#FuzzyScore.mbt

#Overview

#Features

• 🎯 100% Faithful: Identical scores and match positions to VS Code
• ⚡ High Performance: O(|pattern| × |word|) with optimized DP
• 🌍 Unicode Support: Proper UTF-16 handling for international text
• 📍 Match Highlighting: Returns exact positions for UI highlighting
• 🔤 Smart Scoring: Camel case, separators, consecutive matches
• 📚 Well Documented: Comprehensive API documentation and examples

#Quick Start

///|
test "vscode_algorithm" {
  // VS Code's advanced algorithm with match positions
  let (score, positions) = @fuzzyscore.vscode_fuzzy_score_simple(
    "cat", "concatenate", true,
  )
  inspect(score, content="69")
  inspect(positions, content="[3, 4, 5]")
}

#API Reference

#VS Code Algorithm

#vscode_fuzzy_score(pattern: String, word: String, first_match_can_be_weak: Bool) -> (Int, Array[Int])

///|
test "vscode_comprehensive" {
  // Basic usage
  let (score, positions) = @fuzzyscore.vscode_fuzzy_score_simple(
    "swt", "ss_ww_tt", true,
  )
  inspect(score, content="66")
  inspect(positions, content="[1, 3, 6]")

  // Camel case matching
  let (score2, positions2) = @fuzzyscore.vscode_fuzzy_score_simple(
    "fB", "fooBar", true,
  )
  inspect(score2, content="41")
  inspect(positions2, content="[0, 3]")

  // Exact match
  let (score3, positions3) = @fuzzyscore.vscode_fuzzy_score_simple(
    "test", "test", true,
  )
  inspect(score3, content="92")
  inspect(positions3, content="[0, 1, 2, 3]")
}

#Scoring System

///|
test "scoring_examples" {
  // Consecutive matches get exponential bonuses
  let (score1, _) = @fuzzyscore.vscode_fuzzy_score_simple("abc", "abc", true) // 69 - all consecutive
  let (score2, _) = @fuzzyscore.vscode_fuzzy_score_simple("abc", "aXbXc", true) // 63 - with gaps

  // Word boundaries are highly valued
  let (score3, _) = @fuzzyscore.vscode_fuzzy_score_simple("fb", "foo_bar", true) // 39 - separator bonus
  let (score4, _) = @fuzzyscore.vscode_fuzzy_score_simple(
    "tF", "testFile", true,
  ) // 47 - camelCase bonus

  inspect(score1 > score2, content="true")
  inspect(score3 > 32, content="true") // Better than random positions
  inspect(score4 > 32, content="true")
}

#Performance Characteristics

• Time Complexity: O(|pattern| × |word|)
• Space Complexity: O(|word|) for DP arrays + O(|pattern| × |word|) for path reconstruction
• Early Exit: Optimized for cases where no good match is possible
• UTF-16 Optimized: Efficient character code operations

///|
test "performance_test" {
  let long_text = "this_is_a_very_long_file_name_with_many_underscores_and_words_to_test_performance"

  // Algorithm handles long strings efficiently
  let (score, positions) = @fuzzyscore.vscode_fuzzy_score_simple(
    "test", long_text, true,
  )
  inspect(score > 0, content="true")
  inspect(positions.length() == 4, content="true")
}

#Unicode Support

///|
test "unicode_support" {
  // Emoji support
  let (score1, _pos1) = @fuzzyscore.vscode_fuzzy_score_simple(
    "🌙", "moon🌙bit", true,
  )
  inspect(score1 > 0, content="true")

  // CJK characters  
  let (score2, _pos2) = @fuzzyscore.vscode_fuzzy_score_simple(
    "月", "moon月bit", true,
  )
  inspect(score2 > 0, content="true")

  // Accented characters
  let (score3, _pos3) = @fuzzyscore.vscode_fuzzy_score_simple(
    "café", "café_file", true,
  )
  inspect(score3 > 0, content="true")
}

#Real-World Usage

#File Search

///|
test "file_search_example" {
  let files = [
    "src/main.mbt", "test/main_test.mbt", "docs/README.md", "package.json",
  ]

  // Search for "main"
  let results = files
    .map(fn(file) {
      let (score, positions) = @fuzzyscore.vscode_fuzzy_score_simple(
        "main", file, true,
      )
      (file, score, positions)
    })
    .filter(fn(result) { result.1 > 0 })

  // Results are automatically ranked by score
  inspect(results.length() == 2, content="false")
}

#Command Palette

///|
test "command_palette_example" {
  let commands = [
    "File: Open File", "Edit: Find and Replace", "View: Toggle Terminal", "Git: Commit All",
  ]

  // Search for "file"
  let query = "file"
  let matches = commands
    .map(fn(cmd) {
      let (score, positions) = @fuzzyscore.vscode_fuzzy_score_simple(
        query,
        cmd.to_lower(),
        true,
      )
      (cmd, score, positions)
    })
    .filter(fn(result) { result.1 > 0 })

  inspect(matches.length() > 0, content="true")
}

#Algorithm Comparison

#Contributing

1. Preserve Fidelity: Any changes must maintain identical scoring behavior
2. Add Tests: Include comprehensive test cases with expected scores
3. Document Examples: Use test{...} blocks for type-checked examples
4. Performance: Maintain O(n×m) complexity characteristics

#License

#References

• VS Code Source - Original TypeScript implementation
• MoonBit Documentation - Language reference
• Algorithm Paper - Background on fuzzy string matching