# -*- coding: utf-8 -*-
'''
Template render systems
'''

from __future__ import absolute_import

# Import python libs
import codecs
import os
import imp
import logging
import tempfile
import traceback
import sys

# Import third party libs
import jinja2
import jinja2.ext

# Import salt libs
import salt.utils
import salt.utils.yamlencoding
from salt.exceptions import (
    SaltRenderError, CommandExecutionError, SaltInvocationError
)
from salt.utils.jinja import ensure_sequence_filter, show_full_context
from salt.utils.jinja import SaltCacheLoader as JinjaSaltCacheLoader
from salt.utils.jinja import SerializerExtension as JinjaSerializerExtension
from salt.utils.odict import OrderedDict
from salt import __path__ as saltpath
from salt.ext.six import string_types
import salt.ext.six as six

log = logging.getLogger(__name__)


TEMPLATE_DIRNAME = os.path.join(saltpath[0], 'templates')

# FIXME: also in salt/template.py
SLS_ENCODING = 'utf-8'  # this one has no BOM.
SLS_ENCODER = codecs.getencoder(SLS_ENCODING)

ALIAS_WARN = (
        'Starting in 2015.5, cmd.run uses python_shell=False by default, '
        'which doesn\'t support shellisms (pipes, env variables, etc). '
        'cmd.run is currently aliased to cmd.shell to prevent breakage. '
        'Please switch to cmd.shell or set python_shell=True to avoid '
        'breakage in the future, when this aliasing is removed.'
)
ALIASES = {
        'cmd.run': 'cmd.shell',
        'cmd': {'run': 'shell'},
}


class AliasedLoader(object):
    '''
    Light wrapper around the LazyLoader to redirect 'cmd.run' calls to
    'cmd.shell', for easy use of shellisms during templating calls

    Dotted aliases ('cmd.run') must resolve to another dotted alias
    (e.g. 'cmd.shell')

    Non-dotted aliases ('cmd') must resolve to a dictionary of function
    aliases for that module (e.g. {'run': 'shell'})
    '''

    def __init__(self, wrapped):
        self.wrapped = wrapped

    def __getitem__(self, name):
        if name in ALIASES:
            salt.utils.warn_until('Nitrogen', ALIAS_WARN)
            return self.wrapped[ALIASES[name]]
        else:
            return self.wrapped[name]

    def __getattr__(self, name):
        if name in ALIASES:
            salt.utils.warn_until('Nitrogen', ALIAS_WARN)
            return AliasedModule(getattr(self.wrapped, name), ALIASES[name])
        else:
            return getattr(self.wrapped, name)


class AliasedModule(object):
    '''
    Light wrapper around module objects returned by the LazyLoader's getattr
    for the purposes of `salt.cmd.run()` syntax in templates

    Allows for aliasing specific functions, such as `run` to `shell` for easy
    use of shellisms during templating calls
    '''
    def __init__(self, wrapped, aliases):
        self.aliases = aliases
        self.wrapped = wrapped

    def __getattr__(self, name):
        if name in self.aliases:
            salt.utils.warn_until('Nitrogen', ALIAS_WARN)
            return getattr(self.wrapped, self.aliases[name])
        else:
            return getattr(self.wrapped, name)


def wrap_tmpl_func(render_str):

    def render_tmpl(tmplsrc,
                    from_str=False,
                    to_str=False,
                    context=None,
                    tmplpath=None,
                    **kws):

        if context is None:
            context = {}

        # Alias cmd.run to cmd.shell to make python_shell=True the default for
        # templated calls
        if 'salt' in kws:
            kws['salt'] = AliasedLoader(kws['salt'])

        # We want explicit context to overwrite the **kws
        kws.update(context)
        context = kws
        assert 'opts' in context
        assert 'saltenv' in context

        if 'sls' in context:
            slspath = context['sls'].replace('.', '/')
            if tmplpath is not None:
                context['tplpath'] = tmplpath
                if not tmplpath.lower().replace('\\', '/').endswith('/init.sls'):
                    slspath = os.path.dirname(slspath)
                template = tmplpath.replace('\\', '/')
                i = template.rfind(slspath.replace('.', '/'))
                if i != -1:
                    template = template[i:]
                tpldir = os.path.dirname(template).replace('\\', '/')
                tpldata = {
                    'tplfile': template,
                    'tpldir': tpldir,
                    'tpldot': tpldir.replace('/', '.'),
                }
                context.update(tpldata)
            context['slsdotpath'] = slspath.replace('/', '.')
            context['slscolonpath'] = slspath.replace('/', ':')
            context['sls_path'] = slspath.replace('/', '_')
            context['slspath'] = slspath

        if isinstance(tmplsrc, string_types):
            if from_str:
                tmplstr = tmplsrc
            else:
                try:
                    if tmplpath is not None:
                        tmplsrc = os.path.join(tmplpath, tmplsrc)
                    with codecs.open(tmplsrc, 'r', SLS_ENCODING) as _tmplsrc:
                        tmplstr = _tmplsrc.read()
                except (UnicodeDecodeError,
                        ValueError,
                        OSError,
                        IOError) as exc:
                    if salt.utils.is_bin_file(tmplsrc):
                        # Template is a bin file, return the raw file
                        return dict(result=True, data=tmplsrc)
                    log.error(
                        'Exception occurred while reading file '
                        '{0}: {1}'.format(tmplsrc, exc),
                        # Show full traceback if debug logging is enabled
                        exc_info_on_loglevel=logging.DEBUG
                    )
                    raise exc
        else:  # assume tmplsrc is file-like.
            tmplstr = tmplsrc.read()
            tmplsrc.close()
        try:
            output = render_str(tmplstr, context, tmplpath)
            if salt.utils.is_windows():
                # Write out with Windows newlines
                output = os.linesep.join(output.splitlines())

        except SaltRenderError as exc:
            #return dict(result=False, data=str(exc))
            raise
        except Exception:
            return dict(result=False, data=traceback.format_exc())
        else:
            if to_str:  # then render as string
                return dict(result=True, data=output)
            with tempfile.NamedTemporaryFile('wb', delete=False) as outf:
                outf.write(SLS_ENCODER(output)[0])
                # Note: If nothing is replaced or added by the rendering
                #       function, then the contents of the output file will
                #       be exactly the same as the input.
            return dict(result=True, data=outf.name)

    render_tmpl.render_str = render_str
    return render_tmpl


def _get_jinja_error_slug(tb_data):
    '''
    Return the line number where the template error was found
    '''
    try:
        return [
            x
            for x in tb_data if x[2] in ('top-level template code',
                                         'template')
        ][-1]
    except IndexError:
        pass


def _get_jinja_error_message(tb_data):
    '''
    Return an understandable message from jinja error output
    '''
    try:
        line = _get_jinja_error_slug(tb_data)
        return u'{0}({1}):\n{3}'.format(*line)
    except IndexError:
        pass
    return None


def _get_jinja_error_line(tb_data):
    '''
    Return the line number where the template error was found
    '''
    try:
        return _get_jinja_error_slug(tb_data)[1]
    except IndexError:
        pass
    return None


def _get_jinja_error(trace, context=None):
    '''
    Return the error line and error message output from
    a stacktrace.
    If we are in a macro, also output inside the message the
    exact location of the error in the macro
    '''
    if not context:
        context = {}
    out = ''
    error = _get_jinja_error_slug(trace)
    line = _get_jinja_error_line(trace)
    msg = _get_jinja_error_message(trace)
    # if we failed on a nested macro, output a little more info
    # to help debugging
    # if sls is not found in context, add output only if we can
    # resolve the filename
    add_log = False
    template_path = None
    if 'sls' not in context:
        if (
            (error[0] != '<unknown>')
            and os.path.exists(error[0])
        ):
            template_path = error[0]
            add_log = True
    else:
        # the offender error is not from the called sls
        filen = context['sls'].replace('.', '/')
        if (
            not error[0].endswith(filen)
            and os.path.exists(error[0])
        ):
            add_log = True
            template_path = error[0]
    # if we add a log, format explicitly the exeception here
    # by telling to output the macro context after the macro
    # error log place at the beginning
    if add_log:
        if template_path:
            out = '\n{0}\n'.format(msg.splitlines()[0])
            out += salt.utils.get_context(
                salt.utils.fopen(template_path).read(),
                line,
                marker='    <======================')
        else:
            out = '\n{0}\n'.format(msg)
        line = 0
    return line, out


def render_jinja_tmpl(tmplstr, context, tmplpath=None):
    opts = context['opts']
    saltenv = context['saltenv']
    loader = None
    newline = False

    if tmplstr and not isinstance(tmplstr, six.text_type):
        # http://jinja.pocoo.org/docs/api/#unicode
        tmplstr = tmplstr.decode(SLS_ENCODING)

    if tmplstr.endswith('\n'):
        newline = True

    if not saltenv:
        if tmplpath:
            # i.e., the template is from a file outside the state tree
            #
            # XXX: FileSystemLoader is not being properly instantiated here is
            # it? At least it ain't according to:
            #
            #   http://jinja.pocoo.org/docs/api/#jinja2.FileSystemLoader
            loader = jinja2.FileSystemLoader(
                context, os.path.dirname(tmplpath))
    else:
        loader = JinjaSaltCacheLoader(opts, saltenv, pillar_rend=context.get('_pillar_rend', False))

    env_args = {'extensions': [], 'loader': loader}

    if hasattr(jinja2.ext, 'with_'):
        env_args['extensions'].append('jinja2.ext.with_')
    if hasattr(jinja2.ext, 'do'):
        env_args['extensions'].append('jinja2.ext.do')
    if hasattr(jinja2.ext, 'loopcontrols'):
        env_args['extensions'].append('jinja2.ext.loopcontrols')
    env_args['extensions'].append(JinjaSerializerExtension)

    # Pass through trim_blocks and lstrip_blocks Jinja parameters
    # trim_blocks removes newlines around Jinja blocks
    # lstrip_blocks strips tabs and spaces from the beginning of
    # line to the start of a block.
    if opts.get('jinja_trim_blocks', False):
        log.debug('Jinja2 trim_blocks is enabled')
        env_args['trim_blocks'] = True
    if opts.get('jinja_lstrip_blocks', False):
        log.debug('Jinja2 lstrip_blocks is enabled')
        env_args['lstrip_blocks'] = True

    if opts.get('allow_undefined', False):
        jinja_env = jinja2.Environment(**env_args)
    else:
        jinja_env = jinja2.Environment(undefined=jinja2.StrictUndefined,
                                       **env_args)

    jinja_env.filters['strftime'] = salt.utils.date_format
    jinja_env.filters['sequence'] = ensure_sequence_filter
    jinja_env.filters['yaml_dquote'] = salt.utils.yamlencoding.yaml_dquote
    jinja_env.filters['yaml_squote'] = salt.utils.yamlencoding.yaml_squote
    jinja_env.filters['yaml_encode'] = salt.utils.yamlencoding.yaml_encode

    jinja_env.globals['odict'] = OrderedDict
    jinja_env.globals['show_full_context'] = show_full_context

    decoded_context = {}
    for key, value in six.iteritems(context):
        if not isinstance(value, string_types):
            decoded_context[key] = value
            continue

        decoded_context[key] = salt.utils.sdecode(value)

    try:
        template = jinja_env.from_string(tmplstr)
        template.globals.update(decoded_context)
        output = template.render(**decoded_context)
    except jinja2.exceptions.TemplateSyntaxError as exc:
        trace = traceback.extract_tb(sys.exc_info()[2])
        line, out = _get_jinja_error(trace, context=decoded_context)
        if not line:
            tmplstr = ''
        raise SaltRenderError('Jinja syntax error: {0}{1}'.format(exc, out),
                              line,
                              tmplstr)
    except jinja2.exceptions.UndefinedError as exc:
        trace = traceback.extract_tb(sys.exc_info()[2])
        out = _get_jinja_error(trace, context=decoded_context)[1]
        tmplstr = ''
        # Don't include the line number, since it is misreported
        # https://github.com/mitsuhiko/jinja2/issues/276
        raise SaltRenderError(
            'Jinja variable {0}{1}'.format(
                exc, out),
            buf=tmplstr)
    except (SaltInvocationError, CommandExecutionError) as exc:
        trace = traceback.extract_tb(sys.exc_info()[2])
        line, out = _get_jinja_error(trace, context=decoded_context)
        if not line:
            tmplstr = ''
        raise SaltRenderError(
            'Problem running salt function in Jinja template: {0}{1}'.format(
                exc, out),
            line,
            tmplstr)
    except Exception as exc:
        tracestr = traceback.format_exc()
        trace = traceback.extract_tb(sys.exc_info()[2])
        line, out = _get_jinja_error(trace, context=decoded_context)
        if not line:
            tmplstr = ''
        else:
            tmplstr += '\n{0}'.format(tracestr)
        raise SaltRenderError('Jinja error: {0}{1}'.format(exc, out),
                              line,
                              tmplstr,
                              trace=tracestr)

    # Workaround a bug in Jinja that removes the final newline
    # (https://github.com/mitsuhiko/jinja2/issues/75)
    if newline:
        output += '\n'

    return output


def render_mako_tmpl(tmplstr, context, tmplpath=None):
    import mako.exceptions
    from mako.template import Template
    from salt.utils.mako import SaltMakoTemplateLookup

    saltenv = context['saltenv']
    lookup = None
    if not saltenv:
        if tmplpath:
            # i.e., the template is from a file outside the state tree
            from mako.lookup import TemplateLookup
            lookup = TemplateLookup(directories=[os.path.dirname(tmplpath)])
    else:
        lookup = SaltMakoTemplateLookup(context['opts'], saltenv)
    try:
        return Template(
            tmplstr,
            strict_undefined=True,
            uri=context['sls'].replace('.', '/') if 'sls' in context else None,
            lookup=lookup
        ).render(**context)
    except:
        raise SaltRenderError(mako.exceptions.text_error_template().render())


def render_wempy_tmpl(tmplstr, context, tmplpath=None):
    from wemplate.wemplate import TemplateParser as Template
    return Template(tmplstr).render(**context)


def render_genshi_tmpl(tmplstr, context, tmplpath=None):
    '''
    Render a Genshi template. A method should be passed in as part of the
    context. If no method is passed in, xml is assumed. Valid methods are:

    .. code-block:

        - xml
        - xhtml
        - html
        - text
        - newtext
        - oldtext

    Note that the ``text`` method will call ``NewTextTemplate``. If ``oldtext``
    is desired, it must be called explicitly
    '''
    method = context.get('method', 'xml')
    if method == 'text' or method == 'newtext':
        from genshi.template import NewTextTemplate
        tmpl = NewTextTemplate(tmplstr)
    elif method == 'oldtext':
        from genshi.template import OldTextTemplate
        tmpl = OldTextTemplate(tmplstr)
    else:
        from genshi.template import MarkupTemplate
        tmpl = MarkupTemplate(tmplstr)

    return tmpl.generate(**context).render(method)


def render_cheetah_tmpl(tmplstr, context, tmplpath=None):
    '''
    Render a Cheetah template.
    '''
    from Cheetah.Template import Template
    return str(Template(tmplstr, searchList=[context]))


def py(sfn, string=False, **kwargs):  # pylint: disable=C0103
    '''
    Render a template from a python source file

    Returns::

        {'result': bool,
         'data': <Error data or rendered file path>}
    '''
    if not os.path.isfile(sfn):
        return {}

    mod = imp.load_source(
            os.path.basename(sfn).split('.')[0],
            sfn
            )
    # File templates need these set as __var__
    if '__env__' not in kwargs and 'saltenv' in kwargs:
        setattr(mod, '__env__', kwargs['saltenv'])
        builtins = ['salt', 'grains', 'pillar', 'opts']
        for builtin in builtins:
            arg = '__{0}__'.format(builtin)
            setattr(mod, arg, kwargs[builtin])

    for kwarg in kwargs:
        setattr(mod, kwarg, kwargs[kwarg])

    try:
        data = mod.run()
        if string:
            return {'result': True,
                    'data': data}
        tgt = salt.utils.mkstemp()
        with salt.utils.fopen(tgt, 'w+') as target:
            target.write(data)
        return {'result': True,
                'data': tgt}
    except Exception:
        trb = traceback.format_exc()
        return {'result': False,
                'data': trb}


JINJA = wrap_tmpl_func(render_jinja_tmpl)
MAKO = wrap_tmpl_func(render_mako_tmpl)
WEMPY = wrap_tmpl_func(render_wempy_tmpl)
GENSHI = wrap_tmpl_func(render_genshi_tmpl)
CHEETAH = wrap_tmpl_func(render_cheetah_tmpl)

TEMPLATE_REGISTRY = {
    'jinja': JINJA,
    'mako': MAKO,
    'py': py,
    'wempy': WEMPY,
    'genshi': GENSHI,
    'cheetah': CHEETAH,
}
