Added de-duplication for environment list print

Previously, `dnf5 environment list` would print duplicate environment
with the same id and name. It would be confusing for the user to see
duplicate environment names. This patch introduces de-duplication for
the environment list print feature to merge duplicate environment
entries. The original order of the environments is preserved by
assigning an index value to each environment entry.

Fixes: rpm-software-management#1502

libdnf5-cli/output/environmentlist.cpp

@@ -23,13 +23,42 @@ along with libdnf.  If not, see <https://www.gnu.org/licenses/>.
 
 #include <libsmartcols/libsmartcols.h>
 
+#include <map>
+
 namespace libdnf5::cli::output {
 
 namespace {
 
 // environment list table columns
 enum { COL_ENVIRONMENT_ID, COL_ENVIRONMENT_NAME, COL_INSTALLED };
 
+struct EnvironmentListEntry {
+    std::string environmentid;
+    std::string name;
+
+    // Actual comparison operator isn't important as we finally
+    // sort the table by the inserted order.
+    std::strong_ordering operator<=>(const EnvironmentListEntry & other) const {
+        int result = std::strcmp(environmentid.c_str(), other.environmentid.c_str());
+        if (result < 0) {
+            return std::strong_ordering::less;
+        } else if (result > 0) {
+            return std::strong_ordering::greater;
+        }
+        result = std::strcmp(name.c_str(), other.name.c_str());
+        if (result < 0) {
+            return std::strong_ordering::less;
+        } else if (result > 0) {
+            return std::strong_ordering::greater;
+        }
+        return std::strong_ordering::equal;
+    }
+};
+
+struct IndexAndInstalled {
+    int index;
+    bool installed;
+};
 
 struct libscols_table * create_environmentlist_table() {
     struct libscols_table * table = scols_new_table();
@@ -61,12 +90,31 @@ void add_line_into_environmentlist_table(
 
 void print_environmentlist_table(std::vector<std::unique_ptr<IEnvironment>> & environment_list) {
     struct libscols_table * table = create_environmentlist_table();
-    for (auto & environment : environment_list) {
-        add_line_into_environmentlist_table(
-            table,
-            environment->get_environmentid().c_str(),
-            environment->get_name().c_str(),
-            environment->get_installed());
+
+    // de-duplicate environments.
+    // If any of the environments is installed, the entry is considered installed.
+    // To keep the order of environments, we use a map and assign an index to each environment.
+    std::map<EnvironmentListEntry, IndexAndInstalled> environments;
+    int i = 0;
+    for (const auto & environment : environment_list) {
+        EnvironmentListEntry entry{environment->get_environmentid(), environment->get_name()};
+        auto it = environments.find(entry);
+        if (it == environments.end()) {
+            environments[entry] = IndexAndInstalled{.index = i, .installed = environment->get_installed()};
+            i++;
+        } else {
+            it->second.installed = it->second.installed || environment->get_installed();
+        }
+    }
+
+    std::vector<std::pair<EnvironmentListEntry, bool>> environments_sorted;
+    environments_sorted.resize(environments.size());
+    for (const auto & [entry, index_and_installed] : environments) {
+        environments_sorted[index_and_installed.index] = {entry, index_and_installed.installed};
+    }
+
+    for (auto & [entry, installed] : environments_sorted) {
+        add_line_into_environmentlist_table(table, entry.environmentid.c_str(), entry.name.c_str(), installed);
     }
     auto cl = scols_table_get_column(table, COL_ENVIRONMENT_ID);
     scols_sort_table(table, cl);