"""
iri2uri

Copyright (c) 2006 by Joe Gregorio

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SOFTWARE.

Converts an IRI to a URI.

"""
__author__ = "Joe Gregorio (joe@bitworking.org)"
__copyright__ = "Copyright 2006, Joe Gregorio"
__contributors__ = []
__version__ = "1.0.0"
__license__ = "MIT"
__history__ = """
"""

import urlparse


# Convert an IRI to a URI following the rules in RFC 3987
# 
# The characters we need to enocde and escape are defined in the spec:
#
# iprivate =  %xE000-F8FF / %xF0000-FFFFD / %x100000-10FFFD
# ucschar = %xA0-D7FF / %xF900-FDCF / %xFDF0-FFEF
#         / %x10000-1FFFD / %x20000-2FFFD / %x30000-3FFFD
#         / %x40000-4FFFD / %x50000-5FFFD / %x60000-6FFFD
#         / %x70000-7FFFD / %x80000-8FFFD / %x90000-9FFFD
#         / %xA0000-AFFFD / %xB0000-BFFFD / %xC0000-CFFFD
#         / %xD0000-DFFFD / %xE1000-EFFFD

escape_range = [
   (0xA0, 0xD7FF ),
   (0xE000, 0xF8FF ),
   (0xF900, 0xFDCF ),
   (0xFDF0, 0xFFEF),
   (0x10000, 0x1FFFD ),
   (0x20000, 0x2FFFD ),
   (0x30000, 0x3FFFD),
   (0x40000, 0x4FFFD ),
   (0x50000, 0x5FFFD ),
   (0x60000, 0x6FFFD),
   (0x70000, 0x7FFFD ),
   (0x80000, 0x8FFFD ),
   (0x90000, 0x9FFFD),
   (0xA0000, 0xAFFFD ),
   (0xB0000, 0xBFFFD ),
   (0xC0000, 0xCFFFD),
   (0xD0000, 0xDFFFD ),
   (0xE1000, 0xEFFFD),
   (0xF0000, 0xFFFFD ),
   (0x100000, 0x10FFFD)
]
 
def encode(c):
    retval = c
    i = ord(c)
    for low, high in escape_range:
        if i < low:
            break
        if i >= low and i <= high:
            retval = "".join(["%%%2X" % ord(o) for o in c.encode('utf-8')])
            break
    return retval


def iri2uri(uri):
    """Convert an IRI to a URI. Note that IRIs must be 
    passed in a unicode strings. That is, do not utf-8 encode
    the IRI before passing it into the function.""" 
    if isinstance(uri ,unicode):
        (scheme, authority, path, query, fragment) = urlparse.urlsplit(uri)
        authority = authority.encode('idna')
        # For each character in 'ucschar' or 'iprivate'
        #  1. encode as utf-8
        #  2. then %-encode each octet of that utf-8 
        uri = urlparse.urlunsplit((scheme, authority, path, query, fragment))
        uri = "".join([encode(c) for c in uri])
    return uri
        
if __name__ == "__main__":
    import unittest

    class Test(unittest.TestCase):

        def test_uris(self):
            """Test that URIs are invariant under the transformation."""
            invariant = [ 
                u"ftp://ftp.is.co.za/rfc/rfc1808.txt",
                u"http://www.ietf.org/rfc/rfc2396.txt",
                u"ldap://[2001:db8::7]/c=GB?objectClass?one",
                u"mailto:John.Doe@example.com",
                u"news:comp.infosystems.www.servers.unix",
                u"tel:+1-816-555-1212",
                u"telnet://192.0.2.16:80/",
                u"urn:oasis:names:specification:docbook:dtd:xml:4.1.2" ]
            for uri in invariant:
                self.assertEqual(uri, iri2uri(uri))
            
        def test_iri(self):
            """ Test that the right type of escaping is done for each part of the URI."""
            self.assertEqual("http://xn--o3h.com/%E2%98%84", iri2uri(u"http://\N{COMET}.com/\N{COMET}"))
            self.assertEqual("http://bitworking.org/?fred=%E2%98%84", iri2uri(u"http://bitworking.org/?fred=\N{COMET}"))
            self.assertEqual("http://bitworking.org/#%E2%98%84", iri2uri(u"http://bitworking.org/#\N{COMET}"))
            self.assertEqual("#%E2%98%84", iri2uri(u"#\N{COMET}"))
            self.assertEqual("/fred?bar=%E2%98%9A#%E2%98%84", iri2uri(u"/fred?bar=\N{BLACK LEFT POINTING INDEX}#\N{COMET}"))
            self.assertEqual("/fred?bar=%E2%98%9A#%E2%98%84", iri2uri(iri2uri(u"/fred?bar=\N{BLACK LEFT POINTING INDEX}#\N{COMET}")))
            self.assertNotEqual("/fred?bar=%E2%98%9A#%E2%98%84", iri2uri(u"/fred?bar=\N{BLACK LEFT POINTING INDEX}#\N{COMET}".encode('utf-8')))

    unittest.main()