import { describe, it, expect } from 'vitest';
import { detectMention, extractContent, renderBody } from './mention';
import type { MentionDTO } from '$lib/types';

// ─── detectMention ────────────────────────────────────────────────────────────

describe('detectMention', () => {
	it('returns null when text has no @', () => {
		expect(detectMention('hello world', 11)).toBeNull();
	});

	it('returns null when @ is not the most recent trigger word', () => {
		// cursor is past a completed mention (next word started)
		expect(detectMention('hello @Hans Müller more', 22)).toBeNull();
	});

	it('returns empty string immediately after @', () => {
		expect(detectMention('hello @', 7)).toBe('');
	});

	it('returns query text after @', () => {
		expect(detectMention('hello @Han', 10)).toBe('Han');
	});

	it('returns null when @ is preceded by a letter (email address pattern)', () => {
		expect(detectMention('user@example', 12)).toBeNull();
	});

	it('returns query for @ at the very start of string', () => {
		expect(detectMention('@Hans', 5)).toBe('Hans');
	});

	it('returns null when cursor is before the @', () => {
		expect(detectMention('@Hans', 0)).toBeNull();
	});
});

// ─── extractContent ───────────────────────────────────────────────────────────

describe('extractContent', () => {
	it('returns empty arrays for empty string', () => {
		const result = extractContent('', []);
		expect(result.content).toBe('');
		expect(result.mentionedUserIds).toEqual([]);
	});

	it('returns plain content unchanged when no candidates', () => {
		const result = extractContent('Hello world', []);
		expect(result.content).toBe('Hello world');
		expect(result.mentionedUserIds).toEqual([]);
	});

	it('extracts user id when @FirstName LastName is in content', () => {
		const candidates: MentionDTO[] = [{ id: 'uuid-1', firstName: 'Hans', lastName: 'Müller' }];
		const result = extractContent('Hey @Hans Müller how are you?', candidates);
		expect(result.mentionedUserIds).toContain('uuid-1');
	});

	it('deduplicates user ids when same user mentioned twice', () => {
		const candidates: MentionDTO[] = [{ id: 'uuid-1', firstName: 'Hans', lastName: 'Müller' }];
		const result = extractContent('@Hans Müller and @Hans Müller again', candidates);
		expect(result.mentionedUserIds).toHaveLength(1);
		expect(result.mentionedUserIds).toContain('uuid-1');
	});

	it('collects multiple distinct users', () => {
		const candidates: MentionDTO[] = [
			{ id: 'uuid-1', firstName: 'Hans', lastName: 'Müller' },
			{ id: 'uuid-2', firstName: 'Anna', lastName: 'Schmidt' }
		];
		const result = extractContent('@Hans Müller and @Anna Schmidt', candidates);
		expect(result.mentionedUserIds).toContain('uuid-1');
		expect(result.mentionedUserIds).toContain('uuid-2');
	});
});

// ─── renderBody ───────────────────────────────────────────────────────────────

describe('renderBody', () => {
	it('returns escaped plain text when no mentions', () => {
		expect(renderBody('Hello world', [])).toBe('Hello world');
	});

	it('escapes < and > in content', () => {
		const result = renderBody('<script>alert(1)</script>', []);
		expect(result).toContain('&lt;script&gt;');
		expect(result).not.toContain('<script>');
	});

	it('escapes & in content', () => {
		const result = renderBody('AT&T', []);
		expect(result).toContain('AT&amp;T');
	});

	it('wraps @mention in a mention span', () => {
		const mentions: MentionDTO[] = [{ id: 'uuid-1', firstName: 'Hans', lastName: 'Müller' }];
		const result = renderBody('Hey @Hans Müller!', mentions);
		expect(result).toContain('<span');
		expect(result).toContain('class="mention"');
		expect(result).toContain('Hans Müller');
	});

	it('does not double-encode already escaped text', () => {
		const mentions: MentionDTO[] = [{ id: 'uuid-1', firstName: 'Hans', lastName: 'Müller' }];
		const result = renderBody('Check @Hans Müller', mentions);
		expect(result).not.toContain('&amp;');
	});

	it('replaces all occurrences of the same mention', () => {
		const mentions: MentionDTO[] = [{ id: 'uuid-1', firstName: 'Hans', lastName: 'Müller' }];
		const result = renderBody('@Hans Müller and @Hans Müller', mentions);
		const spanCount = (result.match(/<span /g) ?? []).length;
		expect(spanCount).toBe(2);
	});

	it('escapes HTML special chars in mention display names', () => {
		const mentions: MentionDTO[] = [{ id: 'u1', firstName: '<script>', lastName: 'alert(1)' }];
		const result = renderBody('@<script> alert(1)', mentions);
		expect(result).not.toContain('<script>');
		expect(result).toContain('&lt;script&gt;');
	});

	it('converts newlines to <br>', () => {
		const result = renderBody('line1\nline2', []);
		expect(result).toContain('<br>');
		expect(result).not.toContain('\n');
	});
});