Add source code.

include/Database.h

@@ -0,0 +1,59 @@
+#pragma once
+
+#include <optional>
+#include <string>
+#include <vector>
+
+#include "Models.h"
+
+struct sqlite3;
+
+// Works on an in-memory SQLite database that is loaded from, and saved to, a
+// file on request (db save / backup / restore).
+class Database {
+public:
+    Database();
+    ~Database();
+    Database(const Database&) = delete;
+    Database& operator=(const Database&) = delete;
+
+    // Loads `path` into memory if it exists, otherwise starts empty.
+    void open(const std::string& path);
+    void save();
+    std::string backup(const std::string& file);  // empty = timestamped name; returns the file used
+    void restore(const std::string& file);
+
+    bool dirty() const;
+    const std::string& path() const;
+
+    // Accounts
+    std::optional<std::string> findAccount(const std::string& name) const;  // canonical spelling
+    std::vector<std::string> listAccounts() const;
+    void addAccount(const std::string& name);
+    void removeAccount(const std::string& name);
+    void renameAccount(const std::string& name, const std::string& newName);
+
+    // Tasks
+    std::optional<std::string> findTask(const std::string& name) const;  // canonical spelling
+    std::optional<TaskRow> getTask(const std::string& name) const;
+    std::vector<TaskRow> listTasks() const;
+    void addTask(const std::string& name, const std::optional<std::string>& account, const std::string& status);
+    void removeTask(const std::string& name);
+    void renameTask(const std::string& name, const std::string& newName);
+    void setTaskAccount(const std::string& name, const std::optional<std::string>& account);
+    void setTaskStatus(const std::string& name, const std::string& status);
+    void setTaskNotes(const std::string& name, const std::string& notes);
+
+private:
+    using Param = std::optional<std::string>;
+    using Row = std::vector<std::optional<std::string>>;
+
+    void createSchema();
+    void exec(const std::string& sql);
+    std::vector<Row> query(const std::string& sql, const std::vector<Param>& params = {}) const;
+    void run(const std::string& sql, const std::vector<Param>& params);
+
+    sqlite3* db_;
+    std::string path_;
+    bool dirty_;
+};