C and Python API + Smarter account-based wait times

include/Tracker.h

@@ -0,0 +1,83 @@
+#pragma once
+
+#include <ctime>
+#include <optional>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+#include "Database.h"
+#include "Views.h"
+
+enum class ErrorCode { Invalid, NotFound, Exists, Database };
+
+// What went wrong, with a message that can be shown to the user as it is.
+class TrackerError : public std::runtime_error {
+public:
+    TrackerError(ErrorCode code, const std::string& message);
+
+    ErrorCode code() const;
+
+private:
+    ErrorCode code_;
+};
+
+// All the rules for changing accounts and tasks (waits, auto-unwait, status
+// handling...). The prompt and the C API are both thin layers over this class.
+// Each change appends human-readable notes (what the prompt prints), which
+// takeMessages() hands over.
+class Tracker {
+public:
+    explicit Tracker(Database& db);
+
+    const Database& database() const;
+
+    // For tests and simulations: pretend the time is `fixedNow`. 0 = real clock.
+    void setClock(std::time_t fixedNow);
+    std::time_t now() const;
+
+    std::vector<std::string> takeMessages();
+
+    // ---- Accounts -----------------------------------------------------------
+    void addAccount(const std::string& name);
+    void deleteAccount(const std::string& name);
+    void renameAccount(const std::string& name, const std::string& newName);
+
+    // The account hits its limit until `until` (or a clock time such as "16:30",
+    // "4:30pm"; a time that has passed today means tomorrow).
+    void setAccountWait(const std::string& name, std::time_t until);
+    void setAccountWaitText(const std::string& name, const std::string& timeText);
+    // Returns false if the account was not waiting.
+    bool clearAccountWait(const std::string& name);
+
+    // ---- Tasks --------------------------------------------------------------
+    // `statusText` is what the user would type: "testing", "wait 4pm", "wait"...
+    // nullopt = Prompt, without the auto-unwait that an explicit status triggers.
+    void addTask(const std::string& name, const std::optional<std::string>& account,
+                 const std::optional<std::string>& statusText);
+    void deleteTask(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& statusText);
+    // Returns false (and changes nothing) if the notes are the same already.
+    bool setTaskNotes(const std::string& name, const std::string& notes);
+
+    // ---- Computed views -----------------------------------------------------
+    std::vector<TaskInfo> tasks() const;
+    std::vector<AccountInfo> accounts() const;
+
+private:
+    static void requireName(const std::string& name);
+    Status parseStatus(const std::string& text) const;
+    std::string existingAccount(const std::string& name) const;
+    TaskRow existingTask(const std::string& name) const;
+    std::optional<std::time_t> runningWait(const std::string& account) const;
+    void resumeAccount(const std::string& account);
+    void makeTaskFollowAccount(const TaskRow& task);
+    void noteAccountWait(const std::string& taskName);
+    void note(const std::string& message);
+
+    Database& db_;
+    std::time_t fixedNow_;
+    std::vector<std::string> messages_;
+};