From 6bbb4d997102169747b7bc80827b4978c3ddf764 Mon Sep 17 00:00:00 2001
From: shenleban tongying <shenlebantongying@gmail.com>
Date: Sun, 30 Apr 2023 00:31:49 -0400
Subject: [PATCH] feat(metadata): abstract metadata loader

---
 goldendict.pro                |  2 ++
 src/metadata.cc               | 33 +++++++++++++++++++++++++++++++++
 src/metadata.hh               | 19 +++++++++++++++++++
 src/ui/groups_widgets.cc      | 33 +++++++++------------------------
 website/docs/manage_groups.md |  6 +++---
 5 files changed, 66 insertions(+), 27 deletions(-)
 create mode 100644 src/metadata.cc
 create mode 100644 src/metadata.hh

diff --git a/goldendict.pro b/goldendict.pro
index 8f91b9f3..65d9c010 100644
--- a/goldendict.pro
+++ b/goldendict.pro
@@ -363,6 +363,7 @@ HEADERS += \
     src/keyboardstate.hh \
     src/langcoder.hh \
     src/language.hh \
+    src/metadata.hh \
     src/multimediaaudioplayer.hh \
     src/parsecmdline.hh \
     src/resourceschemehandler.hh \
@@ -485,6 +486,7 @@ SOURCES += \
     src/langcoder.cc \
     src/language.cc \
     src/main.cc \
+    src/metadata.cc \
     src/multimediaaudioplayer.cc \
     src/parsecmdline.cc \
     src/resourceschemehandler.cc \
diff --git a/src/metadata.cc b/src/metadata.cc
new file mode 100644
index 00000000..c9060c81
--- /dev/null
+++ b/src/metadata.cc
@@ -0,0 +1,33 @@
+#include "metadata.hh"
+#include "toml.hpp"
+#include <QDebug>
+
+std::optional< Metadata::result > Metadata::load( std::string_view filepath )
+{
+  // by default, the optional will be initialized as std::nullopt
+  Metadata::result result{};
+  toml::table tbl;
+
+  try {
+    tbl = toml::parse_file( filepath );
+  }
+  catch ( toml::parse_error & e ) {
+    qWarning()<< "Failed to load metadata: " << QString::fromUtf8(filepath.data(),filepath.size())
+              << "Reason:" << e.what();
+
+    return std::nullopt;
+  }
+
+  if ( toml::array * categories = tbl.get_as< toml::array >( "categories" ) ) {
+    // result.categories is an optional, it exists, but the vector does not, so we have to create one here
+    result.categories.emplace();
+    for ( auto & el : *categories ) {
+      if ( el.is_string() ) {
+        result.categories.value().emplace_back( std::move( *el.value_exact< std::string >() ) );
+      }
+    }
+  }
+
+  result.name = tbl[ "metadata" ][ "name" ].value_exact< std::string >();
+  return result;
+}
diff --git a/src/metadata.hh b/src/metadata.hh
new file mode 100644
index 00000000..5605dfe9
--- /dev/null
+++ b/src/metadata.hh
@@ -0,0 +1,19 @@
+#pragma once
+#include <QStringView>
+#include <optional>
+#include <vector>
+
+namespace Metadata {
+
+/**
+ * Represent the metadata.toml beside the dictionary files
+ */
+struct result
+{
+  std::optional< std::vector< std::string > > categories;
+  std::optional< std::string > name;
+};
+
+[[nodiscard]] std::optional< Metadata::result > load( std::string_view filepath );
+
+} // namespace Metadata
diff --git a/src/ui/groups_widgets.cc b/src/ui/groups_widgets.cc
index f71f2af5..c6b03fcc 100644
--- a/src/ui/groups_widgets.cc
+++ b/src/ui/groups_widgets.cc
@@ -7,7 +7,7 @@
 #include "config.hh"
 #include "langcoder.hh"
 #include "language.hh"
-#include "toml.hpp"
+#include "metadata.hh"
 
 //#include "initializing.hh"
 
@@ -15,7 +15,6 @@
 #include <QDir>
 #include <QIcon>
 #include <QMap>
-#include <QMultiMap>
 #include <QVector>
 #include <QFileInfo>
 #include <QFileDialog>
@@ -904,30 +903,16 @@ void DictGroupsWidget::groupsByMetadata()
       continue;
 
     auto filePath = Utils::Path::combine( baseDir, "metadata.toml" );
-    if ( !QFile::exists( filePath ) ) {
-      qDebug() << "the dictionary folder:" << baseDir << " contain no metadata.toml";
-      continue;
-    }
-    try {
-      auto config = toml::parse_file( filePath.toStdString() );
 
-      toml::array * categories = config.get_as< toml::array >( "category" );
-      if ( !categories ) {
-        continue;
-      }
-      categories->for_each( [ &groupToDicts, &dict ]( auto && elem ) {
-        if ( elem.is_string() ) {
-          auto group = QString::fromStdString( elem.as_string()->get() ).trimmed();
-
-          if ( group.isEmpty() )
-            return;
-
-          groupToDicts.insert( group, dict );
+    auto dictMetaData = Metadata::load( filePath.toStdString() );
+    if ( dictMetaData && dictMetaData->categories ) {
+      for ( const auto & category : dictMetaData->categories.value() ) {
+        auto group = QString::fromStdString( category ).trimmed();
+        if ( group.isEmpty() ) {
+          continue;
         }
-      } );
-    }
-    catch ( toml::parse_error & e ) {
-      qWarning() << "can not open the metadata.toml" << e.what();
+        groupToDicts.insert( group, dict );
+      }
     }
   }
 
diff --git a/website/docs/manage_groups.md b/website/docs/manage_groups.md
index c7d538a4..28e6614c 100644
--- a/website/docs/manage_groups.md
+++ b/website/docs/manage_groups.md
@@ -80,7 +80,7 @@ The `metadata.toml` should be placed beside dictionary files. One `metadata.toml
 The metadata file uses [TOML](https://toml.io) format.
 
 ```toml
-category = [ "English", "Russian", "Chinese" ]
+categories = [ "English", "Russian", "Chinese" ]
 
 # the following fields have not supported yet.
 [metadata]
@@ -108,12 +108,12 @@ For example,
 
 The content of the metadata `(A)` is
 ```toml
-category = ["en-zh", "汉英词典"]
+categories = ["en-zh", "汉英词典"]
 ```
 
 The content of the metadata `(B)` is
 ```toml
-category = ["图片词典", "en-zh", "汉英词典"]
+categories = ["图片词典", "en-zh", "汉英词典"]
 ```
 
 The structure above will be auto grouped into three groups: