/*

  KLayout Layout Viewer
  Copyright (C) 2006-2016 Matthias Koefferlein

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

*/


#ifndef HDR_layPlugin
#define HDR_layPlugin

#include "laybasicCommon.h"

#include <QFrame>

#include "tlString.h"
#include "tlClassRegistry.h"
#include "tlDeferredExecution.h"
#include "gsiObject.h"
#include "layAbstractMenu.h"

#include <map>
#include <vector>
#include <string>

namespace db
{
  class Manager;
}

namespace lay
{

class Plugin;
class PluginRoot;
class LayoutView;
class Browser;
class ViewService;
class Editable;
class Drawing;
class TechnologyComponentProvider;

/**
 *  @brief The base class for configuration pages
 *
 *  This interface defines some services the configuration page
 *  must provide (i.e. setup, commit)
 */
class LAYBASIC_PUBLIC ConfigPage 
  : public QFrame
{
public:
  ConfigPage (QWidget *parent) 
    : QFrame (parent)
  {
    // .. nothing else ..
  }

  /**
   *  @brief Load the page
   *
   *  The implementation is supposed to fetch the configuration from the
   *  Plugin object provided and load the widgets accordingly.
   */
  virtual void setup (PluginRoot * /*root*/)
  {
    //  the default implementation does nothing.
  }

  /**
   *  @brief Commit the page
   *
   *  The implementation is supposed to read the configuration (and 
   *  throw exceptions if the configuration something is invalid)
   *  and commit the changes through 
   */
  virtual void commit (PluginRoot * /*root*/)
  {
    //  the default implementation does nothing.
  }

};

/**
 *  @brief A menu entry declaration
 */
struct LAYBASIC_PUBLIC MenuEntry
{
  /**
   *  @brief A declaration for a separator
   *
   *  @param menu_name The name of the menu item (see layAbstractMenu.h)
   *  @param insert_pos The position where to insert (see layAbstractMenu.h)
   */
  MenuEntry (const std::string &menu_name_, const std::string &insert_pos_)
    : menu_name (menu_name_), insert_pos (insert_pos_), sub_menu (false)
  {
    // .. 
  }

  /**
   *  @brief A declaration for a menu entry
   *
   *  @param symbol The symbol to send when this menu item is selected
   *  @param menu_name The name of the menu item (see layAbstractMenu.h)
   *  @param insert_pos The position where to insert (see layAbstractMenu.h)
   *  @param title The title to display plus optional icon resource and keyboard shortcut. The format of the string is: <text>["("shortcut")"]["<"icon-resource">"][{"tool-tip"}].
   */
  MenuEntry (const std::string &symbol_, const std::string &menu_name_, const std::string &insert_pos_, const std::string &title_, bool sub_menu_ = false)
    : menu_name (menu_name_), symbol (symbol_), insert_pos (insert_pos_), title (title_), sub_menu (sub_menu_)
  {
    // .. 
  }

  std::string menu_name;
  std::string symbol;
  std::string insert_pos;
  std::string title;
  bool sub_menu;
};

/**
 *  @brief The configuration declaration
 *
 *  For each configurable class a declaration object derived from
 *  this class must be provided through the tl::Registrar registration
 *  mechanism (instantiate a tl::Registrar<tl::Plugin>::Class<Y>
 *  object).
 */
class LAYBASIC_PUBLIC PluginDeclaration
  : public QObject, 
    public gsi::ObjectBase
{
Q_OBJECT 

public:
  /** 
   *  @brief Constructor
   */
  PluginDeclaration ();
  
  /**
   *  @brief Destructor
   */
  virtual ~PluginDeclaration ();

  /**
   *  @brief This method is supposed to deliver the option names available
   *  
   *  @param options A vector of names and default value strings.
   */
  virtual void get_options (std::vector < std::pair<std::string, std::string> > & /*options*/) const
  {
    //  the default implementation does not add any options
  }

  /**
   *  @brief Fetch the configuration page for the configuration dialog
   *
   *  @param title The title to display in the corresponding tab of
   *               the configuration dialog.
   *  @return The configuration page or 0 if there is no page.
   */
  virtual ConfigPage *config_page (QWidget * /*parent*/, std::string & /*title*/) const
  {
    return 0;
  }
  
  /**
   *  @brief Fetch the configuration pages for the configuration dialog
   *
   *  @return A list of titles and ConfigPage instances
   *
   *  This method can be reimplemented alternatively to "config_page" when multiple pages shall be
   *  used. The pages are inserted in the order they are defined. 
   */
  virtual std::vector<std::pair <std::string, ConfigPage *> > config_pages (QWidget * /*parent*/) const
  {
    return std::vector<std::pair <std::string, ConfigPage *> > ();
  }
  
  /**
   *  @brief The global configuration 
   *
   *  By implementing this method, a configuration can be treated globally.
   *  Otherwise the individual plugin object (associated with a view) must handle
   *  the configuration. One example for handling the configuration globally is
   *  dynamic menu configuration.
   */
  virtual bool configure (const std::string & /*name*/, const std::string & /*value*/)
  {
    return false;
  }

  /**
   *  @brief Global menu handler
   *
   *  This menu handler is called before the view specific handler is 
   *  called (lay::Plugin::menu_activated).
   *  The implementation is supposed to return true if it handles the menu entry.
   */
  virtual bool menu_activated (const std::string & /*symbol*/) const
  {
    //  The default implementation does nothing.
    return false;
  }

  /**
   *  @brief Configuration finalization
   *
   *  This method is called after all configuration changes have been applied.
   *  A derived class might implement this method in order to do some post-
   *  processing of the configuration.
   */
  virtual void config_finalize ()
  {
    //  .. the default implementation does nothing ..
  }

  /**
   *  @brief Basic initialization
   *
   *  Reimplementation of this method offers a chance to initialize static resources such as 
   *  dialogs etc.
   */
  virtual void initialize (lay::PluginRoot * /*root*/)
  {
    //  .. the default implementation does nothing ..
  }

  /**
   *  @brief Basic initialization
   *
   *  Reimplementation of this method offers a chance to initialize static resources such as 
   *  dialogs etc.
   *  While initialize is called before any configuration is loaded, "initialized" will be
   *  called after the pugin system has been initially configured.
   */
  virtual void initialized (lay::PluginRoot * /*root*/)
  {
    //  .. the default implementation does nothing ..
  }

  /**
   *  @brief Uninitialize the plugin
   */
  virtual void uninitialize (lay::PluginRoot * /*root*/)
  {
    //  .. the default implementation does nothing ..
  }

  /**
   *  @brief Fetch the menu objects for this plugin
   *
   *  The implementation of this method is supposed to call the base
   *  class'es "get_menu_entries" method and add it's own entries.
   */
  virtual void get_menu_entries (std::vector<lay::MenuEntry> & /*menu_entries*/) const
  {
    //  .. nothing yet ..
  }

  /**
   *  @brief Create a plugin object of the respective kind
   *
   *  This method may return 0 for "dummy" plugins that just register menu entries
   *  or configuration options.
   */
  virtual lay::Plugin *create_plugin (db::Manager * /*manager*/, lay::PluginRoot * /*plugin_root*/, lay::LayoutView * /*view*/) const
  {
    return 0;
  }

  /**
   *  @brief Tell if the plugin implements the "lay::Editable" interface
   *
   *  This method is supposed to return true if the plugin implements the 
   *  lay::Editable interface and wants to be listed as an "edit" mode in the
   *  "Edit" menu. The string returned in "title" is displayed in the "Edit" menu's
   *  corresponding mode entry.
   */
  virtual bool implements_editable (std::string & /*title*/) const
  {
    return false;
  }
  
  /**
   *  @brief Tell if the plugin implements a "lay::ViewService" active mouse mode
   *
   *  This method is supposed to return true if the plugin implements the 
   *  lay::ViewService interface and wants to be listed as an mouse mode in the
   *  "Edit" menu. The string returned in "title" is displayed in the "Edit" menu's
   *  corresponding mode entry.
   */
  virtual bool implements_mouse_mode (std::string & /*title*/) const
  {
    return false;
  }
  
  /**
   *  @brief Returns the technology component provider
   *
   *  If this plugin wants to register a technology component, it's declaration must 
   *  include a technology component provider. This is responsible for creating 
   *  a technology component and an associated editor.
   *
   *  @return The provide object (no ownership is taken) or 0 if no technology component is created.
   */
  virtual const TechnologyComponentProvider *technology_component_provider () const 
  {
    return 0;
  }

  /**
   *  @brief Delivers a unique ID
   *
   *  This ID can be used to connect plugins to menus for example.
   *  Currently the ID is just the address of the declaration object.
   *  The ID is guaranteed to be larger than 0, so negative ID's can be 
   *  used for different purposed.
   */
  int id () const
  {
    return m_id;
  }

  /**
   *  @brief Creates the menu resources for this plugin
   *
   *  This method will create the menu resources for the plugin and perform the 
   *  required connect operations.
   */
  void init_menu ();

  /**
   *  @brief Removes the menu resources associated with this plugin
   */
  void remove_menu_items ();

  /**
   *  @brief Enables this editable part of the plugin
   *
   *  If the editable part of this plugin is enabled, the objects managed by this mode can be manipulated.
   *  Otherwise, the are not considered for selection.
   *  This property can be monitored with the editable_enabled observer.
   */
  void set_editable_enabled (bool f);

  /**
   *  @brief Gets a value indicating whether the editable part of the plugin is enabled
   */
  bool editable_enabled () const
  {
    return m_editable_enabled;
  }

  /**
   *  @brief Notifies that plugin root that a new plugin was registered
   *
   *  This method must be called when a plugin is dynamically created. It is important
   *  that when this method is called, the menu items and other properties are set already. 
   */
  void register_plugin ();

  /**
   *  @brief An event indicating that the editable state has changed
   */
  tl::Event editable_enabled_changed_event;

private slots:
  void toggle_editable_enabled ();
  void generic_menu ();
  void mode_triggered ();

private:
  int m_id;
  std::vector <lay::Action> m_menu_actions;
  lay::Action m_editable_mode_action;
  lay::Action m_mouse_mode_action;
  bool m_editable_enabled;
};

/**
 *  @brief The plugin interface
 *
 *  Each configurable object must be derived from this interface.
 *  An configurable object can have a parent. This way, a hierarchy
 *  of configurable objects is created. The root object not having a
 *  parent acts as the main entry point: it will try to dispatch 
 *  configuration requests to the children.
 *  A node may have a local configuration - it will override any
 *  parent configurations.
 */

class LAYBASIC_PUBLIC Plugin
  : public gsi::ObjectBase,
    virtual public tl::Object
{
public:
  typedef std::map <std::string, std::string>::const_iterator iterator;

  /**
   *  @brief The constructor
   *  
   *  See above for a explanation of the parent-child relationship.
   */
  Plugin (Plugin *parent, bool standalone = false);

  /**
   *  @brief The destructor
   */
  virtual ~Plugin ();

  /**
   *  @brief Gets a value indicating whether this plugin is a standlone plugin
   *
   *  Standalone-Plugins don't receive common events such as menu requests or
   *  mode changes.
   */
  bool is_standalone () const
  {
    return m_standalone;
  }

  /**
   *  @brief Setup
   *
   *  Calling this method will make the root configurable object dump
   *  it's current configuration to this object. The setup method can 
   *  be called in the derived object's constructor for example.
   */
  void config_setup ();
  
  /**
   *  @brief Clear (reset to default) the configuration
   *
   *  If called on a child, local configurations are cleared.
   *  If called on the root, the default configuration is restored.
   */
  void clear_config ();

  /**
   *  @brief Set a certain configuration parameter
   *
   *  This method will promote the configuration to the first child
   *  that accepts it and store the value in the repository for the
   *  root element.
   */
  void config_set (const std::string &name, const std::string &value);

  /**
   *  @brief Set a certain configuration parameter
   *
   *  This method will promote the configuration to the first child
   *  that accepts it and store the value in the repository for the
   *  root element.
   */
  void config_set (const std::string &name, const char *value);

  /**
   *  @brief Set a certain configuration parameter with a given type
   *
   *  This method will promote the configuration to the first child
   *  that accepts it and store the value in the repository for the
   *  root element. It will use tl::to_string to convert the type into
   *  a string.
   */
  template <class T> 
  void config_set (const std::string &name, const T &value)
  {
    config_set (name, tl::to_string (value));
  }

  /**
   *  @brief Set a certain configuration parameter with a given type using a custom string converter
   *
   *  This method will promote the configuration to the first child
   *  that accepts it and store the value in the repository for the
   *  root element. It will use conv.to_string to convert the type into
   *  a string.
   */
  template <class T, class C> 
  void config_set (const std::string &name, const T &value, C conv)
  {
    config_set (name, conv.to_string (value));
  }

  /**
   *  @brief Terminat a sequence of configuration setups
   *
   *  In order to make configuration changes effective, this method
   *  must be called. It calls config_finalize recursively on the 
   *  children.
   */
  void config_end ();

  /**
   *  @brief Get a certain configuration parameter
   *
   *  This method will fetch the parameter from the repository.
   *  It can only be called on the root element.
   *  If no parameter with the given name is known, this method will 
   *  return false and set "value" to empty.
   */
  bool config_get (const std::string &name, std::string &value) const;

  /**
   *  @brief Get a certain configuration parameter
   *
   *  This is a convenience method which behaves similar. It will return the
   *  configuration value for the given configuration option name. However, if the
   *  configuration option with the given name does not exist, simply an 
   *  empty string is returned.
   */
  std::string config_get (const std::string &name) const
  {
    std::string v;
    config_get (name, v);
    return v;
  }

  /**
   *  @brief Get a certain configuration parameter
   *
   *  This method will fetch the parameter from the repository
   *  and try to convert it into the value requested. To convert
   *  it, tl::from_string is used. If an exception is thrown during
   *  the conversion or the value is not present, false is returned.
   */
  template <class T>
  bool config_get (const std::string &name, T &value) const
  {
    T t;
    std::string s;
    if (! config_get (name, s)) {
      return false;
    }
    try {
      tl::from_string (s, t);
      value = t;
      return true;
    } catch (...) {
      return false;
    }
  }

  /**
   *  @brief Get a certain configuration parameter using a custom converter
   *
   *  This method will fetch the parameter from the repository
   *  and try to convert it into the value requested. To convert
   *  it, conv.from_string is used. If an exception is thrown during
   *  the conversion or the value is not present, false is returned.
   */
  template <class T, class C>
  bool config_get (const std::string &name, T &value, C conv) const
  {
    T t;
    std::string s;
    if (! config_get (name, s)) {
      return false;
    }
    try {
      conv.from_string (s, t);
      value = t;
      return true;
    } catch (...) {
      return false;
    }
  }

  /**
   *  @brief Iterator for the key/value pairs: begin iterator
   */
  iterator begin () const
  {
    return m_repository.begin ();
  }

  /**
   *  @brief Iterator for the key/value pairs: end iterator
   */
  iterator end () const
  {
    return m_repository.end ();
  }

  /**
   *  @brief Get the names of all configuration options available
   */
  void get_config_names (std::vector<std::string> &names) const;

  /**
   *  @brief Menu command handler
   *
   *  This method is called if a menu entry registered in the 
   *  plugin declaration is activated. The string passed is the 
   *  symbol of the menu entry.
   */
  virtual void menu_activated (const std::string & /*symbol*/) 
  {
    // .. this implementation does nothing ..
  }

  /**
   *  @brief Return the lay::Browser interface if this object has one
   *
   *  If the object implements the lay::Browser interface, return the pointer to this.
   *  Otherwise the implementation is supposed to return 0.
   */
  virtual lay::Browser *browser_interface ()
  {
    return 0;
  }

  /**
   *  @brief Return the lay::ViewService interface if this object has one
   *
   *  If the object implements the lay::ViewService interface, return the pointer to this.
   *  Otherwise the implementation is supposed to return 0.
   */
  virtual lay::ViewService *view_service_interface ()
  {
    return 0;
  }

  /**
   *  @brief Return the lay::Drawing interface if this object has one
   *
   *  If the object implements the lay::Drawing interface, return the pointer to this.
   *  Otherwise the implementation is supposed to return 0.
   */
  virtual lay::Drawing *drawing_interface ()
  {
    return 0;
  }

  /**
   *  @brief Return the lay::Editable interface if this object has one
   *
   *  If the object implements the lay::Editable interface, return the pointer to this.
   *  Otherwise the implementation is supposed to return 0.
   */
  virtual lay::Editable *editable_interface ()
  {
    return 0;
  }

  /**
   *  @brief Associate a plugin with the plugin declaration for that service (getter)
   */
  const PluginDeclaration *plugin_declaration () const
  {
    return mp_plugin_declaration;
  }

  /**
   *  @brief Associate a service with the plugin declaration for that service (setter)
   *
   *  The association is done when the plugin is created. It should not be changed.
   */
  void set_plugin_declaration (const PluginDeclaration *pd) 
  {
    mp_plugin_declaration = pd;
  }

protected:
  /**
   *  @brief Configure method
   *
   *  This method must be supplied by derived classes. If the class
   *  knows about the configuration option it must consume the value
   *  and return 'true'.
   *  No selection is made for "matching" configuration options for
   *  this class.
   */
  virtual bool configure (const std::string & /*name*/, const std::string & /*value*/)
  {
    return false;
  }

  /**
   *  @brief Configuration finalization
   *
   *  This method is called after all configuration changes have been applied.
   *  A derived class might implement this method in order to do some post-
   *  processing of the configuration.
   */
  virtual void config_finalize ()
  {
    //  .. the default implementation does nothing ..
  }

private:
  Plugin (const Plugin &);
  Plugin &operator= (const Plugin &);

  /**
   *  @brief Do the actual setup or pass to the parent if not the root
   */
  void do_config_setup (Plugin *target);

  /**
   *  @brief Do the actual set or pass to the children if not taken 
   */
  bool do_config_set (const std::string &name, const std::string &value);

  /**
   *  @brief Recursively call config_finalize
   */
  void do_config_end ();

  Plugin *mp_parent;
  const PluginDeclaration *mp_plugin_declaration;
  tl::weak_collection<Plugin> m_children;
  std::map <std::string, std::string> m_repository;
  tl::DeferredMethod<lay::Plugin> dm_finalize_config;
  bool m_standalone;
};

/**
 *  @brief The plugin root element
 *
 *  The first (root) object must be derived from this class.
 *  This class offers the full "plugin" functionality like 
 *  configuration interface etc. but cannot have a parent.
 */

class LAYBASIC_PUBLIC PluginRoot
  : public Plugin
{
public:
  /**
   *  @brief The constructor
   */
  PluginRoot (bool standalone = false);

  /**
   *  @brief Destructor
   */
  ~PluginRoot ();

  /**
   *  @brief Write configuration to a file
   *
   *  If the configuration file cannot be written, false
   *  is returned but no exception is thrown.
   *
   *  @return false, if an error occured.
   */
  bool write_config (const std::string &config_file);

  /**
   *  @brief Read the configuration from a file
   *
   *  This method siletly does nothing, if the config file does not
   *  exist. If it does and an error occured, the error message is printed
   *  on stderr. In both cases, false is returned.
   *
   *  @return false, if an error occured.
   */
  bool read_config (const std::string &config_file);

  /**
   *  @brief The singleton instance of the plugin root
   */
  static PluginRoot *instance ();

  /**
   *  @brief Notifies the plugin root that a new plugin class has been registered
   *
   *  This method is called when a plugin is loaded dynamically during runtime.
   */
  virtual void plugin_registered (lay::PluginDeclaration * /*cls*/) { }

  /**
   *  @brief Notifies the plugin root that a plugin class is about to be removed
   */
  virtual void plugin_removed (lay::PluginDeclaration * /*cls*/) { }

  /**
   *  @brief Selects the given mode 
   *
   *  The implementation is supposed to select the given mode on all related plugins.
   */
  virtual void select_mode (int /*mode*/) { }

private:
  PluginRoot (const PluginRoot &);
  PluginRoot &operator= (const PluginRoot &);
};

/**
 *  @brief A handy function for implementing the configure method
 *
 *  This template compares two values and overwrites the target
 *  with the source if both are different. It returns true, if 
 *  the target was updated indicating that something needs to be
 *  updated.
 */
template <class T>
inline bool test_and_set (T &target, const T &source)
{
  if (target != source) {
    target = source;
    return true;
  } else {
    return false;
  }
}

}

namespace tl
{
  //  make registration available to external DLL's
  template class LAYBASIC_PUBLIC tl::RegisteredClass<lay::PluginDeclaration>;

  //  disable copy ctor for PluginRoot
  template <> struct type_traits<lay::PluginRoot> : public type_traits<void> {
    typedef tl::false_tag has_copy_constructor;
  };

  //  disable copy ctor for Plugin
  template <> struct type_traits<lay::Plugin> : public type_traits<void> {
    typedef tl::false_tag has_copy_constructor;
  };
}

#endif