import abc
import glob
import logging
import os
import re
import shutil
import subprocess

from distutils import dir_util

from autotest_lib.client.common_lib import log
from autotest_lib.client.cros import constants
from autotest_lib.client.bin import utils, package

_DEFAULT_COMMANDS_TO_LOG_PER_TEST = []
_DEFAULT_COMMANDS_TO_LOG_PER_BOOT = [
    'lspci -vvn',
    'gcc --version',
    'ld --version',
    'mount',
    'hostname',
    'uptime',
    # for Downloadable Content (DLC)
    'losetup',
    'dlcservice_util --list',
]
_DEFAULT_COMMANDS_TO_LOG_BEFORE_ITERATION = []
_DEFAULT_COMMANDS_TO_LOG_AFTER_ITERATION = []

_DEFAULT_FILES_TO_LOG_PER_TEST = []
_DEFAULT_FILES_TO_LOG_PER_BOOT = [
    '/proc/pci',
    '/proc/meminfo',
    '/proc/slabinfo',
    '/proc/version',
    '/proc/cpuinfo',
    '/proc/modules',
    '/proc/interrupts',
    '/proc/partitions',
    '/var/log/bios_info.txt',
    '/var/log/messages',
    '/var/log/storage_info.txt',
] + list(constants.LOG_PSTORE_DIRS)
_DEFAULT_FILES_TO_LOG_BEFORE_ITERATION = [
    '/proc/schedstat', '/proc/meminfo', '/proc/slabinfo', '/proc/interrupts'
]
_DEFAULT_FILES_TO_LOG_AFTER_ITERATION = [
    '/proc/schedstat', '/proc/meminfo', '/proc/slabinfo', '/proc/interrupts'
]


class loggable(object):
    """ Abstract class for representing all things "loggable" by sysinfo. """

    def __init__(self, logf, log_in_keyval):
        self.logf = logf
        self.log_in_keyval = log_in_keyval

    def readline(self, logdir):
        """Reads one line from the log.

        @param logdir: The log directory.
        @return A line from the log, or the empty string if the log doesn't
            exist.
        """
        path = os.path.join(logdir, self.logf)
        if os.path.exists(path):
            return utils.read_one_line(path)
        else:
            return ""

    @abc.abstractmethod
    def run(self, logdir):
        """Executes this loggable creating output in logdir.

        @param logdir: The output directory.
        """
        raise NotImplementedError()


class logfile(loggable):
    """Represents a log file."""
    def __init__(self, path, logf=None, log_in_keyval=False):
        if not logf:
            logf = os.path.basename(path)
        super(logfile, self).__init__(logf, log_in_keyval)
        self.path = path


    def __repr__(self):
        r = "sysinfo.logfile(%r, %r, %r)"
        r %= (self.path, self.logf, self.log_in_keyval)
        return r


    def __eq__(self, other):
        if isinstance(other, logfile):
            return (self.path, self.logf) == (other.path, other.logf)
        elif isinstance(other, loggable):
            return False
        return NotImplemented


    def __ne__(self, other):
        result = self.__eq__(other)
        if result is NotImplemented:
            return result
        return not result


    def __hash__(self):
        return hash((self.path, self.logf))


    def run(self, logdir):
        """Copies the log file or directory to the specified directory.

        @param logdir: The log directory.
        """
        if os.path.exists(self.path):
            if os.path.isdir(self.path):
                dst = os.path.join(logdir, self.logf, self.path.lstrip('/'))
                dir_util.copy_tree(self.path, dst)
            else:
                dst = os.path.join(logdir, self.logf)
                shutil.copyfile(self.path, dst)
            logging.debug('Loggable saves logs to %s', dst)


class command(loggable):
    """Represents a command."""
    def __init__(self, cmd, logf=None, log_in_keyval=False, compress_log=False):
        if not logf:
            logf = cmd.replace(" ", "_")
        super(command, self).__init__(logf, log_in_keyval)
        self.cmd = cmd
        if compress_log:
            self.cmd += ' | gzip -9'
            self.logf += '.gz'


    def __repr__(self):
        r = "sysinfo.command(%r, %r, %r)"
        r %= (self.cmd, self.logf, self.log_in_keyval)
        return r


    def __eq__(self, other):
        if isinstance(other, command):
            return (self.cmd, self.logf) == (other.cmd, other.logf)
        elif isinstance(other, loggable):
            return False
        return NotImplemented


    def __ne__(self, other):
        result = self.__eq__(other)
        if result is NotImplemented:
            return result
        return not result


    def __hash__(self):
        return hash((self.cmd, self.logf))


    def run(self, logdir):
        """Runs the command.

        @param logdir: The log directory.
        """
        env = os.environ.copy()
        if "PATH" not in env:
            env["PATH"] = "/usr/bin:/bin"
        logf_path = os.path.join(logdir, self.logf)
        stdin = open(os.devnull, "r")
        stderr = open(os.devnull, "w")
        stdout = open(logf_path, "w")
        try:
            logging.debug('Loggable runs cmd: %s', self.cmd)
            subprocess.call(self.cmd,
                            stdin=stdin,
                            stdout=stdout,
                            stderr=stderr,
                            shell=True,
                            env=env)
        finally:
            for f in (stdin, stdout, stderr):
                f.close()


class base_sysinfo(object):
    """Represents system info."""
    def __init__(self, job_resultsdir):
        self.sysinfodir = self._get_sysinfodir(job_resultsdir)

        # pull in the post-test logs to collect
        self.test_loggables = set()
        for cmd in _DEFAULT_COMMANDS_TO_LOG_PER_TEST:
            self.test_loggables.add(command(cmd))
        for filename in _DEFAULT_FILES_TO_LOG_PER_TEST:
            self.test_loggables.add(logfile(filename))

        # pull in the EXTRA post-boot logs to collect
        self.boot_loggables = set()
        for cmd in _DEFAULT_COMMANDS_TO_LOG_PER_BOOT:
            self.boot_loggables.add(command(cmd))
        for filename in _DEFAULT_FILES_TO_LOG_PER_BOOT:
            self.boot_loggables.add(logfile(filename))

        # pull in the pre test iteration logs to collect
        self.before_iteration_loggables = set()
        for cmd in _DEFAULT_COMMANDS_TO_LOG_BEFORE_ITERATION:
            self.before_iteration_loggables.add(
                command(cmd, logf=cmd.replace(" ", "_") + '.before'))
        for fname in _DEFAULT_FILES_TO_LOG_BEFORE_ITERATION:
            self.before_iteration_loggables.add(
                logfile(fname, logf=os.path.basename(fname) + '.before'))

        # pull in the post test iteration logs to collect
        self.after_iteration_loggables = set()
        for cmd in _DEFAULT_COMMANDS_TO_LOG_AFTER_ITERATION:
            self.after_iteration_loggables.add(
                command(cmd, logf=cmd.replace(" ", "_") + '.after'))
        for fname in _DEFAULT_FILES_TO_LOG_AFTER_ITERATION:
            self.after_iteration_loggables.add(
                logfile(fname, logf=os.path.basename(fname) + '.after'))

        # add in a couple of extra files and commands we want to grab
        self.test_loggables.add(command("df -mP", logf="df"))
        # We compress the dmesg because it can get large when kernels are
        # configured with a large buffer and some tests trigger OOMs or
        # other large "spam" that fill it up...
        self.test_loggables.add(command('dmesg -c',
                                        logf='dmesg',
                                        compress_log=True))
        self.boot_loggables.add(logfile('/proc/cmdline', log_in_keyval=True))
        # log /proc/mounts but with custom filename since we already
        # log the output of the "mount" command as the filename "mount"
        self.boot_loggables.add(logfile('/proc/mounts', logf='proc_mounts'))
        self.boot_loggables.add(command('uname -a',
                                        logf='uname',
                                        log_in_keyval=True))

        # log contents of DLC directories with meaningful filenames
        self.boot_loggables.add(command('tree /var/cache/dlc',
                                        logf='dlc_images'))
        self.boot_loggables.add(command(
            'tree /mnt/stateful_partition/var_overlay/cache/dlc-images',
            logf='dlc_preloaded_images'))

        self._installed_packages = []
        self._journal_cursor = None


    def serialize(self):
        """Returns parameters in a dictionary."""
        return {"boot": self.boot_loggables, "test": self.test_loggables}


    def deserialize(self, serialized):
        """Stores parameters from a dictionary into instance variables.

        @param serialized: A dictionary containing parameters to store as
            instance variables.
        """
        self.boot_loggables = serialized["boot"]
        self.test_loggables = serialized["test"]


    @staticmethod
    def _get_sysinfodir(resultsdir):
        sysinfodir = os.path.join(resultsdir, "sysinfo")
        if not os.path.exists(sysinfodir):
            os.makedirs(sysinfodir)
        return sysinfodir


    def _get_reboot_count(self):
        if not glob.glob(os.path.join(self.sysinfodir, "*")):
            return -1
        else:
            return len(glob.glob(os.path.join(self.sysinfodir, "boot.*")))


    def _get_boot_subdir(self, next=False):
        reboot_count = self._get_reboot_count()
        if next:
            reboot_count += 1
        if reboot_count < 1:
            return self.sysinfodir
        else:
            boot_dir = "boot.%d" % (reboot_count - 1)
            return os.path.join(self.sysinfodir, boot_dir)


    def _get_iteration_subdir(self, test, iteration):
        iter_dir = "iteration.%d" % iteration

        logdir = os.path.join(self._get_sysinfodir(test.outputdir), iter_dir)
        if not os.path.exists(logdir):
            os.mkdir(logdir)
        return logdir


    @log.log_and_ignore_errors("post-reboot sysinfo error:")
    def log_per_reboot_data(self):
        """Logging hook called when a job starts, and again after any reboot."""
        logdir = self._get_boot_subdir(next=True)
        if not os.path.exists(logdir):
            os.mkdir(logdir)

        _run_loggables_ignoring_errors(
                self.test_loggables | self.boot_loggables,
                logdir)

        # also log any installed packages
        installed_path = os.path.join(logdir, "installed_packages")
        installed_packages = "\n".join(package.list_all()) + "\n"
        utils.open_write_close(installed_path, installed_packages)


    @log.log_and_ignore_errors("pre-test sysinfo error:")
    def log_before_each_test(self, test):
        """Logging hook called before a test starts.

        @param test: A test object.
        """
        self._installed_packages = package.list_all()
        if os.path.exists("/var/log/messages"):
            stat = os.stat("/var/log/messages")
            self._messages_size = stat.st_size
            self._messages_inode = stat.st_ino

        self._journal_cursor = get_journal_cursor()
        # We want to only log the journal from this point on, not everything.
        # When you do not filter from the cursor on the journal.gz can be
        # extremely large and take a very long amount of time to compress.
        if self._journal_cursor:
            self.test_loggables.add(command((
                'journalctl -o export -c "{}"'.format(self._journal_cursor)),
                logf='journal',
                compress_log=True))


        # log some sysinfo data into the test keyval file in case system crash.
        test_sysinfodir = self._get_sysinfodir(test.outputdir)
        keyval = self.log_test_keyvals(test_sysinfodir)
        test.write_test_keyval(keyval)

    @log.log_and_ignore_errors("post-test sysinfo error:")
    def log_after_each_test(self, test):
        """Logging hook called after a test finishs.

        @param test: A test object.
        """
        test_sysinfodir = self._get_sysinfodir(test.outputdir)

        # create a symlink in the test sysinfo dir to the current boot
        reboot_dir = self._get_boot_subdir()
        assert os.path.exists(reboot_dir)
        symlink_dest = os.path.join(test_sysinfodir, "reboot_current")
        symlink_src = utils.get_relative_path(reboot_dir,
                                              os.path.dirname(symlink_dest))
        try:
            os.symlink(symlink_src, symlink_dest)
        except Exception, e:
            raise Exception, '%s: whilst linking %s to %s' % (e, symlink_src,
                                                              symlink_dest)

        # run all the standard logging commands
        _run_loggables_ignoring_errors(self.test_loggables, test_sysinfodir)

        # grab any new data from /var/log/messages
        self._log_messages(test_sysinfodir)

        # log some sysinfo data into the test keyval file
        keyval = self.log_test_keyvals(test_sysinfodir)
        test.write_test_keyval(keyval)

        # log any changes to installed packages
        old_packages = set(self._installed_packages)
        new_packages = set(package.list_all())
        added_path = os.path.join(test_sysinfodir, "added_packages")
        added_packages = "\n".join(new_packages - old_packages) + "\n"
        utils.open_write_close(added_path, added_packages)
        removed_path = os.path.join(test_sysinfodir, "removed_packages")
        removed_packages = "\n".join(old_packages - new_packages) + "\n"
        utils.open_write_close(removed_path, removed_packages)


    @log.log_and_ignore_errors("pre-test siteration sysinfo error:")
    def log_before_each_iteration(self, test, iteration=None):
        """Logging hook called before a test iteration.

        @param test: A test object.
        @param iteration: A test iteration.
        """
        if not iteration:
            iteration = test.iteration
        logdir = self._get_iteration_subdir(test, iteration)
        _run_loggables_ignoring_errors(self.before_iteration_loggables, logdir)
        # Start each log with the board name for orientation.
        board = utils.get_board_with_frequency_and_memory()
        logging.info('ChromeOS BOARD = %s', board)
        # Leave some autotest bread crumbs in the system logs.
        utils.system('logger "autotest starting iteration %s on %s"' % (logdir,
                                                                        board),
                     ignore_status=True)


    @log.log_and_ignore_errors("post-test siteration sysinfo error:")
    def log_after_each_iteration(self, test, iteration=None):
        """Logging hook called after a test iteration.

        @param test: A test object.
        @param iteration: A test iteration.
        """
        if not iteration:
            iteration = test.iteration
        logdir = self._get_iteration_subdir(test, iteration)
        _run_loggables_ignoring_errors(self.after_iteration_loggables, logdir)
        utils.system('logger "autotest finished iteration %s"' % logdir,
                     ignore_status=True)


    def _log_messages(self, logdir):
        """Log all of the new data in /var/log/messages."""
        try:
            # log all of the new data in /var/log/messages
            bytes_to_skip = 0
            if hasattr(self, "_messages_size"):
                current_inode = os.stat("/var/log/messages").st_ino
                if current_inode == self._messages_inode:
                    bytes_to_skip = self._messages_size
            in_messages = open("/var/log/messages")
            in_messages.seek(bytes_to_skip)
            out_messages = open(os.path.join(logdir, "messages"), "w")
            out_messages.write(in_messages.read())
            in_messages.close()
            out_messages.close()
        except Exception, e:
            logging.error("/var/log/messages collection failed with %s", e)


    @staticmethod
    def _read_sysinfo_keyvals(loggables, logdir):
        keyval = {}
        for log in loggables:
            if log.log_in_keyval:
                keyval["sysinfo-" + log.logf] = log.readline(logdir)
        return keyval


    def log_test_keyvals(self, test_sysinfodir):
        """Generate keyval for the sysinfo.

        Collects keyval entries to be written in the test keyval.

        @param test_sysinfodir: The test's system info directory.
        """
        keyval = {}

        # grab any loggables that should be in the keyval
        keyval.update(self._read_sysinfo_keyvals(self.test_loggables,
                                                 test_sysinfodir))
        keyval.update(self._read_sysinfo_keyvals(
            self.boot_loggables, os.path.join(test_sysinfodir,
                                              'reboot_current')))

        # remove hostname from uname info
        #   Linux lpt36 2.6.18-smp-230.1 #1 [4069269] SMP Fri Oct 24 11:30:...
        if "sysinfo-uname" in keyval:
            kernel_vers = " ".join(keyval["sysinfo-uname"].split()[2:])
            keyval["sysinfo-uname"] = kernel_vers

        # grab the total avail memory, not used by sys tables
        path = os.path.join(test_sysinfodir, "reboot_current", "meminfo")
        if os.path.exists(path):
            mem_data = open(path).read()
            match = re.search(r'^MemTotal:\s+(\d+) kB$', mem_data, re.MULTILINE)
            if match:
                keyval["sysinfo-memtotal-in-kb"] = match.group(1)

        # guess the system's total physical memory, including sys tables
        keyval["sysinfo-phys-mbytes"] = utils.rounded_memtotal()//1024

        # return what we collected
        return keyval

def _run_loggables_ignoring_errors(loggables, output_dir):
    """Runs the given loggables robustly.

    In the event of any one of the loggables raising an exception, we print a
    traceback and continue on.

    @param loggables: An iterable of base_sysinfo.loggable objects.
    @param output_dir: Path to the output directory.
    """
    for log in loggables:
        try:
            log.run(output_dir)
        except Exception:
            logging.exception(
                    'Failed to collect loggable %r to %s. Continuing...',
                    log, output_dir)

def get_journal_cursor():
    cmd = "/usr/bin/journalctl  -n0 --show-cursor -q"
    try:
        cursor = utils.system_output(cmd)
        prefix = "-- cursor: "
        pos = cursor.find(prefix) + len(prefix)
        return cursor[pos:]
    except Exception, e:
        logging.error("error running journalctl --show-cursor: %s", e)