITableView> = .init(decorative: firstDecorative, kind: .header)
firstSection.append(contentsOf: items)

// Build second section.
let secondHeaderModel: DecorativeView.Model = .init(color: .darkGray, title: "Header 2")
let secondDecorative: ModelDecorative<UITableView> =  .init(model: secondHeaderModel, view: DecorativeView.self)
var secondSection: ModelSection<UITableView> = .init(decorative: secondDecorative, kind: .header)
secondSection.append(contentsOf: items)

// Append the sections to the TableViewDataSource.
dataSource.append(contentsOf: [firstSection, secondSection])

// Load the content into the UITableView.
tableView.reloadData()

// Extension on all ModelCollections regardless of the DataSourceView.
extension ModelCollection {
    func someCustomCode() { ... }
    mutating func someCustomMutatingCode() { ... }
}

// Extension bound to all ModelCollections managing UITableViews.
extension ModelCollection where DataSourceView == UITableView {
    func someCustomTableViewCode() { ... }
    mutating func someCustomMutatingTableViewCode() { ... }
}

final class CustomDataSource: ModelCollection {
    typealias DataSourceView = CollectionViewDataSource.DataSourceView
    typealias Index = CollectionViewDataSource.Index
    
    private var dataSource: CollectionViewDatasource

    // MARK: - ModelCollection

    init() {
        dataSource = .init()
    }

    var startIndex: Index {
        return dataSource.startIndex
    }

    var endIndex: Index {
        return dataSource.endIndex
    }
    
    // ..... 

    // MARK: Custom code

    func someCustomCode() { ... }
}