# -*- coding: utf-8 -*-

# ******************************************************************************
#
# Copyright (C) 2006-2011 Olivier Tilloy <olivier@tilloy.net>
# Copyright (C) 2015-2020 Vincent Vande Vyvre <vincent.vandevyvre@oqapy.eu>
#
# This file is part of the py3exiv2 distribution.
#
# py3exiv2 is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# version 3 as published by the Free Software Foundation.
#
# py3exiv2 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 py3exiv2; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
#
# Maintainer: Vincent Vande Vyvre <vincent.vandevyvre@oqapy.eu>
#
# ******************************************************************************

"""
XMP specific code.
"""

import libexiv2python

from pyexiv2.utils import (FixedOffset, is_fraction, make_fraction,
                          GPSCoordinate, DateTimeFormatter)

import datetime
import re


class XmpValueError(ValueError):

    """
    Exception raised when failing to parse the *value* of an XMP tag.

    :attribute value: the value that fails to be parsed
    :type value: string
    :attribute type: the XMP type of the tag
    :type type: string
    """
    def __init__(self, value, type_):
        self.value = value
        self.type = type_

    def __str__(self):
        return 'Invalid value for XMP type [%s]: [%s]' % \
               (self.type, self.value)


class XmpTag(object):

    """Define an XMP tag.

    Here is a correspondance table between the XMP types and the possible
    python types the value of a tag may take:

    - alt, bag, seq: list of the contained simple type
    - lang alt: dict of (language-code: value)
    - Boolean: boolean
    - Colorant: *[not implemented yet]*
    - Date: :class:`datetime.date`, :class:`datetime.datetime`
    - Dimensions: *[not implemented yet]*
    - Font: *[not implemented yet]*
    - GPSCoordinate: :class:`pyexiv2.utils.GPSCoordinate`
    - Integer: int
    - Locale: *[not implemented yet]*
    - MIMEType: 2-tuple of strings
    - Rational: :class:`fractions.Fraction`
    - Real: *[not implemented yet]*
    - AgentName, ProperName, Text: unicode string
    - Thumbnail: *[not implemented yet]*
    - URI, URL: string
    - XPath: *[not implemented yet]*
    """

    # strptime is not flexible enough to handle all valid Date formats, we use a
    # custom regular expression
    _time_zone_re = r'$|Z|((?P<sign>\+|-)(?P<ohours>\d{2}):(?P<ominutes>\d{2}))'

    _time_re = r'(?P<hours>\d{2})(:(?P<minutes>\d{2})(:(?P<seconds>\d{2})(.(?P<decimal>\d+))?)?(?P<tzd>%s))?' % _time_zone_re

    _date_re = re.compile(r'(?P<year>\d{4})(-(?P<month>\d{2})(-(?P<day>\d{2})(T(?P<time>%s))?)?)?' % _time_re)


    def __init__(self, key, value=None, _tag=None):
        """The tag can be initialized with an optional value which expected
        type depends on the XMP type of the tag.

        Args:
        key -- the key of the tag
        value -- the value of the tag
        """
        super(XmpTag, self).__init__()
        if _tag is not None:
            self._tag = _tag

        else:
            self._tag = libexiv2python._XmpTag(key)

        self._raw_value = None
        self._value = None
        self._value_cookie = False
        if value is not None:
            #type_ = self._tag._getType()
            self._set_value(value)

    def _set_owner(self, metadata):
        self._tag._setParentImage(metadata._image)

    @staticmethod
    def _from_existing_tag(_tag):
        """Build a tag from an already existing libexiv2python._XmpTag.

        """
        tag = XmpTag(_tag._getKey(), _tag=_tag)
        type_ = _tag._getExiv2Type()
        # Do not set the raw_value property, as it would call
        # _tag._set{Text,Array,LangAlt}Value
        # (see https://bugs.launchpad.net/pyexiv2/+bug/582445).
        if type_ == 'XmpText':
            tag._raw_value = _tag._getTextValue()

        elif type_ in ('XmpAlt', 'XmpBag', 'XmpSeq'):
            tag._raw_value = _tag._getArrayValue()

        elif type_ == 'LangAlt':
            tag._raw_value = _tag._getLangAltValue()

        tag._value_cookie = True
        return tag

    @property
    def key(self):
        """The key of the tag in the dotted form
        ``familyName.groupName.tagName`` where ``familyName`` = ``xmp``.

        """
        return self._tag._getKey()

    @property
    def type(self):
        """The XMP type of the tag.

        """
        return self._tag._getType()

    @property
    def name(self):
        """The name of the tag (this is also the third part of the key).

        """
        return self._tag._getName()

    @property
    def title(self):
        """The title (label) of the tag.

        """
        return self._tag._getTitle()

    @property
    def description(self):
        """The description of the tag.

        """
        return self._tag._getDescription()

    def _get_raw_value(self):
        return self._raw_value

    def _set_raw_value(self, value):
        type_ = self._tag._getExiv2Type()
        
        if type_ == 'XmpText':
            self._tag._setTextValue(value)

        elif type_ in ('XmpAlt', 'XmpBag', 'XmpSeq'):
            if not value:
                raise ValueError('Empty array')
            self._tag._setArrayValue(value)

        elif type_ == 'LangAlt':
            if not value:
                raise ValueError('Empty LangAlt')
            self._tag._setLangAltValue(value)

        self._raw_value = value
        self._value_cookie = True

    raw_value = property(fget=_get_raw_value, fset=_set_raw_value,
                         doc='The raw value of the tag as a [list of] ' \
                             'string(s).')

    def _compute_value(self):
        # Lazy computation of the value from the raw value
        if self.type.startswith(('seq', 'bag', 'alt')):
            type_ = self.type[4:]

            if type_.lower().startswith('closed choice of'):
                type_ = type[17:]

            self._value = [self._convert_to_python(v, type_) 
                           for v in self._raw_value]

        elif self.type == 'Lang Alt':
            self._value = {}
            for k, v in self._raw_value.items():
                try:
                    self._value[k] = v
                except TypeError:
                    raise XmpValueError(self._raw_value, self.type)

        elif self.type.lower().startswith('closed choice of'):
            self._value = self._convert_to_python(self._raw_value, 
                                                  self.type[17:])

        elif self.type == '':
            self._value = self._raw_value

        else:
            self._value = self._convert_to_python(self._raw_value, self.type)

        self._value_cookie = False

    def _get_value(self):
        if self._value_cookie:
            self._compute_value()
        return self._value

    def _set_value(self, value):
        type_ = self._tag._getExiv2Type()
        if type_ == 'XmpText':
            stype = self.type
            if stype.lower().startswith('closed choice of'):
                stype = stype[17:]
            self.raw_value = self._convert_to_string(value, stype)

        elif type_ in ('XmpAlt', 'XmpBag', 'XmpSeq'):
            if not isinstance(value, (list, tuple)):
                raise TypeError('Expecting a list of values')

            stype = self.type[4:]
            if stype.lower().startswith('closed choice of'):
                stype = stype[17:]
            self.raw_value = [self._convert_to_string(v, stype) for v in value]

        elif type_ == 'LangAlt':
            if isinstance(value, str):
                value = {'x-default': value}

            if not isinstance(value, dict):
                raise TypeError('Expecting a dictionary mapping language '\
                                'codes to values')

            raw_value = {}
            for k, v in value.items():
                if isinstance(v, str):
                    try:
                        v = v.encode('utf-8')
                    except TypeError:
                        raise XmpValueError(value, type_)
                raw_value[k] = v

            self.raw_value = raw_value

        self._value = value
        self._value_cookie = False

    value = property(fget=_get_value, fset=_set_value,
                     doc='The value of the tag as a [list of] python ' \
                         'object(s).')

    def _convert_to_python(self, value, type_):
        """Convert a raw value to its corresponding python type.

        Args:
        value -- the raw value to be converted
        type_ -- the simple type of the raw value

        Return: the value converted to its corresponding python type

        Raise XmpValueError: if the conversion fails
        """
        if type_ == 'Boolean':
            if value == 'True':
                return True

            elif value == 'False':
                return False

            else:
                raise XmpValueError(value, type_)

        elif type_ == 'Colorant':
            # TODO
            raise NotImplementedError('XMP conversion for type [%s]' % type_)

        elif type_ == 'Date':
            try:
                v = value.replace("Z", "")
                # New in Python-3.7
                # FIXME this break unitest, maybe add a FixedOffset() ...
                return datetime.datetime.fromisoformat(v)
            except:
                pass

            match = self._date_re.match(value)
            if match is None:
                raise XmpValueError(value, type_)

            gd = match.groupdict()
            print(gd)
            if gd['month'] is not None:
                month = int(gd['month'])

            else:
                month = 1

            if gd['day'] is not None:
                day = int(gd['day'])

            else:
                day = 1

            if gd['time'] is None:
                try:
                    return datetime.date(int(gd['year']), month, day)
                except ValueError:
                    raise XmpValueError(value, type_)

            else:
                if gd['minutes'] is None:
                    # Malformed time
                    print(value, type_)
                    raise XmpValueError(value, type_)

                if gd['seconds'] is not None:
                    seconds = int(gd['seconds'])

                else:
                    seconds = 0

                if gd['decimal'] is not None:
                    microseconds = int(float('0.%s' % gd['decimal']) * 1E6)

                else:
                    microseconds = 0

                if gd['tzd'] == 'Z':
                    tzinfo = FixedOffset()

                else:
                    tzinfo = FixedOffset(gd['sign'], int(gd['ohours']),
                                         int(gd['ominutes']))

                try:
                    return datetime.datetime(int(gd['year']), month, day,
                                             int(gd['hours']), int(gd['minutes']),
                                             seconds, microseconds, tzinfo)
                except ValueError:
                    raise XmpValueError(value, type_)

        elif type_ == 'Dimensions':
            # TODO
            raise NotImplementedError('XMP conversion for type [%s]' % type_)

        elif type_ == 'Font':
            # TODO
            raise NotImplementedError('XMP conversion for type [%s]' % type_)

        elif type_ == 'GPSCoordinate':
            try:
                return GPSCoordinate.from_string(value)
            except ValueError:
                raise XmpValueError(value, type_)

        elif type_ == 'Integer':
            try:
                return int(value)
            except ValueError:
                raise XmpValueError(value, type_)

        elif type_ == 'Locale':
            # TODO
            # See RFC 3066
            raise NotImplementedError('XMP conversion for type [%s]' % type_)

        elif type_ == 'MIMEType':
            if value.count('/') != 1:
                raise XmpValueError(value, type_)
            try:
                return tuple(value.split('/', 1))
            except ValueError:
                raise XmpValueError(value, type_)

        elif type_ == 'Rational':
            try:
                return make_fraction(value)
            except (ValueError, ZeroDivisionError):
                raise XmpValueError(value, type_)

        elif type_ == 'Real':
            # TODO
            raise NotImplementedError('XMP conversion for type [%s]' % type_)

        elif type_ in ('AgentName', 'ProperName', 'Text'):
            if isinstance(value, bytes):
                try:
                    value = str(value, 'utf-8')
                except TypeError:
                    raise XmpValueError(value, type_)
            return value

        elif type_ == 'Thumbnail':
            # TODO
            raise NotImplementedError('XMP conversion for type [%s]' % type_)

        elif type_ in ('URI', 'URL'):
            if isinstance(value, bytes):
                try:
                    value = value.decode('utf-8')
                except UnicodeDecodeError:
                    # Unknow encoding, return the raw value
                    pass
            return value

        elif type_ == 'XPath':
            # TODO
            raise NotImplementedError('XMP conversion for type [%s]' % type_)

        raise NotImplementedError('XMP conversion for type [%s]' % type_)

    def _convert_to_string(self, value, type_):
        """Convert a value to its corresponding string representation.

        Args:
        value -- the value to be converted
        type_ -- the simple type of the value

        Return: the value converted to its corresponding string representation

        Raise XmpValueError: if the conversion fails
        """
        if type_ == 'Boolean':
            if isinstance(value, bool):
                return str(value)
            else:
                raise XmpValueError(value, type_)

        elif type_ == 'Date':
            if isinstance(value, (datetime.date, datetime.datetime)):
                return DateTimeFormatter.xmp(value)

            else:
                raise XmpValueError(value, type_)

        elif type_ == 'GPSCoordinate':
            if isinstance(value, GPSCoordinate):
                return str(value)

            else:
                raise XmpValueError(value, type_)

        elif type_ == 'Integer':
            if isinstance(value, int):
                return str(value)

            else:
                raise XmpValueError(value, type_)

        elif type_ == 'MIMEType':
            if isinstance(value, tuple) and len(value) == 2:
                return '/'.join(value)

            else:
                raise XmpValueError(value, type_)

        elif type_ in ('AgentName', 'ProperName', 'Text', 'URI', 'URL'):
            if isinstance(value, str):
                try:
                    return value.encode('utf-8')
                except UnicodeEncodeError:
                    raise XmpValueError(value, type_)

            elif isinstance(value, bytes): 
                return value 

            raise XmpValueError(value, type_)

        elif type_ == 'Rational':
            if is_fraction(value):
                return str(value)

            else:
                raise XmpValueError(value, type_)

        elif type_ == '':
            # Undefined type
            if isinstance(value, str):
                try:
                    return value.encode('utf-8')
                except UnicodeEncodeError:
                    raise XmpValueError(value, type_)

            elif isinstance(value, (datetime.date, datetime.datetime)):
                return DateTimeFormatter.xmp(value)

        raise NotImplementedError('XMP conversion for type [%s]' % type_)

    def __str__(self):
        """Return a string representation of the XMP tag for debugging purposes

        """
        left = '%s [%s]' % (self.key, self.type)
        if self._raw_value is None:
            right = '(No value)'

        else:
             right = self._raw_value

        return '<%s = %s>' % (left, right)

    # Support for pickling.
    def __getstate__(self):
        return (self.key, self.raw_value)

    def __setstate__(self, state):
        key, raw_value = state
        self._tag = libexiv2python._XmpTag(key)
        self.raw_value = raw_value

def initialiseXmpParser():
    """Initialise the xmp parser.

    Calling this method is usually not needed, as encode() and decode() will 
    initialize the XMP Toolkit if necessary.

    The function takes optional pointers to a callback function xmpLockFct and 
    related data pLockData that the parser uses when XMP namespaces are 
    subsequently registered.

    This function itself still is not thread-safe and needs to be 
    called in a thread-safe manner (e.g., on program startup), but if used with 
    suitable additional locking parameters, any subsequent registration of 
    namespaces will be thread-safe.
    """
    libexiv2python._initialiseXmpParser()

def closeXmpParser():
    """Close the xmp parser.

    Terminate the XMP Toolkit and unregister custom namespaces.

    Call this method when the XmpParser is no longer needed to allow the XMP 
    Toolkit to cleanly shutdown. 
    """
    libexiv2python._closeXmpParser()


def register_namespace(name, prefix):
    """Register a custom XMP namespace.

    Overriding the prefix of a known or previously registered namespace is not
    allowed.

    Args:
    name -- the name of the custom namespace (ending with a ``/``),
            typically a URL (e.g. http://purl.org/dc/elements/1.1/)
    prefix -- the prefix for the custom namespace (keys in this namespace
              will be in the form ``Xmp.{prefix}.{something}``)


    Raise ValueError: if the name doesn’t end with a ``/``
    Raise KeyError: if a namespace already exist with this prefix
    """
    # How to set the type of tag 'XmpAlt', 'XmpBag', 'XmpSeq'
    # See: https://www.exiv2.org/doc/xmpsample_8cpp-example.html#a18
    if not name.endswith('/'):
        raise ValueError('Name should end with a /')

    libexiv2python._registerXmpNs(name, prefix)


def unregister_namespace(name):
    """Unregister a custom XMP namespace.

    A custom namespace is identified by its name, **not** by its prefix.

    Attempting to unregister an unknown namespace raises an error, as does
    attempting to unregister a builtin namespace.

    Args:
    name -- the name of the custom namespace (ending with a ``/``),
            typically a URL (e.g. http://purl.org/dc/elements/1.1/)

    Raise ValueError: if the name doesn’t end with a ``/``
    Raise KeyError: if the namespace is unknown or a builtin namespace
    """
    if not name.endswith('/'):
        raise ValueError('Name should end with a /')

    libexiv2python._unregisterXmpNs(name)


def unregister_namespaces():
    """Unregister all custom XMP namespaces.

    Builtin namespaces are not unregistered.
    This function always succeeds.
    """
    libexiv2python._unregisterAllXmpNs()

