#ifndef OFX_PLUGIN_CACHE_H
#define OFX_PLUGIN_CACHE_H

// Copyright OpenFX and contributors to the OpenFX project.
// SPDX-License-Identifier: BSD-3-Clause

#include <string>
#include <vector>
#include <list>
#include <set>
#include <iostream>

#include <stdio.h>

#include "expat.h"

#include "ofxCore.h"
#include "ofxhPropertySuite.h"
#include "ofxhPluginAPICache.h"
#include "ofxhBinary.h"

namespace OFX {

  namespace Host {

    class Host;

    // forward delcarations
    class PluginDesc;   
    class Plugin;
    class PluginBinary;
    class PluginCache;

    /// C++ version of the information kept inside an OfxPlugin struct
    class PluginDesc  {
    protected :
      std::string _pluginApi;  ///< the API I implement
      int _apiVersion;         ///< the version of the API

      std::string _identifier; ///< the identifier of the plugin
      std::string _rawIdentifier; ///< the original identifier of the plugin
      int _versionMajor;       ///< the plugin major version
      int _versionMinor;       ///< the plugin minor version

    public:

      const std::string &getPluginApi() const {
        return _pluginApi;
      }
      
      int getApiVersion() const {
        return _apiVersion;
      }
      
      const std::string &getIdentifier() const {
        return _identifier;
      }

      const std::string &getRawIdentifier() const {
        return _rawIdentifier;
      }
      
      int getVersionMajor() const {
        return _versionMajor;
      }
      
      int getVersionMinor() const  {
        return _versionMinor;
      }

      PluginDesc() : _apiVersion(-1) {
      }

      virtual ~PluginDesc() {}

      PluginDesc(const std::string &api,
                 int apiVersion,
                 const std::string &identifier,
                 const std::string &rawIdentifier,
                 int versionMajor,
                 int versionMinor)
        : _pluginApi(api)
        , _apiVersion(apiVersion)
        , _identifier(identifier)
        , _rawIdentifier(rawIdentifier)
        , _versionMajor(versionMajor)
        , _versionMinor(versionMinor)
      {
      }


      /// constructor for the case where we have already loaded the plugin binary and 
      /// are populating this object from it
      PluginDesc(OfxPlugin *ofxPlugin) {
        _pluginApi = ofxPlugin->pluginApi;
        _apiVersion = ofxPlugin->apiVersion;
        _rawIdentifier = ofxPlugin->pluginIdentifier;
        _identifier = ofxPlugin->pluginIdentifier;

        // Who says the pluginIdentifier is case-insensitive? OFX 1.3 spec doesn't mention this.
        // http://openfx.sourceforge.net/Documentation/1.3/ofxProgrammingReference.html#id472588
        //for (size_t i=0;i<_identifier.size();i++) {
        //  _identifier[i] = tolower(_identifier[i]);
        //}
        _versionMajor = ofxPlugin->pluginVersionMajor;
        _versionMinor = ofxPlugin->pluginVersionMinor;
      }

    };
    
    /// class that we use to manipulate a plugin
    class Plugin : public PluginDesc {
    /// owned by the PluginBinary it lives inside
    /// Plugins can only be pass about either by pointer or reference
    private :
      Plugin(const Plugin&) : PluginDesc() {}                          ///< hidden
      Plugin &operator= (const Plugin&) {return *this;} ///< hidden

    protected :
      PluginBinary *_binary; ///< the file I live inside
      int           _index;  ///< where I live inside that file
    public :
      Plugin();

      PluginBinary *getBinary()
      {
        return _binary;
      }

      const PluginBinary *getBinary() const
      {
        return _binary;
      }

      int getIndex() const
      {
        return _index;
      }

      /// construct this based on the struct returned by the getNthPlugin() in the binary
      Plugin(PluginBinary *bin, int idx, OfxPlugin *o) : PluginDesc(o), _binary(bin), _index(idx)
      {
      }
      
      /// construct me from the cache
      Plugin(PluginBinary *bin, int idx, const std::string &api,
             int apiVersion, const std::string &identifier, 
             const std::string &rawIdentifier,
             int majorVersion, int minorVersion)
        : PluginDesc(api, apiVersion, identifier, rawIdentifier, majorVersion, minorVersion)
        , _binary(bin)
        , _index(idx) 
      {
      }

      virtual ~Plugin() {
      }

      virtual APICache::PluginAPICacheI &getApiHandler() = 0;

      bool trumps(Plugin *other) {
        int myMajor = getVersionMajor();
        int theirMajor = other->getVersionMajor();

        int myMinor = getVersionMinor();
        int theirMinor = other->getVersionMinor();

        if (myMajor > theirMajor) {
          return true;
        }
        
        if (myMajor == theirMajor && myMinor > theirMinor) {
          return true;
        }

        return false;
      }
    };

    class PluginHandle;

    /// class that represents a binary file which holds plugins
    class PluginBinary {
    /// has a set of plugins inside it and which it owns
    /// These are owned by a PluginCache
      friend class PluginHandle;

    protected :
      Binary _binary;                 ///< our binary object, abstracted layer ontop of OS calls, defined in ofxhBinary.h
      std::string _filePath;          ///< full path to the file
      std::string _bundlePath;        ///< path to the .bundle directory
      std::vector<Plugin *> _plugins; ///< my plugins
      time_t _fileModificationTime;   ///< used as a time stamp to check modification times, used for caching
      off_t _fileSize;                ///< file size last time we check, used for caching
      bool _binaryChanged;            ///< whether the timestamp/filesize in this cache is different from that in the actual binary
      
    public :

      /// create one from the cache.  this will invoke the Binary() constructor which
      /// will stat() the file.
      explicit PluginBinary(const std::string &file, const std::string &bundlePath, time_t mtime, off_t size)
        : _binary(file)
        , _filePath(file)
        , _bundlePath(bundlePath)
        , _fileModificationTime(mtime)
        , _fileSize(size)
        , _binaryChanged(false)
      {
        if (isInvalid()) {
          return;
        }
        if (_fileModificationTime != _binary.getTime() || _fileSize != _binary.getSize()) {
          _binaryChanged = true;
        }
      }


      /// constructor which will open a library file, call things inside it, and then 
      /// create Plugin objects as appropriate for the plugins exported therefrom
      explicit PluginBinary(const std::string &file, const std::string &bundlePath, PluginCache *cache)
        : _binary(file)
        , _filePath(file)
        , _bundlePath(bundlePath)
        , _binaryChanged(false)
      {
        loadPluginInfo(cache);
      }
    
      /// dtor
      virtual ~PluginBinary();


      time_t getFileModificationTime() const {
      	return _fileModificationTime;
      }
    
      off_t getFileSize() {
      	return _fileSize;
      }

      const std::string &getFilePath() const {
        return _filePath;
      }
      
      const std::string &getBundlePath() const {
        return _bundlePath;
      }
      
      bool hasBinaryChanged() const {
        return _binaryChanged;
      }

      bool isLoaded() const {
        return _binary.isLoaded();
      }
        
      bool isInvalid() const {
        return _binary.isInvalid();
      }

      void addPlugin(Plugin *pe) {
        _plugins.push_back(pe);
      }

      void loadPluginInfo(PluginCache *);

      /// how many plugins?
      int getNPlugins() const {return (int)_plugins.size(); }

      /// get a plugin 
      Plugin &getPlugin(int idx) {return *_plugins[idx];}

      /// get a plugin 
      const Plugin &getPlugin(int idx) const {return *_plugins[idx];}
    };

    /// wrapper class for Plugin/PluginBinary.  use in a RAIA fashion to make sure the binary gets unloaded when needed and not before.
    class PluginHandle {
      PluginBinary *_b;
      OfxPlugin *_op;

    public:
      PluginHandle(Plugin *p, OFX::Host::Host *_host);
      virtual ~PluginHandle();

      OfxPlugin *getOfxPlugin() {
        return _op;
      }

      OfxPlugin *operator->() {
        return _op;
      }
    };
    
    /// for later 
    struct PluginCacheSupportedApi {
      std::string api;
      int minVersion;
      int maxVersion;
      APICache::PluginAPICacheI *handler;

      PluginCacheSupportedApi(const std::string &_api, int _minVersion, int _maxVersion, APICache::PluginAPICacheI *_handler) :
        api(_api), minVersion(_minVersion), maxVersion(_maxVersion), handler(_handler)
      {
      }
      
      bool matches(const std::string &_api, int _version) const
      {
        if (_api == api && _version >= minVersion && _version <= maxVersion) {
          return true;
        }
        return false;
      }
    };

    /// Where we keep our plugins.    
    class PluginCache {
    protected :
      OFX::Host::Property::PropSpec* _hostSpec;

      std::list<std::string>    _pluginPath;  ///< list of directories to look in
      std::set<std::string>     _nonrecursePath; ///< list of directories to look in (non-recursively)
      std::list<std::string>    _pluginDirs;  ///< list of directories we found
      std::list<PluginBinary *> _binaries; ///< all the binaries we know about, we own these
      std::list<Plugin *>       _plugins;  ///< all the plugins inside the binaries, we don't own these, populated from _binaries
      std::set<std::string>     _knownBinFiles;

      PluginBinary *_xmlCurrentBinary;
      Plugin *_xmlCurrentPlugin;

      std::list<PluginCacheSupportedApi> _apiHandlers;

      void scanDirectory(std::set<std::string> &foundBinFiles, const std::string &dir, bool recurse);

      bool _ignoreCache;
      std::string _cacheVersion;

      bool _dirty;
      bool _enablePluginSeek;       ///< Turn off to make all seekPluginFile() calls return an empty string

      static PluginCache* gPluginCachePtr; ///< singleton plugin cache

    public:
      /// ctor, which inits _pluginPath to default locations and not much else
      PluginCache();

      /// dtor
      ~PluginCache();

      /// get our plugin cache
      static PluginCache* getPluginCache();

      /// clear our plugin cache
      static void clearPluginCache();		

      /// get the list in which plugins are sought
      const std::list<std::string> &getPluginPath() {
        return _pluginPath;
      }

      /// was the cache outdated?
      bool dirty() const {
        return _dirty;
      }

      /// add a file to the plugin path
      void addFileToPath(const std::string &f, bool recurse=true) {
        _pluginPath.push_back(f);
        if (!recurse) {
          _nonrecursePath.insert(f);
        }
      }

      /// prepend a file to the plugin path
      void prependFileToPath(const std::string &f, bool recurse=true) {
        _pluginPath.push_front(f);
        if (!recurse) {
          _nonrecursePath.insert(f);
        }
      }

      /// specify which subdirectory of /usr/OFX or equivilant
      /// (as well as 'Plugins') to look in for plugins.
      void setPluginHostPath(const std::string &hostId);

      /// set the version string to write to the cache, 
      /// and also that we expect on cachess read in
      void setCacheVersion(const std::string &cacheVersion) {
        _cacheVersion = cacheVersion;
      }

      // populate the cache.  must call scanPluginFiles() after to check for changes.
      void readCache(std::istream &is);

      // seek a particular file on the OFX plugin path
      std::string seekPluginFile(const std::string &baseName) const;
      
      /// Sets behaviour of seekPluginFile().
      /// Enable (the default): normal operation; disable: returns an empty string instead
      void setPluginSeekEnabled(bool enabled) { _enablePluginSeek = enabled; }

      /// scan for plugins
      void scanPluginFiles();

      // write the plugin cache output file to the given stream
      void writePluginCache(std::ostream &os) const;
      
      // callback function for the XML
      void elementBeginCallback(void *userData, const XML_Char *name, const XML_Char **attrs);
      void elementCharCallback(void *userData, const XML_Char *data, int len);
      void elementEndCallback(void *userData, const XML_Char *name);

      /// register an API cache handler
      void registerAPICache(const std::string &api, int min, int max, APICache::PluginAPICacheI *apiCache) {
        _apiHandlers.push_back(PluginCacheSupportedApi(api, min, max, apiCache));
      }
      
      /// find the API cache handler for the given api/apiverson
      APICache::PluginAPICacheI* findApiHandler(const std::string &api, int apiver);

      /// obtain a list of plugins to walk through
      const std::list<Plugin *> &getPlugins() const {
        return _plugins;
      }
    };

  }
}

#endif