/*
 * Copyright 2007, Ingo Weinhold, bonefish@cs.tu-berlin.de.
 * Distributed under the terms of the MIT License.
 */

#include <BeOSBuildCompatibility.h>

#include "fssh.h"

#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

#include <vector>

#include "fd.h"
#include "fssh_dirent.h"
#include "fssh_errors.h"
#include "fssh_module.h"
#include "fssh_stat.h"
#include "fssh_string.h"
#include "module.h"
#include "syscalls.h"
#include "vfs.h"


extern fssh_module_info *modules[];


namespace FSShell {

extern fssh_file_system_module_info gRootFileSystem;

const char* kMountPoint = "/myfs";


static fssh_status_t
init_kernel()
{
	fssh_status_t error;

	// init module subsystem
	error = module_init(NULL);
	if (error != FSSH_B_OK) {
		fprintf(stderr, "module_init() failed: %s\n", fssh_strerror(error));
		return error;
	} else
		printf("module_init() succeeded!\n");

	// register built-in modules, i.e. the rootfs and the client FS
	register_builtin_module(&gRootFileSystem.info);
	for (int i = 0; modules[i]; i++)
		register_builtin_module(modules[i]);

	// init VFS
	error = vfs_init(NULL);
	if (error != FSSH_B_OK) {
		fprintf(stderr, "initializing VFS failed: %s\n", fssh_strerror(error));
		return error;
	} else
		printf("VFS initialized successfully!\n");

	// init kernel IO context
	gKernelIOContext = (io_context*)vfs_new_io_context(NULL);
	if (!gKernelIOContext) {
		fprintf(stderr, "creating IO context failed!\n");
		return FSSH_B_NO_MEMORY;
	}

	// mount root FS
	fssh_dev_t rootDev = _kern_mount("/", NULL, "rootfs", 0, NULL, 0);
	if (rootDev < 0) {
		fprintf(stderr, "mounting rootfs failed: %s\n", fssh_strerror(rootDev));
		return rootDev;
	} else
		printf("mounted rootfs successfully!\n");

	// set cwd to "/"	
	error = _kern_setcwd(-1, "/");
	if (error != FSSH_B_OK) {
		fprintf(stderr, "setting cwd failed: %s\n", fssh_strerror(error));
		return error;
	} else
		printf("set cwd successfully!\n");

	// create mount point for the client FS
	error = _kern_create_dir(-1, kMountPoint, 0775);
	if (error != FSSH_B_OK) {
		fprintf(stderr, "creating mount point failed: %s\n",
			fssh_strerror(error));
		return error;
	} else
		printf("mount point created successfully!\n");

	return FSSH_B_OK;
}


// #pragma mark - Command

Command::Command(const char* name, const char* description)
	: fName(name),
	  fDescription(description)
{
}


Command::Command(command_function* function, const char* name,
	const char* description)
	: fName(name),
	  fDescription(description),
	  fFunction(function)
{
}


Command::~Command()
{
}


const char*
Command::Name() const
{
	return fName.c_str();
}


const char*
Command::Description() const
{
	return fDescription.c_str();
}


int
Command::Do(int argc, const char* const* argv)
{
	if (!fFunction) {
		fprintf(stderr, "No function given for command \"%s\"\n", Name());
		return 1;
	}

	return (*fFunction)(argc, argv);
}


// #pragma mark - CommandManager

CommandManager::CommandManager()
{
}


CommandManager*
CommandManager::Default()
{
	if (!sManager)
		sManager = new CommandManager;
	return sManager;
}


void
CommandManager::AddCommand(Command* command)
{
	// The command name may consist of several aliases. Split them and
	// register the command for each of them.
	char _names[1024];
	char* names = _names;
	strcpy(names, command->Name());

	char* cookie;
	while (char* name = strtok_r(names, " /", &cookie)) {
		fCommands[name] = command;
		names = NULL;
	}
}


void
CommandManager::AddCommand(command_function* function, const char* name,
	const char* description)
{
	AddCommand(new Command(function, name, description));
}


void
CommandManager::AddCommands(command_function* function, const char* name,
	const char* description, ...)
{
	va_list args;
	va_start(args, description);

	while (function) {
		AddCommand(function, name, description);

		function = va_arg(args, command_function*);
		if (function) {
			name = va_arg(args, const char*);
			description = va_arg(args, const char*);
		}
	}

	va_end(args);
}


Command*
CommandManager::FindCommand(const char* name) const
{
	CommandMap::const_iterator it = fCommands.find(name);
	if (it == fCommands.end())
		return NULL;

	return it->second;
}


void
CommandManager::ListCommands() const
{
	for (CommandMap::const_iterator it = fCommands.begin();
			it != fCommands.end(); ++it) {
		const char* name = it->first.c_str();
		Command* command = it->second;
		printf("%-16s - %s\n", name, command->Description());
	}
}


CommandManager*	CommandManager::sManager = NULL;


// #pragma mark - Commands


static int
command_cd(int argc, const char* const* argv)
{
	if (argc != 2) {
		fprintf(stderr, "Usage: cd <directory>\n");
		return 1;
	}
	const char* directory = argv[1];

	fssh_status_t error = _kern_setcwd(-1, directory);
	if (error != FSSH_B_OK) {
		fprintf(stderr, "Error: cd %s: %s\n", directory, fssh_strerror(error));
		return 1;
	}

	return 0;
}


static int
command_help(int argc, const char* const* argv)
{
	printf("supported commands:\n");
	CommandManager::Default()->ListCommands();
	return 0;
}


static void
list_entry(const char* file, const char* name = NULL)
{
	// construct path, if a leaf name is given
	std::string path;
	if (name) {
		path = file;
		path += '/';
		path += name;
		file = path.c_str();
	} else
		name = file;

	// stat the file
	struct fssh_stat st;
	fssh_status_t error = _kern_read_stat(-1, file, false, &st, sizeof(st));
	if (error != FSSH_B_OK) {
		fprintf(stderr, "Error: Failed to stat() \"%s\": %s\n", file,
			fssh_strerror(error));
		return;
	}

	// get time
	struct tm time;
	time_t fileTime = st.fssh_st_mtime;
	localtime_r(&fileTime, &time);

	// get permissions
	std::string permissions;
	fssh_mode_t mode = st.fssh_st_mode;
	// user
	permissions += ((mode & FSSH_S_IRUSR) ? 'r' : '-');
	permissions += ((mode & FSSH_S_IWUSR) ? 'w' : '-');
	if (mode & FSSH_S_ISUID)
		permissions += 's';
	else
		permissions += ((mode & FSSH_S_IXUSR) ? 'x' : '-');
	// group
	permissions += ((mode & FSSH_S_IRGRP) ? 'r' : '-');
	permissions += ((mode & FSSH_S_IWGRP) ? 'w' : '-');
	if (mode & FSSH_S_ISGID)
		permissions += 's';
	else
		permissions += ((mode & FSSH_S_IXGRP) ? 'x' : '-');
	// others
	permissions += ((mode & FSSH_S_IROTH) ? 'r' : '-');
	permissions += ((mode & FSSH_S_IWOTH) ? 'w' : '-');
	permissions += ((mode & FSSH_S_IXOTH) ? 'x' : '-');

	// get file type
	char fileType = '?';
	if (FSSH_S_ISREG(mode)) {
		fileType = '-';
	} else if (FSSH_S_ISLNK(mode)) {
		fileType = 'l';
	} else if (FSSH_S_ISBLK(mode)) {
		fileType = 'b';
	} else if (FSSH_S_ISDIR(mode)) {
		fileType = 'd';
	} else if (FSSH_S_ISCHR(mode)) {
		fileType = 'c';
	} else if (FSSH_S_ISFIFO(mode)) {
		fileType = 'f';
	} else if (FSSH_S_ISINDEX(mode)) {
		fileType = 'i';
	}

	// get link target
	std::string nameSuffix;
	if (FSSH_S_ISLNK(mode)) {
		char buffer[FSSH_B_PATH_NAME_LENGTH];
		fssh_size_t size = sizeof(buffer);
		error = _kern_read_link(-1, file, buffer, &size);
		if (error == FSSH_B_OK) {
			nameSuffix += " -> ";
			nameSuffix += buffer;
		} else {
			fprintf(stderr, "Error: Failed to read symlink \"%s\": %s\n", file,
				fssh_strerror(error));
		}
	}

	printf("%c%s %2d %2d %10lld %d-%02d-%02d %02d:%02d:%02d %s%s\n",
		fileType, permissions.c_str(), (int)st.fssh_st_uid, (int)st.fssh_st_gid,
		st.fssh_st_size,
		1900 + time.tm_year, 1 + time.tm_mon, time.tm_mday,
		time.tm_hour, time.tm_min, time.tm_sec,
		name, nameSuffix.c_str());
}


static int
command_ls(int argc, const char* const* argv)
{
	const char* const currentDirFiles[] = { ".", NULL };
	const char* const* files;
	if (argc >= 2)
		files = argv + 1;
	else
		files = currentDirFiles;

	for (; *files; files++) {
		const char* file = *files;
		// stat file
		struct fssh_stat st;
		fssh_status_t error = _kern_read_stat(-1, file, false, &st, sizeof(st));
		if (error != FSSH_B_OK) {
			fprintf(stderr, "Error: Failed to stat() \"%s\": %s\n", file,
				fssh_strerror(error));
			continue;
		}

		// if it is a directory, print its entries
		if (FSSH_S_ISDIR(st.fssh_st_mode)) {
			printf("%s:\n", file);

			// open dir
			int fd = _kern_open_dir(-1, file);
			if (fd < 0) {
				fprintf(stderr, "Error: Failed to open dir \"%s\": %s\n",
					file, fssh_strerror(fd));
				continue;
			}

			// iterate through the entries
			char buffer[sizeof(fssh_dirent) + FSSH_B_FILE_NAME_LENGTH];
			fssh_dirent* entry = (fssh_dirent*)buffer;
			fssh_ssize_t entriesRead = 0;
			while ((entriesRead = _kern_read_dir(fd, entry, sizeof(buffer), 1))
					== 1) {
				list_entry(file, entry->d_name);
			}

			if (entriesRead < 0) {
				fprintf(stderr, "Error: reading dir \"%s\" failed: %s\n",
					file, fssh_strerror(entriesRead));
			}

			// close dir
			error = _kern_close(fd);
			if (error != FSSH_B_OK) {
				fprintf(stderr, "Error: Closing dir \"%s\" (fd: %d) failed: "
					"%s\n", file, fd, fssh_strerror(error));
				continue;
			}

		} else
			list_entry(file);
	}

	return 0;
}


static int
command_quit(int argc, const char* const* argv)
{
	return COMMAND_RESULT_EXIT;
}


static void
register_commands()
{
	CommandManager::Default()->AddCommands(
		command_cd,		"cd", "change current directory",
		command_ls,		"ls", "list files or directories",
		command_help,	"help", "list supported commands",
		command_quit,	"quit/exit", "quit the shell",
		NULL
	);
}


// #pragma mark - ArgVector


class ArgVector {
public:
	ArgVector()
		: fArgc(0),
		  fArgv(NULL)
	{
	}

	~ArgVector()
	{
		_Cleanup();
	}

	int Argc() const
	{
		return fArgc;
	}

	const char* const* Argv() const
	{
		return fArgv;
	}

	bool Parse(const char* commandLine)
	{
		_Cleanup();

		// init temporary arg/argv storage
		std::string currentArg;
		std::vector<std::string> argVector;

		fCurrentArg = &currentArg;
		fCurrentArgStarted = false;
		fArgVector = &argVector;

		for (; *commandLine; commandLine++) {
			char c = *commandLine;

			// whitespace delimits args and is otherwise ignored
			if (isspace(c)) {
				_PushCurrentArg();
				continue;
			}

			switch (c) {
				case '\'':
					// quoted string -- no quoting
					while (*++commandLine != '\'') {
						c = *commandLine;
						if (c == '\0') {
							fprintf(stderr, "Error: Unterminated quoted "
								"string.\n");
							return false;
						}
						_PushCharacter(c);
					}
					break;

				case '"':
					// quoted string -- some quoting
					while (*++commandLine != '"') {
						c = *commandLine;
						if (c == '\0') {
							fprintf(stderr, "Error: Unterminated quoted "
								"string.\n");
							return false;
						}

						if (c == '\\') {
							c = *++commandLine;
							if (c == '\0') {
								fprintf(stderr, "Error: Unterminated quoted "
									"string.\n");
								return false;
							}

							// only '\' and '"' can be quoted, otherwise the
							// the '\' is treated as a normal char
							if (c != '\\' && c != '"')
								_PushCharacter('\\');
						}

						_PushCharacter(c);
					}
					break;

				case '\\':
					// quoted char
					c = *++commandLine;
					if (c == '\0') {
						fprintf(stderr, "Error: Command line ends with "
							"'\\'.\n");
						return false;
					}
					_PushCharacter(c);
					break;

				default:
					// normal char
					_PushCharacter(c);
					break;
			}
		}

		// commit last arg
		_PushCurrentArg();

		// build arg vector
		fArgc = argVector.size();
		fArgv = new char*[fArgc + 1];
		for (int i = 0; i < fArgc; i++) {
			int len = argVector[i].length();
			fArgv[i] = new char[len + 1];
			memcpy(fArgv[i], argVector[i].c_str(), len + 1);
		}
		fArgv[fArgc] = NULL;

		return true;
	}

private:
	void _Cleanup()
	{
		if (fArgv) {
			for (int i = 0; i < fArgc; i++)
				delete[] fArgv[i];
			delete[] fArgv;
		}
	}

	void _PushCurrentArg()
	{
		if (fCurrentArgStarted) {
			fArgVector->push_back(*fCurrentArg);
			fCurrentArgStarted = false;
		}
	}

	void _PushCharacter(char c)
	{
		if (!fCurrentArgStarted) {
			*fCurrentArg = "";
			fCurrentArgStarted = true;
		}

		*fCurrentArg += c;
	}

private:
	// temporaries
	std::string*				fCurrentArg;
	bool						fCurrentArgStarted;
	std::vector<std::string>*	fArgVector;

	int							fArgc;
	char**						fArgv;
};


// #pragma mark - input loop


static char*
read_command_line(char* buffer, int bufferSize)
{
	// print prompt (including cwd, if available)
	char directory[FSSH_B_PATH_NAME_LENGTH];
	if (_kern_getcwd(directory, sizeof(directory)) == FSSH_B_OK)
		printf("fssh:%s> ", directory);
	else
		printf("fssh> ");
	fflush(stdout);

	// read input line
	return fgets(buffer, bufferSize, stdin);
}


static void
input_loop()
{
	static const int kInputBufferSize = 100 * 1024;
	char* inputBuffer = new char[kInputBufferSize];

	for (;;) {
		// read command line
		if (!read_command_line(inputBuffer, kInputBufferSize))
			break;

		// construct argv vector
		ArgVector argVector;
		if (!argVector.Parse(inputBuffer) || argVector.Argc() == 0)
			continue;
		int argc = argVector.Argc();
		const char* const* argv = argVector.Argv();

		// find command
		Command* command = CommandManager::Default()->FindCommand(argv[0]);
		if (!command) {
			fprintf(stderr, "Error: Invalid command \"%s\". Type \"help\" for "
				"a list of supported commands\n", argv[0]);
			continue;
		}

		int result = command->Do(argc, argv);
		if (result == COMMAND_RESULT_EXIT)
			break;
	}

	delete[] inputBuffer;
}


}	// namespace FSShell


using namespace FSShell;


int
main(int argc, const char* const* argv)
{
	if (argc != 2) {
		fprintf(stderr, "Usage: ...\n");
		return 1;
	}

	const char* device = argv[1];

	// get FS module
	if (!modules[0]) {
		fprintf(stderr, "Couldn't find FS module!\n");
		return 1;
	}
	const char* fsName = modules[0]->name;

	fssh_status_t error;

	// init kernel
	error = init_kernel();
	if (error != FSSH_B_OK) {
		fprintf(stderr, "initializing kernel failed: %s\n",
			fssh_strerror(error));
		return error;
	} else
		printf("kernel initialized successfully!\n");

	// mount FS
	fssh_dev_t fsDev = _kern_mount(kMountPoint, device, fsName, 0, NULL, 0);
	if (fsDev < 0) {
		fprintf(stderr, "mounting FS failed: %s\n", fssh_strerror(fsDev));
		return 1;
	} else
		printf("mounted FS successfully!\n");

	// register commands
	register_commands();

	// process commands
	input_loop();

	// unmount FS
	_kern_setcwd(-1, "/");	// avoid a "busy" vnode
	error = _kern_unmount(kMountPoint, 0);
	if (error != FSSH_B_OK) {
		fprintf(stderr, "unmounting FS failed: %s\n", fssh_strerror(error));
		return error;
	} else
		printf("FS unmounted successfully!\n");

	return 0;
}