Add project files

source/BreezeCore/include/breeze/Sdks.hpp

@@ -0,0 +1,69 @@
+#pragma once
+
+#include <filesystem>
+#include <optional>
+#include <string>
+#include <vector>
+
+#include "breeze/Project.hpp"
+#include "breeze/Version.hpp"
+
+/// SDK versions, where they come from and what moving a project between them means.
+///
+/// An SDK version is a snapshot of the whole template: breeze/ (the SDK proper, replaced as a whole
+/// on a change), plus the files the project owns and starts from (project/Configuration.cmake, the
+/// root CMakeLists.txt, CMakePresets.json, the dot files). Versions come from a *source*, either a
+/// git repository whose tags are versions (v1.2.0, 1.2.0) or a directory with one subdirectory per
+/// version.
+namespace breeze::sdk
+{
+
+	class Source
+	{
+	public:
+		struct Entry
+		{
+			Version version;
+			/// The tag, or the directory name, it was found under.
+			std::string ref;
+		};
+
+		/// The configured source (`breeze config sdk-source`, or BREEZE_SDK_SOURCE); throws Error
+		/// when there is none.
+		static Source configured();
+
+		explicit Source(std::string location);
+
+		[[nodiscard]] const std::string& location() const { return m_location; }
+
+		/// All versions, oldest first.
+		[[nodiscard]] std::vector<Entry> versions() const;
+
+		/// The files of one version, fetched into the CLI's cache on first use.
+		[[nodiscard]] std::filesystem::path snapshot(const Entry& entry) const;
+
+		/// "latest" (or nothing), or a version number: the matching entry. Throws Error, listing
+		/// what exists, when there is no such version.
+		[[nodiscard]] Entry resolve(const std::optional<std::string>& wanted) const;
+
+	private:
+		std::string m_location;
+		bool m_isRepository = false;
+	};
+
+	/// Creates ./<name> from an SDK version: a project with that SDK, the settings set to the new
+	/// project's name and id, no demo modules, and one executable module named after the project.
+	void createProject(const std::string& name, const std::optional<std::string>& id,
+					   const std::optional<std::string>& sdkVersion);
+
+	/// Reports which SDK versions exist and whether the project is behind.
+	void update(const Project& project);
+
+	/// Moves the project to the newest version with the same major as its own.
+	void upgrade(const Project& project);
+
+	/// Moves the project to exactly this version, whichever way and across majors, and a legacy
+	/// (flat) project to the breeze/ layout.
+	void migrate(const Project& project, const std::string& version);
+
+}