"""Helpers for writing unit tests."""

from collections.abc import Iterable
from io import BytesIO
import os
import shutil
import sys
import tempfile
from unittest import TestCase as _TestCase
from fontTools.misc.py23 import tobytes
from fontTools.misc.xmlWriter import XMLWriter


def parseXML(xmlSnippet):
    """Parses a snippet of XML.

    Input can be either a single string (unicode or UTF-8 bytes), or a
    a sequence of strings.

    The result is in the same format that would be returned by
    XMLReader, but the parser imposes no constraints on the root
    element so it can be called on small snippets of TTX files.
    """
    # To support snippets with multiple elements, we add a fake root.
    reader = TestXMLReader_()
    xml = b"<root>"
    if isinstance(xmlSnippet, bytes):
        xml += xmlSnippet
    elif isinstance(xmlSnippet, str):
        xml += tobytes(xmlSnippet, 'utf-8')
    elif isinstance(xmlSnippet, Iterable):
        xml += b"".join(tobytes(s, 'utf-8') for s in xmlSnippet)
    else:
        raise TypeError("expected string or sequence of strings; found %r"
                        % type(xmlSnippet).__name__)
    xml += b"</root>"
    reader.parser.Parse(xml, 0)
    return reader.root[2]


class FakeFont:
    def __init__(self, glyphs):
        self.glyphOrder_ = glyphs
        self.reverseGlyphOrderDict_ = {g: i for i, g in enumerate(glyphs)}
        self.lazy = False
        self.tables = {}

    def __getitem__(self, tag):
        return self.tables[tag]

    def __setitem__(self, tag, table):
        self.tables[tag] = table

    def get(self, tag, default=None):
        return self.tables.get(tag, default)

    def getGlyphID(self, name):
        return self.reverseGlyphOrderDict_[name]

    def getGlyphName(self, glyphID):
        if glyphID < len(self.glyphOrder_):
            return self.glyphOrder_[glyphID]
        else:
            return "glyph%.5d" % glyphID

    def getGlyphOrder(self):
        return self.glyphOrder_

    def getReverseGlyphMap(self):
        return self.reverseGlyphOrderDict_

    def getGlyphNames(self):
        return sorted(self.getGlyphOrder())


class TestXMLReader_(object):
    def __init__(self):
        from xml.parsers.expat import ParserCreate
        self.parser = ParserCreate()
        self.parser.StartElementHandler = self.startElement_
        self.parser.EndElementHandler = self.endElement_
        self.parser.CharacterDataHandler = self.addCharacterData_
        self.root = None
        self.stack = []

    def startElement_(self, name, attrs):
        element = (name, attrs, [])
        if self.stack:
            self.stack[-1][2].append(element)
        else:
            self.root = element
        self.stack.append(element)

    def endElement_(self, name):
        self.stack.pop()

    def addCharacterData_(self, data):
        self.stack[-1][2].append(data)


def makeXMLWriter(newlinestr='\n'):
    # don't write OS-specific new lines
    writer = XMLWriter(BytesIO(), newlinestr=newlinestr)
    # erase XML declaration
    writer.file.seek(0)
    writer.file.truncate()
    return writer


def getXML(func, ttFont=None):
    """Call the passed toXML function and return the written content as a
    list of lines (unicode strings).
    Result is stripped of XML declaration and OS-specific newline characters.
    """
    writer = makeXMLWriter()
    func(writer, ttFont)
    xml = writer.file.getvalue().decode("utf-8")
    # toXML methods must always end with a writer.newline()
    assert xml.endswith("\n")
    return xml.splitlines()


class MockFont(object):
    """A font-like object that automatically adds any looked up glyphname
    to its glyphOrder."""

    def __init__(self):
        self._glyphOrder = ['.notdef']

        class AllocatingDict(dict):
            def __missing__(reverseDict, key):
                self._glyphOrder.append(key)
                gid = len(reverseDict)
                reverseDict[key] = gid
                return gid
        self._reverseGlyphOrder = AllocatingDict({'.notdef': 0})
        self.lazy = False

    def getGlyphID(self, glyph, requireReal=None):
        gid = self._reverseGlyphOrder[glyph]
        return gid

    def getReverseGlyphMap(self):
        return self._reverseGlyphOrder

    def getGlyphName(self, gid):
        return self._glyphOrder[gid]

    def getGlyphOrder(self):
        return self._glyphOrder


class TestCase(_TestCase):

    def __init__(self, methodName):
        _TestCase.__init__(self, methodName)
        # Python 3 renamed assertRaisesRegexp to assertRaisesRegex,
        # and fires deprecation warnings if a program uses the old name.
        if not hasattr(self, "assertRaisesRegex"):
            self.assertRaisesRegex = self.assertRaisesRegexp


class DataFilesHandler(TestCase):

    def setUp(self):
        self.tempdir = None
        self.num_tempfiles = 0

    def tearDown(self):
        if self.tempdir:
            shutil.rmtree(self.tempdir)

    def getpath(self, testfile):
        folder = os.path.dirname(sys.modules[self.__module__].__file__)
        return os.path.join(folder, "data", testfile)

    def temp_dir(self):
        if not self.tempdir:
            self.tempdir = tempfile.mkdtemp()

    def temp_font(self, font_path, file_name):
        self.temp_dir()
        temppath = os.path.join(self.tempdir, file_name)
        shutil.copy2(font_path, temppath)
        return temppath