From 1ef2ae7216791b6cdfc610859a9b05151d33ade6 Mon Sep 17 00:00:00 2001
From: Steffan Andrews <stef@orchetect.com>
Date: Tue, 26 Jul 2022 12:10:05 -0700
Subject: [PATCH] `Collection`: Added `longest()` and `longestIndex()`

---
 .../OTCore/Extensions/Swift/Collections.swift | 41 +++++++++++++++++++
 .../Extensions/Swift/Collections Tests.swift  | 26 ++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/Sources/OTCore/Extensions/Swift/Collections.swift b/Sources/OTCore/Extensions/Swift/Collections.swift
index 60fcf55..55ea5d7 100644
--- a/Sources/OTCore/Extensions/Swift/Collections.swift
+++ b/Sources/OTCore/Extensions/Swift/Collections.swift
@@ -859,6 +859,47 @@ extension Collection where Element: StringProtocol {
     }
 }
 
+// MARK: - longest() / longestIndex()
+
+extension Collection where Element: StringProtocol {
+    
+    /// **OTCore:**
+    /// Returns the longest string in the collection.
+    /// If more than one element are the same length as the longest element, the first will be returned.
+    /// - complexity: O(*n*)
+    @inlinable @_disfavoredOverload
+    public func longest() -> Element? {
+        
+        guard let idx = longestIndex() else { return nil }
+        return self[idx]
+        
+    }
+    
+    /// **OTCore:**
+    /// Returns the index of the longest string in the collection.
+    /// If more than one element are the same length as the longest element, the first will be returned.
+    /// - complexity: O(*n*)
+    @inlinable @_disfavoredOverload
+    public func longestIndex() -> Index? {
+        
+        guard !isEmpty else { return nil }
+        
+        var longestIndex: Index = startIndex
+        var longestLength: Int = self[startIndex].count
+        
+        for index in indices {
+            let elementLength = self[index].count
+            if elementLength > longestLength {
+                longestIndex = index
+                longestLength = elementLength
+            }
+        }
+        
+        return longestIndex
+        
+    }
+}
+
 // MARK: - stringValueArrayLiteral
 
 extension Collection where Element: BinaryInteger {
diff --git a/Tests/OTCoreTests/Extensions/Swift/Collections Tests.swift b/Tests/OTCoreTests/Extensions/Swift/Collections Tests.swift
index 20fbe82..1c3b3f3 100644
--- a/Tests/OTCoreTests/Extensions/Swift/Collections Tests.swift	
+++ b/Tests/OTCoreTests/Extensions/Swift/Collections Tests.swift	
@@ -1165,6 +1165,8 @@ class Extensions_Swift_Collections_Tests: XCTestCase {
         
     }
     
+    // MARK: - shortest() / shortestIndex()
+    
     func testStringProtocol_Shortest() {
         
         XCTAssertEqual([String]().shortest(), nil)
@@ -1187,6 +1189,30 @@ class Extensions_Swift_Collections_Tests: XCTestCase {
         
     }
     
+    // MARK: - longest() / longestIndex()
+    
+    func testStringProtocol_Longest() {
+        
+        XCTAssertEqual([String]().longest(), nil)
+        XCTAssertEqual([""].longest(), "")
+        XCTAssertEqual(["A"].longest(), "A")
+        XCTAssertEqual(["A", "1", "xy", "", "abc"].longest(), "abc")
+        XCTAssertEqual(["abc", "123", "A", "1", "xyz"].longest(), "abc")
+        XCTAssertEqual(["123", "abc", "1", "A", "xyz"].longest(), "123")
+        
+    }
+    
+    func testStringProtocol_LongestIndex() {
+        
+        XCTAssertEqual([String]().longestIndex(), nil)
+        XCTAssertEqual([""].longestIndex(), 0)
+        XCTAssertEqual(["A"].longestIndex(), 0)
+        XCTAssertEqual(["A", "1", "xy", "", "abc"].longestIndex(), 4)
+        XCTAssertEqual(["abc", "123", "A", "1", "xyz"].longestIndex(), 0)
+        XCTAssertEqual(["123", "abc", "1", "A", "xyz"].longestIndex(), 0)
+        
+    }
+    
     // MARK: - .stringValueArrayLiteral
     
     func teststringValueArrayLiteral() {