# -*- Mode: Python; test-case-name: morituri.test.test_common_checksum -*-
# vi:si:et:sw=4:sts=4:ts=4

# Morituri - for those about to RIP

# Copyright (C) 2009 Thomas Vander Stichele

# This file is part of morituri.
#
# morituri 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.
#
# morituri 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 morituri.  If not, see <http://www.gnu.org/licenses/>.

import os
import struct
import zlib

import gst

from morituri.common import common
from morituri.common import gstreamer as cgstreamer
from morituri.common import log
from morituri.common import task

from morituri.extern.task import gstreamer
from morituri.extern.task import task as etask

from morituri.program.arc import accuraterip_checksum


# checksums are not CRC's. a CRC is a specific type of checksum.


class ChecksumTask(log.Loggable, gstreamer.GstPipelineTask):
    """
    I am a task that calculates a checksum of the decoded audio data.

    @ivar checksum: the resulting checksum
    """

    logCategory = 'ChecksumTask'

    # this object needs a main loop to stop
    description = 'Calculating checksum'

    def __init__(self, path, sampleStart=0, sampleLength=-1):
        """
        A sample is considered a set of samples for each channel;
        ie 16 bit stereo is 4 bytes per sample.
        If sampleLength < 0 it is treated as 'unknown' and calculated.

        @type  path:       unicode
        @type  sampleStart: int
        @param sampleStart: the sample to start at
        """

        # sampleLength can be e.g. -588 when it is -1 * SAMPLES_PER_FRAME

        assert type(path) is unicode, "%r is not unicode" % path

        self.logName = "ChecksumTask 0x%x" % id(self)

        # use repr/%r because path can be unicode
        if sampleLength < 0:
            self.debug(
                'Creating checksum task on %r from sample %d until the end',
                path, sampleStart)
        else:
            self.debug(
                'Creating checksum task on %r from sample %d for %d samples',
                path, sampleStart, sampleLength)

        if not os.path.exists(path):
            raise IndexError('%r does not exist' % path)

        self._path = path
        self._sampleStart = sampleStart
        self._sampleLength = sampleLength
        self._sampleEnd = None
        self._checksum = 0
        self._bytes = 0 # number of bytes received
        self._first = None
        self._last = None
        self._adapter = gst.Adapter()

        self.checksum = None # result

        cgstreamer.removeAudioParsers()

    ### gstreamer.GstPipelineTask implementations

    def getPipelineDesc(self):
        return '''
            filesrc location="%s" !
            decodebin name=decode ! audio/x-raw-int !
            appsink name=sink sync=False emit-signals=True
            ''' % gstreamer.quoteParse(self._path).encode('utf-8')

    def _getSampleLength(self):
        # get length in samples of file
        sink = self.pipeline.get_by_name('sink')

        self.debug('query duration')
        try:
            length, qformat = sink.query_duration(gst.FORMAT_DEFAULT)
        except gst.QueryError, e:
            self.setException(e)
            return None

        # wavparse 0.10.14 returns in bytes
        if qformat == gst.FORMAT_BYTES:
            self.debug('query returned in BYTES format')
            length /= 4
        self.debug('total sample length of file: %r', length)

        return length


    def paused(self):
        sink = self.pipeline.get_by_name('sink')

        length = self._getSampleLength()
        if length is None:
            return

        if self._sampleLength < 0:
            self._sampleLength = length - self._sampleStart
            self.debug('sampleLength is queried as %d samples',
                self._sampleLength)
        else:
            self.debug('sampleLength is known, and is %d samples' %
                self._sampleLength)

        self._sampleEnd = self._sampleStart + self._sampleLength - 1
        self.debug('sampleEnd is sample %d' % self._sampleEnd)

        self.debug('event')


        if self._sampleStart == 0 and self._sampleEnd + 1 == length:
            self.debug('No need to seek, crcing full file')
        else:
            # the segment end only is respected since -good 0.10.14.1
            event = gst.event_new_seek(1.0, gst.FORMAT_DEFAULT,
                gst.SEEK_FLAG_FLUSH,
                gst.SEEK_TYPE_SET, self._sampleStart,
                gst.SEEK_TYPE_SET, self._sampleEnd + 1) # half-inclusive
            self.debug('CRCing %r from frame %d to frame %d (excluded)' % (
                self._path,
                self._sampleStart / common.SAMPLES_PER_FRAME,
                (self._sampleEnd + 1) / common.SAMPLES_PER_FRAME))
            # FIXME: sending it with sampleEnd set screws up the seek, we
            # don't get # everything for flac; fixed in recent -good
            result = sink.send_event(event)
            self.debug('event sent, result %r', result)
            if not result:
                self.error('Failed to select samples with GStreamer seek event')
        sink.connect('new-buffer', self._new_buffer_cb)
        sink.connect('eos', self._eos_cb)

        self.debug('scheduling setting to play')
        # since set_state returns non-False, adding it as timeout_add
        # will repeatedly call it, and block the main loop; so
        #   gobject.timeout_add(0L, self.pipeline.set_state, gst.STATE_PLAYING)
        # would not work.

        def play():
            self.pipeline.set_state(gst.STATE_PLAYING)
            return False
        self.schedule(0, play)

        #self.pipeline.set_state(gst.STATE_PLAYING)
        self.debug('scheduled setting to play')

    def stopped(self):
        self.debug('stopped')
        if not self._last:
            # see http://bugzilla.gnome.org/show_bug.cgi?id=578612
            self.debug(
                'not a single buffer gotten, setting exception EmptyError')
            self.setException(common.EmptyError('not a single buffer gotten'))
            return
        else:
            self._checksum = self._checksum % 2 ** 32
            self.debug("last buffer's sample offset %r", self._last.offset)
            self.debug("last buffer's sample size %r", len(self._last) / 4)
            last = self._last.offset + len(self._last) / 4 - 1
            self.debug("last sample offset in buffer: %r", last)
            self.debug("requested sample end: %r", self._sampleEnd)
            self.debug("requested sample length: %r", self._sampleLength)
            self.debug("checksum: %08X", self._checksum)
            self.debug("bytes: %d", self._bytes)
            if self._sampleEnd != last:
                msg = 'did not get all samples, %d of %d missing' % (
                    self._sampleEnd - last, self._sampleEnd)
                self.warning(msg)
                self.setExceptionAndTraceback(common.MissingFrames(msg))
                return

        self.checksum = self._checksum

    ### subclass methods

    def do_checksum_buffer(self, buf, checksum):
        """
        Subclasses should implement this.

        @param buf:      a byte buffer containing two 16-bit samples per
                         channel.
        @type  buf:      C{str}
        @param checksum: the checksum so far, as returned by the
                         previous call.
        @type  checksum: C{int}
        """
        raise NotImplementedError

    ### private methods

    def _new_buffer_cb(self, sink):
        buf = sink.emit('pull-buffer')
        gst.log('received new buffer at offset %r with length %r' % (
            buf.offset, buf.size))
        if self._first is None:
            self._first = buf.offset
            self.debug('first sample is sample offset %r', self._first)
        self._last = buf

        assert len(buf) % 4 == 0, "buffer is not a multiple of 4 bytes"

        # FIXME: gst-python 0.10.14.1 doesn't have adapter_peek/_take wrapped
        # see http://bugzilla.gnome.org/show_bug.cgi?id=576505
        self._adapter.push(buf)

        while self._adapter.available() >= common.BYTES_PER_FRAME:
            # FIXME: in 0.10.14.1, take_buffer leaks a ref
            buf = self._adapter.take_buffer(common.BYTES_PER_FRAME)

            self._checksum = self.do_checksum_buffer(buf, self._checksum)
            self._bytes += len(buf)

            # update progress
            sample = self._first + self._bytes / 4
            samplesDone = sample - self._sampleStart
            progress = float(samplesDone) / float((self._sampleLength))
            # marshal to the main thread
            self.schedule(0, self.setProgress, progress)

    def _eos_cb(self, sink):
        # get the last one; FIXME: why does this not get to us before ?
        #self._new_buffer_cb(sink)
        self.debug('eos, scheduling stop')
        self.schedule(0, self.stop)


class CRC32Task(ChecksumTask):
    """
    I do a simple CRC32 check.
    """

    description = 'Calculating CRC'

    def do_checksum_buffer(self, buf, checksum):
        return zlib.crc32(buf, checksum)


class FastAccurateRipChecksumTask(etask.Task):
    description = 'Calculating (Fast) AccurateRip checksum'

    def __init__(self, path, trackNumber, trackCount, wave, v2=False):
        self.path = path
        self.trackNumber = trackNumber
        self.trackCount = trackCount
        self._wave = wave
        self._v2 = v2
        self.checksum = None

    def start(self, runner):
        etask.Task.start(self, runner)
        self.schedule(0.0, self._arc)

    def _arc(self):
        arc = accuraterip_checksum(self.path, self.trackNumber, self.trackCount,
                self._wave, self._v2)
        self.checksum = arc

        self.stop()


class AccurateRipChecksumTask(ChecksumTask):
    """
    I implement the AccurateRip checksum.

    See http://www.accuraterip.com/
    """

    description = 'Calculating AccurateRip checksum'

    def __init__(self, path, trackNumber, trackCount, sampleStart=0,
            sampleLength=-1):
        ChecksumTask.__init__(self, path, sampleStart, sampleLength)
        self._trackNumber = trackNumber
        self._trackCount = trackCount
        self._discFrameCounter = 0 # 1-based

    def __repr__(self):
        return "<AccurateRipCheckSumTask of track %d in %r>" % (
            self._trackNumber, self._path)

    def do_checksum_buffer(self, buf, checksum):
        self._discFrameCounter += 1

        # on first track ...
        if self._trackNumber == 1:
            # ... skip first 4 CD frames
            if self._discFrameCounter <= 4:
                gst.debug('skipping frame %d' % self._discFrameCounter)
                return checksum
            # ... on 5th frame, only use last value
            elif self._discFrameCounter == 5:
                values = struct.unpack("<I", buf[-4:])
                checksum += common.SAMPLES_PER_FRAME * 5 * values[0]
                checksum &= 0xFFFFFFFF
                return checksum

        # on last track, skip last 5 CD frames
        if self._trackNumber == self._trackCount:
            discFrameLength = self._sampleLength / common.SAMPLES_PER_FRAME
            if self._discFrameCounter > discFrameLength - 5:
                self.debug('skipping frame %d', self._discFrameCounter)
                return checksum

        # self._bytes is updated after do_checksum_buffer
        factor = self._bytes / 4 + 1
        values = struct.unpack("<%dI" % (len(buf) / 4), buf)
        for value in values:
            checksum += factor * value
            factor += 1
            # offset = self._bytes / 4 + i + 1
            # if offset % common.SAMPLES_PER_FRAME == 0:
            #   print 'frame %d, ends before %d, last value %08x, CRC %08x' % (
            #     offset / common.SAMPLES_PER_FRAME, offset, value, sum)

        checksum &= 0xFFFFFFFF
        return checksum


class TRMTask(task.GstPipelineTask):
    """
    I calculate a MusicBrainz TRM fingerprint.

    @ivar trm: the resulting trm
    """

    trm = None
    description = 'Calculating fingerprint'

    def __init__(self, path):
        if not os.path.exists(path):
            raise IndexError('%s does not exist' % path)

        self.path = path
        self._trm = None
        self._bus = None

    def getPipelineDesc(self):
        return '''
            filesrc location="%s" !
            decodebin ! audioconvert ! audio/x-raw-int !
            trm name=trm !
            appsink name=sink sync=False emit-signals=True''' % self.path

    def parsed(self):
        sink = self.pipeline.get_by_name('sink')
        sink.connect('new-buffer', self._new_buffer_cb)

    def paused(self):
        gst.debug('query duration')

        self._length, qformat = self.pipeline.query_duration(gst.FORMAT_TIME)
        gst.debug('total length: %r' % self._length)
        gst.debug('scheduling setting to play')
        # since set_state returns non-False, adding it as timeout_add
        # will repeatedly call it, and block the main loop; so
        #   gobject.timeout_add(0L, self.pipeline.set_state, gst.STATE_PLAYING)
        # would not work.


    # FIXME: can't move this to base class because it triggers too soon
    # in the case of checksum

    def bus_eos_cb(self, bus, message):
        gst.debug('eos, scheduling stop')
        self.schedule(0, self.stop)

    def bus_tag_cb(self, bus, message):
        taglist = message.parse_tag()
        if 'musicbrainz-trmid' in taglist.keys():
            self._trm = taglist['musicbrainz-trmid']

    def _new_buffer_cb(self, sink):
        # this is just for counting progress
        buf = sink.emit('pull-buffer')
        position = buf.timestamp
        if buf.duration != gst.CLOCK_TIME_NONE:
            position += buf.duration
        self.setProgress(float(position) / self._length)

    def stopped(self):
        self.trm = self._trm

class MaxSampleTask(ChecksumTask):
    """
    I check for the biggest sample value.
    """

    description = 'Finding highest sample value'

    def do_checksum_buffer(self, buf, checksum):
        values = struct.unpack("<%dh" % (len(buf) / 2), buf)
        absvalues = [abs(v) for v in values]
        m = max(absvalues)
        if checksum < m:
            checksum = m

        return checksum