/* AgentCore: the Qt wrapper around one cst_agent_t.
 *
 * The engine runs turns on a worker thread; every cst_agent_hooks_t callback
 * is turned into a Qt signal, and the two hooks that need an answer
 * (on_permission, on_ask_user) block the worker until the GUI replies. No
 * HTTP, no socket: the GUI owns the engine in its own process. */

#ifndef CST_APP_AGENTCORE_H
#define CST_APP_AGENTCORE_H

#include <QByteArray>
#include <QMutex>
#include <QObject>
#include <QString>
#include <QWaitCondition>

#include "cst_agent.h"
#include "cst_tools.h"

class QThread;

class AgentCore : public QObject {
  Q_OBJECT
  Q_PROPERTY(bool running READ running NOTIFY runningChanged)
  Q_PROPERTY(QString workspace READ workspace NOTIFY workspaceChanged)
  Q_PROPERTY(QString mode READ mode NOTIFY modeChanged)
  Q_PROPERTY(QString provider READ provider NOTIFY configChanged)
  Q_PROPERTY(QString model READ model NOTIFY configChanged)
  Q_PROPERTY(int approval READ approval WRITE setApproval NOTIFY approvalChanged)
  Q_PROPERTY(bool planMode READ planMode WRITE setPlanMode NOTIFY planModeChanged)
  Q_PROPERTY(QString todo READ todo NOTIFY todoChanged)

 public:
  explicit AgentCore(QObject *parent = nullptr);
  ~AgentCore() override;

  /* Start the engine on a workspace. provider/model/apiKey may be empty to
   * fall back to the saved credentials and the provider's default model. */
  bool open(const QString &workspace, const QString &provider,
            const QString &model, const QString &apiKey, QString *err);
  void close();

  bool running() const { return m_running; }
  QString workspace() const { return m_workspace; }
  QString mode() const { return QString::fromUtf8(m_cfg.mode); }
  QString provider() const { return QString::fromUtf8(m_cfg.provider); }
  QString model() const { return QString::fromUtf8(m_cfg.model); }
  int approval() const { return m_cfg.approval; }
  bool planMode() const { return m_cfg.plan_mode != 0; }
  QString todo() const { return m_todo; }

  /* Markdown -> HTML with the engine's own renderer (cst_web_md_html), so a
   * message looks the same here as it does in the WebUI. */
  Q_INVOKABLE QString renderMarkdown(const QString &text) const;

  /* The engine, for the parts that need it (tool registration). */
  cst_agent_t *agent() const { return m_agent; }
  const cst_agent_config_t *config() const { return &m_cfg; }

  /* Ask a question; emits the streaming signals, then turnFinished(). */
  Q_INVOKABLE void send(const QString &prompt);
  Q_INVOKABLE void cancel();

  /* Consent: answers map to CST_PERM_*. */
  Q_INVOKABLE void answerPermission(int choice);
  Q_INVOKABLE void answerQuestion(const QString &answer);

  Q_INVOKABLE void setMode(const QString &mode);        /* coding | general */
  Q_INVOKABLE void setApproval(int approval);           /* cst_approval_t */
  Q_INVOKABLE void setPlanMode(bool on);

  /* Tools the front end implements itself. The engine copies the definition
   * (strings included), so a stack value is fine; ud must outlive it.
   * owner is what unregisterOwner() later matches. */
  bool registerTool(const cst_tool_def_t *def);
  void unregisterOwner(const QString &owner);
  /* Re-probe platform tools after a service appeared or went away. */
  void reloadToolMeta() { cst_tool_meta_reload(); }

  /* Answer every consent question with "once" (the C smoke test, headless
   * runs, a --yes flag). */
  void setAutoApprove(bool on) { m_autoApprove = on; }

 signals:
  void configChanged();
  void approvalChanged();
  void planModeChanged();
  void statusChanged(const QString &text);
  void assistantDelta(const QString &text);
  void thinkDelta(const QString &text);
  void toolEvent(const QString &phase, const QString &name,
                 const QString &detail);
  void toolResult(const QString &name, int exitCode, const QString &output);
  void todoChanged(const QString &text);
  void permissionRequested(const QString &tool, const QString &detail,
                           const QString &preview);
  void questionAsked(const QString &question, const QString &options);
  void turnFinished(int rc, const QString &err);
  void runningChanged();
  void workspaceChanged();
  void modeChanged();

 private:
  friend class Turn;
  void finishTurn(int rc, const QString &err);
  void setRunning(bool on);

  /* Hook trampolines (C, run on the worker thread). */
  static void hookStatus(const char *msg, void *ud);
  static void hookAssistant(const char *text, size_t len, void *ud);
  static void hookThink(const char *text, size_t len, void *ud);
  static void hookToolEvent(const char *phase, const ctl_tool_call_t *call,
                            const char *detail, void *ud);
  static void hookToolResult(const ctl_tool_call_t *call, const char *out,
                             size_t len, int exit_code, void *ud);
  static void hookTodo(const char *text, void *ud);
  static int hookPermission(const char *tool, const char *detail,
                            const char *preview, void *ud);
  static int hookAskUser(const char *question, const char *options, char *ans,
                         size_t ans_sz, void *ud);
  /* Post a lambda onto the GUI thread. */
  template <typename F>
  void post(F f) {
    QMetaObject::invokeMethod(this, f, Qt::QueuedConnection);
  }

  cst_agent_t *m_agent = nullptr;
  cst_agent_config_t m_cfg;
  cst_agent_hooks_t m_hooks;
  QString m_workspace;
  QThread *m_turn = nullptr;
  bool m_running = false;
  bool m_closing = false;

  /* consent handshake between the worker and the GUI thread */
  QMutex m_askMu;
  QWaitCondition m_askCv;
  int m_permAnswer = CST_PERM_DENY;
  bool m_permPending = false;
  QString m_question;
  QString m_todo;
  QByteArray m_answer;
  bool m_questionPending = false;
  bool m_autoApprove = false;
};

#endif /* CST_APP_AGENTCORE_H */