""" Ensure that all XML files in the Bcfg2 repository validate
according to their respective schemas. """

import os
import sys
import glob
import fnmatch
import lxml.etree
from subprocess import Popen, PIPE, STDOUT
import Bcfg2.Server.Lint


class Validate(Bcfg2.Server.Lint.ServerlessPlugin):
    """ Ensure that all XML files in the Bcfg2 repository validate
    according to their respective schemas. """

    def __init__(self, *args, **kwargs):
        Bcfg2.Server.Lint.ServerlessPlugin.__init__(self, *args, **kwargs)

        #: A dict of <file glob>: <schema file> that maps files in the
        #: Bcfg2 specification to their schemas.  The globs are
        #: extended :mod:`fnmatch` globs that also support ``**``,
        #: which matches any number of any characters, including
        #: forward slashes.  The schema files are relative to the
        #: schema directory, which can be controlled by the
        #: ``bcfg2-lint --schema`` option.
        self.filesets = \
            {"Metadata/groups.xml": "metadata.xsd",
             "Metadata/clients.xml": "clients.xsd",
             "Cfg/**/info.xml": "info.xsd",
             "Cfg/**/privkey.xml": "privkey.xsd",
             "Cfg/**/pubkey.xml": "pubkey.xsd",
             "Cfg/**/authorizedkeys.xml": "authorizedkeys.xsd",
             "Cfg/**/authorized_keys.xml": "authorizedkeys.xsd",
             "SSHbase/**/info.xml": "info.xsd",
             "SSLCA/**/info.xml": "info.xsd",
             "TGenshi/**/info.xml": "info.xsd",
             "TCheetah/**/info.xml": "info.xsd",
             "Bundler/*.xml": "bundle.xsd",
             "Bundler/*.genshi": "bundle.xsd",
             "Pkgmgr/*.xml": "pkglist.xsd",
             "Base/*.xml": "base.xsd",
             "Rules/*.xml": "rules.xsd",
             "Defaults/*.xml": "defaults.xsd",
             "etc/report-configuration.xml": "report-configuration.xsd",
             "Deps/*.xml": "deps.xsd",
             "Decisions/*.xml": "decisions.xsd",
             "Packages/sources.xml": "packages.xsd",
             "GroupPatterns/config.xml": "grouppatterns.xsd",
             "AWSTags/config.xml": "awstags.xsd",
             "NagiosGen/config.xml": "nagiosgen.xsd",
             "FileProbes/config.xml": "fileprobes.xsd",
             "SSLCA/**/cert.xml": "sslca-cert.xsd",
             "SSLCA/**/key.xml": "sslca-key.xsd",
             "GroupLogic/groups.xml": "grouplogic.xsd"
             }

        self.filelists = {}
        self.get_filelists()

    def Run(self):
        schemadir = self.config['schema']

        for path, schemaname in self.filesets.items():
            try:
                filelist = self.filelists[path]
            except KeyError:
                filelist = []

            if filelist:
                # avoid loading schemas for empty file lists
                schemafile = os.path.join(schemadir, schemaname)
                schema = self._load_schema(schemafile)
                if schema:
                    for filename in filelist:
                        self.validate(filename, schemafile, schema=schema)

        self.check_properties()

    @classmethod
    def Errors(cls):
        return {"schema-failed-to-parse": "warning",
                "properties-schema-not-found": "warning",
                "xml-failed-to-parse": "error",
                "xml-failed-to-read": "error",
                "xml-failed-to-verify": "error",
                "input-output-error": "error"}

    def check_properties(self):
        """ Check Properties files against their schemas. """
        for filename in self.filelists['props']:
            schemafile = "%s.xsd" % os.path.splitext(filename)[0]
            if os.path.exists(schemafile):
                self.validate(filename, schemafile)
            else:
                self.LintError("properties-schema-not-found",
                               "No schema found for %s" % filename)
                # ensure that it at least parses
                self.parse(filename)

    def parse(self, filename):
        """ Parse an XML file, raising the appropriate LintErrors if
        it can't be parsed or read.  Return the
        lxml.etree._ElementTree parsed from the file.

        :param filename: The full path to the file to parse
        :type filename: string
        :returns: lxml.etree._ElementTree - the parsed data"""
        try:
            return lxml.etree.parse(filename)
        except SyntaxError:
            lint = Popen(["xmllint", filename], stdout=PIPE, stderr=STDOUT)
            self.LintError("xml-failed-to-parse",
                           "%s fails to parse:\n%s" % (filename,
                                                       lint.communicate()[0]))
            lint.wait()
            return False
        except IOError:
            self.LintError("xml-failed-to-read",
                           "Failed to open file %s" % filename)
            return False

    def validate(self, filename, schemafile, schema=None):
        """ Validate a file against the given schema.

        :param filename: The full path to the file to validate
        :type filename: string
        :param schemafile: The full path to the schema file to
                           validate against
        :type schemafile: string
        :param schema: The loaded schema to validate against.  This
                       can be used to avoid parsing a single schema
                       file for every file that needs to be validate
                       against it.
        :type schema: lxml.etree.Schema
        :returns: bool - True if the file validates, false otherwise
        """
        if schema is None:
            # if no schema object was provided, instantiate one
            schema = self._load_schema(schemafile)
            if not schema:
                return False
        datafile = self.parse(filename)
        if not schema.validate(datafile):
            cmd = ["xmllint"]
            if self.files is None:
                cmd.append("--xinclude")
            cmd.extend(["--noout", "--schema", schemafile, filename])
            lint = Popen(cmd, stdout=PIPE, stderr=STDOUT)
            output = lint.communicate()[0]
            # py3k fix
            if not isinstance(output, str):
                output = output.decode('utf-8')
            if lint.wait():
                self.LintError("xml-failed-to-verify",
                               "%s fails to verify:\n%s" % (filename, output))
                return False
        return True

    def get_filelists(self):
        """ Get lists of different kinds of files to validate.  This
        doesn't return anything, but it sets
        :attr:`Bcfg2.Server.Lint.Validate.Validate.filelists` to a
        dict whose keys are path globs given in
        :attr:`Bcfg2.Server.Lint.Validate.Validate.filesets` and whose
        values are lists of the full paths to all files in the Bcfg2
        repository (or given with ``bcfg2-lint --stdin``) that match
        the glob."""
        if self.files is not None:
            listfiles = lambda p: fnmatch.filter(self.files,
                                                 os.path.join('*', p))
        else:
            listfiles = lambda p: glob.glob(os.path.join(self.config['repo'],
                                                         p))

        for path in self.filesets.keys():
            if '/**/' in path:
                if self.files is not None:
                    self.filelists[path] = listfiles(path)
                else:  # self.files is None
                    fpath, fname = path.split('/**/')
                    self.filelists[path] = []
                    for root, _, files in \
                            os.walk(os.path.join(self.config['repo'],
                                                 fpath)):
                        self.filelists[path].extend([os.path.join(root, f)
                                                     for f in files
                                                     if f == fname])
            else:
                self.filelists[path] = listfiles(path)

        self.filelists['props'] = listfiles("Properties/*.xml")

    def _load_schema(self, filename):
        """ Load an XML schema document, returning the Schema object
        and raising appropriate lint errors on failure.

        :param filename: The full path to the schema file to load.
        :type filename: string
        :returns: lxml.etree.Schema - The loaded schema data
        """
        try:
            return lxml.etree.XMLSchema(lxml.etree.parse(filename))
        except IOError:
            err = sys.exc_info()[1]
            self.LintError("input-output-error", str(err))
        except lxml.etree.XMLSchemaParseError:
            err = sys.exc_info()[1]
            self.LintError("schema-failed-to-parse",
                           "Failed to process schema %s: %s" %
                           (filename, err))
        return None
