SQLStudio: Execute statements in SQL server

Make the link between SQLStudio and the SQLServer so that statements
written in the editor window are executed by LibSQL when the 'Run'
button is clicked.

Userland/DevTools/SQLStudio/MainWidget.cpp

@@ -19,6 +19,9 @@
 #include <LibGUI/TextEditor.h>
 #include <LibGUI/Toolbar.h>
 #include <LibGUI/ToolbarContainer.h>
+#include <LibSQL/AST/Lexer.h>
+#include <LibSQL/AST/Token.h>
+#include <LibSQL/SQLClient.h>
 
 #include "MainWidget.h"
 #include "ScriptEditor.h"
@@ -138,7 +141,10 @@ MainWidget::MainWidget()
     });
 
     m_run_script_action = GUI::Action::create("Run script", { Mod_Alt, Key_F9 }, Gfx::Bitmap::try_load_from_file("/res/icons/16x16/play.png").release_value_but_fixme_should_propagate_errors(), [&](auto&) {
-        TODO();
+        m_current_line_for_parsing = 0;
+        // TODO select the database to use in UI.
+        m_connection_id = m_sql_client->connect("test");
+        read_next_sql_statement_of_editor();
     });
 
     auto& toolbar_container = add<GUI::ToolbarContainer>();
@@ -194,6 +200,11 @@ MainWidget::MainWidget()
     m_query_results_widget->set_layout<GUI::VerticalBoxLayout>();
     m_query_results_widget->layout()->set_margins(6);
     m_query_results_table_view = m_query_results_widget->add<GUI::TableView>();
+
+    m_sql_client = SQL::SQLClient::try_create().release_value_but_fixme_should_propagate_errors();
+    m_sql_client->on_execution_success = [this](int, bool, int, int, int) {
+        read_next_sql_statement_of_editor();
+    };
 }
 
 void MainWidget::initialize_menu(GUI::Window* window)
@@ -363,4 +374,74 @@ void MainWidget::drop_event(GUI::DropEvent& drop_event)
     }
 }
 
+String MainWidget::read_next_sql_statement_of_editor()
+{
+    StringBuilder piece;
+    do {
+        if (!piece.is_empty())
+            piece.append('\n');
+
+        auto line_maybe = read_next_line_of_editor();
+
+        if (!line_maybe.has_value())
+            return {};
+
+        auto& line = line_maybe.value();
+        auto lexer = SQL::AST::Lexer(line);
+
+        piece.append(line);
+
+        bool is_first_token = true;
+        bool is_command = false;
+        bool last_token_ended_statement = false;
+        bool tokens_found = false;
+
+        for (SQL::AST::Token token = lexer.next(); token.type() != SQL::AST::TokenType::Eof; token = lexer.next()) {
+            tokens_found = true;
+            switch (token.type()) {
+            case SQL::AST::TokenType::ParenOpen:
+                ++m_editor_line_level;
+                break;
+            case SQL::AST::TokenType::ParenClose:
+                --m_editor_line_level;
+                break;
+            case SQL::AST::TokenType::SemiColon:
+                last_token_ended_statement = true;
+                break;
+            case SQL::AST::TokenType::Period:
+                if (is_first_token)
+                    is_command = true;
+                break;
+            default:
+                last_token_ended_statement = is_command;
+                break;
+            }
+
+            is_first_token = false;
+        }
+
+        if (tokens_found)
+            m_editor_line_level = last_token_ended_statement ? 0 : (m_editor_line_level > 0 ? m_editor_line_level : 1);
+    } while ((m_editor_line_level > 0) || piece.is_empty());
+
+    auto statement_id = m_sql_client->sql_statement(m_connection_id, piece.to_string());
+    m_sql_client->async_statement_execute(statement_id);
+
+    return piece.to_string();
+}
+
+Optional<String> MainWidget::read_next_line_of_editor()
+{
+    auto editor = dynamic_cast<ScriptEditor*>(m_tab_widget->active_widget());
+    if (!editor)
+        return {};
+    if (m_current_line_for_parsing < editor->document().line_count()) {
+        String result = editor->document().line(m_current_line_for_parsing).to_utf8();
+        m_current_line_for_parsing++;
+        return result;
+    } else {
+        return {};
+    }
+}
+
 }