Added ability to convert LitItem collection from ListParser to hierar…

…chal representation

Proton/Sources/Swift/Core/ListParser.swift

@@ -46,6 +46,16 @@ public struct ListItem {
     }
 }
 
+public class ListItemNode {
+    public let item: ListItem
+    public internal(set) var children: [ListItemNode]
+
+    init(item: ListItem, children: [ListItemNode]) {
+        self.item = item
+        self.children = children
+    }
+}
+
 /// Provides helper function to convert between `NSAttributedString` and `[ListItem]`
 public struct ListParser {
 
@@ -104,6 +114,37 @@ public struct ListParser {
         }
         return items
     }
+
+    /// Creates hierarchical representation of `ListItem` from the provided collection based on levels of each of the items
+    /// - Parameter listItems: ListItems to convert
+    /// - Returns: Collection of `ListItemNode` with each node having children nodes based on level of individual list items.
+    public static func createListItemNodes(from listItems: [ListItem]) -> [ListItemNode] {
+        var result = [ListItemNode]()
+        var stack: [(node: ListItemNode, level: Int)] = []
+
+        for item in listItems {
+            let newNode = ListItemNode(item: item, children: [])
+
+            // Pop from the stack until the current item's parent is found
+            while let last = stack.last, last.level >= item.level {
+                stack.removeLast()
+            }
+
+            if let last = stack.last {
+                // If there's a parent, add this node to its children
+                stack[stack.count - 1].node.children.append(newNode)
+            } else {
+                // If there's no parent, this is a root node
+                result.append(newNode)
+            }
+
+            // Push the current node onto the stack
+            stack.append((newNode, item.level))
+        }
+
+        // Since we've been directly modifying the nodes in the stack, the `result` array now contains the fully constructed tree
+        return result
+    }
 
     private static func parseList(in attributedString: NSAttributedString, rangeInOriginalString: NSRange, indent: CGFloat, attributeValue: Any?) -> [(range: NSRange, listItem: ListItem)] {
         var items = [(range: NSRange, listItem: ListItem)]()

Proton/Tests/Core/ListParserTests.swift

@@ -111,6 +111,36 @@ class ListParserTests: XCTestCase {
         XCTAssertEqual(list[3].listItem.text.string, text2)
     }
 
+    func testParsesMultiLevelListIntoListNodes() {
+        let paraStyle1 = NSMutableParagraphStyle.forListLevel(1)
+        let paraStyle2 = NSMutableParagraphStyle.forListLevel(2)
+
+        let text1 = "This is line 1. This is line 1. This is line 1. This is line 1.\n"
+        let text1a = "Subitem 1 Subitem 1.\n"
+        let text1b = "SubItem 2 SubItem 2.\n"
+        let text2 = "This is line 2. This is line 2. This is line 2."
+
+        let attributedString = NSMutableAttributedString(string: text1, attributes: [.paragraphStyle: paraStyle1])
+        attributedString.append(NSAttributedString(string: text1a, attributes: [.paragraphStyle: paraStyle2]))
+        attributedString.append(NSAttributedString(string: text1b, attributes: [.paragraphStyle: paraStyle2]))
+        attributedString.append(NSAttributedString(string: text2, attributes: [.paragraphStyle: paraStyle1]))
+        attributedString.addAttribute(.listItem, value: 1, range: attributedString.fullRange)
+
+        let list = ListParser.parse(attributedString: attributedString)
+        let nodes = ListParser.createListItemNodes(from: list.map { $0.listItem })
+        XCTAssertEqual(nodes.count, 2)
+
+        XCTAssertEqual(nodes[0].item.level, 1)
+        XCTAssertEqual(nodes[0].children[0].item.level, 2)
+        XCTAssertEqual(nodes[0].children[1].item.level, 2)
+        XCTAssertEqual(nodes[1].item.level, 1)
+
+        XCTAssertEqual(nodes[0].item.text.string, String(text1.prefix(text1.count - 1)))
+        XCTAssertEqual(nodes[0].children[0].item.text.string, String(text1a.prefix(text1a.count - 1)))
+        XCTAssertEqual(nodes[0].children[1].item.text.string, String(text1b.prefix(text1b.count - 1)))
+        XCTAssertEqual(nodes[1].item.text.string, text2)
+    }
+
     func testParsesMultiLevelRepeatingList() {
         let levels = 3
         let paraStyles = (1...levels).map { NSMutableParagraphStyle.forListLevel($0) }
@@ -123,6 +153,47 @@ class ListParserTests: XCTestCase {
             attributedString.append(NSAttributedString(string: text, attributes: [.paragraphStyle: style]))
         }
 
+        attributedString.addAttribute(.listItem, value: 1, range: attributedString.fullRange)
+        let list = ListParser.parse(attributedString: attributedString)
+        let nodes = ListParser.createListItemNodes(from: list.map { $0.listItem })
+
+        XCTAssertEqual(nodes.count, 4)
+        for node in nodes {
+            XCTAssertEqual(node.item.text.string, "Text")
+            XCTAssertEqual(node.item.level, 1)
+        }
+
+        XCTAssertEqual(nodes[0].children.count, 0)
+
+        XCTAssertEqual(nodes[1].children.count, 2)
+        XCTAssertTrue(nodes[1].children.allSatisfy { $0.item.level == 2 })
+
+        XCTAssertEqual(nodes[1].children[0].children.count, 0)
+
+        XCTAssertEqual(nodes[1].children[1].children.count, 2)
+        XCTAssertTrue(nodes[1].children[1].children.allSatisfy { $0.item.level == 3 })
+
+
+        XCTAssertEqual(nodes[2].children.count, 0)
+
+        XCTAssertEqual(nodes[3].children[0].children.count, 0)
+
+        XCTAssertEqual(nodes[3].children[1].children.count, 2)
+        XCTAssertTrue(nodes[3].children[1].children.allSatisfy { $0.item.level == 3 })
+    }
+
+    func testParsesMultiLevelRepeatingListNodes() {
+        let levels = 3
+        let paraStyles = (1...levels).map { NSMutableParagraphStyle.forListLevel($0) }
+
+        let text = "Text\n"
+        let attributedString = NSMutableAttributedString()
+        for i in 0..<levels * 2 {
+            let style = paraStyles[i % levels]
+            attributedString.append(NSAttributedString(string: text, attributes: [.paragraphStyle: style]))
+            attributedString.append(NSAttributedString(string: text, attributes: [.paragraphStyle: style]))
+        }
+
         attributedString.addAttribute(.listItem, value: 1, range: attributedString.fullRange)
         let list = ListParser.parse(attributedString: attributedString)
         XCTAssertEqual(list.count, 12)