// Tests for pure search-snippet extraction (F8).

import 'package:flutter_test/flutter_test.dart';

import 'package:badnote/editor/search/search_snippet.dart';

void main() {
  test('returns null for empty query, empty source, or no match', () {
    expect(snippetFor('hello world', ''), isNull);
    expect(snippetFor('', 'x'), isNull);
    expect(snippetFor('hello world', 'zzz'), isNull);
  });

  test('case-insensitive match, offset preserved within the snippet', () {
    final s = snippetFor('The Quick Brown Fox', 'quick', window: 80)!;
    expect(s.match.toLowerCase(), 'quick');
    expect(s.text.substring(s.matchStart, s.matchStart + s.matchLength),
        'Quick');
  });

  test('short source is returned whole, no truncation', () {
    final s = snippetFor('alpha beta gamma', 'beta', window: 80)!;
    expect(s.text, 'alpha beta gamma');
    expect(s.truncatedStart, isFalse);
    expect(s.truncatedEnd, isFalse);
    expect(s.matchStart, 'alpha '.length);
  });

  test('long source is windowed and truncated on both sides', () {
    final source = '${'a' * 200} needle ${'b' * 200}';
    final s = snippetFor(source, 'needle', window: 40)!;
    expect(s.truncatedStart, isTrue);
    expect(s.truncatedEnd, isTrue);
    expect(s.match, 'needle');
    // Window is ~40 + match; nowhere near the full 400+ source.
    expect(s.text.length, lessThan(80));
  });

  test('match near the start has no leading truncation', () {
    final source = 'needle ${'b' * 200}';
    final s = snippetFor(source, 'needle', window: 40)!;
    expect(s.truncatedStart, isFalse);
    expect(s.matchStart, 0);
    expect(s.truncatedEnd, isTrue);
  });

  test('match near the end has no trailing truncation', () {
    final source = '${'a' * 200} needle';
    final s = snippetFor(source, 'needle', window: 40)!;
    expect(s.truncatedEnd, isFalse);
    expect(s.truncatedStart, isTrue);
  });

  test('the full match is included even when longer than the window', () {
    final long = 'x' * 100;
    final s = snippetFor('pre $long post', long, window: 10)!;
    expect(s.match, long);
    expect(s.matchLength, 100);
  });

  test('finds the FIRST occurrence', () {
    final s = snippetFor('cat dog cat', 'cat', window: 80)!;
    expect(s.matchStart, 0);
  });
}