"""
Functions for converting UFO1 or UFO2 files into UFO3 format.

Currently provides functionality for converting kerning rules
and kerning groups. Conversion is only supported _from_ UFO1
or UFO2, and _to_ UFO3.
"""

# adapted from the UFO spec


def convertUFO1OrUFO2KerningToUFO3Kerning(kerning, groups, glyphSet=()):
    """Convert kerning data in UFO1 or UFO2 syntax into UFO3 syntax.

    Args:
      kerning:
          A dictionary containing the kerning rules defined in
          the UFO font, as used in :class:`.UFOReader` objects.
      groups:
          A dictionary containing the groups defined in the UFO
          font, as used in :class:`.UFOReader` objects.
      glyphSet:
        Optional; a set of glyph objects to skip (default: None).

    Returns:
      1. A dictionary representing the converted kerning data.
      2. A copy of the groups dictionary, with all groups renamed to UFO3 syntax.
      3. A dictionary containing the mapping of old group names to new group names.

    """
    # gather known kerning groups based on the prefixes
    firstReferencedGroups, secondReferencedGroups = findKnownKerningGroups(groups)
    # Make lists of groups referenced in kerning pairs.
    for first, seconds in list(kerning.items()):
        if first in groups and first not in glyphSet:
            if not first.startswith("public.kern1."):
                firstReferencedGroups.add(first)
        for second in list(seconds.keys()):
            if second in groups and second not in glyphSet:
                if not second.startswith("public.kern2."):
                    secondReferencedGroups.add(second)
    # Create new names for these groups.
    firstRenamedGroups = {}
    for first in firstReferencedGroups:
        # Make a list of existing group names.
        existingGroupNames = list(groups.keys()) + list(firstRenamedGroups.keys())
        # Remove the old prefix from the name
        newName = first.replace("@MMK_L_", "")
        # Add the new prefix to the name.
        newName = "public.kern1." + newName
        # Make a unique group name.
        newName = makeUniqueGroupName(newName, existingGroupNames)
        # Store for use later.
        firstRenamedGroups[first] = newName
    secondRenamedGroups = {}
    for second in secondReferencedGroups:
        # Make a list of existing group names.
        existingGroupNames = list(groups.keys()) + list(secondRenamedGroups.keys())
        # Remove the old prefix from the name
        newName = second.replace("@MMK_R_", "")
        # Add the new prefix to the name.
        newName = "public.kern2." + newName
        # Make a unique group name.
        newName = makeUniqueGroupName(newName, existingGroupNames)
        # Store for use later.
        secondRenamedGroups[second] = newName
    # Populate the new group names into the kerning dictionary as needed.
    newKerning = {}
    for first, seconds in list(kerning.items()):
        first = firstRenamedGroups.get(first, first)
        newSeconds = {}
        for second, value in list(seconds.items()):
            second = secondRenamedGroups.get(second, second)
            newSeconds[second] = value
        newKerning[first] = newSeconds
    # Make copies of the referenced groups and store them
    # under the new names in the overall groups dictionary.
    allRenamedGroups = list(firstRenamedGroups.items())
    allRenamedGroups += list(secondRenamedGroups.items())
    for oldName, newName in allRenamedGroups:
        group = list(groups[oldName])
        groups[newName] = group
    # Return the kerning and the groups.
    return newKerning, groups, dict(side1=firstRenamedGroups, side2=secondRenamedGroups)


def findKnownKerningGroups(groups):
    """Find all kerning groups in a UFO1 or UFO2 font that use known prefixes.

    In some cases, not all kerning groups will be referenced
    by the kerning pairs in a UFO. The algorithm for locating
    groups in :func:`convertUFO1OrUFO2KerningToUFO3Kerning` will
    miss these unreferenced groups. By scanning for known prefixes,
    this function will catch all of the prefixed groups.

    The prefixes and sides by this function are:

    @MMK_L_ - side 1
    @MMK_R_ - side 2

    as defined in the UFO1 specification.

    Args:
        groups:
          A dictionary containing the groups defined in the UFO
          font, as read by :class:`.UFOReader`.

    Returns:
        Two sets; the first containing the names of all
        first-side kerning groups identified in the ``groups``
        dictionary, and the second containing the names of all
        second-side kerning groups identified.

        "First-side" and "second-side" are with respect to the
        writing direction of the script.

        Example::

          >>> testGroups = {
          ...     "@MMK_L_1" : None,
          ...     "@MMK_L_2" : None,
          ...     "@MMK_L_3" : None,
          ...     "@MMK_R_1" : None,
          ...     "@MMK_R_2" : None,
          ...     "@MMK_R_3" : None,
          ...     "@MMK_l_1" : None,
          ...     "@MMK_r_1" : None,
          ...     "@MMK_X_1" : None,
          ...     "foo" : None,
          ... }
          >>> first, second = findKnownKerningGroups(testGroups)
          >>> sorted(first) == ['@MMK_L_1', '@MMK_L_2', '@MMK_L_3']
          True
          >>> sorted(second) == ['@MMK_R_1', '@MMK_R_2', '@MMK_R_3']
          True
    """
    knownFirstGroupPrefixes = ["@MMK_L_"]
    knownSecondGroupPrefixes = ["@MMK_R_"]
    firstGroups = set()
    secondGroups = set()
    for groupName in list(groups.keys()):
        for firstPrefix in knownFirstGroupPrefixes:
            if groupName.startswith(firstPrefix):
                firstGroups.add(groupName)
                break
        for secondPrefix in knownSecondGroupPrefixes:
            if groupName.startswith(secondPrefix):
                secondGroups.add(groupName)
                break
    return firstGroups, secondGroups


def makeUniqueGroupName(name, groupNames, counter=0):
    """Make a kerning group name that will be unique within the set of group names.

    If the requested kerning group name already exists within the set, this
    will return a new name by adding an incremented counter to the end
    of the requested name.

    Args:
        name:
          The requested kerning group name.
        groupNames:
          A list of the existing kerning group names.
        counter:
          Optional; a counter of group names already seen (default: 0). If
          :attr:`.counter` is not provided, the function will recurse,
          incrementing the value of :attr:`.counter` until it finds the
          first unused ``name+counter`` combination, and return that result.

    Returns:
        A unique kerning group name composed of the requested name suffixed
        by the smallest available integer counter.
    """
    # Add a number to the name if the counter is higher than zero.
    newName = name
    if counter > 0:
        newName = "%s%d" % (newName, counter)
    # If the new name is in the existing group names, recurse.
    if newName in groupNames:
        return makeUniqueGroupName(name, groupNames, counter + 1)
    # Otherwise send back the new name.
    return newName


def test():
    """
    Tests for :func:`.convertUFO1OrUFO2KerningToUFO3Kerning`.

    No known prefixes.

    >>> testKerning = {
    ...     "A" : {
    ...         "A" : 1,
    ...         "B" : 2,
    ...         "CGroup" : 3,
    ...         "DGroup" : 4
    ...     },
    ...     "BGroup" : {
    ...         "A" : 5,
    ...         "B" : 6,
    ...         "CGroup" : 7,
    ...         "DGroup" : 8
    ...     },
    ...     "CGroup" : {
    ...         "A" : 9,
    ...         "B" : 10,
    ...         "CGroup" : 11,
    ...         "DGroup" : 12
    ...     },
    ... }
    >>> testGroups = {
    ...     "BGroup" : ["B"],
    ...     "CGroup" : ["C"],
    ...     "DGroup" : ["D"],
    ... }
    >>> kerning, groups, maps = convertUFO1OrUFO2KerningToUFO3Kerning(
    ...     testKerning, testGroups, [])
    >>> expected = {
    ...     "A" : {
    ...         "A": 1,
    ...         "B": 2,
    ...         "public.kern2.CGroup": 3,
    ...         "public.kern2.DGroup": 4
    ...     },
    ...     "public.kern1.BGroup": {
    ...         "A": 5,
    ...         "B": 6,
    ...         "public.kern2.CGroup": 7,
    ...         "public.kern2.DGroup": 8
    ...     },
    ...     "public.kern1.CGroup": {
    ...         "A": 9,
    ...         "B": 10,
    ...         "public.kern2.CGroup": 11,
    ...         "public.kern2.DGroup": 12
    ...     }
    ... }
    >>> kerning == expected
    True
    >>> expected = {
    ...     "BGroup": ["B"],
    ...     "CGroup": ["C"],
    ...     "DGroup": ["D"],
    ...     "public.kern1.BGroup": ["B"],
    ...     "public.kern1.CGroup": ["C"],
    ...     "public.kern2.CGroup": ["C"],
    ...     "public.kern2.DGroup": ["D"],
    ... }
    >>> groups == expected
    True

    Known prefixes.

    >>> testKerning = {
    ...     "A" : {
    ...         "A" : 1,
    ...         "B" : 2,
    ...         "@MMK_R_CGroup" : 3,
    ...         "@MMK_R_DGroup" : 4
    ...     },
    ...     "@MMK_L_BGroup" : {
    ...         "A" : 5,
    ...         "B" : 6,
    ...         "@MMK_R_CGroup" : 7,
    ...         "@MMK_R_DGroup" : 8
    ...     },
    ...     "@MMK_L_CGroup" : {
    ...         "A" : 9,
    ...         "B" : 10,
    ...         "@MMK_R_CGroup" : 11,
    ...         "@MMK_R_DGroup" : 12
    ...     },
    ... }
    >>> testGroups = {
    ...     "@MMK_L_BGroup" : ["B"],
    ...     "@MMK_L_CGroup" : ["C"],
    ...     "@MMK_L_XGroup" : ["X"],
    ...     "@MMK_R_CGroup" : ["C"],
    ...     "@MMK_R_DGroup" : ["D"],
    ...     "@MMK_R_XGroup" : ["X"],
    ... }
    >>> kerning, groups, maps = convertUFO1OrUFO2KerningToUFO3Kerning(
    ...     testKerning, testGroups, [])
    >>> expected = {
    ...     "A" : {
    ...         "A": 1,
    ...         "B": 2,
    ...         "public.kern2.CGroup": 3,
    ...         "public.kern2.DGroup": 4
    ...     },
    ...     "public.kern1.BGroup": {
    ...         "A": 5,
    ...         "B": 6,
    ...         "public.kern2.CGroup": 7,
    ...         "public.kern2.DGroup": 8
    ...     },
    ...     "public.kern1.CGroup": {
    ...         "A": 9,
    ...         "B": 10,
    ...         "public.kern2.CGroup": 11,
    ...         "public.kern2.DGroup": 12
    ...     }
    ... }
    >>> kerning == expected
    True
    >>> expected = {
    ...     "@MMK_L_BGroup": ["B"],
    ...     "@MMK_L_CGroup": ["C"],
    ...     "@MMK_L_XGroup": ["X"],
    ...     "@MMK_R_CGroup": ["C"],
    ...     "@MMK_R_DGroup": ["D"],
    ...     "@MMK_R_XGroup": ["X"],
    ...     "public.kern1.BGroup": ["B"],
    ...     "public.kern1.CGroup": ["C"],
    ...     "public.kern1.XGroup": ["X"],
    ...     "public.kern2.CGroup": ["C"],
    ...     "public.kern2.DGroup": ["D"],
    ...     "public.kern2.XGroup": ["X"],
    ... }
    >>> groups == expected
    True

    >>> from .validators import kerningValidator
    >>> kerningValidator(kerning)
    (True, None)

    Mixture of known prefixes and groups without prefixes.

    >>> testKerning = {
    ...     "A" : {
    ...         "A" : 1,
    ...         "B" : 2,
    ...         "@MMK_R_CGroup" : 3,
    ...         "DGroup" : 4
    ...     },
    ...     "BGroup" : {
    ...         "A" : 5,
    ...         "B" : 6,
    ...         "@MMK_R_CGroup" : 7,
    ...         "DGroup" : 8
    ...     },
    ...     "@MMK_L_CGroup" : {
    ...         "A" : 9,
    ...         "B" : 10,
    ...         "@MMK_R_CGroup" : 11,
    ...         "DGroup" : 12
    ...     },
    ... }
    >>> testGroups = {
    ...     "BGroup" : ["B"],
    ...     "@MMK_L_CGroup" : ["C"],
    ...     "@MMK_R_CGroup" : ["C"],
    ...     "DGroup" : ["D"],
    ... }
    >>> kerning, groups, maps = convertUFO1OrUFO2KerningToUFO3Kerning(
    ...     testKerning, testGroups, [])
    >>> expected = {
    ...     "A" : {
    ...         "A": 1,
    ...         "B": 2,
    ...         "public.kern2.CGroup": 3,
    ...         "public.kern2.DGroup": 4
    ...     },
    ...     "public.kern1.BGroup": {
    ...         "A": 5,
    ...         "B": 6,
    ...         "public.kern2.CGroup": 7,
    ...         "public.kern2.DGroup": 8
    ...     },
    ...     "public.kern1.CGroup": {
    ...         "A": 9,
    ...         "B": 10,
    ...         "public.kern2.CGroup": 11,
    ...         "public.kern2.DGroup": 12
    ...     }
    ... }
    >>> kerning == expected
    True
    >>> expected = {
    ...     "BGroup": ["B"],
    ...     "@MMK_L_CGroup": ["C"],
    ...     "@MMK_R_CGroup": ["C"],
    ...     "DGroup": ["D"],
    ...     "public.kern1.BGroup": ["B"],
    ...     "public.kern1.CGroup": ["C"],
    ...     "public.kern2.CGroup": ["C"],
    ...     "public.kern2.DGroup": ["D"],
    ... }
    >>> groups == expected
    True
    """


if __name__ == "__main__":
    import doctest

    doctest.testmod()