From 1d26df390b5d678fc407a7ac144c77384b822e49 Mon Sep 17 00:00:00 2001
From: Jairo Tylera <Tylerian@users.noreply.github.com>
Date: Thu, 1 Nov 2018 00:28:30 +0100
Subject: [PATCH] Add AutoLayoutSizeSource (#110)

A SizeSource that calculates a view size based on its auto-layout constraints.

Update AutoLayoutSizeSource

It now supports updating the view with a given closure, and customization of the fittingPriority for layout size calculations.

Fixed code linting
---
 Sources/SizeSource/AutoLayoutSizeSource.swift | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 Sources/SizeSource/AutoLayoutSizeSource.swift

diff --git a/Sources/SizeSource/AutoLayoutSizeSource.swift b/Sources/SizeSource/AutoLayoutSizeSource.swift
new file mode 100644
index 0000000..c4313ee
--- /dev/null
+++ b/Sources/SizeSource/AutoLayoutSizeSource.swift
@@ -0,0 +1,28 @@
+import UIKit
+
+public typealias ClosureViewUpdateFn<Data, View> = (View, Data, Int) -> Void
+
+open class AutoLayoutSizeSource<Data, View: UIView>: SizeSource<Data> {
+  private let dummyView: View
+  private let dummyViewUpdater: ClosureViewUpdateFn<Data, View>
+  private let horizontalFittingPriority: UILayoutPriority
+  private let verticalFittingPriority: UILayoutPriority
+   public init(dummyView: View.Type, 
+              horizontalFittingPriority: UILayoutPriority = .defaultHigh, 
+              verticalFittingPriority: UILayoutPriority = .defaultLow, 
+              viewUpdater: @escaping ClosureViewUpdateFn<Data, View>) {
+    
+    self.dummyView = View()
+    self.dummyViewUpdater = viewUpdater
+    self.horizontalFittingPriority = horizontalFittingPriority
+    self.verticalFittingPriority = verticalFittingPriority
+  }
+   open override func size(at index: Int, data: Data, collectionSize: CGSize) -> CGSize {
+    self.dummyViewUpdater(self.dummyView, data, index)
+    
+    return self.dummyView.systemLayoutSizeFitting(
+      collectionSize, 
+      withHorizontalFittingPriority: self.horizontalFittingPriority, 
+      verticalFittingPriority: self.verticalFittingPriority)
+  }
+}