/**
 * TDD Test Suite for DocumentNavigator Widget
 *
 * Tests the Substack-style floating navigation widget for document headings.
 * Following TDD methodology: write tests first, then implement functionality.
 */

// Simple test runner for browser environment
class DocumentNavigatorTestRunner {
    constructor() {
        this.tests = [];
        this.results = {
            passed: 0,
            failed: 0,
            total: 0
        };
    }

    test(name, testFn) {
        this.tests.push({ name, testFn });
    }

    expect(actual) {
        return {
            toBe: (expected) => {
                if (actual !== expected) {
                    throw new Error(`Expected ${actual} to be ${expected}`);
                }
            },
            toBeInstanceOf: (expectedClass) => {
                if (!(actual instanceof expectedClass)) {
                    throw new Error(`Expected ${actual} to be instance of ${expectedClass.name}`);
                }
            },
            toBeTruthy: () => {
                if (!actual) {
                    throw new Error(`Expected ${actual} to be truthy`);
                }
            },
            toBeFalsy: () => {
                if (actual) {
                    throw new Error(`Expected ${actual} to be falsy`);
                }
            },
            toContain: (expected) => {
                if (typeof actual === 'string' && !actual.includes(expected)) {
                    throw new Error(`Expected "${actual}" to contain "${expected}"`);
                }
                if (Array.isArray(actual) && !actual.includes(expected)) {
                    throw new Error(`Expected array to contain ${expected}`);
                }
            },
            toHaveLength: (expected) => {
                if (actual.length !== expected) {
                    throw new Error(`Expected length ${actual.length} to be ${expected}`);
                }
            },
            toBeGreaterThan: (expected) => {
                if (actual <= expected) {
                    throw new Error(`Expected ${actual} to be greater than ${expected}`);
                }
            }
        };
    }

    async run() {
        console.log('🧪 Running DocumentNavigator TDD Test Suite...\n');

        for (const { name, testFn } of this.tests) {
            this.results.total++;

            try {
                await testFn.call(this);
                this.results.passed++;
                console.log(`✅ ${name}`);
            } catch (error) {
                this.results.failed++;
                console.log(`❌ ${name}`);
                console.log(`   ${error.message}\n`);
            }
        }

        this.printSummary();
    }

    printSummary() {
        console.log(`\n📊 Test Results:`);
        console.log(`   Passed: ${this.results.passed}`);
        console.log(`   Failed: ${this.results.failed}`);
        console.log(`   Total:  ${this.results.total}`);

        if (this.results.failed === 0) {
            console.log(`\n🎉 All tests passed!`);
        } else {
            console.log(`\n❌ ${this.results.failed} test(s) failed.`);
        }
    }
}

// Create test runner
const runner = new DocumentNavigatorTestRunner();

// Test Suite: DocumentNavigator Widget
runner.test('DocumentNavigator class should exist and be importable', async function() {
    // This test will fail initially - we haven't created the class yet
    try {
        const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');
        this.expect(DocumentNavigator).toBeTruthy();
        this.expect(typeof DocumentNavigator).toBe('function');
    } catch (error) {
        throw new Error(`DocumentNavigator class not found: ${error.message}`);
    }
});

runner.test('DocumentNavigator should extend UIWidget', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');
    const { UIWidget } = await import('../widgets/base/UIWidget.js');

    const navigator = new DocumentNavigator();
    this.expect(navigator).toBeInstanceOf(UIWidget);
});

runner.test('DocumentNavigator should initialize with default configuration', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    const navigator = new DocumentNavigator();

    // Test default configuration
    this.expect(navigator.config.position).toBe('left');
    this.expect(navigator.config.collapsed).toBe(true);
    this.expect(navigator.config.autoHide).toBe(true);
    this.expect(navigator.config.maxHeadingLevel).toBe(3);
    this.expect(navigator.config.enableScrollSpy).toBe(true);
});

runner.test('DocumentNavigator should accept custom configuration', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    const customConfig = {
        position: 'right',
        collapsed: false,
        maxHeadingLevel: 4,
        theme: 'dark'
    };

    const navigator = new DocumentNavigator(customConfig);

    this.expect(navigator.config.position).toBe('right');
    this.expect(navigator.config.collapsed).toBe(false);
    this.expect(navigator.config.maxHeadingLevel).toBe(4);
    this.expect(navigator.config.theme).toBe('dark');
});

runner.test('DocumentNavigator should render floating panel element', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    const navigator = new DocumentNavigator();
    await navigator.render();

    this.expect(navigator.element).toBeInstanceOf(HTMLElement);
    this.expect(navigator.element.classList.contains('document-navigator')).toBeTruthy();
    this.expect(navigator.element.style.position).toBe('fixed');
});

runner.test('DocumentNavigator should have toggle button in collapsed state', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    const navigator = new DocumentNavigator({ collapsed: true });
    await navigator.render();

    const toggleButton = navigator.findElement('.navigator-toggle');
    this.expect(toggleButton).toBeInstanceOf(HTMLElement);
    this.expect(toggleButton.style.display).not.toBe('none');

    const navList = navigator.findElement('.navigator-list');
    this.expect(navList.style.display).toBe('none');
});

runner.test('DocumentNavigator should extract headings from document', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    // Create test document with headings
    const testContainer = document.createElement('div');
    testContainer.innerHTML = `
        <h1 id="heading1">First Heading</h1>
        <p>Some content</p>
        <h2 id="heading2">Second Heading</h2>
        <h3 id="heading3">Third Heading</h3>
        <p>More content</p>
        <h2 id="heading4">Fourth Heading</h2>
    `;
    document.body.appendChild(testContainer);

    const navigator = new DocumentNavigator({
        container: testContainer,
        maxHeadingLevel: 3
    });

    const headings = navigator.extractHeadings();

    this.expect(headings).toHaveLength(4);
    this.expect(headings[0].tagName).toBe('H1');
    this.expect(headings[0].textContent).toBe('First Heading');
    this.expect(headings[1].tagName).toBe('H2');
    this.expect(headings[2].tagName).toBe('H3');
    this.expect(headings[3].tagName).toBe('H2');

    // Cleanup
    document.body.removeChild(testContainer);
});

runner.test('DocumentNavigator should build navigation hierarchy', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    // Create test document with nested headings
    const testContainer = document.createElement('div');
    testContainer.innerHTML = `
        <h1>Chapter 1</h1>
        <h2>Section 1.1</h2>
        <h3>Subsection 1.1.1</h3>
        <h3>Subsection 1.1.2</h3>
        <h2>Section 1.2</h2>
        <h1>Chapter 2</h1>
    `;
    document.body.appendChild(testContainer);

    const navigator = new DocumentNavigator({ container: testContainer });
    await navigator.render();

    const navItems = navigator.buildNavigationTree();

    // Should have hierarchical structure
    this.expect(navItems).toHaveLength(2); // 2 H1 elements
    this.expect(navItems[0].children).toHaveLength(2); // 2 H2 under first H1
    this.expect(navItems[0].children[0].children).toHaveLength(2); // 2 H3 under first H2

    // Cleanup
    document.body.removeChild(testContainer);
});

runner.test('DocumentNavigator should handle click navigation', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    // Create test document
    const testContainer = document.createElement('div');
    testContainer.innerHTML = `
        <h1 id="target-heading">Target Heading</h1>
        <p style="height: 1000px;">Spacer content</p>
    `;
    document.body.appendChild(testContainer);

    const navigator = new DocumentNavigator({ container: testContainer });
    await navigator.render();

    // Simulate click on navigation item
    const navItem = navigator.findElement('[data-target="target-heading"]');
    this.expect(navItem).toBeTruthy();

    // Mock scrollIntoView for testing
    const targetElement = document.getElementById('target-heading');
    let scrollCalled = false;
    targetElement.scrollIntoView = () => { scrollCalled = true; };

    // Click navigation item
    navItem.click();

    this.expect(scrollCalled).toBeTruthy();

    // Cleanup
    document.body.removeChild(testContainer);
});

runner.test('DocumentNavigator should support expand/collapse functionality', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    const navigator = new DocumentNavigator({ collapsed: true });
    await navigator.render();

    // Should start collapsed
    this.expect(navigator.isCollapsed).toBeTruthy();

    const toggleButton = navigator.findElement('.navigator-toggle');
    const navList = navigator.findElement('.navigator-list');

    // Toggle to expanded
    await navigator.expand();
    this.expect(navigator.isCollapsed).toBeFalsy();
    this.expect(navList.style.display).not.toBe('none');

    // Toggle back to collapsed
    await navigator.collapse();
    this.expect(navigator.isCollapsed).toBeTruthy();
    this.expect(navList.style.display).toBe('none');
});

runner.test('DocumentNavigator should implement scroll spy functionality', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    // Create test document with multiple sections
    const testContainer = document.createElement('div');
    testContainer.innerHTML = `
        <div style="height: 100px;"></div>
        <h1 id="section1">Section 1</h1>
        <div style="height: 400px;"></div>
        <h2 id="section2">Section 2</h2>
        <div style="height: 400px;"></div>
        <h2 id="section3">Section 3</h2>
        <div style="height: 400px;"></div>
    `;
    document.body.appendChild(testContainer);

    const navigator = new DocumentNavigator({
        container: testContainer,
        enableScrollSpy: true
    });
    await navigator.render();

    // Test current section detection
    const currentSection = navigator.getCurrentSection();
    this.expect(currentSection).toBeTruthy();

    // Cleanup
    document.body.removeChild(testContainer);
});

runner.test('DocumentNavigator should handle responsive behavior', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    const navigator = new DocumentNavigator({ autoHide: true });
    await navigator.render();

    // Mock viewport resize
    const originalInnerWidth = window.innerWidth;

    // Test mobile viewport
    Object.defineProperty(window, 'innerWidth', { value: 500, configurable: true });
    navigator.handleResize();
    this.expect(navigator.element.style.display).toBe('none');

    // Test desktop viewport
    Object.defineProperty(window, 'innerWidth', { value: 1200, configurable: true });
    navigator.handleResize();
    this.expect(navigator.element.style.display).not.toBe('none');

    // Restore original
    Object.defineProperty(window, 'innerWidth', { value: originalInnerWidth, configurable: true });
});

runner.test('DocumentNavigator should provide keyboard navigation support', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    const navigator = new DocumentNavigator();
    await navigator.render();

    // Test keyboard shortcuts
    let expandCalled = false;
    let collapseCalled = false;

    navigator.expand = async () => { expandCalled = true; };
    navigator.collapse = async () => { collapseCalled = true; };

    // Simulate keyboard events
    const element = navigator.element;

    // Test Escape key (should collapse)
    const escapeEvent = new KeyboardEvent('keydown', { key: 'Escape' });
    element.dispatchEvent(escapeEvent);
    this.expect(collapseCalled).toBeTruthy();

    // Test Enter/Space key (should expand)
    const enterEvent = new KeyboardEvent('keydown', { key: 'Enter' });
    element.dispatchEvent(enterEvent);
    this.expect(expandCalled).toBeTruthy();
});

runner.test('DocumentNavigator should emit events for user interactions', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    const navigator = new DocumentNavigator();
    await navigator.render();

    // Test event emission
    let navigationEvent = null;
    navigator.addEventListener('navigate', (e) => {
        navigationEvent = e;
    });

    let toggleEvent = null;
    navigator.addEventListener('toggle', (e) => {
        toggleEvent = e;
    });

    // Trigger navigation
    navigator.navigateToHeading('test-heading');
    this.expect(navigationEvent).toBeTruthy();
    this.expect(navigationEvent.detail.target).toBe('test-heading');

    // Trigger toggle
    await navigator.toggle();
    this.expect(toggleEvent).toBeTruthy();
});

runner.test('DocumentNavigator should handle empty document gracefully', async function() {
    const { DocumentNavigator } = await import('../widgets/navigation/DocumentNavigator.js');

    // Create empty container
    const emptyContainer = document.createElement('div');
    document.body.appendChild(emptyContainer);

    const navigator = new DocumentNavigator({ container: emptyContainer });

    const headings = navigator.extractHeadings();
    this.expect(headings).toHaveLength(0);

    await navigator.render();
    const navList = navigator.findElement('.navigator-list');
    this.expect(navList.children).toHaveLength(0);

    // Should show empty state message
    const emptyMessage = navigator.findElement('.navigator-empty');
    this.expect(emptyMessage).toBeTruthy();

    // Cleanup
    document.body.removeChild(emptyContainer);
});

// Export test runner for use in HTML
window.runDocumentNavigatorTests = () => runner.run();

console.log('📋 DocumentNavigator TDD Test Suite loaded. Run with: runDocumentNavigatorTests()');

export { runner };