# Copyright (c) 2004 Divmod.
# See LICENSE for details.

import warnings
from zope.interface import implementer

from twisted.python import components

from nevow.util import Deferred, DeferredList, getPOSTCharset

from nevow import inevow, tags
from nevow.context import WovenContext

import formless
from formless.formutils import enumerate
from formless import iformless

faketag = tags.html()


def exceptblock(f, handler, exception, *a, **kw):
    try:
        result = f(*a, **kw)
    except exception as e:
        return handler(e)
    if isinstance(result, Deferred):
        def _(fail):
            fail.trap(exception)
            return handler(fail.value)
        return result.addErrback(_)
    else:
        return result

@implementer(iformless.IInputProcessor)
class ProcessGroupBinding(components.Adapter):


    def process(self, context, boundTo, data):
        ## THE SPEC: self.original.typedValue.iface.__spec__
        spec = self.original.typedValue.iface.__spec__
        resultList = [None] * len(spec)
        message = ''
        results = {}
        failures = {}
        waiters = []
        for i, sub in enumerate(spec):
            def _process():
                # note, _process only works because it is called IMMEDIATELY
                # in the loop, watch out for confusing behavior if it is called
                # later when 'i' has changed
                resulti = resultList[i] = iformless.IInputProcessor(sub).process(context, boundTo, data, autoConfigure = False)
                # Merge the valid value in case another fails
                results.update(resulti)
            def _except(e):
                errors = context.locate(iformless.IFormErrors)
                # XXX: It seems like this should only ever be called with a WovenContext
                # XXX: if it's using context.key. But it seems that it's only ever called with
                # XXX: a PageContext, so context.key used to be '' always?
                
                errors.updateErrors(getattr(context, 'key', ''), e.errors)
                pf = e.partialForm
                err = e.errors
                msg = e.formErrorMessage
                ## Set an error message for this group of bindings
                errors.setError(getattr(context, 'key', ''), msg)
                # Merge the failed value
                results.update(pf)
                # Merge the error message
                failures.update(e.errors)
            maybe = exceptblock(_process, _except, formless.ValidateError)
            if isinstance(maybe, Deferred):
                waiters.append(maybe)
        def _finish(ignored):
            if not failures:
                for specobj, result in zip(spec, resultList):
                    specobj.configure(boundTo, result)
            else:
                #print "There were validation errors. The errors were: ", failures
                raise formless.ValidateError(failures, 'Error:', results)
        return DeferredList(waiters).addBoth(_finish)

@implementer(iformless.IInputProcessor)
class ProcessMethodBinding(components.Adapter):


    def process(self, context, boundTo, data, autoConfigure = True):
        """Knows how to process a dictionary of lists
        where the dictionary may contain a key with the same
        name as some of the arguments to the MethodBinding
        instance.
        """
        typedValue = self.original.typedValue
        results = {}
        failures = {}
        if '----' in data:
            ## ---- is the "direct object", the one argument you can specify using the command line without saying what the argument name is
            data[typedValue.arguments[0].name] = data['----']
            del data['----']
        for binding in typedValue.arguments:
            name = binding.name
            try:
                context = WovenContext(context, faketag)
                context.remember(binding, iformless.IBinding)
                results[name] = iformless.IInputProcessor(binding.typedValue).process(context, boundTo, data.get(name, ['']))
            except formless.InputError as e:
                results[name] = data.get(name, [''])[0]
                failures[name] = e.reason

        if failures:
            #print "There were validation errors. The errors were: ", failures
            raise formless.ValidateError(failures, "Error:", results)

        if autoConfigure:
            def _except(e):
                failures[''] = e.reason # self.original.name
                raise formless.ValidateError(failures, e.reason, results)
            return exceptblock(self.original.configure, _except, formless.InputError,
                               boundTo, results)
        return results

@implementer(iformless.IInputProcessor)
class ProcessPropertyBinding(components.Adapter):


    def process(self, context, boundTo, data, autoConfigure = True):
        """Knows how to process a dictionary of lists
        where the dictionary may contain a key with the
        same name as the property binding's name.
        """
        binding = self.original
        context.remember(binding, iformless.IBinding)
        result = {}
        try:
            result[binding.name] = iformless.IInputProcessor(binding.typedValue).process(context, boundTo, data.get(binding.name, ['']))
        except formless.InputError as e:
            result[binding.name] = data.get(binding.name, [''])
            raise formless.ValidateError({binding.name: e.reason}, e.reason, result)

        if autoConfigure:
            try:
                return self.original.configure(boundTo, result)
            except formless.InputError as e:
                result[binding.name] = data.get(binding.name, [''])
                raise formless.ValidateError({binding.name: e.reason}, e.reason, result)
        return result

@implementer(iformless.IInputProcessor)
class ProcessTyped(components.Adapter):


    def process(self, context, boundTo, data):
        """data is a list of strings at this point
        """
        typed = self.original
        val = data[0]
        if typed.str:
            try:
                val = val.decode(getPOSTCharset(context), 'replace')
            except LookupError:
                val = val.decode('utf-8', 'replace')
        if typed.strip:
            val = val.strip()
        if val == '' or val is None:
            if typed.required:
                raise formless.InputError(typed.requiredFailMessage)
            else:
                return typed.null
        try:
            return typed.coerce(val, boundTo)
        except TypeError as e:
            warnings.warn('Typed.coerce takes two values now, the value to coerce and the configurable in whose context the coerce is taking place. %s %s' % (typed.__class__, typed))
            return typed.coerce(val)

@implementer(iformless.IInputProcessor)
class ProcessPassword(components.Adapter):


    def process(self, context, boundTo, data):
        """Password needs to look at two passwords in the data,
        """
        typed = self.original
        pw1 = data[0]
        args = context.locate(inevow.IRequest).args
        binding = context.locate(iformless.IBinding)
        pw2 = args.get("%s____2" % binding.name, [''])[0]
        if typed.strip:
            pw1 = pw1.strip()
            pw2 = pw2.strip()
        if pw1 != pw2:
            raise formless.InputError("Passwords do not match. Please reenter.")
        elif pw1 == '':
            if typed.required:
                raise formless.InputError(typed.requiredFailMessage)
            else:
                return typed.null
        val = data[0]
        if typed.str:
            try:
                val = val.decode(getPOSTCharset(context), 'replace')
            except LookupError:
                val = val.decode('utf-8', 'replace')
        try:
            return typed.coerce(val, boundTo)
        except TypeError:
            warnings.warn('Typed.coerce takes two values now, the value to coerce and the configurable in whose context the coerce is taking place. %s %s' % (typed.__class__, typed))
            return typed.coerce(data[0])

@implementer(iformless.IInputProcessor)
class ProcessRequest(components.Adapter):


    def process(self, context, boundTo, data):
        return context.locate(inevow.IRequest)


@implementer(iformless.IInputProcessor)
class ProcessContext(components.Adapter):


    def process(self, context, boundTo, data):
        return context


@implementer(iformless.IInputProcessor)
class ProcessUpload(components.Adapter):


    def process(self, context, boundTo, data):

        typed = self.original
        bind = context.locate(iformless.IBinding)

        # TOTAL HACK: this comes from outer space
        fields = context.locate(inevow.IRequest).fields
        try:
            field = fields[bind.name]
        except KeyError:
            return ''
        
        def hasContent(field):
            """Test if the uploaded file has any content by looking for a single byte.
            """
            file = field.file
            pos = file.tell()
            file.seek(0)
            ch = file.read(1)
            file.seek(pos)
            return ch != ''
        
        # Testing for required'ness is a bit of a hack (not my fault!) ...
        # The upload is only considered missing if both the file name and content
        # are empty. That allows for files with content called ' ' and empty files
        # with a sensible name.

        # field might be a list, if multiple files were uploaded with the same
        # name.
        if isinstance(field, list):
            fieldList = field
        else:
            fieldList = [field]

        for maybeEmptyField in fieldList:
            if maybeEmptyField.filename.strip() or hasContent(maybeEmptyField):
                break
        else:
            if typed.required:
                raise formless.InputError(typed.requiredFailMessage)
            else:
                return typed.null
            
        return field


def process(typed, data, configurable=None, ctx=None):
    if ctx is None:
        from nevow.testutil import FakeRequest
        from nevow import context
        fr = FakeRequest()
        if type(data) is dict:
            fr.args = data
        ctx = context.RequestContext(tag=fr)
        ctx.remember(fr, inevow.IRequest)
        ctx.remember(None, inevow.IData)

    try:
        return iformless.IInputProcessor(typed).process(ctx, configurable, data, autoConfigure=False)
    except TypeError:
        return iformless.IInputProcessor(typed).process(ctx, configurable, data)
        

