From c577716b3178d80ccabe6ed4aca90d81b60b2693 Mon Sep 17 00:00:00 2001
From: Matthew Kenigsberg <matthew@floxdev.com>
Date: Mon, 21 Aug 2023 14:15:38 -0600
Subject: [PATCH] feat: prep work for fuzzy matching

---
 include/flox/pkgdb/read.hh |  9 +++++
 src/pkgdb/query-builder.cc |  5 +++
 src/pkgdb/read.cc          | 43 ++++++++++++++++++++++++
 tests/read.cc              | 67 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 124 insertions(+)
 create mode 100644 tests/read.cc

diff --git a/include/flox/pkgdb/read.hh b/include/flox/pkgdb/read.hh
index a4503167..4713e50b 100644
--- a/include/flox/pkgdb/read.hh
+++ b/include/flox/pkgdb/read.hh
@@ -23,6 +23,7 @@
 #include "flox/core/exceptions.hh"
 #include "flox/core/types.hh"
 #include "flox/core/command.hh"
+#include "flox/package.hh"
 
 
 /* -------------------------------------------------------------------------- */
@@ -251,6 +252,14 @@ class PkgDbReadOnly {
 
 };  /* End class `PkgDbReadOnly' */
 
+/**
+ * Calculate a distance that can be used to order packages by how close they
+ * are to a match string.
+ * @param Package The Package to 
+ * @param match String to look for in Package's fields.
+ * @return Distance between pkg and match.
+*/
+std::optional<size_t> distanceFromMatch( Package & pkg, std::string match );
 
 /* -------------------------------------------------------------------------- */
 
diff --git a/src/pkgdb/query-builder.cc b/src/pkgdb/query-builder.cc
index 3c943227..ddfe68d9 100644
--- a/src/pkgdb/query-builder.cc
+++ b/src/pkgdb/query-builder.cc
@@ -37,6 +37,11 @@ buildPkgQuery( PkgQueryArgs && params )
     {
       q.where( column( "pname" ) == ":pname" );
     }
+  
+  if ( params.match.has_value() && !params.match->empty() )
+    {
+      q.where( "( name LIKE '%:match%' ) OR ( description LIKE '%:match%' )" );
+    }
 
   if ( params.version.has_value() )
     {
diff --git a/src/pkgdb/read.cc b/src/pkgdb/read.cc
index 672275ba..75c4afda 100644
--- a/src/pkgdb/read.cc
+++ b/src/pkgdb/read.cc
@@ -319,6 +319,49 @@ PkgDbReadOnly::getDescendantAttrSets( row_id root )
 }
 
 
+/* -------------------------------------------------------------------------- */
+
+  std::optional<size_t>
+distanceFromMatch( Package & pkg, std::string match )
+{
+  if ( match.empty() ) { return std::nullopt; }
+
+  std::string pname = pkg.getPname();
+  // TODO match on attrName. That's not currently possible because attrName is
+  // meaningful for flakes, but for catalogs, only the attrName of parent is
+  // meaningful (attrName is a version string).
+
+  // Don't give description any weight if pname matches exactly. It's not
+  // especially meaningful if a description mentions its own name.
+  if ( pname == match )
+    {
+      // pname matches exactly
+      return 0;
+    }
+
+  bool pnameMatches = (pname.find(match) != std::string::npos);
+  auto description = pkg.getDescription();
+  bool descriptionMatches = (description.has_value() && description->find(match) != std::string::npos);
+
+  if ( pnameMatches ) {
+    if ( descriptionMatches )
+      {
+        // pname and description match
+        return 1;
+      }
+    // only pname matches
+    return 2;
+  }
+
+  if ( descriptionMatches )
+    {
+      // only description matches
+      return 3;
+    }
+  // nothing matches
+  return 4;
+}
+
 /* -------------------------------------------------------------------------- */
 
   }  /* End Namespace `flox::pkgdb' */
diff --git a/tests/read.cc b/tests/read.cc
new file mode 100644
index 00000000..d1263de8
--- /dev/null
+++ b/tests/read.cc
@@ -0,0 +1,67 @@
+/* ========================================================================== *
+ *
+ * @file read.cc
+ *
+ * @brief Tests for `read.cc`.
+ *
+ *
+ * -------------------------------------------------------------------------- */
+
+#include <assert.h>
+
+#include "flox/pkgdb/read.hh"
+#include "test.hh"
+#include "flox/flake-package.hh"
+
+/* -------------------------------------------------------------------------- */
+
+/**
+ * Test ability to add `AttrSet` rows.
+ * This test should run before all others since it essentially expects
+ * `AttrSets` to be empty.
+ */
+  bool
+test_distanceFromMatch()
+{
+  // auto pkg = flox::FlakePackage();
+  // flox::pkgdb::distanceFromMatch(pkg, "match");
+  return true;
+}
+
+/* ========================================================================== */
+
+  int
+main( int argc, char * argv[] )
+{
+  int ec = EXIT_SUCCESS;
+# define RUN_TEST( ... )  _RUN_TEST( ec, __VA_ARGS__ )
+
+/* -------------------------------------------------------------------------- */
+
+  nix::Verbosity verbosity;
+  if ( ( 1 < argc ) && ( std::string_view( argv[1] ) == "-v" ) )
+    {
+      verbosity = nix::lvlDebug;
+    }
+  else
+    {
+      verbosity = nix::lvlWarn;
+    }
+
+/* -------------------------------------------------------------------------- */
+
+  {
+    RUN_TEST( distanceFromMatch );
+  }
+
+/* -------------------------------------------------------------------------- */
+
+  return ec;
+}
+
+
+/* -------------------------------------------------------------------------- *
+ *
+ *
+ *
+ * ========================================================================== */