/*]  Copyright (c) 2009-2010, Charles McGarvey  [**************************
**]  All rights reserved.
*
* vi:ts=4 sw=4 tw=75
*
* Distributable under the terms and conditions of the 2-clause BSD license;
* see the file COPYING for a complete text of the license.
*
**************************************************************************/

#include "config.h"

#ifdef USE_HOTLOADING
#include <sys/inotify.h>
#include <sys/ioctl.h>
#endif

#include <queue>

#include <boost/algorithm/string.hpp>
#include <boost/weak_ptr.hpp>
#include <stlplus/portability/file_system.hpp>

#include "hash.hh"
#include "resource.hh"


#ifndef BUF_SIZE
#define BUF_SIZE 4096
#endif


namespace moof {
	

bool resource::call_registry(const std::string& extension,
							 loader_ptr& loader,
							 registry_action action)
{
	static type_lookup table;

	switch (action)
	{
		case set:
		{
			if (loader) table[extension] = loader;
			else        table.erase(extension);
			break;
		}

		case lookup:
		{
			std::map<std::string,loader_ptr>::iterator it;
			it = table.find(extension);
			if (it != table.end()) loader = (*it).second;
			break;
		}
	}

	return loader;
}

static std::string search_paths_;

typedef boost::weak_ptr<resource> resource_weakptr;
static hash<std::string,resource_weakptr,hash_function> resource_table_;

static hash<std::string,std::string,hash_function> prefix_table_;


#ifdef USE_HOTLOADING
static hash<int,std::string,hash_function> monitor_lookup_;
static int monitor_fd_ = inotify_init1(IN_NONBLOCK);
#endif

int resource::reload_as_needed()
{
	int num_resources = 0;

#ifdef USE_HOTLOADING
	log_info("hotloading?");
	char bytes[BUF_SIZE];
	int num_bytes;
	if (0 < (num_bytes = read(monitor_fd_, bytes, num_bytes)))
	{
		char* end = bytes + num_bytes;
		char* byte = bytes;

		log_warning("num_bytes:", num_bytes);
		log_error("1");

		while (byte < end)
		{
			struct inotify_event* event = (struct inotify_event*)byte;

			if (event->mask & IN_IGNORED)
			{
				log_warning("watch", event->wd, "removed");
			}

			log_error("2");
			hash<int,std::string,hash_function>::iterator it;
			it = monitor_lookup_.find(event->wd);
			if (it != monitor_lookup_.end())
			{
				log_error("3");
				std::string path = (*it).second;
				monitor_lookup_.erase(it);
				resource::reload(path);
			}

			byte += sizeof(*event) + event->len;

			++num_resources;
		}
	}
#endif

	return num_resources;
}


resource::~resource()
{
#ifdef USE_HOTLOADING
	inotify_rm_watch(monitor_fd_, wd_);
#endif
}


resource_ptr resource::load(const std::string& name,
							const std::string& ext)
{
	return load_with_path(find_file(name, ext));
}

resource_ptr resource::load(const std::string& name)
{
	return load_with_path(find_file(name));
}


resource_ptr resource::load_with_path(const std::string& path)
{
	std::string extension = stlplus::extension_part(path);

	hash<std::string,resource_weakptr,hash_function>::iterator it;
	it = resource_table_.find(path);
	if (it != resource_table_.end())
	{
		resource_weakptr rsrc = (*it).second;
		resource_ptr locked = rsrc.lock();
		if (locked) return locked;
	}

	loader_ptr loader;
	call_registry(extension, loader, lookup);
	if (loader)
	{
		resource_ptr rsrc(loader->load(path));
		rsrc->set_loader(path, loader);
		resource_table_[path] = rsrc;

#ifdef USE_HOTLOADING
		int wd = inotify_add_watch(monitor_fd_, path.c_str(), IN_MODIFY);
		rsrc->set_watch_descriptor(wd);
		monitor_lookup_[wd] = path;
#endif

		log_info("loaded", rsrc.get());
		return rsrc;
	}

	log_warning("cannot load resource of unknown type:", path);
	return resource_ptr();
}


resource_ptr resource::reload(std::string& path)
{
	log_info("reloading...", path);
	hash<std::string,resource_weakptr,hash_function>::iterator it;
	it = resource_table_.find(path);
	if (it != resource_table_.end())
	{
		resource_weakptr rsrc = (*it).second;
		resource_ptr locked = rsrc.lock();
		if (locked)
		{
			locked->reload();
			return locked;
		}
	}

	return load(path);
}

void resource::reload()
{
	log_info("reloaded", path_);

	resource* resource = loader_->load(path_);
	//*this = *resource;
	resource_ = resource->resource_;
	typeinfo_ = resource->typeinfo_;
	unloader_ = resource->unloader_;

#ifdef USE_HOTLOADING
	int wd = inotify_add_watch(monitor_fd_, path_.c_str(), IN_MODIFY);
	set_watch_descriptor(wd);
	monitor_lookup_[wd] = path_;
#endif

	delete resource;
}


void resource::add_search_paths(const std::string& paths)
{
	search_paths_ = paths;
}


std::string resource::find_file(const std::string& name)
{
	std::vector<std::string> paths;
	boost::split(paths, search_paths_, boost::is_any_of(":"));

	std::string ext = stlplus::extension_part(name);
	std::string prefix("hi");

	loader_ptr loader;
	call_registry(ext, loader, lookup);
	if (loader) prefix = loader->prefix();

	log_info("find_file:", ext, prefix);

	std::vector<std::string>::iterator it;
	for (it = paths.begin(); it != paths.end(); ++it)
	{
		std::string path = stlplus::create_filespec(*it, name);
		log_info("looking for", name, "at", path);
		if (stlplus::file_exists(path)) return path;
		
		// try it with the prefix added
		if (!prefix.empty())
		{
			*it = stlplus::create_filespec(*it, prefix);
			path = stlplus::create_filespec(*it, name);
			log_info("looking for", name, "at", path);
			if (stlplus::file_exists(path)) return path;
		}
	}


	log_error("cannot find resource file:", name);
	return std::string();
}

std::string resource::find_file(const std::string& name,
								const std::string& ext)
{
	std::string actual_ext = stlplus::extension_part(name);
	if (actual_ext != ext)
	{
		return find_file(stlplus::create_filename(name, ext));
	}
	return find_file(name);
}


} // namespace moof