"""
C.11.5 Index and Glossary (p211)

"""

import os
from plasTeX.Tokenizer import Token, EscapeSequence
from plasTeX import Command, Environment, IgnoreCommand, encoding
from plasTeX.Logging import getLogger
from plasTeX.Base.LaTeX.Sectioning import SectionUtils

from typing import Optional

log = getLogger()

try:
    from plasTeX.Base.LaTeX.pyuca import Collator
    collator = Collator(os.path.join(os.path.dirname(__file__), 'allkeys.txt')).sort_key
except ImportError:
    collator = lambda x: x.lower()

try:
    from unidecode import unidecode
except ImportError:
    log.warning('Cannot find unidecode lib. Expect issues with index sorting')
    def unidecode(s): # type: ignore
        return s


class hyperpage(IgnoreCommand):
    args = 'page:nox'

class hyperindexformat(IgnoreCommand):
    args = 'fmt:nox page:nox'

class IndexUtils(object):
    """ Helper functions for generating indexes """

    linkType = 'index' # type: Optional[str]
    level = Command.CHAPTER_LEVEL

    class Index(Command):
        """
        Utility class used to surface the index entries to the renderer

        """

        def __init__(self, *args, **kwargs):
            Command.__init__(self, *args, **kwargs)
            self.pages = []
            self.key = []
            self.sortkey = ''

        @property
        def totallen(self):
            """ Return the total number of entries generated by this entry """
            total = 1
            for item in self:
                total += item.totallen
            return total

        def __repr__(self):
            return '%s%s --> %s' % (''.join([x.source for x in self.key]),
                                    ', '.join([str(x) for x in self.pages]),
                                    Command.__repr__(self))

    class IndexGroup(list):
        title = None

    def invoke(self, tex):
        if isinstance(self, Environment):
            Environment.invoke(self, tex)
        else:
            Command.invoke(self, tex)
        self.attributes['title'] = self.ownerDocument.createElement('indexname').expand(tex)

    @property
    def groups(self):
        """
        Group index entries into batches according to the first letter

        """
        batches = []
        current = ''
        for item in self:
            try:
                label = title = unidecode(item.sortkey[0]).upper()
                if title in encoding.stringletters():
                    pass
                elif title == '_':
                     title = '_ (Underscore)'
                else:
                     label = title = 'Symbols'
            except IndexError:
                label = title = 'Symbols'
            if current != title:
                newgroup = self.IndexGroup()
                newgroup.title = title
                newgroup.id = label
                batches.append(newgroup)
                current = title
            batches[-1].append(item)

        for item in batches:
            item[:] = self.splitColumns(item,
                self.ownerDocument.config['document']['index-columns'])

        return batches

    def splitColumns(self, items, cols):
        """
        Divide the index entries into the specified number of columns

        Required Arguments:
        items -- list of column entries
        cols -- number of columns to create

        Returns:
        list of length `cols' containing groups of column entries

        """
        entries = [(0,0)]
        # Find the total number of entries
        grandtotal = 0
        for item in items:
            entries.append((item.totallen, item))
            grandtotal += entries[-1][0]
        entries.pop(0)
        entries.reverse()

        # Get total number of entries per column
        coltotal = int(grandtotal / cols)

        # Group entries into columns
        current = 0
        output = [[]]
        for num, item in entries:
            current += num
            if len(output) >= cols:
                output[-1].append(item)
            elif current > coltotal:
                output.append([item])
                current = num
            elif current == coltotal:
                output[-1].append(item)
                output.append([])
                current = 0
            else:
                output[-1].append(item)

        output.reverse()
        for item in output:
            item.reverse()

        # Get rid of empty columns
        output = [x for x in output if x]

        # Pad to the correct number of columns
        for i in range(cols-len(output)):
            output.append([])

        return output

    def digest(self, tokens):
        """ Sort and group index entries """
        if isinstance(self, Environment):
            Environment.digest(self, tokens)
            if self.macroMode == self.MODE_END:
                return
            # Throw it all away, we don't need it.  We'll be generating
            # our own index entries below.
            while self.childNodes:
                self.pop()
        else:
            Command.digest(self, tokens)
        doc = self.ownerDocument
        current = self
        entries = sorted(self.ownerDocument.userdata.get('index', []))
        prev = IndexEntry([], None)
        for item in entries:
            # See how many levels we need to add/subtract between this one
            # and the previous
            common = 0
            for prevkey, itemkey in zip(zip(prev.sortkey, prev.key),
                                        zip(item.sortkey, item.key)):
                if prevkey == itemkey:
                    common += 1
                    continue
                break

#           print
#           print item
#           print (prev.key, prev.sortkey), (item.key, item.sortkey), common

            # Pop out to the common level
            i = common
            while i < len(prev.key):
#               print 'POP'
                current = current.parentNode
                i += 1

            # Add the appropriate number of levels
            i = common
            while i < len(item.key):
#               print 'ADD', item.sortkey[i]
                newidx = self.Index()
                newidx.key = item.key[i]
                newidx.sortkey = item.sortkey[i]
                newidx.parentNode = current
                current.append(newidx)
                current = newidx
                i += 1

            # Add the current page and format it
            current.pages.append(IndexDestination(item.type, item.node))
            if item.format is not None:
                text = doc.createTextNode(str(len(current.pages)))
                ipn = item.format.getElementsByTagName('index-page-number')
                if ipn:
                    ipn = ipn[0]
                    ipn.parentNode.replaceChild(text, ipn)
                item.node.append(item.format)
            else:
                text = doc.createTextNode(str(len(current.pages)))
                item.node.append(text)
            prev = item

class IndexDestination(object):
    def __init__(self, type, node):
        self._cr_type = type
        self._cr_node = node

    @property
    def see(self):
        return self._cr_type == IndexEntry.TYPE_SEE

    @property
    def seealso(self):
        return self._cr_type == IndexEntry.TYPE_SEEALSO

    @property
    def normal(self):
        return not(self.see) and not(self.seealso)

    def __getattribute__(self, name):
        if name.startswith('_cr_') or name in ['see', 'seealso', 'normal']:
            return object.__getattribute__(self, name)
        if self._cr_type and name in ['url']:
            return None
        return getattr(self._cr_node, name)

    def __str__(self):
        return str(self._cr_node)

class theindex(IndexUtils, Environment, SectionUtils):
    blockType = True
    level = Environment.CHAPTER_LEVEL
    counter = 'chapter'

class printindex(IndexUtils, Command, SectionUtils):
    blockType = True
    level = Command.CHAPTER_LEVEL
    counter = 'chapter'

class makeindex(Command):
    pass

class makeglossary(Command):
    pass

class glossary(Command):
    args = 'entry:nox'

class index(Command):
    args = 'entry:nox'

    @property
    def textContent(self):
        return ''

    def invoke(self, tex):
        result = Command.invoke(self, tex)
        sortkey, key, format = [], [], []
        entry = iter(self.attributes['entry'])
        current = []
        alphanumeric = [Token.CC_OTHER, Token.CC_LETTER, Token.CC_SPACE]

        # Parse the index tokens
        for tok in entry:
            if tok.catcode in alphanumeric:
                # Escape character
                if tok == '"':
                    for tok in entry:
                        current.append(tok)
                        break
                # Entry separator
                elif tok == '!':
                    key.append(current)
                    if len(sortkey) < len(key):
                        sortkey.append(current)
                    current = []
                # Sort key separator
                elif tok == '@':
                    sortkey.append(current)
                    current = []
                # Format separator
                elif tok == '|':
                    key.append(current)
                    if len(sortkey) < len(key):
                        sortkey.append(current)
                    current = format
                else:
                    current.append(tok)
                continue
            # Everything else
            current.append(tok)

        # Make sure to get the stuff at the end
        if not format:
            key.append(current)
            if len(sortkey) < len(key):
                sortkey.append(current)

        # Convert the sort keys to strings
        for i, item in enumerate(sortkey):
            sortkey[i] = tex.expandTokens(item).textContent

        # Expand the key tokens
        for i, item in enumerate(key):
            key[i] = tex.expandTokens(item)

        # Get the format element
        type = IndexEntry.TYPE_NORMAL
        if not format:
            format = None
        else:
            macro = []
            while format and format[0].catcode == Token.CC_LETTER:
                macro.append(format.pop(0))
            if macro:
                macro = ''.join(macro)
                format.insert(0, EscapeSequence(macro))
                if macro == 'see':
                    type = IndexEntry.TYPE_SEE
                elif macro == 'seealso':
                    type = IndexEntry.TYPE_SEEALSO
            format.append(EscapeSequence('index-page-number'))
            format = tex.expandTokens(format)

        # Store the index information in the document
        userdata = self.ownerDocument.userdata
        if 'index' not in userdata:
            userdata['index'] = []
        userdata['index'].append(IndexEntry(key, self, sortkey, format, type))

        return result



class IndexEntry(object):
    """
    Utility class used to assist in the sorting of index entries

    """

    TYPE_NORMAL = 0
    TYPE_SEE = 1
    TYPE_SEEALSO = 2

    def __init__(self, key, node, sortkey=None, format=None, type=0):
        """
        Required Arguments:
        key -- a list of keys for the index entry
        node -- the node of the document that the index entry is
            associated with
        sortkey -- a list of sort keys, one per key, to be used for
            sorting instead of the key values
        format -- formatting that should be used to format the
            destination of the index entry
        type -- the type of entry that this is: TYPE_NORMAL, TYPE_SEE,
            or TYPE_SEEALSO

        """
        self.key = key
        if not sortkey:
            self.sortkey = key
        else:
            self.sortkey = []
            for i, sk in enumerate(sortkey):
                if sk is None:
                    self.sortkey.append(key[i].textContent)
                else:
                    self.sortkey.append(sk)
        self.format = format
        self.node = node
        self.type = type

    @property
    def see(self):
        return self.type == type(self).TYPE_SEE

    @property
    def seealso(self):
        return self.type == type(self).TYPE_SEEALSO

    @property
    def normal(self):
        return not(self.see) and not(self.seealso)

    def __lt__(self, other):
        key_self = list(zip([collator(x) for x in self.sortkey if isinstance(x, str)],
                            [collator(x.textContent) for x in self.key],
                            self.key))
        key_other = list(zip([collator(x) for x in other.sortkey if isinstance(x, str)],
                             [collator(x.textContent) for x in other.key],
                             other.key))
        if key_self < key_other:
            return True
        elif key_self > key_other:
            return False
        return (len(self.key) < len(other.key))

    def __repr__(self):
        if self.format is None:
            return ' '.join(['@'.join(self.sortkey),
                             '!'.join([x.source for x in self.key])])
        else:
            return ' '.join(['@'.join(self.sortkey),
                             '!'.join([x.source for x in self.key]),
                             ' '.join([x.source for x in self.format])])

    def __str__(self):
        return repr(self)

class IndexPageNumber(Command):
    macroName = 'index-page-number'