#!/usr/bin/env python3

import argparse
import json
import sys

r"""
Validates the PEL message registry JSON, which includes checking it against
a JSON schema using the jsonschema module as well as doing some extra checks
that can't be encoded in the schema.
"""


def check_duplicate_names(registry_json):
    r"""
    Check that there aren't any message registry entries with the same
    'Name' field.  There may be a use case for this in the future, but there
    isn't right now.

    registry_json: The message registry JSON
    """

    names = []
    for entry in registry_json["PELs"]:
        if entry["Name"] in names:
            sys.exit("Found multiple uses of error {}".format(entry["Name"]))
        else:
            names.append(entry["Name"])


def check_duplicate_reason_codes(registry_json):
    r"""
    Check that there aren't any message registry entries with the same
    'ReasonCode' field.

    registry_json: The message registry JSON
    """

    reasonCodes = []
    for entry in registry_json["PELs"]:
        if entry["SRC"]["ReasonCode"] in reasonCodes:
            sys.exit(
                "Found duplicate SRC reason code {}".format(
                    entry["SRC"]["ReasonCode"]
                )
            )
        else:
            reasonCodes.append(entry["SRC"]["ReasonCode"])


def check_component_id(registry_json):
    r"""
    Check that the upper byte of the ComponentID field matches the upper byte
    of the ReasonCode field, but not on "11" type SRCs where they aren't
    supposed to match.

    registry_json: The message registry JSON
    """

    for entry in registry_json["PELs"]:
        # Don't check on "11" SRCs as those reason codes aren't supposed to
        # match the component ID.
        if entry["SRC"].get("Type", "") == "11":
            continue

        if "ComponentID" in entry:
            id = int(entry["ComponentID"], 16)
            reason_code = int(entry["SRC"]["ReasonCode"], 16)

            if (id & 0xFF00) != (reason_code & 0xFF00):
                sys.exit(
                    "Found mismatching component ID {} vs reason "
                    "code {} for error {}".format(
                        entry["ComponentID"],
                        entry["SRC"]["ReasonCode"],
                        entry["Name"],
                    )
                )


def check_message_args(registry_json):
    r"""
    Check that if the Message field uses the '%' style placeholders that there
    are that many entries in the MessageArgSources field.  Also checks that
    the MessageArgSources field is present but only if there are placeholders.

    registry_json: The message registry JSON
    """

    for entry in registry_json["PELs"]:
        num_placeholders = entry["Documentation"]["Message"].count("%")
        if num_placeholders == 0:
            continue

        if "MessageArgSources" not in entry["Documentation"]:
            sys.exit(
                "Missing MessageArgSources property for error {}".format(
                    entry["Name"]
                )
            )

        if num_placeholders != len(
            entry["Documentation"]["MessageArgSources"]
        ):
            sys.exit(
                "Different number of placeholders found in "
                "Message vs MessageArgSources for error {}".format(
                    entry["Name"]
                )
            )


def validate_schema(registry, schema):
    r"""
    Validates the passed in JSON against the passed in schema JSON

    registry: Path of the file containing the registry JSON
    schema:   Path of the file containing the schema JSON
              Use None to skip the pure schema validation
    """

    with open(registry) as registry_handle:
        registry_json = json.load(registry_handle)

        if schema:
            import jsonschema

            with open(schema) as schema_handle:
                schema_json = json.load(schema_handle)

                try:
                    jsonschema.validate(registry_json, schema_json)
                except jsonschema.ValidationError as e:
                    print(e)
                    sys.exit("Schema validation failed")

        check_duplicate_names(registry_json)

        check_duplicate_reason_codes(registry_json)

        check_component_id(registry_json)

        check_message_args(registry_json)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="PEL message registry validator"
    )

    parser.add_argument(
        "-s",
        "--schema-file",
        dest="schema_file",
        help="The message registry JSON schema file",
        required=True,
    )

    parser.add_argument(
        "-r",
        "--registry-file",
        dest="registry_file",
        help="The message registry JSON file",
        required=True,
    )

    parser.add_argument(
        "-k",
        "--skip-schema-validation",
        action="store_true",
        dest="skip_schema",
        help="Skip running schema validation. Only do the extra checks.",
    )

    args = parser.parse_args()

    schema = args.schema_file
    if args.skip_schema:
        schema = None

    validate_schema(args.registry_file, schema)