Merge branch 'master' into debian

1 files changed, 127 insertions, 0 deletions

diff --git a/src/database/table.hpp b/src/database/table.hpp
new file mode 100644
index 0000000..411ac6a
--- /dev/null
+++ b/src/database/table.hpp
@@ -0,0 +1,127 @@
+#pragma once
+
+#include <database/select_query.hpp>
+#include <database/type_to_sql.hpp>
+#include <logger/logger.hpp>
+#include <database/row.hpp>
+
+#include <algorithm>
+#include <string>
+#include <set>
+
+using namespace std::string_literals;
+
+std::set<std::string> get_all_columns_from_table(sqlite3* db, const std::string& table_name);
+
+template <typename ColumnType>
+void add_column_to_table(sqlite3* db, const std::string& table_name)
+{
+  const std::string name = ColumnType::name;
+  std::string query{"ALTER TABLE "s + table_name + " ADD " + ColumnType::name + " " + TypeToSQLType<typename ColumnType::real_type>::type};
+  log_debug(query);
+  char* error;
+  const auto result = sqlite3_exec(db, query.data(), nullptr, nullptr, &error);
+  if (result != SQLITE_OK)
+    {
+      log_error("Error adding column ", name, " to table ", table_name, ": ",  error);
+      sqlite3_free(error);
+    }
+}
+
+template <typename... T>
+class Table
+{
+  static_assert(sizeof...(T) > 0, "Table cannot be empty");
+  using ColumnTypes = std::tuple<T...>;
+
+ public:
+  using RowType = Row<T...>;
+
+  Table(std::string name):
+      name(std::move(name))
+  {}
+
+  void upgrade(sqlite3* db)
+  {
+    const auto existing_columns = get_all_columns_from_table(db, this->name);
+    add_column_if_not_exists(db, existing_columns);
+  }
+
+  void create(sqlite3* db)
+  {
+    std::string res{"CREATE TABLE IF NOT EXISTS "};
+    res += this->name;
+    res += " (\n";
+    this->add_column_create(res);
+    res += ")";
+
+    log_debug(res);
+
+    char* error;
+    const auto result = sqlite3_exec(db, res.data(), nullptr, nullptr, &error);
+    log_debug("result: ", +result);
+    if (result != SQLITE_OK)
+      {
+        log_error("Error executing query: ", error);
+        sqlite3_free(error);
+      }
+  }
+
+  RowType row()
+  {
+    return {this->name};
+  }
+
+  SelectQuery<T...> select()
+  {
+    SelectQuery<T...> select(this->name);
+    return select;
+  }
+
+  const std::string& get_name() const
+  {
+    return this->name;
+  }
+
+ private:
+
+  template <std::size_t N=0>
+  typename std::enable_if<N < sizeof...(T), void>::type
+  add_column_if_not_exists(sqlite3* db, const std::set<std::string>& existing_columns)
+  {
+    using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnTypes>()))>::type;
+    if (existing_columns.count(ColumnType::name) != 1)
+      {
+        add_column_to_table<ColumnType>(db, this->name);
+      }
+    add_column_if_not_exists<N+1>(db, existing_columns);
+  }
+  template <std::size_t N=0>
+  typename std::enable_if<N == sizeof...(T), void>::type
+  add_column_if_not_exists(sqlite3*, const std::set<std::string>&)
+  {}
+
+  template <std::size_t N=0>
+  typename std::enable_if<N < sizeof...(T), void>::type
+  add_column_create(std::string& str)
+  {
+    using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnTypes>()))>::type;
+    using RealType = typename ColumnType::real_type;
+    str += ColumnType::name;
+    str += " ";
+    str += TypeToSQLType<RealType>::type;
+    str += " "s + ColumnType::options;
+    if (N != sizeof...(T) - 1)
+      str += ",";
+    str += "\n";
+
+    add_column_create<N+1>(str);
+  }
+
+  template <std::size_t N=0>
+  typename std::enable_if<N == sizeof...(T), void>::type
+  add_column_create(std::string&)
+  { }
+
+  const std::string name;
+};