/***************************************************************
 *
 * Copyright (C) 2025, Pelican Project, Morgridge Institute for Research
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you
 * may not use this file except in compliance with the License.  You may
 * obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 ***************************************************************/

#include "../src/Posc.hh"
#include "../src/shortfile.hh"

#include <XrdOss/XrdOssDefaultSS.hh>
#include <XrdOuc/XrdOucEnv.hh>
#include <XrdSys/XrdSysLogger.hh>
#include <XrdVersion.hh>

#include <gtest/gtest.h>

#include <chrono>
#include <fcntl.h>
#include <string>
#include <thread>

class TestPosc : public testing::Test {
  protected:
	virtual std::string GetConfig() {
		std::stringstream ss;
		ss << "oss.localroot " << m_temp_dir << "\n";
		ss << "posc.prefix "
		   << "/posc_test\n"
			  "posc.trace debug\n";
		return ss.str();
	}

	void SetUp() override {
		setenv("XRDINSTANCE", "xrootd", 1);
		char tmp_configfn[] = "/tmp/xrootd-gtest.cfg.XXXXXX";
		auto result = mkstemp(tmp_configfn);
		ASSERT_NE(result, -1) << "Failed to create temp file ("
							  << strerror(errno) << ", errno=" << errno << ")";
		m_configfn = std::string(tmp_configfn);

		auto temp_dir = std::filesystem::temp_directory_path() /
						"gtest_temp_xrootd_localroot"; // Generate a unique name
		std::error_code ec;
		if (!std::filesystem::create_directory(temp_dir, ec)) {
			ASSERT_FALSE(ec)
				<< "Failed to create temp directory: " << ec.message();
		}
		m_temp_dir = temp_dir.string();

		auto contents = GetConfig();
		ASSERT_FALSE(contents.empty());
		ASSERT_TRUE(writeShortFile(m_configfn, contents, 0))
			<< "Failed to write to temp file (" << strerror(errno)
			<< ", errno=" << errno << ")";
	}

	void TearDown() override {
		if (!m_configfn.empty()) {
			auto rv = unlink(m_configfn.c_str());
			ASSERT_EQ(rv, 0) << "Failed to delete temp file ("
							 << strerror(errno) << ", errno=" << errno << ")";
		}
		if (!m_temp_dir.empty()) {
			std::error_code ec;
			auto rv = std::filesystem::remove_all(m_temp_dir, ec);
			ASSERT_NE(rv, -1)
				<< "Failed to delete temp directory (" << ec.message()
				<< ", errno=" << ec.value() << ")";
		}
	}

	std::string GetConfigFile() const { return m_configfn; }

  private:
	std::string m_temp_dir;
	std::string m_configfn;
};

TEST_F(TestPosc, BasicFileVisibility) {
	XrdSysLogger logger(2, 0);
	XrdOucEnv env;

	XrdVERSIONINFODEF(XrdOssDefault, Oss, XrdVNUMBER, XrdVERSION);

	XrdOss *default_oss =
		XrdOssDefaultSS(&logger, GetConfigFile().c_str(), XrdOssDefault);

	ASSERT_NE(default_oss, nullptr) << "Failed to get Posc OSS instance";

	std::unique_ptr<XrdSysError> log(new XrdSysError(&logger, "posc_"));
	PoscFileSystem *posc_fs_raw;
	try {
		posc_fs_raw = new PoscFileSystem(default_oss, std::move(log),
										 GetConfigFile().c_str(), &env);
	} catch (const std::exception &e) {
		FAIL() << "Failed to create PoscFileSystem: " << e.what();
	}
	std::unique_ptr<PoscFileSystem> posc_fs(posc_fs_raw);

	std::unique_ptr<XrdOssDF> fp(posc_fs->newFile());
	ASSERT_NE(fp, nullptr) << "Failed to create new file object";

	fp->Open("/testfile.txt", O_CREAT | O_RDWR, 0644, env);

	auto rv = posc_fs->Stat("/testfile.txt", nullptr, 0, &env);
	ASSERT_NE(rv, 0) << "Temporary file is visible";
	ASSERT_EQ(rv, -ENOENT)
		<< "Stat on not-visible file should have resulted in ENOENT: "
		<< strerror(-rv);

	ASSERT_EQ(fp->Close(), 0) << "Failed to close file";

	struct stat sb;
	rv = posc_fs->Stat("/testfile.txt", &sb, 0, &env);

	ASSERT_EQ(rv, 0) << "Stat on created file failed: " << strerror(-rv);
	ASSERT_TRUE(S_ISREG(sb.st_mode))
		<< "Stat on created file did not return regular file";
	ASSERT_EQ(sb.st_size, 0) << "Stat on created file did not return size 0";

	fp->Open("/testfile2.txt", O_CREAT | O_RDWR, 0644, env);
	auto write_size = strlen("Hello, POSC!");
	ASSERT_EQ(fp->Write("Hello, POSC!", 0, write_size), write_size);

	rv = posc_fs->Stat("/testfile2.txt", nullptr, 0, &env);
	ASSERT_NE(rv, 0) << "Temporary file is visible";
	ASSERT_EQ(rv, -ENOENT)
		<< "Stat on not-visible file should have resulted in ENOENT: "
		<< strerror(-rv);

	ASSERT_EQ(fp->Close(), 0) << "Failed to close file";

	memset(&sb, '\0', sizeof(sb));
	rv = posc_fs->Stat("/testfile2.txt", &sb, 0, &env);

	ASSERT_EQ(rv, 0) << "Stat on created file failed: " << strerror(-rv);
	ASSERT_TRUE(S_ISREG(sb.st_mode))
		<< "Stat on created file did not return regular file";
	ASSERT_EQ(sb.st_size, write_size)
		<< "Stat on created file did not return size " << write_size;
}

TEST_F(TestPosc, BasicFilesystemVisibility) {
	XrdSysLogger logger(2, 0);
	XrdOucEnv env;

	XrdVERSIONINFODEF(XrdOssDefault, Oss, XrdVNUMBER, XrdVERSION);

	XrdOss *default_oss =
		XrdOssDefaultSS(&logger, GetConfigFile().c_str(), XrdOssDefault);

	ASSERT_NE(default_oss, nullptr) << "Failed to get Posc OSS instance";

	std::unique_ptr<XrdSysError> log(new XrdSysError(&logger, "posc_"));
	PoscFileSystem *posc_fs_raw;
	try {
		posc_fs_raw = new PoscFileSystem(default_oss, std::move(log),
										 GetConfigFile().c_str(), &env);
	} catch (const std::exception &e) {
		FAIL() << "Failed to create PoscFileSystem: " << e.what();
	}
	ASSERT_NE(posc_fs_raw, nullptr) << "Failed to allocate filesystem object";
	std::unique_ptr<PoscFileSystem> posc_fs(posc_fs_raw);

	// Should not be able to stat the POSC directory
	struct stat buff;
	auto rv = posc_fs->Stat("/posc_test", &buff);
	ASSERT_NE(rv, 0) << "Expected stat of hidden directory to fail";
	ASSERT_EQ(rv, -ENOENT)
		<< "Expected stat of hidden directory to fail with ENOENT; got "
		<< strerror(errno);

	// Should not be able to create the POSC directory
	rv = posc_fs->Mkdir("/posc_test/foo", 0755, 1, &env);
	ASSERT_NE(rv, 0) << "Expected mkdir inside POSC dir to fail";
	ASSERT_EQ(rv, -EIO)
		<< "Expected mkdir inside POSC dir to result in an EIO.  Got "
		<< strerror(errno);

	// Listing of the parent directory should not contain the POSC directory
	auto dp_raw = posc_fs->newDir();
	ASSERT_NE(dp_raw, nullptr);
	std::unique_ptr<XrdOssDF> dp(dp_raw);
	rv = dp->Opendir("/", env);
	ASSERT_EQ(rv, 0) << "Failed to open root directory";
	char fname[NAME_MAX];
	while (((rv = dp->Readdir(fname, NAME_MAX)) == 0) && (fname[0] != '\0')) {
		fprintf(stderr, "File component: %s\n", fname);
	}
	ASSERT_EQ(rv, 0) << "Failed to list directory: " << strerror(-rv);
	ASSERT_EQ(dp->Close(), 0) << "Failed to close root directory";
}

TEST_F(TestPosc, TempfileUpdate) {
	XrdSysLogger logger(2, 0);
	XrdOucEnv env;

	XrdVERSIONINFODEF(XrdOssDefault, Oss, XrdVNUMBER, XrdVERSION);

	XrdOss *default_oss =
		XrdOssDefaultSS(&logger, GetConfigFile().c_str(), XrdOssDefault);

	ASSERT_NE(default_oss, nullptr) << "Failed to get Posc OSS instance";

	std::unique_ptr<XrdSysError> log(new XrdSysError(&logger, "posc_"));
	PoscFileSystem *posc_fs_raw;
	try {
		posc_fs_raw = new PoscFileSystem(default_oss, std::move(log),
										 GetConfigFile().c_str(), &env);
	} catch (const std::exception &e) {
		FAIL() << "Failed to create PoscFileSystem: " << e.what();
	}
	std::unique_ptr<PoscFileSystem> posc_fs(posc_fs_raw);

	std::unique_ptr<XrdOssDF> fp(posc_fs->newFile());
	ASSERT_NE(fp, nullptr) << "Failed to create new file object";

	fp->Open("/testfile.txt", O_CREAT | O_RDWR, 0644, env);

	auto pfp = dynamic_cast<PoscFile *>(fp.get());
	ASSERT_NE(fp, nullptr)
		<< "Returned file pointer should be of type PoscFile";

	auto posc_filename = pfp->GetPoscFilename();
	ASSERT_FALSE(posc_filename.empty())
		<< "POSC file is not opened in POSC mode";

	struct stat buff;
	auto rv = default_oss->Stat(posc_filename.c_str(), &buff, 0, &env);
	ASSERT_EQ(rv, 0) << "Failed to stat underlying POSC file";

#ifdef __APPLE__
	struct timespec now = buff.st_mtimespec;
#else
	struct timespec now = buff.st_mtim;
#endif

	auto now_chrono = std::chrono::time_point<std::chrono::system_clock,
											  std::chrono::nanoseconds>(
		std::chrono::seconds(now.tv_sec) +
		std::chrono::nanoseconds(now.tv_nsec));

	PoscFile::SetFileUpdateDuration(std::chrono::nanoseconds(100));

	std::this_thread::sleep_for(std::chrono::milliseconds(1500));

	PoscFile::UpdateOpenFiles();

	memset(&buff, '\0', sizeof(buff));
	rv = default_oss->Stat(posc_filename.c_str(), &buff, 0, &env);
	ASSERT_EQ(rv, 0) << "Failed to stat underlying POSC file";

#ifdef __APPLE__
	now = buff.st_mtimespec;
#else
	now = buff.st_mtim;
#endif

	auto update_chrono = std::chrono::time_point<std::chrono::system_clock,
												 std::chrono::nanoseconds>(
		std::chrono::seconds(now.tv_sec) +
		std::chrono::nanoseconds(now.tv_nsec));

	ASSERT_TRUE(update_chrono > now_chrono)
		<< "POSC file mtime was not updated after UpdateOpenFiles call";

	// Try expiring the user files - shouldn't do anything as the default
	// timeout is quite large.
	posc_fs->ExpireFiles();

	rv = default_oss->Stat(posc_filename.c_str(), &buff, 0, &env);
	ASSERT_EQ(rv, 0) << "Failed to stat underlying POSC file";

	// Decrease the file expiration time, sleep, and then expire again.
	PoscFileSystem::SetFileTimeout(std::chrono::nanoseconds(100));
	std::this_thread::sleep_for(std::chrono::milliseconds(1));

	posc_fs->ExpireFiles();

	rv = default_oss->Stat(posc_filename.c_str(), &buff, 0, &env);
	ASSERT_NE(rv, 0) << "Expire failed to delete underlying user file";
	ASSERT_EQ(rv, -ENOENT) << "Unexpected error when stating POSC file: "
						   << strerror(errno);
}

TEST_F(TestPosc, CreateENOENT) {
	XrdSysLogger logger(2, 0);
	XrdOucEnv env;

	XrdVERSIONINFODEF(XrdOssDefault, Oss, XrdVNUMBER, XrdVERSION);

	XrdOss *default_oss =
		XrdOssDefaultSS(&logger, GetConfigFile().c_str(), XrdOssDefault);

	ASSERT_NE(default_oss, nullptr) << "Failed to get Posc OSS instance";

	std::unique_ptr<XrdSysError> log(new XrdSysError(&logger, "posc_"));
	PoscFileSystem *posc_fs_raw;
	try {
		posc_fs_raw = new PoscFileSystem(default_oss, std::move(log),
										 GetConfigFile().c_str(), &env);
	} catch (const std::exception &e) {
		FAIL() << "Failed to create PoscFileSystem: " << e.what();
	}
	std::unique_ptr<PoscFileSystem> posc_fs(posc_fs_raw);

	std::unique_ptr<XrdOssDF> fp(posc_fs->newFile());
	ASSERT_NE(fp, nullptr) << "Failed to create new file object";

	auto rv = fp->Open("/subdir/testfile.txt", O_CREAT | O_RDWR, 0644, env);
	ASSERT_NE(rv, 0) << "Open should have failed";
	ASSERT_EQ(rv, -ENOENT)
		<< "Open on non-existent path should have resulted in ENOENT: "
		<< strerror(-rv);

	posc_fs->Mkdir("/subdir", 0755, 1, &env);

	rv = fp->Open("/subdir/testfile.txt", O_CREAT | O_RDWR, 0644, env);
	ASSERT_EQ(rv, 0) << "Open on newly created directory failed: "
					 << strerror(-rv);
	ASSERT_EQ(fp->Close(), 0) << "Failed to close file";
}