//********************************** Banshee Engine (www.banshee3d.com) **************************************************//
//**************** Copyright (c) 2016 Marko Pintera (marko.pintera@gmail.com). All rights reserved. **********************//
#pragma once

#define BS_MAX_STACKTRACE_DEPTH 200
#define BS_MAX_STACKTRACE_NAME_BYTES 1024

namespace bs
{
	/** @addtogroup Internal-Utility
	 *  @{
	 */

	/** @addtogroup Error-Internal
	 *  @{
	 */

	/** Saves crash data and notifies the user when a crash occurs. */
	// TODO - Crashes are reported in the same process as the main application. This can be a problem if the crash was caused
	// by heap. Any further use of the heap by the reporting methods will cause a silent crash, failing to log it. A more
	// appropriate way of doing it should be to resume another process to actually handle the crash.
	//  - Perhaps an even better option would be to use a private heap for all engine allocations. So when corruptions does
	//    happen the crash handler can use the default heap with no issues.
	class BS_UTILITY_EXPORT CrashHandler
	{
	public:
		CrashHandler();
		~CrashHandler();

		/** Constructs and starts the module. */
		static void startUp()
		{
			if(_instance() == nullptr)
				_instance() = bs_new<CrashHandler>();
		}

		/** Shuts down this module and frees any resources it is using. */
		static void shutDown()
		{
			if(_instance() != nullptr)
			{
				bs_delete(_instance());
				_instance() = nullptr;
			}
		}

		/** Returns a reference to the module instance. */
		static CrashHandler& instance() { return *_instance(); }

		/**
		 * Records a crash with a custom error message.
		 *
		 * @param[in]	type		Type of the crash that occurred. For example "InvalidParameter".
		 * @param[in]	description	More detailed description of the issue that caused the crash.
		 * @param[in]	function	Optional name of the function where the error occurred.
		 * @param[in]	file		Optional name of the source code file in which the code that crashed the program exists.
		 * @param[in]	line		Optional source code line at which the crash was triggered at.
		 */
		void reportCrash(const String& type, const String& description, const String& function = StringUtil::BLANK,
			const String& file = StringUtil::BLANK, UINT32 line = 0) const;

#if BS_PLATFORM == BS_PLATFORM_WIN32
		/**
		 * Records a crash resulting from a Windows-specific SEH exception.
		 *
		 * @param[in]	exceptionData	Exception data returned from GetExceptionInformation()
		 * @return						Code that signals the __except exception handler on how to proceed.
		 *
		 * @note	Available in Windows builds only.
		 */
		int reportCrash(void* exceptionData) const;
#endif

		/**
		 * Returns a string containing a current stack trace. If function can be found in the symbol table its readable
		 * name will be present in the stack trace, otherwise just its address.
		 *
		 * @return	String containing the call stack with each function on its own line.
		 */
		static String getStackTrace();
	private:
		/** Does what it says. Internal utility function used by reportCrash(). */
		void logErrorAndStackTrace(const String& message, const String& stackTrace) const;
		/** Does what it says. Internal utility function used by reportCrash(). */
		void logErrorAndStackTrace(const String& type,
		                           const String& description,
		                           const String& function,
		                           const String& file,
		                           UINT32 line) const;
		/** Does what it says. Internal utility function used by reportCrash(). */
		void saveCrashLog() const;
		/** Creates the crash report directory and returns its path. */
		static const Path& getCrashFolder();
		/** Returns the current time as a string timestamp.  This is used
		 * to name the crash report directory.. */
		static String getCrashTimestamp();

		/** Returns a singleton instance of this module. */
		static CrashHandler*& _instance() { static CrashHandler* inst = nullptr; return inst; }

		/** The name of the crash reports directory. */
		static const String sCrashReportFolder;
		/** The name of the HTML crash log file. */
		static const String sCrashLogName;
		/** Error message to display on program failure. */
		static const String sFatalErrorMsg;

#if BS_PLATFORM == BS_PLATFORM_WIN32
		struct Data;
		Data* m;
#endif
	};

	/** Easier way of accessing the CrashHandler. */
	BS_UTILITY_EXPORT CrashHandler& gCrashHandler();

	/** @} */
	/** @} */
}