"""\
A library of useful helper classes to the SAX classes, for the
convenience of application and driver writers.
"""

import os, urllib.parse, urllib.request
import io
import codecs
from . import handler
from . import xmlreader

def __dict_replace(s, d):
 """Replace substrings of a string using a dictionary."""
 for key, value in d.items():
 s = s.replace(key, value)
 return s

def escape(data, entities={}):
 """Escape &, <, and > in a string of data.

 You can escape other strings of data by passing a dictionary as
 the optional entities parameter. The keys and values must all be
 strings; each key will be replaced with its corresponding value.
 """

 # must do ampersand first
 data = data.replace("&", "&amp;")
 data = data.replace(">", "&gt;")
 data = data.replace("<", "&lt;")
 if entities:
 data = __dict_replace(data, entities)
 return data

def unescape(data, entities={}):
 """Unescape &amp;, &lt;, and &gt; in a string of data.

 You can unescape other strings of data by passing a dictionary as
 the optional entities parameter. The keys and values must all be
 strings; each key will be replaced with its corresponding value.
 """
 data = data.replace("&lt;", "<")
 data = data.replace("&gt;", ">")
 if entities:
 data = __dict_replace(data, entities)
 # must do ampersand last
 return data.replace("&amp;", "&")

def quoteattr(data, entities={}):
 """Escape and quote an attribute value.

 Escape &, <, and > in a string of data, then quote it for use as
 an attribute value. The \" character will be escaped as well, if
 necessary.

 You can escape other strings of data by passing a dictionary as
 the optional entities parameter. The keys and values must all be
 strings; each key will be replaced with its corresponding value.
 """
 entities = {**entities, '\n': '&#10;', '\r': '&#13;', '\t':'&#9;'}
 data = escape(data, entities)
 if '"' in data:
 if "'" in data:
 data = '"%s"' % data.replace('"', "&quot;")
 else:
 data = "'%s'" % data
 else:
 data = '"%s"' % data
 return data


def _gettextwriter(out, encoding):
 if out is None:
 import sys
 return sys.stdout

 if isinstance(out, io.TextIOBase):
 # use a text writer as is
 return out

 if isinstance(out, (codecs.StreamWriter, codecs.StreamReaderWriter)):
 # use a codecs stream writer as is
 return out

 # wrap a binary writer with TextIOWrapper
 if isinstance(out, io.RawIOBase):
 # Keep the original file open when the TextIOWrapper is
 # destroyed
 class _wrapper:
 __class__ = out.__class__
 def __getattr__(self, name):
 return getattr(out, name)
 buffer = _wrapper()
 buffer.close = lambda: None
 else:
 # This is to handle passed objects that aren't in the
 # IOBase hierarchy, but just have a write method
 buffer = io.BufferedIOBase()
 buffer.writable = lambda: True
 buffer.write = out.write
 try:
 # TextIOWrapper uses this methods to determine
 # if BOM (for UTF-16, etc) should be added
 buffer.seekable = out.seekable
 buffer.tell = out.tell
 except AttributeError:
 pass
 return io.TextIOWrapper(buffer, encoding=encoding,
 errors='xmlcharrefreplace',
 newline='\n',
 write_through=True)

class XMLGenerator(handler.ContentHandler):

 def __init__(self, out=None, encoding="iso-8859-1", short_empty_elements=False):
 handler.ContentHandler.__init__(self)
 out = _gettextwriter(out, encoding)
 self._write = out.write
 self._flush = out.flush
 self._ns_contexts = [{}] # contains uri -> prefix dicts
 self._current_context = self._ns_contexts[-1]
 self._undeclared_ns_maps = []
 self._encoding = encoding
 self._short_empty_elements = short_empty_elements
 self._pending_start_element = False

 def _qname(self, name):
 """Builds a qualified name from a (ns_url, localname) pair"""
 if name[0]:
 # Per http://www.w3.org/XML/1998/namespace, The 'xml' prefix is
 # bound by definition to http://www.w3.org/XML/1998/namespace. It
 # does not need to be declared and will not usually be found in
 # self._current_context.
 if 'http://www.w3.org/XML/1998/namespace' == name[0]:
 return 'xml:' + name[1]
 # The name is in a non-empty namespace
 prefix = self._current_context[name[0]]
 if prefix:
 # If it is not the default namespace, prepend the prefix
 return prefix + ":" + name[1]
 # Return the unqualified name
 return name[1]

 def _finish_pending_start_element(self,endElement=False):
 if self._pending_start_element:
 self._write('>')
 self._pending_start_element = False

 # ContentHandler methods

 def startDocument(self):
 self._write('<?xml version="1.0" encoding="%s"?>\n' %
 self._encoding)

 def endDocument(self):
 self._flush()

 def startPrefixMapping(self, prefix, uri):
 self._ns_contexts.append(self._current_context.copy())
 self._current_context[uri] = prefix
 self._undeclared_ns_maps.append((prefix, uri))

 def endPrefixMapping(self, prefix):
 self._current_context = self._ns_contexts[-1]
 del self._ns_contexts[-1]

 def startElement(self, name, attrs):
 self._finish_pending_start_element()
 self._write('<' + name)
 for (name, value) in attrs.items():
 self._write(' %s=%s' % (name, quoteattr(value)))
 if self._short_empty_elements:
 self._pending_start_element = True
 else:
 self._write(">")

 def endElement(self, name):
 if self._pending_start_element:
 self._write('/>')
 self._pending_start_element = False
 else:
 self._write('</%s>' % name)

 def startElementNS(self, name, qname, attrs):
 self._finish_pending_start_element()
 self._write('<' + self._qname(name))

 for prefix, uri in self._undeclared_ns_maps:
 if prefix:
 self._write(' xmlns:%s="%s"' % (prefix, uri))
 else:
 self._write(' xmlns="%s"' % uri)
 self._undeclared_ns_maps = []

 for (name, value) in attrs.items():
 self._write(' %s=%s' % (self._qname(name), quoteattr(value)))
 if self._short_empty_elements:
 self._pending_start_element = True
 else:
 self._write(">")

 def endElementNS(self, name, qname):
 if self._pending_start_element:
 self._write('/>')
 self._pending_start_element = False
 else:
 self._write('</%s>' % self._qname(name))

 def characters(self, content):
 if content:
 self._finish_pending_start_element()
 if not isinstance(content, str):
 content = str(content, self._encoding)
 self._write(escape(content))

 def ignorableWhitespace(self, content):
 if content:
 self._finish_pending_start_element()
 if not isinstance(content, str):
 content = str(content, self._encoding)
 self._write(content)

 def processingInstruction(self, target, data):
 self._finish_pending_start_element()
 self._write('<?%s %s?>' % (target, data))


class XMLFilterBase(xmlreader.XMLReader):
 """This class is designed to sit between an XMLReader and the
 client application's event handlers. By default, it does nothing
 but pass requests up to the reader and events on to the handlers
 unmodified, but subclasses can override specific methods to modify
 the event stream or the configuration requests as they pass
 through."""

 def __init__(self, parent = None):
 xmlreader.XMLReader.__init__(self)
 self._parent = parent

 # ErrorHandler methods

 def error(self, exception):
 self._err_handler.error(exception)

 def fatalError(self, exception):
 self._err_handler.fatalError(exception)

 def warning(self, exception):
 self._err_handler.warning(exception)

 # ContentHandler methods

 def setDocumentLocator(self, locator):
 self._cont_handler.setDocumentLocator(locator)

 def startDocument(self):
 self._cont_handler.startDocument()

 def endDocument(self):
 self._cont_handler.endDocument()

 def startPrefixMapping(self, prefix, uri):
 self._cont_handler.startPrefixMapping(prefix, uri)

 def endPrefixMapping(self, prefix):
 self._cont_handler.endPrefixMapping(prefix)

 def startElement(self, name, attrs):
 self._cont_handler.startElement(name, attrs)

 def endElement(self, name):
 self._cont_handler.endElement(name)

 def startElementNS(self, name, qname, attrs):
 self._cont_handler.startElementNS(name, qname, attrs)

 def endElementNS(self, name, qname):
 self._cont_handler.endElementNS(name, qname)

 def characters(self, content):
 self._cont_handler.characters(content)

 def ignorableWhitespace(self, chars):
 self._cont_handler.ignorableWhitespace(chars)

 def processingInstruction(self, target, data):
 self._cont_handler.processingInstruction(target, data)

 def skippedEntity(self, name):
 self._cont_handler.skippedEntity(name)

 # DTDHandler methods

 def notationDecl(self, name, publicId, systemId):
 self._dtd_handler.notationDecl(name, publicId, systemId)

 def unparsedEntityDecl(self, name, publicId, systemId, ndata):
 self._dtd_handler.unparsedEntityDecl(name, publicId, systemId, ndata)

 # EntityResolver methods

 def resolveEntity(self, publicId, systemId):
 return self._ent_handler.resolveEntity(publicId, systemId)

 # XMLReader methods

 def parse(self, source):
 self._parent.setContentHandler(self)
 self._parent.setErrorHandler(self)
 self._parent.setEntityResolver(self)
 self._parent.setDTDHandler(self)
 self._parent.parse(source)

 def setLocale(self, locale):
 self._parent.setLocale(locale)

 def getFeature(self, name):
 return self._parent.getFeature(name)

 def setFeature(self, name, state):
 self._parent.setFeature(name, state)

 def getProperty(self, name):
 return self._parent.getProperty(name)

 def setProperty(self, name, value):
 self._parent.setProperty(name, value)

 # XMLFilter methods

 def getParent(self):
 return self._parent

 def setParent(self, parent):
 self._parent = parent

# --- Utility functions

def prepare_input_source(source, base=""):
 """This function takes an InputSource and an optional base URL and
 returns a fully resolved InputSource object ready for reading."""

 if isinstance(source, os.PathLike):
 source = os.fspath(source)
 if isinstance(source, str):
 source = xmlreader.InputSource(source)
 elif hasattr(source, "read"):
 f = source
 source = xmlreader.InputSource()
 if isinstance(f.read(0), str):
 source.setCharacterStream(f)
 else:
 source.setByteStream(f)
 if hasattr(f, "name") and isinstance(f.name, str):
 source.setSystemId(f.name)

 if source.getCharacterStream() is None and source.getByteStream() is None:
 sysid = source.getSystemId()
 basehead = os.path.dirname(os.path.normpath(base))
 sysidfilename = os.path.join(basehead, sysid)
 if os.path.isfile(sysidfilename):
 source.setSystemId(sysidfilename)
 f = open(sysidfilename, "rb")
 else:
 source.setSystemId(urllib.parse.urljoin(base, sysid))
 f = urllib.request.urlopen(source.getSystemId())

 source.setByteStream(f)

 return source