# -*- coding: utf-8; mode: python; -*-
#
#  GStreamer Debug Viewer - View and analyze GStreamer debug log files
#
#  Copyright (C) 2007 René Stadler <mail@renestadler.de>
#
#  This program is free software; you can redistribute it and/or modify it
#  under the terms of the GNU General Public License as published by the Free
#  Software Foundation; either version 3 of the License, or (at your option)
#  any later version.
#
#  This program is distributed in the hope that it will be useful, but WITHOUT
#  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
#  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
#  more details.
#
#  You should have received a copy of the GNU General Public License along with
#  this program.  If not, see <http://www.gnu.org/licenses/>.

"""GStreamer Debug Viewer Data module."""

import os
import logging
import re

# Nanosecond resolution (like gst.SECOND)
SECOND = 1000000000

def time_args (ts):

    secs = ts // SECOND

    return "%i:%02i:%02i.%09i" % (secs // 60**2,
                                  secs // 60 % 60,
                                  secs % 60,
                                  ts % SECOND,)

def time_args_no_hours (ts):

    secs = ts // SECOND

    return "%02i:%02i.%09i" % (secs // 60,
                               secs % 60,
                               ts % SECOND,)

def parse_time (st):

    """Parse time strings that look like "0:00:00.0000000"."""

    h, m, s = st.split (":")
    secs, subsecs = s.split (".")

    return (long ((int (h) * 60**2 + int (m) * 60) * SECOND) +
            long (secs) * SECOND + long (subsecs))

class DebugLevel (int):

    __names = ["NONE", "ERROR", "WARN", "INFO", "DEBUG", "LOG"]
    __instances = {}

    def __new__ (cls, level):

        try:
            level_int = int (level)
        except (ValueError, TypeError,):
            try:
                level_int = cls.__names.index (level.upper ())
            except ValueError:
                raise ValueError ("no debug level named %r" % (level,))
        if level_int in cls.__instances:
            return cls.__instances[level_int]
        else:
            new_instance = int.__new__ (cls, level_int)
            new_instance.name = cls.__names[level_int]
            cls.__instances[level_int] = new_instance
            return new_instance

    def __repr__ (self):

        return "<%s %s (%i)>" % (type (self).__name__, self.__names[self], self,)

    def higher_level (self):

        if self == len (self.__names) - 1:
            raise ValueError ("already the highest debug level")

        return DebugLevel (self + 1)

    def lower_level (self):

        if self == 0:
            raise ValueError ("already the lowest debug level")

        return DebugLevel (self - 1)

debug_level_none = DebugLevel ("NONE")
debug_level_error = DebugLevel ("ERROR")
debug_level_warning = DebugLevel ("WARN")
debug_level_info = DebugLevel ("INFO")
debug_level_debug = DebugLevel ("DEBUG")
debug_level_log = DebugLevel ("LOG")
debug_levels = [debug_level_none,
                debug_level_log,
                debug_level_debug,
                debug_level_info,
                debug_level_warning,
                debug_level_error]

# For stripping color codes:
_escape = re.compile ("\x1b\\[[0-9;]*m")
def strip_escape (s):

    # FIXME: This can be optimized further!

    while "\x1b" in s:
        s = _escape.sub ("", s)
    return s

def default_log_line_regex_ ():

    # "DEBUG             "
    LEVEL = "([A-Z]+)\s+"
    # "0x8165430 "
    THREAD = r"(0x[0-9a-f]+)\s+" #r"\((0x[0-9a-f]+) - "
    # "0:00:00.777913000  "
    TIME = r"(\d+:\d\d:\d\d\.\d+)\s+"
    CATEGORY = "([A-Za-z0-9_-]+)\s+" # "GST_REFCOUNTING ", "flacdec "
    # "  3089 "
    PID = r"(\d+)\s+"
    FILENAME = r"([^:]+):"
    LINE = r"(\d+):"
    FUNCTION = "([A-Za-z0-9_]+):"
    # FIXME: When non-g(st)object stuff is logged with *_OBJECT (like
    # buffers!), the address is printed *without* <> brackets!
    OBJECT = "(?:<([^>]+)> )?"
    MESSAGE = "(.+)"

    # New log format:
    expressions = [TIME, PID, THREAD, LEVEL, CATEGORY, FILENAME, LINE, FUNCTION,
                   OBJECT, MESSAGE]
    # Old log format:
    ## expressions = [LEVEL, THREAD, TIME, CATEGORY, PID, FILENAME, LINE,
    ##                FUNCTION, OBJECT, MESSAGE]

    return expressions

def default_log_line_regex ():
    
    expressions = default_log_line_regex_ ()
    return re.compile ("".join (expressions))

class Producer (object):

    def __init__ (self):

        self.consumers = []

    def have_load_started (self):

        for consumer in self.consumers:
            consumer.handle_load_started ()

    def have_load_finished (self):

        for consumer in self.consumers:
            consumer.handle_load_finished ()

class LineCache (Producer):

    _lines_per_iteration = 50000

    def __init__ (self, fileobj, dispatcher):

        Producer.__init__ (self)

        self.logger = logging.getLogger ("linecache")
        self.dispatcher = dispatcher

        self.__fileobj = fileobj
        self.__fileobj.seek (0, 2)
        self.__file_size = self.__fileobj.tell ()
        self.__fileobj.seek (0)

        self.offsets = []
        self.levels = [] # FIXME

    def start_loading (self):

        self.logger.debug ("dispatching load process")
        self.have_load_started ()
        self.dispatcher (self.__process ())

    def get_progress (self):

        return float (self.__fileobj.tell ()) / self.__file_size

    def __process (self):

        offsets = self.offsets
        levels = self.levels

        dict_levels = {"D" : debug_level_debug, "L" : debug_level_log,
                       "I" : debug_level_info, "E" : debug_level_error,
                       "W" : debug_level_warning, " " : debug_level_none}
        rexp = re.compile (r"\d:\d\d:\d\d\.\d+\s+\d+\s+0x[0-9a-f]+\s+([DLIEW ])")

        # Moving attribute lookups out of the loop:
        readline = self.__fileobj.readline
        tell = self.__fileobj.tell
        rexp_match = rexp.match
        levels_append = levels.append
        offsets_append = offsets.append
        dict_levels_get = dict_levels.get

        self.__fileobj.seek (0)
        limit = self._lines_per_iteration
        i = 0
        while True:
            offset = tell ()
            line = readline ()
            if not line:
                break
            match = rexp_match (line)
            if match is None:
                continue
            levels_append (dict_levels_get (match.group (1), debug_level_none))
            offsets_append (offset)
            i += 1
            if i >= limit:
                i = 0
                yield True

        self.have_load_finished ()
        yield False

class LogLine (list):

    _line_regex = default_log_line_regex ()

    @classmethod
    def parse_full (cls, line_string):

        match = cls._line_regex.match (line_string)
        if match is None:
            ## raise ValueError ("not a valid log line (%r)" % (line_string,))
            groups = [0, 0, 0, 0, "", "", 0, "", "", 0]
            return cls (groups)

        line = cls (match.groups ())
        # Timestamp.
        line[0] = parse_time (line[0])
        # PID.
        line[1] = int (line[1])
        # Thread.
        line[2] = int (line[2], 16)
        # Level (this is handled in LineCache).
        line[3] = 0
        # Line.
        line[6] = int (line[6])
        # Message start offset.
        line[9] = match.start (9 + 1)

        for col_id in (4,   # COL_CATEGORY
                       5,   # COL_FILENAME
                       7,   # COL_FUNCTION,
                       8,): # COL_OBJECT
            line[col_id] = intern (line[col_id] or "")

        return line

    def line_string (self, message = None):

        # Replicates gstreamer/gst/gstinfo.c:gst_debug_log_default.

        ts, pid, thread, level, category, filename, line, function, object_, message_offset = self

        if isinstance (message_offset, str):
            message = message_offset

        # FIXME: Regarding object_, this doesn't fully replicate the formatting!
        return "%s %5d 0x%x %s %20s %s:%d:%s:<%s> %s" % (time_args (ts), pid, thread, level.name.ljust (5),
                                                         category, filename, line, function,
                                                         object_, message,)

class LogLines (object):

    def __init__ (self, fileobj, line_cache):

        self.__fileobj = fileobj
        self.__line_cache = line_cache

    def __len__ (self):

        return len (self.__line_cache.offsets)

    def __getitem__ (self, line_index):

        offset = self.__line_cache.offsets[line_index]
        self.__fileobj.seek (offset)
        line_string = self.__fileobj.readline ()
        line = LogLine.parse_full (line_string)
        msg = line_string[line[-1]:]
        line[-1] = msg
        return line

    def __iter__ (self):

        l = len (self)
        i = 0
        while i < l:
            yield self[i]
            i += 1

class LogFile (Producer):

    def __init__ (self, filename, dispatcher):

        import mmap

        Producer.__init__ (self)

        self.logger = logging.getLogger ("logfile")

        self.path = os.path.normpath (os.path.abspath (filename))
        self.__real_fileobj = file (filename, "rb")
        self.fileobj = mmap.mmap (self.__real_fileobj.fileno (), 0, prot = mmap.PROT_READ)
        self.line_cache = LineCache (self.fileobj, dispatcher)
        self.line_cache.consumers.append (self)

    def get_full_line (self, line_index):

        offset = self.line_cache.offsets[line_index]
        self.fileobj.seek (offset)
        line_string = self.fileobj.readline ()
        line = LogLine.parse_full (line_string)
        msg = line_string[line[-1]:]
        line[-1] = msg
        return line

    def start_loading (self):

        self.logger.debug ("starting load")
        self.line_cache.start_loading ()

    def get_load_progress (self):

        return self.line_cache.get_progress ()

    def handle_load_started (self):

        # Chain up to our consumers:
        self.have_load_started ()

    def handle_load_finished (self):

        self.lines = LogLines (self.fileobj, self.line_cache)

        # Chain up to our consumers:
        self.have_load_finished ()