Allow user to only select column_types that make sense in the current context

The context being either multi-split or two-split. There's no use
in selecting a Transaction ID column in two-split mode for example.
Similarly none of the 'Transfer xzy' types will be used in
multi-split mode.

src/import-export/csv-imp/assistant-csv-trans-import.cpp

@@ -229,25 +229,21 @@ csv_import_trans_load_settings (CsvImportTrans *info)
     }
 
     // Set start row
-    info->parse_data->skip_start_lines = info->settings_data.header_rows;
     GtkAdjustment *adj = gtk_spin_button_get_adjustment (GTK_SPIN_BUTTON(info->start_row_spin));
     gtk_adjustment_set_upper (adj, info->parse_data->parsed_lines.size());
     gtk_spin_button_set_value (GTK_SPIN_BUTTON(info->start_row_spin),
             info->settings_data.header_rows);
 
     // Set end row
-    info->parse_data->skip_end_lines = info->settings_data.footer_rows;
     adj = gtk_spin_button_get_adjustment (GTK_SPIN_BUTTON(info->end_row_spin));
     gtk_adjustment_set_upper (adj, info->parse_data->parsed_lines.size());
     gtk_spin_button_set_value (GTK_SPIN_BUTTON(info->end_row_spin),
             info->settings_data.footer_rows);
 
     // Set Alternate rows
-    info->parse_data->skip_alt_lines = info->settings_data.skip_alt_rows;
     gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON(info->skip_rows), info->settings_data.skip_alt_rows);
 
     // Set Multi-split indicator
-    info->parse_data->multi_split = info->settings_data.multi_split;
     gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON(info->multi_split_cbutton), info->settings_data.multi_split);
 
     // Set Import Format
@@ -818,7 +814,9 @@ void csv_import_trans_multisplit_cb (GtkWidget *checkbox, gpointer user_data)
     CsvImportTrans *info = (CsvImportTrans*) user_data;
 
     /* Set the skip_alt_lines variable */
-    info->parse_data->multi_split = gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON(checkbox));
+    auto multi_split = gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON(checkbox));
+    info->parse_data->set_multi_split (multi_split);
+    gnc_csv_preview_update_assist (info);
 }
 
 
@@ -1289,7 +1287,7 @@ static void column_type_changed (GtkCellRenderer* renderer, gchar* path,
     g_object_get (renderer, "model", &model, "text-column", &textColumn, NULL);
     gtk_tree_model_get (model, new_text_iter,
             textColumn, &new_text,
-            1, &new_col_type,            // Invisible column in the combobox' model containing the colum type
+            1, &new_col_type,            // Invisible column in the combobox' model containing the column type
             -1);
 
     /* Get an iterator for the first (and only) row. */
@@ -1615,9 +1613,7 @@ bool get_list_of_accounts (CsvImportTrans* info, GtkTreeModel *store)
 }
 
 
-/* Loads the preview's data into its data treeview. not_empty is true
- * when the data treeview already contains data, false otherwise
- * (e.g. the first time this function is called on a preview).
+/* Loads the preview's data into its data treeview.
  *
  * @param info The data being previewed
  */
@@ -1717,11 +1713,17 @@ static void gnc_csv_preview_update_assist (CsvImportTrans* info)
     auto combostore = gtk_list_store_new (2, G_TYPE_STRING, G_TYPE_INT);
     for (auto col_type : gnc_csv_col_type_strs)
     {
-        GtkTreeIter iter;
-        gtk_list_store_append (combostore, &iter);
-        gtk_list_store_set (combostore, &iter, 0, _(col_type.second),
-                                               1, static_cast<int>(col_type.first),
-                                               -1);
+        /* Only add column types that make sense in
+         * the chosen import mode (multi-split vs two-split).
+         */
+        if (sanitize_trans_prop(col_type.first, info->parse_data->multi_split) == col_type.first)
+        {
+            GtkTreeIter iter;
+            gtk_list_store_append (combostore, &iter);
+            gtk_list_store_set (combostore, &iter, 0, _(col_type.second),
+                                                   1, static_cast<int>(col_type.first),
+                                                   -1);
+        }
     }
 
     /* Insert columns into the data and column type treeviews. */

src/import-export/csv-imp/gnc-csv-trans-settings.cpp

@@ -57,6 +57,7 @@ const std::string no_settings{N_("No Settings")};
 #define CSV_COL_TYPES    "ColumnTypes"
 #define CSV_COL_WIDTHS   "ColumnWidths"
 
+G_GNUC_UNUSED static QofLogModule log_module = GNC_MOD_IMPORT;
 
 /**************************************************
  * find
@@ -200,7 +201,16 @@ CsvTransSettings::load (const std::string& group)
         auto col_types_it = std::find_if (gnc_csv_col_type_strs.begin(),
                 gnc_csv_col_type_strs.end(), test_prop_type_str (col_types_str[i]));
         if (col_types_it != gnc_csv_col_type_strs.end())
-            column_types.push_back(col_types_it->first);
+        {
+            /* Found a valid column type. Now check whether it is allowed
+             * in the selected mode (two-split vs multi-split) */
+            auto prop = sanitize_trans_prop (col_types_it->first, multi_split);
+                column_types.push_back(prop);
+            if (prop != col_types_it->first)
+                PWARN("Found column type '%s', but this is blacklisted when multi-split mode is %s. "
+                        "Inserting column type 'NONE' instead'.",
+                        col_types_it->second, multi_split ? "enabled" : "disabled");
+        }
     }
     if (col_types_str)
         g_strfreev (col_types_str);

src/import-export/csv-imp/gnc-trans-props.cpp

@@ -70,6 +70,29 @@ std::map<GncTransPropType, const char*> gnc_csv_col_type_strs = {
         { GncTransPropType::TREC_DATE, N_("Transfer Reconcile Date") }
 };
 
+/* Below two vectors define which properties the user *can't* select
+ * in two-split or multi-split mode (mostly because they don't make
+ * sense in that context).
+ */
+std::vector<GncTransPropType> twosplit_blacklist = {
+        GncTransPropType::UNIQUE_ID };
+std::vector<GncTransPropType> multisplit_blacklist = {
+        GncTransPropType::TACTION,
+        GncTransPropType::TACCOUNT,
+        GncTransPropType::TMEMO,
+        GncTransPropType::TREC_STATE,
+        GncTransPropType::TREC_DATE
+};
+
+GncTransPropType sanitize_trans_prop (GncTransPropType prop, bool multi_split)
+{
+    auto bl = multi_split ? multisplit_blacklist : twosplit_blacklist;
+    if (std::find(bl.begin(), bl.end(), prop) == bl.end())
+        return prop;
+    else
+        return GncTransPropType::NONE;
+}
+
 /* Regular expressions used to parse dates per date format */
 const char* date_regex[] = {
                              "(?:"                                   // either y-m-d

src/import-export/csv-imp/gnc-trans-props.hpp

@@ -79,7 +79,6 @@ enum class GncTransPropType {
  *  changes to enum class GncTransPropType ! */
 extern std::map<GncTransPropType, const char*> gnc_csv_col_type_strs;
 
-
 /** Functor to check if the above map has an element of which
  *  the value equals name. To be used with std::find_if.
  */
@@ -94,6 +93,15 @@ private:
     const char *m_name;
 };
 
+/** Some properties only make sense in a multi-split context.
+ *  Inversely some also only make sense in a two-split context.
+ *  Below function will test a property against a given context
+ *  and will return that property if it makes sense
+ *  or GncTransPropType::NONE if not.
+ */
+GncTransPropType sanitize_trans_prop (GncTransPropType prop, bool multi_split);
+
+
 time64 parse_date (const std::string &date_str, int format);
 
 struct GncPreTrans

src/import-export/csv-imp/gnc-tx-import.cpp

@@ -57,7 +57,6 @@ const gchar* currency_format_user[] = {N_("Locale"),
                                       };
 
 
-
 /** Constructor for GncTxImport.
  * @return Pointer to a new GncCSvParseData
  */
@@ -132,6 +131,24 @@ void GncTxImport::convert_encoding (const std::string& encoding)
         tokenizer->encoding(encoding);
 }
 
+/** Toggles the multi-split state of the importer and will subsequently
+ *  sanitize the column_types list. All types that don't make sense
+ *  in the new state are reset to type GncTransPropType::NONE.
+ * @param multi_split_val Boolean value with desired state (multi-split
+ * vs two-split).
+ */
+void GncTxImport::set_multi_split (bool multi_split_val)
+{
+    multi_split = multi_split_val;
+    for (auto col_it = column_types.begin(); col_it != column_types.end();
+            col_it++)
+    {
+        auto san_prop = sanitize_trans_prop (*col_it, multi_split);
+        if (san_prop != *col_it)
+            *col_it = san_prop;
+    }
+}
+
 /** Loads a file into a GncTxImport. This is the first function
  * that must be called after creating a new GncTxImport. As long as
  * this function didn't run successfully, the importer can't proceed.

src/import-export/csv-imp/gnc-tx-import.hpp

@@ -98,6 +98,8 @@ public:
     void load_file (const std::string& filename);
     void convert_encoding (const std::string& encoding);
 
+    void set_multi_split (bool multi_split_val);
+
     void tokenize (bool guessColTypes);
 
     /** This function will attempt to convert all tokenized lines into