#!python
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# vi: set ft=python sts=4 ts=4 sw=4 et:
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#
#   See COPYING file distributed along with the NiBabel package for the
#   copyright and license terms.
#
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# Copyright (C) 2011 Christian Haselgrove

import sys
import os
import stat
import errno
import time
import locale
import logging
import fuse
import nibabel as nib
import nibabel.dft as dft

from optparse import OptionParser, Option

uid = os.getuid()
gid = os.getgid()
encoding = locale.getdefaultlocale()[1]

fuse.fuse_python_api = (0, 2)

logger = logging.getLogger('nibabel.dft')

class FileHandle:

    def __init__(self, fno):
        self.fno = fno
        self.keep_cache = False
        self.direct_io = False
        return

    def __str__(self):
        return 'FileHandle(%d)' % self.fno

class DICOMFS(fuse.Fuse):

    def __init__(self, *args, **kwargs):
        self.followlinks = kwargs.pop('followlinks', False)
        fuse.Fuse.__init__(self, *args, **kwargs)
        self.fhs = {}
        return

    def get_paths(self):
        paths = {}
        for study in dft.get_studies(self.dicom_path, self.followlinks):
            pd = paths.setdefault(study.patient_name_or_uid(), {})
            patient_info = 'patient information\n'
            patient_info = 'name: %s\n' % study.patient_name
            patient_info += 'ID: %s\n' % study.patient_id
            patient_info += 'birth date: %s\n' % study.patient_birth_date
            patient_info += 'sex: %s\n' % study.patient_sex
            pd['INFO'] = patient_info.encode('ascii', 'replace')
            study_datetime = '%s_%s' % (study.date, study.time)
            study_info = 'study info\n'
            study_info += 'UID: %s\n' % study.uid
            study_info += 'date: %s\n' % study.date
            study_info += 'time: %s\n' % study.time
            study_info += 'comments: %s\n' % study.comments
            d = {'INFO': study_info.encode('ascii', 'replace')}
            for series in study.series:
                series_info = 'series info\n'
                series_info += 'UID: %s\n' % series.uid
                series_info += 'number: %s\n' % series.number
                series_info += 'description: %s\n' % series.description
                series_info += 'rows: %d\n' % series.rows
                series_info += 'columns: %d\n' % series.columns
                series_info += 'bits allocated: %d\n' % series.bits_allocated
                series_info += 'bits stored: %d\n' % series.bits_stored
                series_info += 'storage instances: %d\n' % len(series.storage_instances)
                d[series.number] = {'INFO': series_info.encode('ascii', 'replace'),
                                    '%s.nii' % series.number: (series.nifti_size, series.as_nifti),
                                    '%s.png' % series.number: (series.png_size, series.as_png)}
            pd[study_datetime] = d
        return paths

    def match_path(self, path):
        wd = self.get_paths()
        if path == '/':
            logger.debug('return root')
            return wd
        for part in path.lstrip('/').split('/'):
            logger.debug("path:%s part:%s" % (path, part))
            if part not in wd:
                return None
            wd = wd[part]
        logger.debug('return')
        return wd

    def readdir(self, path, fh):
        logger.info('readdir %s' % (path,))
        matched_path = self.match_path(path)
        if matched_path is None:
            return -errno.ENOENT
        logger.debug('matched %s' % (matched_path,))
        fnames = [ k.encode('ascii', 'replace') for k in matched_path.keys() ]
        fnames.append('.')
        fnames.append('..')
        return [ fuse.Direntry(f) for f in fnames ]

    def getattr(self, path):
        logger.debug('getattr %s' % path)
        matched_path = self.match_path(path)
        logger.debug('matched: %s' % (matched_path,))
        now = time.time()
        st = fuse.Stat()
        if isinstance(matched_path, dict):
            st.st_mode = stat.S_IFDIR | 0755
            st.st_ctime = now
            st.st_mtime = now
            st.st_atime = now
            st.st_uid = uid
            st.st_gid = gid
            st.st_nlink = len(matched_path)
            return st
        if isinstance(matched_path, str):
            st.st_mode = stat.S_IFREG | 0644
            st.st_ctime = now
            st.st_mtime = now
            st.st_atime = now
            st.st_uid = uid
            st.st_gid = gid
            st.st_size = len(matched_path)
            st.st_nlink = 1
            return st
        if isinstance(matched_path, tuple):
            st.st_mode = stat.S_IFREG | 0644
            st.st_ctime = now
            st.st_mtime = now
            st.st_atime = now
            st.st_uid = uid
            st.st_gid = gid
            st.st_size = matched_path[0]()
            st.st_nlink = 1
            return st
        return -errno.ENOENT

    def open(self, path, flags):
        logger.debug('open %s' % (path,))
        matched_path = self.match_path(path)
        if matched_path is None:
            return -errno.ENOENT
        for i in range(1, 10):
            if i not in self.fhs:
                if isinstance(matched_path, str):
                    self.fhs[i] = matched_path
                elif isinstance(matched_path, tuple):
                    self.fhs[i] = matched_path[1]()
                else:
                    raise -errno.EFTYPE
                return FileHandle(i)
        raise -errno.ENFILE

    # not done
    def read(self, path, size, offset, fh):
        logger.debug('read')
        logger.debug(path)
        logger.debug(size)
        logger.debug(offset)
        logger.debug(fh)
        return self.fhs[fh.fno][offset:offset+size]

    def release(self, path, flags, fh):
        logger.debug('release')
        logger.debug(path)
        logger.debug(fh)
        del self.fhs[fh.fno]
        return

def get_opt_parser():
    # use module docstring for help output
    p = OptionParser(
                usage="%s [OPTIONS] <DIRECTORY CONTAINING DICOMSs> <mount point>"
                      % os.path.basename(sys.argv[0]),
                version="%prog " + nib.__version__)

    p.add_options([
        Option("-v", "--verbose", action="count",
               dest="verbose", default=0,
               help="make noise.  Could be specified multiple times"),
        ])

    p.add_options([
        Option("-L", "--follow-links", action="store_true",
               dest="followlinks", default=False,
               help="Follow symbolic links in DICOM directory"),
        ])
    return p

if __name__ == '__main__':
    parser = get_opt_parser()
    (opts, files) = parser.parse_args()

    if opts.verbose:
        logger.addHandler(logging.StreamHandler(sys.stdout))
        logger.setLevel(opts.verbose > 1 and logging.DEBUG or logging.INFO)

    if len(files) != 2:
        sys.stderr.write("Please provide two arguments:\n%s\n"  % parser.usage)
        sys.exit(1)

    fs = DICOMFS(dash_s_do='setsingle', followlinks=opts.followlinks)
    fs.parse(['-f', '-s', files[1]])
    fs.dicom_path = files[0].decode(encoding)
    try:
        fs.main()
    except fuse.FuseError:
        # fuse prints the error message
        sys.exit(1)

    sys.exit(0)

# eof
