Implement CLI suggestions in case of errors thanks to Levenshtein dis…

…tance to all option names computation

src/engine/include/commandlineoptionsparser.hpp

@@ -15,6 +15,7 @@
 #include "cct_vector.hpp"
 #include "commandlineoption.hpp"
 #include "durationstring.hpp"
+#include "levenshteindistancecalculator.hpp"
 #include "stringhelpers.hpp"
 
 namespace cct {
@@ -53,20 +54,26 @@ class CommandLineOptionsParser {
   }
 
   OptValueType parse(std::span<const char*> groupedArguments) {
-    std::unordered_map<CommandLineOption, CallbackType> callbacks;
-    callbacks.reserve(_opts.size());
+    _callbacks.clear();
+    _callbacks.reserve(_opts.size());
     OptValueType data;
     for (const auto& [cmdLineOption, prop] : _opts) {
-      callbacks[cmdLineOption] = registerCallback(cmdLineOption, prop, data);
+      _callbacks[cmdLineOption] = registerCallback(cmdLineOption, prop, data);
     }
     const int nbArgs = static_cast<int>(groupedArguments.size());
     for (int argPos = 0; argPos < nbArgs; ++argPos) {
       std::string_view argStr(groupedArguments[argPos]);
       if (std::ranges::none_of(_opts, [argStr](const auto& opt) { return opt.first.matches(argStr); })) {
-        throw invalid_argument("Unrecognized command-line option {}", argStr);
+        const auto [possibleOptionIdx, minDistance] = minLevenshteinDistanceOpt(argStr);
+
+        if (minDistance <= 2) {
+          throw invalid_argument("Unrecognized command-line option '{}' - did you mean '{}'?", argStr,
+                                 _opts[possibleOptionIdx].first.fullName());
+        }
+        throw invalid_argument("Unrecognized command-line option '{}'", argStr);
       }
 
-      for (auto& callback : callbacks) {
+      for (auto& callback : _callbacks) {
         callback.second(argPos, groupedArguments);
       }
     }
@@ -250,7 +257,17 @@ class CommandLineOptionsParser {
     return lenFirstRows + 3;
   }
 
+  std::pair<int, int> minLevenshteinDistanceOpt(std::string_view argStr) const {
+    vector<int> minDistancesToFullNameOptions(_opts.size());
+    LevenshteinDistanceCalculator calc;
+    std::ranges::transform(_opts, minDistancesToFullNameOptions.begin(),
+                           [argStr, &calc](const auto opt) { return calc(opt.first.fullName(), argStr); });
+    auto optIt = std::ranges::min_element(minDistancesToFullNameOptions);
+    return {optIt - minDistancesToFullNameOptions.begin(), *optIt};
+  }
+
   vector<CommandLineOptionWithValue> _opts;
+  std::unordered_map<CommandLineOption, CallbackType> _callbacks;
 };
 
 }  // namespace cct

src/engine/src/coincentercommands.cpp

@@ -33,7 +33,6 @@ vector<CoincenterCmdLineOptions> CoincenterCommands::ParseOptions(int argc, cons
   CoincenterCmdLineOptions globalOptions;
 
   // Support for command line multiple commands. Only full name flags are supported for multi command line commands.
-  // Note: maybe it better to just decommission short hand flags.
   while (parserIt.hasNext()) {
     std::span<const char *> groupedArguments = parserIt.next();
 

src/tech/CMakeLists.txt

@@ -45,6 +45,14 @@ add_unit_test(
     CCT_DISABLE_SPDLOG
 )
 
+add_unit_test(
+    levenshteindistancecalculator_test
+    src/levenshteindistancecalculator.cpp
+    test/levenshteindistancecalculator_test.cpp
+    DEFINITIONS
+    CCT_DISABLE_SPDLOG
+)
+
 add_unit_test(
     flatkeyvaluestring_test
     test/flatkeyvaluestring_test.cpp

src/tech/include/levenshteindistancecalculator.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <string_view>
+
+#include "cct_vector.hpp"
+
+namespace cct {
+class LevenshteinDistanceCalculator {
+ public:
+  LevenshteinDistanceCalculator() noexcept = default;
+
+  /// Computes the levenshtein distance between both input words.
+  /// Complexity is in 'word1.length() * word2.length()' in time,
+  /// min(word1.length(), word2.length()) in space.
+  int operator()(std::string_view word1, std::string_view word2);
+
+ private:
+  // This is only for caching purposes, so that repeated calls to distance calculation do not allocate memory each time
+  vector<int> _minDistance;
+};
+}  // namespace cct

src/tech/include/stringhelpers.hpp

@@ -1,9 +1,9 @@
 #pragma once
 
-#include <string.h>
-
 #include <charconv>
 #include <concepts>
+#include <cstring>
+#include <string_view>
 
 #include "cct_config.hpp"
 #include "cct_exception.hpp"
@@ -14,7 +14,7 @@ namespace cct {
 
 namespace details {
 template <class SizeType>
-inline void ToChars(char *first, SizeType s, std::integral auto i) {
+void ToChars(char *first, SizeType s, std::integral auto i) {
   if (auto [ptr, errc] = std::to_chars(first, first + s, i); CCT_UNLIKELY(errc != std::errc())) {
     throw exception("Unable to decode integral into string");
   }

src/tech/src/levenshteindistancecalculator.cpp

@@ -0,0 +1,40 @@
+#include "levenshteindistancecalculator.hpp"
+
+#include <algorithm>
+#include <numeric>
+
+namespace cct {
+int LevenshteinDistanceCalculator::operator()(std::string_view word1, std::string_view word2) {
+  if (word1.size() > word2.size()) {
+    std::swap(word1, word2);
+  }
+
+  const int l1 = static_cast<int>(word1.size()) + 1;
+  if (l1 > static_cast<int>(_minDistance.size())) {
+    // Favor insert instead of resize to ensure reallocations are exponential
+    _minDistance.insert(_minDistance.end(), l1 - _minDistance.size(), 0);
+  }
+
+  std::iota(_minDistance.begin(), _minDistance.end(), 0);
+
+  const int l2 = static_cast<int>(word2.size()) + 1;
+  for (int word2Pos = 1; word2Pos < l2; ++word2Pos) {
+    int previousDiagonal = _minDistance[0];
+
+    ++_minDistance[0];
+
+    for (int word1Pos = 1; word1Pos < l1; ++word1Pos) {
+      const int previousDiagonalSave = _minDistance[word1Pos];
+      if (word1[word1Pos - 1] == word2[word2Pos - 1]) {
+        _minDistance[word1Pos] = previousDiagonal;
+      } else {
+        _minDistance[word1Pos] =
+            std::min(std::min(_minDistance[word1Pos - 1], _minDistance[word1Pos]), previousDiagonal) + 1;
+      }
+      previousDiagonal = previousDiagonalSave;
+    }
+  }
+
+  return _minDistance[l1 - 1];
+}
+}  // namespace cct

src/tech/test/levenshteindistancecalculator_test.cpp

@@ -0,0 +1,50 @@
+#include "levenshteindistancecalculator.hpp"
+
+#include <gtest/gtest.h>
+
+namespace cct {
+
+TEST(LevenshteinDistanceCalculator, CornerCases) {
+  LevenshteinDistanceCalculator calc;
+
+  EXPECT_EQ(calc("", "tata"), 4);
+  EXPECT_EQ(calc("tutu", ""), 4);
+}
+
+TEST(LevenshteinDistanceCalculator, SimpleCases) {
+  LevenshteinDistanceCalculator calc;
+
+  EXPECT_EQ(calc("horse", "ros"), 3);
+  EXPECT_EQ(calc("intention", "execution"), 5);
+  EXPECT_EQ(calc("niche", "chien"), 4);
+}
+
+TEST(LevenshteinDistanceCalculator, TypicalCases) {
+  LevenshteinDistanceCalculator calc;
+
+  EXPECT_EQ(calc("--orderbook", "orderbook"), 2);
+  EXPECT_EQ(calc("--timeout-match", "--timeot-match"), 1);
+  EXPECT_EQ(calc("--no-multi-trade", "--no-mukti-trade"), 1);
+  EXPECT_EQ(calc("--updt-price", "--update-price"), 2);
+}
+
+TEST(LevenshteinDistanceCalculator, ExtremeCases) {
+  LevenshteinDistanceCalculator calc;
+
+  EXPECT_EQ(
+      calc(
+          "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the "
+          "industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and "
+          "scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into "
+          "electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release "
+          "of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software "
+          "like Aldus PageMaker including versions of Lorem Ipsum.",
+          "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the "
+          "industrj's standard dummytext ever since the 1500s, when an unknown printer took a galley of type and "
+          "scrambled iT to make a type specimen book. I has survived not only five centuroes, but also the leap into "
+          "electronic typesetting, i remaining essentially unchanged. It was popularised in the 1960s with the release "
+          "of Letraset sheets; containing Lorem Ipsum passages, and more recently with desktogp publishing software "
+          "like Aldus PageMaker including versions of Lorem Ipsum."),
+      9);
+}
+}  // namespace cct