"""provides simpleTAL extensions for CubicWeb

:organization: Logilab

:copyright: 2001-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

import sys

import re

from os.path import exists, isdir, join

from logging import getLogger

from StringIO import StringIO

from simpletal import simpleTAL, simpleTALES

from logilab.common.decorators import cached

LOGGER = getLogger('cubicweb.tal')

class LoggerAdapter(object):

    def __init__(self, tal_logger):

        self.tal_logger = tal_logger

    def debug(self, msg):

        LOGGER.debug(msg)

    def warn(self, msg):

        LOGGER.warning(msg)

    def __getattr__(self, attrname):

        return getattr(self.tal_logger, attrname)

class CubicWebContext(simpleTALES.Context):

    """add facilities to access entity / resultset"""

    def __init__(self, options=None, allowPythonPath=1):

        simpleTALES.Context.__init__(self, options, allowPythonPath)

        self.log = LoggerAdapter(self.log)

    def update(self, context):

        for varname, value in context.items():

            self.addGlobal(varname, value)

    def addRepeat(self, name, var, initialValue):

        simpleTALES.Context.addRepeat(self, name, var, initialValue)

# XXX FIXME need to find a clean to define OPCODE values for extensions

I18N_CONTENT = 18

I18N_REPLACE = 19

RQL_EXECUTE  = 20

# simpleTAL uses the OPCODE values to define priority over commands.

# TAL_ITER should have the same priority than TAL_REPEAT (i.e. 3), but

# we can't use the same OPCODE for two different commands without changing

# the simpleTAL implementation. Another solution would be to totally override

# the REPEAT implementation with the ITER one, but some specific operations

# (involving len() for instance) are not implemented for ITER, so we prefer

# to keep both implementations for now, and to fool simpleTAL by using a float

# number between 3 and 4

TAL_ITER     = 3.1

# FIX simpleTAL HTML 4.01 stupidity

# (simpleTAL never closes tags like INPUT, IMG, HR ...)

simpleTAL.HTML_FORBIDDEN_ENDTAG.clear()

class CubicWebTemplateCompiler(simpleTAL.HTMLTemplateCompiler):

    """extends default compiler by adding i18n:content commands"""

    def __init__(self):

        simpleTAL.HTMLTemplateCompiler.__init__(self)

        self.commandHandler[I18N_CONTENT] = self.compile_cmd_i18n_content

        self.commandHandler[I18N_REPLACE] = self.compile_cmd_i18n_replace

        self.commandHandler[RQL_EXECUTE] = self.compile_cmd_rql

        self.commandHandler[TAL_ITER] = self.compile_cmd_tal_iter

    def setTALPrefix(self, prefix):

        simpleTAL.TemplateCompiler.setTALPrefix(self, prefix)

        self.tal_attribute_map['i18n:content'] = I18N_CONTENT

        self.tal_attribute_map['i18n:replace'] = I18N_REPLACE

        self.tal_attribute_map['rql:execute'] = RQL_EXECUTE

        self.tal_attribute_map['tal:iter'] = TAL_ITER

    def compile_cmd_i18n_content(self, argument):

        # XXX tal:content structure=, text= should we support this ?

        structure_flag = 0

        return (I18N_CONTENT, (argument, False, structure_flag, self.endTagSymbol))

    def compile_cmd_i18n_replace(self, argument):

        # XXX tal:content structure=, text= should we support this ?

        structure_flag = 0

        return (I18N_CONTENT, (argument, True, structure_flag, self.endTagSymbol))

    def compile_cmd_rql(self, argument):

        return (RQL_EXECUTE, (argument, self.endTagSymbol))

    def compile_cmd_tal_iter(self, argument):

        original_id, (var_name, expression, end_tag_symbol) = \

                     simpleTAL.HTMLTemplateCompiler.compileCmdRepeat(self, argument)

        return (TAL_ITER, (var_name, expression, self.endTagSymbol))

    def getTemplate(self):

        return CubicWebTemplate(self.commandList, self.macroMap, self.symbolLocationTable)

    def compileCmdAttributes (self, argument):

        """XXX modified to support single attribute

        definition ending by a ';'

        backport this to simpleTAL

        """

        # Compile tal:attributes into attribute command

        # Argument: [(attributeName, expression)]

        # Break up the list of attribute settings first

        commandArgs = []

        # We only want to match semi-colons that are not escaped

        argumentSplitter =  re.compile(r'(?<!;);(?!;)')

        for attributeStmt in argumentSplitter.split(argument):

            if not attributeStmt.strip():

                continue

            #  remove any leading space and un-escape any semi-colons

            attributeStmt = attributeStmt.lstrip().replace(';;', ';')

            # Break each attributeStmt into name and expression

            stmtBits = attributeStmt.split(' ')

            if (len (stmtBits) < 2):

                # Error, badly formed attributes command

                msg = "Badly formed attributes command '%s'.  Attributes commands must be of the form: 'name expression[;name expression]'" % argument

                self.log.error(msg)

                raise simpleTAL.TemplateParseException(self.tagAsText(self.currentStartTag), msg)

            attName = stmtBits[0]

            attExpr = " ".join(stmtBits[1:])

            commandArgs.append((attName, attExpr))

        return (simpleTAL.TAL_ATTRIBUTES, commandArgs)

class CubicWebTemplateInterpreter(simpleTAL.TemplateInterpreter):

    """provides implementation for interpreting cubicweb extensions"""

    def __init__(self):

        simpleTAL.TemplateInterpreter.__init__(self)

        self.commandHandler[I18N_CONTENT] = self.cmd_i18n

        self.commandHandler[TAL_ITER] = self.cmdRepeat

        # self.commandHandler[RQL_EXECUTE] = self.cmd_rql

    def cmd_i18n(self, command, args):

        """i18n:content and i18n:replace implementation"""

        string, replace_flag, structure_flag, end_symbol = args

        if replace_flag:

            self.outputTag = 0

        result = self.context.globals['_'](string)

        self.tagContent = (0, result)

        self.movePCForward = self.symbolTable[end_symbol]

        self.programCounter += 1

class CubicWebTemplate(simpleTAL.HTMLTemplate):

    """overrides HTMLTemplate.expand() to systematically use CubicWebInterpreter

    """

    def expand(self, context, outputFile):

        interpreter = CubicWebTemplateInterpreter()

        interpreter.initialise(context, outputFile)

        simpleTAL.HTMLTemplate.expand(self, context, outputFile,# outputEncoding='unicode',

                                      interpreter=interpreter)

    def expandInline(self, context, outputFile, interpreter):

        """ Internally used when expanding a template that is part of a context."""

        try:

            interpreter.execute(self)

        except UnicodeError, unierror:

            LOGGER.exception(str(unierror))

            raise simpleTALES.ContextContentException("found non-unicode %r string in Context!" % unierror.args[1]), None, sys.exc_info()[-1]

def compile_template(template):

    """compiles a TAL template string

    :type template: unicode

    :param template: a TAL-compliant template string

    """

    string_buffer = StringIO(template)

    compiler = CubicWebTemplateCompiler()

    compiler.parseTemplate(string_buffer) # , inputEncoding='unicode')

    return compiler.getTemplate()

def compile_template_file(filepath):

    """compiles a TAL template file

    :type filepath: str

    :param template: path of the file to compile

    """

    fp = file(filepath)

    file_content = unicode(fp.read()) # template file should be pure ASCII

    fp.close()

    return compile_template(file_content)

def evaluatePython (self, expr):

    if not self.allowPythonPath:

        return self.false

    globals = {}

    for name, value in self.globals.items():

        if isinstance (value, simpleTALES.ContextVariable):

            value = value.rawValue()

        globals[name] = value

    globals['path'] = self.pythonPathFuncs.path

    globals['string'] = self.pythonPathFuncs.string

    globals['exists'] = self.pythonPathFuncs.exists

    globals['nocall'] = self.pythonPathFuncs.nocall

    globals['test'] = self.pythonPathFuncs.test

    locals = {}

    for name, value in self.locals.items():

        if (isinstance (value, simpleTALES.ContextVariable)):

            value = value.rawValue()

        locals[name] = value

    # XXX precompile expr will avoid late syntax error

    try:

        result = eval(expr, globals, locals)

    except Exception, ex:

        ex = ex.__class__('in %r: %s' % (expr, ex))

        raise ex, None, sys.exc_info()[-1]

    if (isinstance (result, simpleTALES.ContextVariable)):

        return result.value()

    return result

simpleTALES.Context.evaluatePython = evaluatePython

class talbased(object):

    def __init__(self, filename, write=True):

##         if not osp.isfile(filepath):

##             # print "[tal.py] just for tests..."

##             # get parent frame

##             directory = osp.abspath(osp.dirname(sys._getframe(1).f_globals['__file__']))

##             filepath = osp.join(directory, filepath)

        self.filename = filename

        self.write = write

    def __call__(self, viewfunc):

        def wrapped(instance, *args, **kwargs):

            variables = viewfunc(instance, *args, **kwargs)

            html = instance.tal_render(self._compiled_template(instance), variables)

            if self.write:

                instance.w(html)

            else:

                return html

        return wrapped

    def _compiled_template(self, instance):

        for fileordirectory in instance.config.vregistry_path():

            filepath = join(fileordirectory, self.filename)

            if isdir(fileordirectory) and exists(filepath):

                return compile_template_file(filepath)

        raise Exception('no such template %s' % self.filename)

    _compiled_template = cached(_compiled_template, 0)