#!/usr/bin/env python3
"""Script to generate top level resource collection URIs.

Parses the Redfish schema to determine what are the top level collection URIs
and writes them to a generated .hpp file as an unordered_set.  Also generates
a map of URIs that contain a top level collection as part of their subtree.
Those URIs as well as those of their immediate children as written as an
unordered_map.  These URIs are need by Redfish Aggregation

generates redfish-core/include/aggregation_utils.hpp
"""

import os
import xml.etree.ElementTree as ET

WARNING = """/****************************************************************
 *                 READ THIS WARNING FIRST
 * This is an auto-generated header which contains definitions
 * for Redfish DMTF defined schemas.
 * DO NOT modify this registry outside of running the
 * update_schemas.py script.  The definitions contained within
 * this file are owned by DMTF.  Any modifications to these files
 * should be first pushed to the relevant registry in the DMTF
 * github organization.
 ***************************************************************/"""

SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
REDFISH_SCHEMA_DIR = os.path.realpath(
    os.path.join(SCRIPT_DIR, "..", "static", "redfish", "v1", "schema")
)
CPP_OUTFILE = os.path.realpath(
    os.path.join(
        SCRIPT_DIR, "..", "redfish-core", "include", "aggregation_utils.hpp"
    )
)


# Odata string types
EDMX = "{http://docs.oasis-open.org/odata/ns/edmx}"
EDM = "{http://docs.oasis-open.org/odata/ns/edm}"

seen_paths = set()


def parse_node(target_entitytype, path, top_collections, found_top, xml_file):
  """Parses a single node in the Redfish schema."""
  filepath = os.path.join(REDFISH_SCHEMA_DIR, xml_file)
  tree = ET.parse(filepath)
  root = tree.getroot()

  # Map xml URIs to their associated namespace
  xml_map = {}
  for ref in root.findall(EDMX + "Reference"):
    uri = ref.get("Uri")
    if uri is None:
      continue
    file = uri.split("/").pop()
    for inc in ref.findall(EDMX + "Include"):
      namespace = inc.get("Namespace")
      if namespace is None:
        continue
      xml_map[namespace] = file

  parse_root(root, target_entitytype, path, top_collections, found_top, xml_map)


# Given a root node we want to parse the tree to find all instances of a
# specific EntityType.  This is a separate routine so that we can rewalk the
# current tree when a NavigationProperty Type links to the current file.
def parse_root(
    root, target_entitytype, path, top_collections, found_top, xml_map
):
  """Parses a single root node in the Redfish schema."""
  ds = root.find(EDMX + "DataServices")
  if ds is None:
    return
  for schema in ds.findall(EDM + "Schema"):
    for entity_type in schema.findall(EDM + "EntityType"):
      name = entity_type.get("Name")
      if name != target_entitytype:
        continue
      for nav_prop in entity_type.findall(EDM + "NavigationProperty"):
        parse_navigation_property(
            root,
            name,
            nav_prop,
            path,
            top_collections,
            found_top,
            xml_map,
        )

    # These ComplexType objects contain links to actual resources or
    # resource collections
    for complex_type in schema.findall(EDM + "ComplexType"):
      name = complex_type.get("Name")
      if name != target_entitytype:
        continue
      for nav_prop in complex_type.findall(EDM + "NavigationProperty"):
        parse_navigation_property(
            root,
            name,
            nav_prop,
            path,
            top_collections,
            found_top,
            xml_map,
        )


# Helper function which expects a NavigationProperty to be passed in.  We need
# this because NavigationProperty appears under both EntityType and ComplexType
def parse_navigation_property(
    root, curr_entitytype, element, path, top_collections, found_top, xml_map  # pylint: disable=unused-argument
):
  """Parses a single NavigationProperty."""
  if element.tag != (EDM + "NavigationProperty"):
    return

  # We don't want to actually parse this property if it's just an excerpt
  for annotation in element.findall(EDM + "Annotation"):
    term = annotation.get("Term")
    if term == "Redfish.ExcerptCopy":
      return

  # We don't want to aggregate JsonSchemas as well as anything under
  # AccountService or SessionService
  nav_name = element.get("Name")
  if nav_name in ["JsonSchemas", "AccountService", "SessionService"]:
    return

  nav_type = element.get("Type")
  if "Collection" in nav_type:
    # Type is either Collection(<Namespace>.<TypeName>) or
    # Collection(<NamespaceName>.<NamespaceVersion>.<TypeName>)
    if nav_type.startswith("Collection"):
      qualified_name = nav_type.split("(")[1].split(")")[0]
      # Do we need to parse this file or another file?
      qualified_name_split = qualified_name.split(".")
      if len(qualified_name_split) == 3:
        typename = qualified_name_split[2]
      else:
        typename = qualified_name_split[1]
      file_key = qualified_name_split[0]

      # If we contain a collection array then we don't want to add the
      # name to the path if we're a collection schema
      if nav_name != "Members":
        path += "/" + nav_name
        if path in seen_paths:
          return
        seen_paths.add(path)

        # Did we find the top level collection in the current path or
        # did we previously find it?
        if not found_top:
          top_collections.add(path)
          found_top = True

      member_id = typename + "Id"
      prev_count = path.count(member_id)
      if prev_count:
        new_path = path + "/{" + member_id + str(prev_count + 1) + "}"
      else:
        new_path = path + "/{" + member_id + "}"

    # type is "<Namespace>.<TypeName>", both should end with "Collection"
    else:
      # Escape if we've found a circular dependency like SubProcessors
      if path.count(nav_name) >= 2:
        return

      nav_type_split = nav_type.split(".")
      if (len(nav_type_split) != 2) and (
          nav_type_split[0] != nav_type_split[1]
      ):
        # We ended up with something like Resource.ResourceCollection
        return
      file_key = nav_type_split[0]
      typename = nav_type_split[1]
      new_path = path + "/" + nav_name

    # Did we find the top level collection in the current path or did we
    # previously find it?
    if not found_top:
      top_collections.add(new_path)
      found_top = True

  # NavigationProperty is not for a collection
  else:
    # Bail if we've found a circular dependency like MetricReport
    if path.count(nav_name):
      return

    new_path = path + "/" + nav_name
    nav_type_split = nav_type.split(".")
    file_key = nav_type_split[0]
    typename = nav_type_split[1]

  # We need to specially handle certain URIs since the Name attribute from the
  # schema is not used as part of the path
  # TODO: Expand this section to add special handling across the entirety of # pylint: disable=g-bad-todo
  # the Redfish tree
  new_path2 = ""
  if new_path == "/redfish/v1/Tasks":
    new_path2 = "/redfish/v1/TaskService"

  # If we had to apply special handling then we need to remove the inital
  # version of the URI if it was previously added
  if new_path2 != "":  # pylint: disable=g-explicit-bool-comparison
    if new_path in seen_paths:
      seen_paths.remove(new_path)
    new_path = new_path2

  # No need to parse the new URI if we've already done so
  if new_path in seen_paths:
    return
  seen_paths.add(new_path)

  # We can stop parsing if we've found a top level collection
  # TODO: Don't return here when we want to walk the entire tree instead # pylint: disable=g-bad-todo
  if found_top:
    return

  # If the namespace of the NavigationProperty's Type is not in our xml map
  # then that means it inherits from elsewhere in the current file
  if file_key in xml_map:
    parse_node(
        typename, new_path, top_collections, found_top, xml_map[file_key]
    )
  else:
    parse_root(root, typename, new_path, top_collections, found_top, xml_map)


def generate_top_collections():
  """Generates the top level collections and writes them to a file."""
  # We need to separately track top level resources as well as all URIs that
  # are upstream from a top level resource.  We shouldn't combine these into
  # a single structure because:
  #
  # 1) We want direct lookup of top level collections for prefix handling
  # purposes.
  #
  # 2) A top level collection will not always be one level below the service
  # root.  For example, we need to aggregate
  # /redfish/v1/CompositionService/ActivePool and we do not currently support
  # CompositionService.  If a satellite BMC implements it then we would need
  # to display a link to CompositionService under /redfish/v1 even though
  # CompositionService is not a top level collection.

  # Contains URIs for all top level collections
  top_collections = set()

  # Begin parsing from the Service Root
  curr_path = "/redfish/v1"
  seen_paths.add(curr_path)
  parse_node(
      "ServiceRoot", curr_path, top_collections, False, "ServiceRoot_v1.xml"
  )

  print("Finished traversal!")

  TOTAL = len(top_collections)  # pylint: disable=invalid-name
  with open(CPP_OUTFILE, "w") as hpp_file:
    hpp_file.write(
        "// NOLINTBEGIN\n"
        "#pragma once\n"
        "{WARNING}\n"
        "// clang-format off\n"
        "#include <array>\n"
        "#include <string_view>\n"
        "\n"
        "namespace redfish\n"
        "{{\n"
        '// Note that each URI actually begins with "/redfish/v1"\n'
        "// They've been omitted to save space and reduce search time\n"
        "constexpr std::array<std::string_view, {TOTAL}> "
        "topCollections{{\n".format(WARNING=WARNING, TOTAL=TOTAL)
    )

    for collection in sorted(top_collections):
      # All URIs start with "/redfish/v1".  We can omit that portion to
      # save memory and reduce lookup time
      hpp_file.write('    "{}",\n'.format(collection.split("/redfish/v1")[1]))

    hpp_file.write("};\n} // namespace redfish\n// NOLINTEND\n")