// Copyright (C) 2009-present, Panagiotis Christopoulos Charitos and contributors.
// All rights reserved.
// Code licensed under the BSD License.
// http://www.anki3d.org/LICENSE

#include <AnKi/Util/Process.h>
#include <AnKi/Util/Array.h>
#include <AnKi/Util/Thread.h>
#if !ANKI_OS_ANDROID
#	include <ThirdParty/Reproc/reproc/include/reproc/reproc.h>
#	include <ThirdParty/Subprocess/subprocess.h>
#endif
#if ANKI_POSIX
#	include <unistd.h>
#endif

namespace anki {

Process::~Process()
{
	destroy();
}

void Process::destroy()
{
#if !ANKI_OS_ANDROID
	if(m_handle)
	{
		ProcessStatus status;
		[[maybe_unused]] const Error err = getStatus(status);
		if(status == ProcessStatus::kRunning)
		{
			ANKI_UTIL_LOGE("Process is still running. Forgot to wait for it");
		}

		m_handle = reproc_destroy(m_handle);
	}
#endif
}

Error Process::start(CString executable, const DynamicArray<String>& arguments, const DynamicArray<String>& environment, ProcessOptions options)
{
	// Set args and env
	Array<const Char*, kMaxArgs> args;
	Array<const Char*, kMaxEnv> env;

	args[0] = executable.cstr();
	for(U32 i = 0; i < arguments.getSize(); ++i)
	{
		args[i + 1] = arguments[i].cstr();
		ANKI_ASSERT(args[i + 1]);
	}
	args[arguments.getSize() + 1] = nullptr;

	for(U32 i = 0; i < environment.getSize(); ++i)
	{
		env[i] = environment[i].cstr();
		ANKI_ASSERT(env[i]);
	}
	env[environment.getSize()] = nullptr;

	return startInternal(&args[0], &env[0], options);
}

Error Process::start(CString executable, ConstWeakArray<CString> arguments, ConstWeakArray<CString> environment, ProcessOptions options)
{
	// Set args and env
	Array<const Char*, kMaxArgs> args;
	Array<const Char*, kMaxEnv> env;

	args[0] = executable.cstr();
	for(U32 i = 0; i < arguments.getSize(); ++i)
	{
		args[i + 1] = arguments[i].cstr();
		ANKI_ASSERT(args[i + 1]);
	}
	args[arguments.getSize() + 1] = nullptr;

	for(U32 i = 0; i < environment.getSize(); ++i)
	{
		env[i] = environment[i].cstr();
		ANKI_ASSERT(env[i]);
	}
	env[environment.getSize()] = nullptr;

	return startInternal(&args[0], &env[0], options);
}

Error Process::startInternal(const Char* args[], const Char* env[], ProcessOptions options)
{
#if !ANKI_OS_ANDROID
	ANKI_ASSERT(m_handle == nullptr && "Already started");

	// Start process
	m_handle = reproc_new();

	reproc_options reprocOptions = {};

	reprocOptions.env.behavior = REPROC_ENV_EXTEND;
	if(env[0] != nullptr)
	{
		reprocOptions.env.extra = &env[0];
	}
	reprocOptions.nonblocking = true;

	reprocOptions.redirect.in.type = REPROC_REDIRECT_DISCARD;
	reprocOptions.redirect.err.type = (!!(options & ProcessOptions::kOpenStderr)) ? REPROC_REDIRECT_PIPE : REPROC_REDIRECT_DISCARD;
	reprocOptions.redirect.out.type = (!!(options & ProcessOptions::kOpenStdout)) ? REPROC_REDIRECT_PIPE : REPROC_REDIRECT_DISCARD;

	I32 ret = reproc_start(m_handle, &args[0], reprocOptions);
	if(ret < 0)
	{
		ANKI_UTIL_LOGE("reproc_start() failed: %s", reproc_strerror(ret));
		m_handle = reproc_destroy(m_handle);
		return Error::kUserData;
	}

	ret = reproc_close(m_handle, REPROC_STREAM_IN);
	if(ret < 0)
	{
		ANKI_UTIL_LOGE("reproc_close() failed: %s. Ignoring", reproc_strerror(ret));
		m_handle = reproc_destroy(m_handle);
		return Error::kUserData;
	}
#else
	(void)args;
	(void)env;
	(void)options;
#endif

	return Error::kNone;
}

Error Process::wait(Second timeout, ProcessStatus* pStatus, I32* pExitCode)
{
#if !ANKI_OS_ANDROID
	ANKI_ASSERT(m_handle);
	ProcessStatus status;
	I32 exitCode;

	// Compute timeout in ms
	I32 rtimeout;
	if(timeout < 0.0)
	{
		rtimeout = REPROC_INFINITE;
	}
	else
	{
		// Cap the timeout to 1h to avoid overflows when converting to ms
		if(timeout > 1.0_hour)
		{
			ANKI_UTIL_LOGW("Timeout unreasonably high (%f sec). Will cap it to 1h", timeout);
			timeout = 1.0_hour;
		}

		rtimeout = I32(timeout * 1000.0);
	}

	// Wait
	const I32 ret = reproc_wait(m_handle, rtimeout);
	if(ret == REPROC_ETIMEDOUT)
	{
		status = ProcessStatus::kRunning;
		exitCode = 0;
	}
	else
	{
		status = ProcessStatus::kNotRunning;
		exitCode = ret;
	}

	if(pStatus)
	{
		*pStatus = status;
	}

	if(pExitCode)
	{
		*pExitCode = exitCode;
	}

	ANKI_ASSERT(!(status == ProcessStatus::kRunning && timeout < 0.0));
#else
	(void)timeout;
	(void)pStatus;
	(void)pExitCode;
#endif

	return Error::kNone;
}

Error Process::getStatus(ProcessStatus& status)
{
#if !ANKI_OS_ANDROID
	ANKI_ASSERT(m_handle);
	ANKI_CHECK(wait(0.0, &status, nullptr));
#else
	(void)status;
#endif

	return Error::kNone;
}

Error Process::kill(ProcessKillSignal k)
{
#if !ANKI_OS_ANDROID
	ANKI_ASSERT(m_handle);

	I32 ret;
	CString funcName;
	if(k == ProcessKillSignal::kNormal)
	{
		ret = reproc_terminate(m_handle);
		funcName = "reproc_terminate";
	}
	else
	{
		ANKI_ASSERT(k == ProcessKillSignal::kForce);
		ret = reproc_kill(m_handle);
		funcName = "reproc_kill";
	}

	if(ret < 0)
	{
		ANKI_UTIL_LOGE("%s() failed: %s", funcName.cstr(), reproc_strerror(ret));
		return Error::kFunctionFailed;
	}
#else
	(void)k;
#endif

	return Error::kNone;
}

Error Process::readFromStdout(String& text)
{
#if !ANKI_OS_ANDROID
	return readCommon(REPROC_STREAM_OUT, text);
#else
	(void)text;
	return Error::kNone;
#endif
}

Error Process::readFromStderr(String& text)
{
#if !ANKI_OS_ANDROID
	return readCommon(REPROC_STREAM_ERR, text);
#else
	(void)text;
	return Error::kNone;
#endif
}

#if !ANKI_OS_ANDROID
Error Process::readCommon(I32 reprocStream, String& text)
{
	ANKI_ASSERT(m_handle);

	// Limit the iterations in case the process writes to FD constantly
	U32 maxIterations = 16;
	while(maxIterations--)
	{
		Array<Char, 256> buff;

		const I32 ret = reproc_read(m_handle, REPROC_STREAM(reprocStream), reinterpret_cast<U8*>(&buff[0]), buff.getSize() - 1);

		if(ret == 0 || ret == REPROC_EPIPE || ret == REPROC_EWOULDBLOCK)
		{
			// No data or all data have bee read or something that I don't get
			break;
		}

		if(ret < 0)
		{
			ANKI_UTIL_LOGE("reproc_read() failed: %s", reproc_strerror(ret));
			return Error::kFunctionFailed;
		}

		buff[ret] = '\0';
		text += &buff[0];
	}

	return Error::kNone;
}
#endif

Error Process::callProcess(CString executable, ConstWeakArray<CString> arguments, String* stdOut, String* stdErr, I32& exitCode)
{
#if !ANKI_OS_ANDROID
	if(true)
	{
		ProcessOptions options = ProcessOptions::kNone;
		options |= (stdOut) ? ProcessOptions::kOpenStdout : ProcessOptions::kNone;
		options |= (stdErr) ? ProcessOptions::kOpenStderr : ProcessOptions::kNone;

		Process proc;
		ANKI_CHECK(proc.start(executable, arguments, {}, options));

		ANKI_CHECK(proc.wait(-1.0, nullptr, &exitCode));

		if(stdOut)
		{
			ANKI_CHECK(proc.readFromStdout(*stdOut));
		}

		if(stdErr)
		{
			ANKI_CHECK(proc.readFromStderr(*stdErr));
		}

		proc.destroy();
	}
	else
	{
		Array<const char*, 128> args;
		U32 count = 0;
		args[count++] = executable.cstr();
		for(U32 i = 0; i < arguments.getSize(); ++i)
		{
			args[count++] = arguments[i].cstr();
		}
		args[count] = nullptr;

		const int options = subprocess_option_inherit_environment | subprocess_option_no_window | subprocess_option_search_user_path;
		struct subprocess_s subprocess;
		int err = subprocess_create(&args[0], options, &subprocess);
		if(err)
		{
			ANKI_UTIL_LOGE("subprocess_create() failed");
			return Error::kFunctionFailed;
		}

		err = subprocess_join(&subprocess, &exitCode);
		if(err)
		{
			ANKI_UTIL_LOGE("subprocess_join() failed");
			subprocess_terminate(&subprocess);
			return Error::kFunctionFailed;
		}

		if(stdOut)
		{
			ANKI_ASSERT(!"TODO");
		}

		if(stdErr)
		{
			ANKI_ASSERT(!"TODO");
		}

		subprocess_destroy(&subprocess);
	}
#else
	(void)executable;
	(void)arguments;
	(void)stdOut;
	(void)stdErr;
	(void)exitCode;
#endif

	return Error::kNone;
}

U32 getCurrentProcessId()
{
#if ANKI_OS_WINDOWS
	return GetCurrentProcessId();
#elif ANKI_POSIX
	return getpid();
#endif
}

} // end namespace anki