Add an utility to list all installed packages

1 files changed, 74 insertions, 0 deletions

diff --git a/src/command.cpp b/src/command.cpp
new file mode 100644
index 0000000..4066c23
--- /dev/null
+++ b/src/command.cpp
@@ -0,0 +1,74 @@
+#include "command.h"
+#include <cassert>
+
+namespace katja
+{
+    void list::execute() const
+    {
+        for (const auto& package : katja::read_package_database())
+        {
+            std::cout << package.second.name()
+                << " " << package.second.version()
+                << " (" << package.second.tag() << ")"
+                << std::endl;
+        }
+    }
+
+    void help::execute() const
+    {
+        std::cout << "Usage:\n"
+            "\tkatja {info|help} [OPTIONS]\n\n";
+    }
+
+    command_exception::command_exception(const command_exception_t exception_type,
+        std::vector<std::string> failed_arguments) noexcept
+        : m_exception_type(exception_type), m_failed_arguments(failed_arguments)
+    {
+    }
+
+    const char *command_exception::what() const noexcept
+    {
+        switch (m_exception_type)
+        {
+            case command_exception_t::no_command:
+                return "No command specified.";
+            case command_exception_t::too_many_arguments:
+                return "Too many arguments given.";
+            case command_exception_t::unknown_command:
+                return "Unknown command.";
+        }
+        assert(false);
+    }
+
+    const std::vector<std::string>& command_exception::failed_arguments() const noexcept
+    {
+        return m_failed_arguments;
+    }
+
+    std::unique_ptr<command> parse_command_line(int argc, char **argv)
+    {
+        if (argc > 2)
+        {
+            std::vector<std::string> failed_arguments;
+
+            for (std::size_t i = 2; i < argc; ++i)
+            {
+                failed_arguments.push_back(argv[i]);
+            }
+            throw command_exception(command_exception_t::unknown_command);
+        }
+        else if (argc < 2)
+        {
+            throw command_exception(command_exception_t::no_command);
+        }
+        if (strcmp(argv[1], "list") == 0)
+        {
+            return std::make_unique<list>();
+        }
+        else if (strcmp(argv[1], "help") == 0)
+        {
+            return std::make_unique<help>();
+        }
+        throw command_exception(command_exception_t::unknown_command, { argv[1] });
+    }
+}