    """Generate Python code from PSP templates.

    This module holds the classes that generate the Python code resulting
    from the PSP template file. As the parser encounters PSP elements,
    it creates a new Generator object for that type of element.
    Each of these elements is put into a list maintained by the
    ParseEventHandler object. When it comes time to output the source code,
    each generator is called in turn to create its source.

    (c) Copyright by Jay Love, 2000 (mailto:jsliv@jslove.org)

    Permission to use, copy, modify, and distribute this software and its
    documentation for any purpose and without fee or royalty is hereby granted,
    provided that the above copyright notice appear in all copies and that
    both that copyright notice and this permission notice appear in
    supporting documentation or portions thereof, including modifications,
    that you make.

    This software is based in part on work done by the Jakarta group.

    """

    import os

    import PSPUtils, BraceConverter

    # This is global so that the ParseEventHandler and this module agree:
    ResponseObject = 'res'

    class GenericGenerator(object):
        """Base class for all the generators"""

        def __init__(self, ctxt=None):
            self._ctxt = ctxt
            self.phase = 'Service'

    class ExpressionGenerator(GenericGenerator):
        """This class handles expression blocks.

        It simply outputs the (hopefully) python expression within the block
        wrapped with a _formatter() call.

        """

        def __init__(self, chars):
            self.chars = chars
            GenericGenerator.__init__(self)

        def generate(self, writer, phase=None):
            writer.println('res.write(_formatter(%s))'
                % PSPUtils.removeQuotes(self.chars))

    class CharDataGenerator(GenericGenerator):
        """This class handles standard character output, mostly HTML.

        It just dumps it out. Need to handle all the escaping of characters.
        It's just skipped for now.

        """

        def __init__(self, chars):
            GenericGenerator.__init__(self)
            self.chars = chars

        def generate(self, writer, phase=None):
            # Quote any existing backslash so generated Python will not
            # interpret it when running.
            self.chars = self.chars.replace('\\', r'\\')
            # Quote any single quotes so it does not get confused with
            # our triple-quotes:
            self.chars = self.chars.replace('"', r'\"')
            self.generateChunk(writer)

        def generateChunk(self, writer, start=0, stop=None):
            writer.printIndent() # gives one level of indentation
            writer.printChars(ResponseObject+'.write("""')
            writer.printChars(self.chars)
            writer.printChars('""")')
            writer.printChars('\n')

        def mergeData(self, cdGen):
            self.chars += cdGen.chars

    class ScriptGenerator(GenericGenerator):
        """Generate scripts."""

        def __init__(self, chars, attrs):
            GenericGenerator.__init__(self)
            self.chars = chars

        def generate(self, writer, phase=None):
            self.chars = PSPUtils.normalizeIndentation(self.chars)
            if writer._useBraces:
                # Send lines to be output by the braces generator:
                bc = BraceConverter.BraceConverter()
                lines = PSPUtils.splitLines(PSPUtils.removeQuotes(self.chars))
                for line in lines:
                    bc.parseLine(line, writer)
                return
            # Check for whitespace at the beginning and if less than 2 spaces, remove:
            if self.chars.startswith(' ') and not self.chars.startswith('  '):
                self.chars = self.chars.lstrip()
            lines = PSPUtils.splitLines(PSPUtils.removeQuotes(self.chars))
            if not lines:
                return # ignore any empty tag
            # userIndent check
            if lines[-1].endswith('$'):
                lastline = lines[-1] = lines[-1][:-1]
                if not lastline:
                    lastline = lines[-2] # handle endscript marker on its own line
                count = 0
                while lastline[count].isspace():
                    count += 1
                userIndent = lastline[:count]
            else:
                userIndent = writer._emptyString
                lastline = lines[-1]
            # Print out code (moved from above):
            writer._userIndent = writer._emptyString # reset to none
            writer.printList(lines)
            writer.printChars('\n')
            # Check for a block:
            commentstart = lastline.find('#') # @@ this fails if '#' part of string
            if commentstart >= 0:
                lastline = lastline[:commentstart]
            blockcheck = lastline.rstrip()
            if blockcheck.endswith(':'):
                writer.pushIndent()
                writer.println()
                writer._blockcount = writer._blockcount+1
                # Check for end of block, "pass" by itself:
            if self.chars.strip() == 'pass' and writer._blockcount > 0:
                writer.popIndent()
                writer.println()
                writer._blockcount -= 1
            # Set userIndent for subsequent HTML:
            writer._userIndent = userIndent

    class EndBlockGenerator(GenericGenerator):

        def __init__(self):
            GenericGenerator.__init__(self)

        def generate(self, writer, phase=None):
            if writer._blockcount > 0:
                writer.popIndent()
                writer.println()
                writer._blockcount -= 1
            writer._userIndent = writer._emptyString

    class ScriptFileGenerator(GenericGenerator):
        """Add Python code at the file/module level."""

        def __init__(self, chars, attrs):
            GenericGenerator.__init__(self)
            self.phase = 'psp:file'
            self.attrs = attrs
            self.chars = chars

        def generate(self, writer, phase=None):
            writer.println('\n# File level user code')
            pySrc = PSPUtils.normalizeIndentation(self.chars)
            pySrc = PSPUtils.splitLines(PSPUtils.removeQuotes(pySrc))
            writer.printList(pySrc)

    class ScriptClassGenerator(GenericGenerator):
        """Add Python code at the class level."""

        def __init__(self, chars, attrs):
            GenericGenerator.__init__(self)
            self.phase = 'psp:class'
            self.attrs = attrs
            self.chars = chars

        def generate(self, writer, phase=None):
            writer.println('# Class level user code\n')
            pySrc = PSPUtils.normalizeIndentation(self.chars)
            pySrc = PSPUtils.splitLines(PSPUtils.removeQuotes(pySrc))
            writer.printList(pySrc)

    class MethodGenerator(GenericGenerator):
        """Generate class methods defined in the PSP page.

        There are two parts to method generation.
        This class handles getting the method name and parameters set up.

        """

        def __init__(self, chars, attrs):
            GenericGenerator.__init__(self)
            self.phase = 'Declarations'
            self.attrs = attrs

        def generate(self, writer, phase=None):
            writer.printIndent()
            writer.printChars('def ')
            writer.printChars(self.attrs['name'])
            writer.printChars('(')
            # self.attrs['params']
            writer.printChars('self')
            if 'params' in self.attrs and self.attrs['params']:
                writer.printChars(', ')
                writer.printChars(self.attrs['params'])
            writer.printChars('):\n')
            if self.attrs['name'] == 'awake':
                writer._awakeCreated = True
                writer.pushIndent()
                writer.println('self.initPSP()\n')
                writer.popIndent()
                writer.println()

    class MethodEndGenerator(GenericGenerator):
        """Part of class method generation.

        After MethodGenerator, MethodEndGenerator actually generates
        the code for the method body.

        """

        def __init__(self, chars, attrs):
            GenericGenerator.__init__(self)
            self.phase = 'Declarations'
            self.attrs = attrs
            self.chars = chars

        def generate(self, writer, phase=None):
            writer.pushIndent()
            writer.printList(PSPUtils.splitLines(PSPUtils.removeQuotes(self.chars)))
            writer.printChars('\n')
            writer.popIndent()

    class IncludeGenerator(GenericGenerator):
        """Handle psp:include directives.

        This is a new version of this directive that actually
        forwards the request to the specified page.

        """

        _theFunction = ('__pspincludepath = "%s"\n'
            'self.transaction().application().includeURL('
            'self.transaction(), __pspincludepath)')

        def __init__(self, attrs, param, ctxt):
            GenericGenerator.__init__(self, ctxt)
            self.attrs = attrs
            self.param = param
            self.scriptgen = None

            self.url = attrs.get('path')
            if self.url is None:
                raise AttributeError('No path attribute in include')

            self.scriptgen = ScriptGenerator(self._theFunction % self.url, None)

        def generate(self, writer, phase=None):
            """Just insert theFunction."""
            self.scriptgen.generate(writer, phase)

    class InsertGenerator(GenericGenerator):
        """Include files designated by the psp:insert syntax.

        If the attribute 'static' is set to True or 1, we include the file now,
        at compile time. Otherwise, we use a function added to every PSP page
        named __includeFile, which reads the file at run time.

        """

        def __init__(self, attrs, param, ctxt):
            GenericGenerator.__init__(self, ctxt)
            self.attrs = attrs
            self.param = param
            self.scriptgen = None

            self.page = attrs.get('file')
            if not self.page:
                raise AttributeError('No file attribute in include')
            thepath = self._ctxt.resolveRelativeURI(self.page)
            if not os.path.exists(thepath):
                print self.page
                raise IOError('Invalid included file %r' % thepath)
            self.page = thepath

            self.static = str(attrs.get('static')).lower() in ('true', 'yes', '1')
            if not self.static:
                self.scriptgen = ScriptGenerator("self.__includeFile('%s')"
                    % thepath.replace('\\', '\\\\'), None)

        def generate(self, writer, phase=None):
            # JSP does this in the servlet. I'm doing it here because
            # I have triple quotes. Note: res.write statements inflate
            # the size of the resulting classfile when it is cached.
            # Cut down on those by using a single res.write on the whole
            # file, after escaping any triple-double quotes.
            if self.static:
                data = open(self.page).read()
                data = data.replace('"""', r'\"""')
                writer.println('res.write("""' + data + '""")')
                writer.println()
            else:
                self.scriptgen.generate(writer, phase)