//
//  MTMathUILabelLineWrappingTests.swift
//  SwiftMathTests
//
//  Tests for line wrapping functionality in MTMathUILabel
//

import XCTest
@testable import SwiftUIMath

class MTMathUILabelLineWrappingTests: XCTestCase {

    func testBasicIntrinsicContentSize() {
        let label = MTMathUILabel()
        label.latex = "\\(x + y\\)"
        label.font = MTFontManager.fontManager.defaultFont

        // Debug: check if parsing worked
        XCTAssertNotNil(label.mathList, "Math list should not be nil")
        XCTAssertNil(label.error, "Should have no parsing error, got: \(String(describing: label.error))")
        XCTAssertNotNil(label.font, "Font should not be nil")

        let size = label.intrinsicContentSize

        XCTAssertGreaterThan(size.width, 0, "Width should be greater than 0, got \(size.width)")
        XCTAssertGreaterThan(size.height, 0, "Height should be greater than 0, got \(size.height)")
    }

    func testTextModeIntrinsicContentSize() {
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Hello World}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        let size = label.intrinsicContentSize

        XCTAssertGreaterThan(size.width, 0, "Width should be greater than 0, got \(size.width)")
        XCTAssertGreaterThan(size.height, 0, "Height should be greater than 0, got \(size.height)")
    }

    func testLongTextIntrinsicContentSize() {
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Rappelons la conversion : 1 km équivaut à 1000 m.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        let size = label.intrinsicContentSize

        XCTAssertGreaterThan(size.width, 0, "Width should be greater than 0, got \(size.width)")
        XCTAssertGreaterThan(size.height, 0, "Height should be greater than 0, got \(size.height)")
    }

    func testSizeThatFitsWithoutConstraint() {
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Hello World}\\)"
        label.font = MTFontManager.fontManager.defaultFont

        let size = label.sizeThatFits(CGSize.zero)

        XCTAssertGreaterThan(size.width, 0, "Width should be greater than 0, got \(size.width)")
        XCTAssertGreaterThan(size.height, 0, "Height should be greater than 0, got \(size.height)")
    }

    func testSizeThatFitsWithWidthConstraint() {
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Rappelons la conversion : 1 km équivaut à 1000 m.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        // Get unconstrained size first
        let unconstrainedSize = label.sizeThatFits(CGSize.zero)
        XCTAssertGreaterThan(unconstrainedSize.width, 0, "Unconstrained width should be > 0")

        // Test with width constraint (use 300 since longest word might be ~237pt)
        let constrainedSize = label.sizeThatFits(CGSize(width: 300, height: CGFloat.greatestFiniteMagnitude))

        XCTAssertGreaterThan(constrainedSize.width, 0, "Constrained width should be greater than 0, got \(constrainedSize.width)")
        XCTAssertLessThan(constrainedSize.width, unconstrainedSize.width, "Constrained width (\(constrainedSize.width)) should be less than unconstrained (\(unconstrainedSize.width))")
        XCTAssertGreaterThan(constrainedSize.height, 0, "Constrained height should be greater than 0, got \(constrainedSize.height)")

        // When constrained, height should increase when text wraps
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height,
                            "Constrained height (\(constrainedSize.height)) should be > unconstrained (\(unconstrainedSize.height)) when text wraps")
    }

    func testPreferredMaxLayoutWidth() {
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Rappelons la conversion : 1 km équivaut à 1000 m.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        // Get unconstrained size
        let unconstrainedSize = label.intrinsicContentSize

        // Now set preferred max width (use 300 since longest word might be ~237pt)
        label.preferredMaxLayoutWidth = 300
        let constrainedSize = label.intrinsicContentSize

        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be greater than 0, got \(constrainedSize.width)")
        XCTAssertLessThan(constrainedSize.width, unconstrainedSize.width, "Constrained width (\(constrainedSize.width)) should be < unconstrained (\(unconstrainedSize.width))")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Constrained height (\(constrainedSize.height)) should be > unconstrained (\(unconstrainedSize.height)) due to wrapping")
    }

    func testWordBoundaryBreaking() {
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Word1 Word2 Word3 Word4 Word5}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text
        label.preferredMaxLayoutWidth = 150

        let size = label.intrinsicContentSize

        XCTAssertGreaterThan(size.width, 0, "Width should be greater than 0, got \(size.width)")
        XCTAssertGreaterThan(size.height, 0, "Height should be greater than 0, got \(size.height)")

        // Verify it actually uses the layout
        label.frame = CGRect(origin: .zero, size: size)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
    }

    func testEmptyLatex() {
        let label = MTMathUILabel()
        label.latex = ""
        label.font = MTFontManager.fontManager.defaultFont

        let size = label.intrinsicContentSize

        // Empty latex should still return a valid size (might be zero or minimal)
        XCTAssertGreaterThanOrEqual(size.width, 0, "Width should be >= 0 for empty latex, got \(size.width)")
        XCTAssertGreaterThanOrEqual(size.height, 0, "Height should be >= 0 for empty latex, got \(size.height)")
    }

    func testMathAndTextMixed() {
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Result: } x^2 + y^2 = z^2\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        let size = label.intrinsicContentSize

        XCTAssertGreaterThan(size.width, 0, "Width should be greater than 0, got \(size.width)")
        XCTAssertGreaterThan(size.height, 0, "Height should be greater than 0, got \(size.height)")
    }

    func testDebugSizeThatFitsWithConstraint() {
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Word1 Word2 Word3 Word4 Word5}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        let unconstr = label.sizeThatFits(CGSize.zero)
        let constr = label.sizeThatFits(CGSize(width: 150, height: 999))

        XCTAssertLessThan(constr.width, unconstr.width, "Constrained (\(constr.width)) should be < unconstrained (\(unconstr.width))")
        XCTAssertGreaterThan(constr.height, unconstr.height, "Constrained height (\(constr.height)) should be > unconstrained (\(unconstr.height))")
    }

    func testAccentedCharactersWithLineWrapping() {
        let label = MTMathUILabel()
        // French text with accented characters: è, é, à
        label.latex = "\\(\\text{Rappelons la relation entre kilomètres et mètres.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        // Get unconstrained size
        let unconstrainedSize = label.intrinsicContentSize

        // Set a width constraint that should cause wrapping
        label.preferredMaxLayoutWidth = 250
        let constrainedSize = label.intrinsicContentSize

        // Verify wrapping occurred
        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertLessThan(constrainedSize.width, unconstrainedSize.width, "Constrained width should be < unconstrained")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        // Verify the label can render without errors
        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testUnicodeWordBreaking_EquivautCase() {
        // Specific test for the reported issue: "équivaut" should not break at "é"
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Rappelons la conversion : 1 km équivaut à 1000 m.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        // Set the exact width constraint from the bug report
        label.preferredMaxLayoutWidth = 235
        let constrainedSize = label.intrinsicContentSize

        // Verify the label can render without errors
        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")

        // Verify that the text wrapped (multiple lines)
        XCTAssertGreaterThan(constrainedSize.height, 20, "Should have wrapped to multiple lines")

        // The critical check: ensure "équivaut" is not broken in the middle
        // We can't easily check the exact line breaks, but we can verify:
        // 1. The rendering succeeded without crashes
        // 2. The display has reasonable dimensions
        XCTAssertGreaterThan(constrainedSize.width, 100, "Width should be reasonable")
        XCTAssertLessThan(constrainedSize.width, 250, "Width should respect constraint")
    }

    func testMixedTextMathNoTruncation() {
        // Test for truncation bug: content should wrap, not be lost
        // Input: \(\text{Calculer le discriminant }\Delta=b^{2}-4ac\text{ avec }a=1\text{, }b=-1\text{, }c=-5\)
        let label = MTMathUILabel()
        label.latex = "\\(\\text{Calculer le discriminant }\\Delta=b^{2}-4ac\\text{ avec }a=1\\text{, }b=-1\\text{, }c=-5\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        // Set width constraint that should cause wrapping
        label.preferredMaxLayoutWidth = 235
        let constrainedSize = label.intrinsicContentSize

        // Verify the label can render without errors
        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")

        // Verify content is not truncated - should wrap to multiple lines
        XCTAssertGreaterThan(constrainedSize.height, 30, "Should wrap to multiple lines (not truncate)")

        // Check that we have multiple display elements (wrapped content)
        if let displayList = label.displayList {
            XCTAssertGreaterThan(displayList.subDisplays.count, 1, "Should have multiple display elements from wrapping")
        }
    }

    func testNumberProtection_FrenchDecimal() {
        let label = MTMathUILabel()
        // French decimal number should NOT be broken
        label.latex = "\\(\\text{La valeur de pi est approximativement 3,14 dans ce calcul simple.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        // Constrain to force wrapping, but 3,14 should stay together
        label.preferredMaxLayoutWidth = 200
        let size = label.intrinsicContentSize

        // Verify it renders without error
        label.frame = CGRect(origin: .zero, size: size)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testNumberProtection_ThousandsSeparator() {
        let label = MTMathUILabel()
        // Number with comma separator should stay together
        label.latex = "\\(\\text{The population is approximately 1,000,000 people in this city.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        label.preferredMaxLayoutWidth = 200
        let size = label.intrinsicContentSize

        label.frame = CGRect(origin: .zero, size: size)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testNumberProtection_MixedWithText() {
        let label = MTMathUILabel()
        // Mixed numbers and text - numbers should be protected
        label.latex = "\\(\\text{Results: 3.14, 2.71, and 1.41 are important constants.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        label.preferredMaxLayoutWidth = 180
        let size = label.intrinsicContentSize

        label.frame = CGRect(origin: .zero, size: size)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    // MARK: - International Text Tests

    func testChineseTextWrapping() {
        let label = MTMathUILabel()
        // Chinese text: "Mathematical equations are an important tool for describing natural phenomena"
        label.latex = "\\(\\text{数学方程式は自然現象を記述するための重要なツールです。}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        // Get unconstrained size
        let unconstrainedSize = label.intrinsicContentSize

        // Set constraint to force wrapping
        label.preferredMaxLayoutWidth = 200
        let constrainedSize = label.intrinsicContentSize

        // Chinese should wrap (can break between characters)
        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertLessThanOrEqual(constrainedSize.width, 200, "Width should not exceed constraint")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testJapaneseTextWrapping() {
        let label = MTMathUILabel()
        // Japanese text (Hiragana + Kanji): "This is a mathematics explanation"
        label.latex = "\\(\\text{これは数学の説明です。計算式を使います。}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        let unconstrainedSize = label.intrinsicContentSize

        label.preferredMaxLayoutWidth = 180
        let constrainedSize = label.intrinsicContentSize

        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertLessThanOrEqual(constrainedSize.width, 180, "Width should not exceed constraint")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testKoreanTextWrapping() {
        let label = MTMathUILabel()
        // Korean text: "Mathematics is a very important subject"
        label.latex = "\\(\\text{수학은 매우 중요한 과목입니다. 방정식을 배웁니다.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        label.preferredMaxLayoutWidth = 200
        let constrainedSize = label.intrinsicContentSize

        // Korean uses spaces, should wrap at word boundaries
        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertLessThanOrEqual(constrainedSize.width, 200, "Width should not exceed constraint")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testMixedLatinCJKWrapping() {
        let label = MTMathUILabel()
        // Mixed English and Chinese
        label.latex = "\\(\\text{The equation is 方程式: } x^2 + y^2 = r^2 \\text{ です。}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        label.preferredMaxLayoutWidth = 250
        let constrainedSize = label.intrinsicContentSize

        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertLessThanOrEqual(constrainedSize.width, 250, "Width should not exceed constraint")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testEmojiGraphemeClusters() {
        let label = MTMathUILabel()
        // Emoji and complex grapheme clusters should not be broken
        label.latex = "\\(\\text{Math is fun! 🎉📐📊 The formula is } E = mc^2 \\text{ 🚀✨}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        label.preferredMaxLayoutWidth = 200
        let size = label.intrinsicContentSize

        // Should wrap but not break emoji
        XCTAssertGreaterThan(size.width, 0, "Width should be > 0")
        XCTAssertLessThanOrEqual(size.width, 200, "Width should not exceed constraint")

        label.frame = CGRect(origin: .zero, size: size)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testLongEnglishMultiSentence() {
        let label = MTMathUILabel()
        // Standard English multi-sentence paragraph
        label.latex = "\\(\\text{Mathematics is the study of numbers, shapes, and patterns. It is used in science, engineering, and everyday life. Equations help us solve problems.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        let unconstrainedSize = label.intrinsicContentSize

        label.preferredMaxLayoutWidth = 300
        let constrainedSize = label.intrinsicContentSize

        // Should wrap at word boundaries (spaces)
        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertLessThanOrEqual(constrainedSize.width, 300, "Width should not exceed constraint")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testSpanishAccentedText() {
        let label = MTMathUILabel()
        // Spanish with various accents
        label.latex = "\\(\\text{La ecuación es muy útil para cálculos científicos y matemáticos.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        let unconstrainedSize = label.intrinsicContentSize

        label.preferredMaxLayoutWidth = 220
        let constrainedSize = label.intrinsicContentSize

        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertLessThanOrEqual(constrainedSize.width, 220, "Width should not exceed constraint")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testGermanUmlautsWrapping() {
        let label = MTMathUILabel()
        // German with umlauts
        label.latex = "\\(\\text{Mathematische Gleichungen können für Berechnungen verwendet werden.}\\)"
        label.font = MTFontManager.fontManager.defaultFont
        label.labelMode = .text

        let unconstrainedSize = label.intrinsicContentSize

        label.preferredMaxLayoutWidth = 250
        let constrainedSize = label.intrinsicContentSize

        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertLessThanOrEqual(constrainedSize.width, 250, "Width should not exceed constraint")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    // MARK: - Tests for Complex Math Expressions with Line Breaking

    func testComplexExpressionWithRadicalWrapping() {
        // This is the reported issue: y=x^{2}+3x+4x+9x+8x+8+\sqrt{\dfrac{3x^{2}+5x}{\cos x}}
        // The sqrt part is displayed on the second line and overlaps the first line
        let label = MTMathUILabel()
        label.latex = "y=x^{2}+3x+4x+9x+8x+8+\\sqrt{\\dfrac{3x^{2}+5x}{\\cos x}}"
        label.font = MTFontManager.fontManager.defaultFont

        // Get unconstrained size first
        let unconstrainedSize = label.intrinsicContentSize
        XCTAssertGreaterThan(unconstrainedSize.width, 0, "Unconstrained width should be > 0")
        XCTAssertGreaterThan(unconstrainedSize.height, 0, "Unconstrained height should be > 0")

        // Now constrain the width to force wrapping
        label.preferredMaxLayoutWidth = 200
        let constrainedSize = label.intrinsicContentSize

        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertLessThanOrEqual(constrainedSize.width, 200, "Width should not exceed constraint")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        // Layout and check for overlapping
        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")

        // Check that displays don't overlap by examining positions
        // Group displays by line (similar y positions) and check for overlap between lines
        if let displayList = label.displayList {
            // Group displays by line based on their y position
            var lineGroups: [[MTDisplay]] = []
            var currentLineDisplays: [MTDisplay] = []
            var currentLineY: CGFloat? = nil
            let yTolerance: CGFloat = 15.0  // Displays within 15 units are considered on same line (accounts for superscripts/subscripts)
            
            for display in displayList.subDisplays {
                if let lineY = currentLineY {
                    if abs(display.position.y - lineY) < yTolerance {
                        // Same line
                        currentLineDisplays.append(display)
                    } else {
                        // New line
                        lineGroups.append(currentLineDisplays)
                        currentLineDisplays = [display]
                        currentLineY = display.position.y
                    }
                } else {
                    // First display
                    currentLineDisplays = [display]
                    currentLineY = display.position.y
                }
            }
            if !currentLineDisplays.isEmpty {
                lineGroups.append(currentLineDisplays)
            }
            
            // Check for overlap between consecutive lines
            for i in 1..<lineGroups.count {
                let previousLine = lineGroups[i-1]
                let currentLine = lineGroups[i]
                
                // Find the minimum bottom edge of previous line (Y-up: bottom = pos - desc, smaller Y)
                let previousLineMinBottom = previousLine.map { $0.position.y - $0.descent }.min() ?? 0
                
                // Find the maximum top edge of current line (Y-up: top = pos + asc, larger Y)
                let currentLineMaxTop = currentLine.map { $0.position.y + $0.ascent }.max() ?? 0
                
                // Check for overlap: if current line's top > previous line's bottom, they overlap
                // (In Y-up coordinate system: positive Y is upward, negative Y is downward)
                // Allow 0.5 points tolerance for floating-point precision and small adjustments
                XCTAssertLessThanOrEqual(currentLineMaxTop, previousLineMinBottom + 0.5,
                                       "Line \(i) (top at \(currentLineMaxTop)) overlaps with line \(i-1) (bottom at \(previousLineMinBottom))")
            }
        }
    }

    func testRadicalWithFractionInsideWrapping() {
        // Simplified version: just a radical with a fraction inside
        let label = MTMathUILabel()
        label.latex = "x+y+z+\\sqrt{\\dfrac{a}{b}}"
        label.font = MTFontManager.fontManager.defaultFont

        let unconstrainedSize = label.intrinsicContentSize

        label.preferredMaxLayoutWidth = 100
        let constrainedSize = label.intrinsicContentSize

        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }

    func testTallElementsOnSecondLine() {
        // Test case with tall fractions and radicals breaking to second line
        let label = MTMathUILabel()
        label.latex = "a+b+c+\\dfrac{x^2+y^2}{z^2}+\\sqrt{\\dfrac{p}{q}}"
        label.font = MTFontManager.fontManager.defaultFont

        let unconstrainedSize = label.intrinsicContentSize

        label.preferredMaxLayoutWidth = 150
        let constrainedSize = label.intrinsicContentSize

        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")

        // Verify no overlapping displays between lines
        if let displayList = label.displayList {
            // Group displays by line
            var lineGroups: [[MTDisplay]] = []
            var currentLineDisplays: [MTDisplay] = []
            var currentLineY: CGFloat? = nil
            let yTolerance: CGFloat = 15.0
            
            for display in displayList.subDisplays {
                if let lineY = currentLineY {
                    if abs(display.position.y - lineY) < yTolerance {
                        currentLineDisplays.append(display)
                    } else {
                        lineGroups.append(currentLineDisplays)
                        currentLineDisplays = [display]
                        currentLineY = display.position.y
                    }
                } else {
                    currentLineDisplays = [display]
                    currentLineY = display.position.y
                }
            }
            if !currentLineDisplays.isEmpty {
                lineGroups.append(currentLineDisplays)
            }
            
            // Check for overlap between consecutive lines
            for i in 1..<lineGroups.count {
                let previousLine = lineGroups[i-1]
                let currentLine = lineGroups[i]
                
                let previousLineMinBottom = previousLine.map { $0.position.y - $0.descent }.min() ?? 0
                let currentLineMaxTop = currentLine.map { $0.position.y + $0.ascent }.max() ?? 0
                
                // Allow 0.5 points tolerance for floating-point precision
                XCTAssertLessThanOrEqual(currentLineMaxTop, previousLineMinBottom + 0.5,
                                       "Line \(i) overlaps with line \(i-1)")
            }
        }
    }

    func testMultipleLinesWithVaryingHeights() {
        // Test expression that should wrap to multiple lines with different heights
        let label = MTMathUILabel()
        label.latex = "x+y+z+a+b+c+\\sqrt{d}+e+f+g+h+\\dfrac{i}{j}+k"
        label.font = MTFontManager.fontManager.defaultFont

        let unconstrainedSize = label.intrinsicContentSize

        label.preferredMaxLayoutWidth = 120
        let constrainedSize = label.intrinsicContentSize

        XCTAssertGreaterThan(constrainedSize.width, 0, "Width should be > 0")
        XCTAssertGreaterThan(constrainedSize.height, unconstrainedSize.height, "Height should increase when wrapped")

        label.frame = CGRect(origin: .zero, size: constrainedSize)
        #if os(macOS)
        label.layout()
        #else
        label.layoutSubviews()
        #endif

        XCTAssertNotNil(label.displayList, "Display list should be created")
        XCTAssertNil(label.error, "Should have no rendering error")
    }
}