diff --git a/__tests__/Services/InputService.test.ts b/__tests__/Services/InputService.test.ts
index 0f8158d..5d8f4f2 100644
--- a/__tests__/Services/InputService.test.ts
+++ b/__tests__/Services/InputService.test.ts
@@ -1,12 +1,12 @@
-import { describe, it, expect, beforeEach } from 'vitest';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
 import { InputService } from '../../Services/InputService';
+import { SearchTrigger } from '../../Enums/SearchTrigger';
 
 /**
  * UNIT TESTS
  *
- * These tests cover the straightforward methods of InputService that don't
- * require complex DOM/Selection API mocking. Methods involving cursor manipulation
- * and Selection/Range APIs are not covered here due to testing complexity.
+ * These tests cover both simple methods and DOM/Selection API methods using JSDOM.
+ * JSDOM provides the DOM environment needed for cursor manipulation and Range/Selection APIs.
  */
 
 describe('InputService', () => {
@@ -330,4 +330,711 @@ describe('InputService', () => {
 			expect(service.stripHtml(html)).toBe('Text beforeInside tagText after');
 		});
 	});
+
+	describe('getPlainTextFromClipboard', () => {
+		it('should extract text/plain from DataTransfer', () => {
+			const mockClipboardData = {
+				getData: vi.fn((type: string) => {
+					if (type === 'text/plain') return 'Plain text content';
+					return '';
+				})
+			} as unknown as DataTransfer;
+
+			const result = service.getPlainTextFromClipboard(mockClipboardData);
+			expect(result).toBe('Plain text content');
+			expect(mockClipboardData.getData).toHaveBeenCalledWith('text/plain');
+		});
+
+		it('should return empty string for null clipboard', () => {
+			const result = service.getPlainTextFromClipboard(null);
+			expect(result).toBe('');
+		});
+
+		it('should return empty string when getData returns empty', () => {
+			const mockClipboardData = {
+				getData: vi.fn(() => '')
+			} as unknown as DataTransfer;
+
+			const result = service.getPlainTextFromClipboard(mockClipboardData);
+			expect(result).toBe('');
+		});
+
+		it('should handle clipboard with no text/plain data', () => {
+			const mockClipboardData = {
+				getData: vi.fn(() => null)
+			} as unknown as DataTransfer;
+
+			const result = service.getPlainTextFromClipboard(mockClipboardData);
+			expect(result).toBe('');
+		});
+	});
+
+	describe('hasUnauthorizedHTML', () => {
+		let element: HTMLDivElement;
+
+		beforeEach(() => {
+			element = document.createElement('div');
+			element.contentEditable = 'true';
+		});
+
+		it('should return false for text-only content', () => {
+			element.textContent = 'Plain text content';
+			expect(service.hasUnauthorizedHTML(element)).toBe(false);
+		});
+
+		it('should return false for BR tags (browser auto-insert)', () => {
+			const br = document.createElement('br');
+			element.appendChild(br);
+			expect(service.hasUnauthorizedHTML(element)).toBe(false);
+		});
+
+		it('should return false for DIV with only text content', () => {
+			const div = document.createElement('div');
+			div.textContent = 'Text in div';
+			element.appendChild(div);
+			expect(service.hasUnauthorizedHTML(element)).toBe(false);
+		});
+
+		it('should return false for DIV with BR tags', () => {
+			const div = document.createElement('div');
+			div.textContent = 'Line 1';
+			const br = document.createElement('br');
+			div.appendChild(br);
+			div.appendChild(document.createTextNode('Line 2'));
+			element.appendChild(div);
+			expect(service.hasUnauthorizedHTML(element)).toBe(false);
+		});
+
+		it('should return false for search trigger elements', () => {
+			const trigger = document.createElement('span');
+			trigger.className = 'search-trigger';
+			trigger.textContent = '#tag';
+			element.appendChild(trigger);
+			expect(service.hasUnauthorizedHTML(element)).toBe(false);
+		});
+
+		it('should return false for mixed text, BR, DIV, and search triggers', () => {
+			element.appendChild(document.createTextNode('Text '));
+			const trigger = document.createElement('span');
+			trigger.className = 'search-trigger';
+			element.appendChild(trigger);
+			element.appendChild(document.createTextNode(' more text'));
+			const br = document.createElement('br');
+			element.appendChild(br);
+			const div = document.createElement('div');
+			div.textContent = 'Div content';
+			element.appendChild(div);
+
+			expect(service.hasUnauthorizedHTML(element)).toBe(false);
+		});
+
+		it('should return true for SPAN tags (non-search-trigger)', () => {
+			const span = document.createElement('span');
+			span.textContent = 'Regular span';
+			element.appendChild(span);
+			expect(service.hasUnauthorizedHTML(element)).toBe(true);
+		});
+
+		it('should return true for STRONG tags', () => {
+			const strong = document.createElement('strong');
+			strong.textContent = 'Bold text';
+			element.appendChild(strong);
+			expect(service.hasUnauthorizedHTML(element)).toBe(true);
+		});
+
+		it('should return true for IMG tags', () => {
+			const img = document.createElement('img');
+			img.src = 'test.png';
+			element.appendChild(img);
+			expect(service.hasUnauthorizedHTML(element)).toBe(true);
+		});
+
+		it('should return true for SCRIPT tags', () => {
+			const script = document.createElement('script');
+			script.textContent = 'alert("test")';
+			element.appendChild(script);
+			expect(service.hasUnauthorizedHTML(element)).toBe(true);
+		});
+
+		it('should return true for A (anchor) tags', () => {
+			const a = document.createElement('a');
+			a.href = 'http://example.com';
+			a.textContent = 'Link';
+			element.appendChild(a);
+			expect(service.hasUnauthorizedHTML(element)).toBe(true);
+		});
+
+		it('should detect unauthorized HTML in nested DIVs', () => {
+			const div = document.createElement('div');
+			const span = document.createElement('span');
+			span.textContent = 'Nested span';
+			div.appendChild(span);
+			element.appendChild(div);
+			expect(service.hasUnauthorizedHTML(element)).toBe(true);
+		});
+
+		it('should return true for deeply nested unauthorized elements', () => {
+			const div1 = document.createElement('div');
+			const div2 = document.createElement('div');
+			const unauthorized = document.createElement('em');
+			unauthorized.textContent = 'Italic';
+			div2.appendChild(unauthorized);
+			div1.appendChild(div2);
+			element.appendChild(div1);
+			expect(service.hasUnauthorizedHTML(element)).toBe(true);
+		});
+
+		it('should handle empty element', () => {
+			expect(service.hasUnauthorizedHTML(element)).toBe(false);
+		});
+
+		it('should handle element with only whitespace', () => {
+			element.textContent = '   \n   ';
+			expect(service.hasUnauthorizedHTML(element)).toBe(false);
+		});
+	});
+
+	describe('DOM Manipulation Methods', () => {
+		let element: HTMLDivElement;
+
+		beforeEach(() => {
+			// Create a contentEditable element
+			element = document.createElement('div');
+			element.contentEditable = 'true';
+			element.textContent = 'Hello World';
+			document.body.appendChild(element);
+		});
+
+		afterEach(() => {
+			document.body.removeChild(element);
+		});
+
+		describe('getCursorPosition', () => {
+			it('should return -1 when no selection exists', () => {
+				// Clear any existing selection
+				const selection = window.getSelection();
+				if (selection) {
+					selection.removeAllRanges();
+				}
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(-1);
+			});
+
+			it('should return cursor position at start of text', () => {
+				const range = document.createRange();
+				const selection = window.getSelection();
+				const textNode = element.firstChild as Text;
+
+				range.setStart(textNode, 0);
+				range.setEnd(textNode, 0);
+				selection?.removeAllRanges();
+				selection?.addRange(range);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(0);
+			});
+
+			it('should return cursor position in middle of text', () => {
+				const range = document.createRange();
+				const selection = window.getSelection();
+				const textNode = element.firstChild as Text;
+
+				range.setStart(textNode, 6); // After "Hello "
+				range.setEnd(textNode, 6);
+				selection?.removeAllRanges();
+				selection?.addRange(range);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(6);
+			});
+
+			it('should return cursor position at end of text', () => {
+				const range = document.createRange();
+				const selection = window.getSelection();
+				const textNode = element.firstChild as Text;
+
+				range.setStart(textNode, 11); // After "Hello World"
+				range.setEnd(textNode, 11);
+				selection?.removeAllRanges();
+				selection?.addRange(range);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(11);
+			});
+
+			it('should handle nested elements', () => {
+				element.innerHTML = '';
+				element.appendChild(document.createTextNode('Hello '));
+				const span = document.createElement('span');
+				span.textContent = 'World';
+				element.appendChild(span);
+
+				const range = document.createRange();
+				const selection = window.getSelection();
+				const spanTextNode = span.firstChild as Text;
+
+				range.setStart(spanTextNode, 2); // "Wo" - position 8 overall
+				range.setEnd(spanTextNode, 2);
+				selection?.removeAllRanges();
+				selection?.addRange(range);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(8);
+			});
+		});
+
+		describe('setCursorPosition', () => {
+			it('should return false for non-contentEditable element', () => {
+				const nonEditable = document.createElement('div');
+				nonEditable.textContent = 'Not editable';
+				document.body.appendChild(nonEditable);
+
+				const result = service.setCursorPosition(nonEditable, 5);
+				expect(result).toBe(false);
+
+				document.body.removeChild(nonEditable);
+			});
+
+			it('should set cursor at start of text', () => {
+				const result = service.setCursorPosition(element, 0);
+				expect(result).toBe(true);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(0);
+			});
+
+			it('should set cursor in middle of text', () => {
+				const result = service.setCursorPosition(element, 6);
+				expect(result).toBe(true);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(6);
+			});
+
+			it('should set cursor at end of text', () => {
+				const result = service.setCursorPosition(element, 11);
+				expect(result).toBe(true);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(11);
+			});
+
+			it('should clamp position beyond text length', () => {
+				const result = service.setCursorPosition(element, 999);
+				expect(result).toBe(true);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(11); // Max length
+			});
+
+			it('should set cursor from end with fromEnd=true', () => {
+				const result = service.setCursorPosition(element, 5, true);
+				expect(result).toBe(true);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(6); // 11 - 5 = 6
+			});
+
+			it('should set cursor at start when fromEnd position exceeds length', () => {
+				const result = service.setCursorPosition(element, 999, true);
+				expect(result).toBe(true);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(0);
+			});
+
+			it('should handle nested elements', () => {
+				element.innerHTML = '';
+				element.appendChild(document.createTextNode('Hello '));
+				const span = document.createElement('span');
+				span.textContent = 'World';
+				element.appendChild(span);
+
+				const result = service.setCursorPosition(element, 8);
+				expect(result).toBe(true);
+
+				const position = service.getCursorPosition(element);
+				expect(position).toBe(8);
+			});
+
+			it('should focus the element when setting cursor', () => {
+				const focusSpy = vi.spyOn(element, 'focus');
+				service.setCursorPosition(element, 5);
+				expect(focusSpy).toHaveBeenCalled();
+			});
+		});
+
+		describe('insertTextAtCursor', () => {
+			it('should insert text at cursor position', () => {
+				service.setCursorPosition(element, 6); // After "Hello "
+				service.insertTextAtCursor('Beautiful ', element);
+
+				expect(element.textContent).toBe('Hello Beautiful World');
+			});
+
+			it('should replace selected text', () => {
+				const range = document.createRange();
+				const selection = window.getSelection();
+				const textNode = element.firstChild as Text;
+
+				range.setStart(textNode, 6);
+				range.setEnd(textNode, 11); // Select "World"
+				selection?.removeAllRanges();
+				selection?.addRange(range);
+
+				service.insertTextAtCursor('Universe', element);
+				expect(element.textContent).toBe('Hello Universe');
+			});
+
+			it('should not insert when no selection exists', () => {
+				const selection = window.getSelection();
+				selection?.removeAllRanges();
+
+				const originalText = element.textContent;
+				service.insertTextAtCursor('Test', element);
+				expect(element.textContent).toBe(originalText);
+			});
+
+			it('should warn and not insert for non-contentEditable element', () => {
+				const nonEditable = document.createElement('div');
+				nonEditable.textContent = 'Not editable';
+				document.body.appendChild(nonEditable);
+
+				const consoleSpy = vi.spyOn(console, 'warn');
+				service.insertTextAtCursor('Test', nonEditable);
+
+				expect(consoleSpy).toHaveBeenCalledWith('Element must be contenteditable');
+				document.body.removeChild(nonEditable);
+			});
+		});
+
+		describe('insertElementAtCursor', () => {
+			it('should insert element at cursor position', () => {
+				service.setCursorPosition(element, 6); // After "Hello "
+
+				const span = document.createElement('span');
+				span.textContent = 'Beautiful ';
+				service.insertElementAtCursor(span, element);
+
+				expect(element.textContent).toBe('Hello Beautiful World');
+				expect(element.querySelector('span')).toBeTruthy();
+			});
+
+			it('should insert search trigger element', () => {
+				service.setCursorPosition(element, 6);
+
+				const trigger = document.createElement('span');
+				trigger.className = 'search-trigger';
+				trigger.textContent = '#tag';
+				service.insertElementAtCursor(trigger, element);
+
+				expect(element.textContent).toBe('Hello #tagWorld');
+				expect(element.querySelector('.search-trigger')).toBeTruthy();
+			});
+
+			it('should replace selected text with element', () => {
+				const range = document.createRange();
+				const selection = window.getSelection();
+				const textNode = element.firstChild as Text;
+
+				range.setStart(textNode, 6);
+				range.setEnd(textNode, 11); // Select "World"
+				selection?.removeAllRanges();
+				selection?.addRange(range);
+
+				const span = document.createElement('span');
+				span.textContent = 'Universe';
+				service.insertElementAtCursor(span, element);
+
+				expect(element.textContent).toBe('Hello Universe');
+			});
+
+			it('should not insert when no selection exists', () => {
+				const selection = window.getSelection();
+				selection?.removeAllRanges();
+
+				const childrenBefore = element.childNodes.length;
+				const span = document.createElement('span');
+				service.insertElementAtCursor(span, element);
+				expect(element.childNodes.length).toBe(childrenBefore);
+			});
+
+			it('should warn and not insert for non-contentEditable element', () => {
+				const nonEditable = document.createElement('div');
+				nonEditable.textContent = 'Not editable';
+				document.body.appendChild(nonEditable);
+
+				const consoleSpy = vi.spyOn(console, 'warn');
+				const span = document.createElement('span');
+				service.insertElementAtCursor(span, nonEditable);
+
+				expect(consoleSpy).toHaveBeenCalledWith('Element must be contenteditable');
+				document.body.removeChild(nonEditable);
+			});
+		});
+
+		describe('deleteTextRange', () => {
+			it('should delete text range in middle', () => {
+				service.deleteTextRange(6, 11, element); // Delete "World"
+				expect(element.textContent).toBe('Hello ');
+			});
+
+			it('should delete from start', () => {
+				service.deleteTextRange(0, 6, element); // Delete "Hello "
+				expect(element.textContent).toBe('World');
+			});
+
+			it('should delete entire content', () => {
+				service.deleteTextRange(0, 11, element);
+				expect(element.textContent).toBe('');
+			});
+
+			it('should delete single character', () => {
+				service.deleteTextRange(5, 6, element); // Delete space
+				expect(element.textContent).toBe('HelloWorld');
+			});
+
+			it('should set cursor position after deletion', () => {
+				service.deleteTextRange(6, 11, element); // Delete "World"
+				const cursorPos = service.getCursorPosition(element);
+				expect(cursorPos).toBe(6);
+			});
+
+			it('should handle nested elements', () => {
+				element.innerHTML = '';
+				element.appendChild(document.createTextNode('Hello '));
+				const span = document.createElement('span');
+				span.textContent = 'World';
+				element.appendChild(span);
+
+				service.deleteTextRange(6, 9, element); // Delete "Wor"
+				expect(element.textContent).toBe('Hello ld');
+			});
+
+			it('should warn for non-contentEditable element', () => {
+				const nonEditable = document.createElement('div');
+				nonEditable.textContent = 'Not editable';
+				document.body.appendChild(nonEditable);
+
+				const consoleSpy = vi.spyOn(console, 'warn');
+				service.deleteTextRange(0, 3, nonEditable);
+
+				expect(consoleSpy).toHaveBeenCalledWith('Element must be contenteditable');
+				expect(nonEditable.textContent).toBe('Not editable'); // Unchanged
+				document.body.removeChild(nonEditable);
+			});
+
+			it('should handle invalid range gracefully', () => {
+				const originalText = element.textContent;
+				const consoleErrorSpy = vi.spyOn(console, 'error');
+
+				// Try to delete with reversed positions (though implementation may handle this)
+				service.deleteTextRange(999, 1000, element);
+
+				// Text should either be unchanged or empty depending on implementation
+				// We just verify it doesn't crash
+				expect(consoleErrorSpy).not.toHaveBeenCalled();
+			});
+		});
+
+		describe('getPreviousNode', () => {
+			it('should return null when no selection exists', () => {
+				const selection = window.getSelection();
+				selection?.removeAllRanges();
+
+				const result = service.getPreviousNode();
+				expect(result).toBeNull();
+			});
+
+			it('should return null when cursor is at start', () => {
+				service.setCursorPosition(element, 0);
+				const result = service.getPreviousNode();
+				expect(result).toBeNull();
+			});
+
+			it('should return null when cursor is in text node', () => {
+				service.setCursorPosition(element, 5);
+				const result = service.getPreviousNode();
+				expect(result).toBeNull();
+			});
+
+			it('should return search trigger element when cursor is after it', () => {
+				element.innerHTML = 'Text ';
+				const trigger = document.createElement('span');
+				trigger.className = 'search-trigger';
+				trigger.textContent = '#tag';
+				element.appendChild(trigger);
+				element.appendChild(document.createTextNode(' more'));
+
+				// Position cursor right after the trigger element
+				const range = document.createRange();
+				const selection = window.getSelection();
+				range.setStart(element, 2); // After text node and trigger
+				range.setEnd(element, 2);
+				selection?.removeAllRanges();
+				selection?.addRange(range);
+
+				const result = service.getPreviousNode();
+				expect(result).toBe(trigger);
+			});
+
+			it('should return null when previous element is not a search trigger', () => {
+				element.innerHTML = 'Text ';
+				const span = document.createElement('span');
+				span.textContent = 'regular span';
+				element.appendChild(span);
+				element.appendChild(document.createTextNode(' more'));
+
+				const range = document.createRange();
+				const selection = window.getSelection();
+				range.setStart(element, 2); // After text node and span
+				range.setEnd(element, 2);
+				selection?.removeAllRanges();
+				selection?.addRange(range);
+
+				const result = service.getPreviousNode();
+				expect(result).toBeNull();
+			});
+
+			it('should return null when selection is not collapsed', () => {
+				const range = document.createRange();
+				const selection = window.getSelection();
+				const textNode = element.firstChild as Text;
+
+				range.setStart(textNode, 0);
+				range.setEnd(textNode, 5); // Select "Hello"
+				selection?.removeAllRanges();
+				selection?.addRange(range);
+
+				const result = service.getPreviousNode();
+				expect(result).toBeNull();
+			});
+		});
+
+		describe('getNodeAtCursorPosition', () => {
+			it('should return node at cursor position', () => {
+				service.setCursorPosition(element, 5);
+				const node = service.getNodeAtCursorPosition();
+
+				// Should return the parent element or text node
+				expect(node).toBeTruthy();
+			});
+
+			it('should return null when no selection exists', () => {
+				const selection = window.getSelection();
+				selection?.removeAllRanges();
+
+				const node = service.getNodeAtCursorPosition();
+				// JSDOM may return an empty Selection, so node might be null or a node
+				// We just verify it doesn't crash
+				expect(node === null || node instanceof Node).toBe(true);
+			});
+
+			it('should return parent node for text nodes', () => {
+				service.setCursorPosition(element, 5);
+				const node = service.getNodeAtCursorPosition();
+
+				// Since cursor is in text, it should return the parent (element)
+				expect(node?.nodeType).toBe(Node.ELEMENT_NODE);
+			});
+
+			it('should handle nested elements', () => {
+				element.innerHTML = '';
+				element.appendChild(document.createTextNode('Hello '));
+				const span = document.createElement('span');
+				span.textContent = 'World';
+				element.appendChild(span);
+
+				service.setCursorPosition(element, 8); // Inside span
+				const node = service.getNodeAtCursorPosition();
+
+				expect(node).toBeTruthy();
+			});
+		});
+
+		describe('sanitizeToPlainText', () => {
+			it('should remove all HTML and keep plain text', () => {
+				element.innerHTML = 'Hello <strong>World</strong>';
+				service.setCursorPosition(element, 5);
+
+				service.sanitizeToPlainText(element);
+
+				expect(element.textContent).toBe('Hello World');
+				expect(element.innerHTML).toBe('Hello World');
+			});
+
+			it('should preserve cursor position after sanitization', () => {
+				element.innerHTML = 'Hello <strong>Bold</strong> World';
+				service.setCursorPosition(element, 11); // After "Hello Bold "
+
+				service.sanitizeToPlainText(element);
+
+				const cursorPos = service.getCursorPosition(element);
+				expect(cursorPos).toBe(11);
+			});
+
+			it('should handle cursor at start', () => {
+				element.innerHTML = '<em>Italic</em> text';
+				service.setCursorPosition(element, 0);
+
+				service.sanitizeToPlainText(element);
+
+				expect(element.textContent).toBe('Italic text');
+				const cursorPos = service.getCursorPosition(element);
+				expect(cursorPos).toBe(0);
+			});
+
+			it('should handle cursor at end', () => {
+				element.innerHTML = 'Text <span>with span</span>';
+				const textLength = element.textContent?.length || 0;
+				service.setCursorPosition(element, textLength);
+
+				service.sanitizeToPlainText(element);
+
+				expect(element.textContent).toBe('Text with span');
+				const cursorPos = service.getCursorPosition(element);
+				expect(cursorPos).toBe(14);
+			});
+
+			it('should handle empty element', () => {
+				element.innerHTML = '';
+				service.sanitizeToPlainText(element);
+
+				expect(element.textContent).toBe('');
+			});
+
+			it('should handle element with only HTML tags', () => {
+				element.innerHTML = '<br><br>';
+				service.sanitizeToPlainText(element);
+
+				expect(element.innerHTML).toBe('');
+			});
+
+			it('should remove search trigger elements but keep text', () => {
+				element.innerHTML = 'Query ';
+				const trigger = document.createElement('span');
+				trigger.className = 'search-trigger';
+				trigger.textContent = '#tag';
+				element.appendChild(trigger);
+				element.appendChild(document.createTextNode(' text'));
+
+				service.sanitizeToPlainText(element);
+
+				expect(element.textContent).toBe('Query #tag text');
+				expect(element.querySelector('.search-trigger')).toBeNull();
+			});
+
+			it('should handle nested HTML structures', () => {
+				element.innerHTML = '<div><p>Nested <strong>content</strong></p></div>';
+				service.setCursorPosition(element, 7); // After "Nested "
+
+				service.sanitizeToPlainText(element);
+
+				expect(element.textContent).toBe('Nested content');
+				const cursorPos = service.getCursorPosition(element);
+				expect(cursorPos).toBe(7);
+			});
+		});
+	});
 });