# Copyright 2016 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Define API Loggers."""

import collections
import re

from google.cloud.logging_v2._helpers import _add_defaults_to_filter
from google.cloud.logging_v2.entries import LogEntry
from google.cloud.logging_v2.entries import ProtobufEntry
from google.cloud.logging_v2.entries import StructEntry
from google.cloud.logging_v2.entries import TextEntry
from google.cloud.logging_v2.resource import Resource
from google.cloud.logging_v2.handlers._monitored_resources import detect_resource
from google.cloud.logging_v2._instrumentation import _add_instrumentation

from google.api_core.exceptions import InvalidArgument
from google.rpc.error_details_pb2 import DebugInfo

import google.cloud.logging_v2
import google.protobuf.message

_GLOBAL_RESOURCE = Resource(type="global", labels={})


_OUTBOUND_ENTRY_FIELDS = (  # (name, default)
    ("type_", None),
    ("log_name", None),
    ("payload", None),
    ("labels", None),
    ("insert_id", None),
    ("severity", None),
    ("http_request", None),
    ("timestamp", None),
    ("resource", _GLOBAL_RESOURCE),
    ("trace", None),
    ("span_id", None),
    ("trace_sampled", None),
    ("source_location", None),
)

_STRUCT_EXTRACTABLE_FIELDS = ["severity", "trace", "span_id"]


class Logger(object):
    """Loggers represent named targets for log entries.

    See https://cloud.google.com/logging/docs/reference/v2/rest/v2/projects.logs
    """

    def __init__(self, name, client, *, labels=None, resource=None):
        """
        Args:
            name (str): The name of the logger.
            client (~logging_v2.client.Client):
                A client which holds credentials and project configuration
                for the logger (which requires a project).
            resource (Optional[~logging_v2.Resource]): a monitored resource object
                representing the resource the code was run on. If not given, will
                be inferred from the environment.
            labels (Optional[dict]): Mapping of default labels for entries written
                via this logger.

        """
        if not resource:
            # infer the correct monitored resource from the local environment
            resource = detect_resource(client.project)
        self.name = name
        self._client = client
        self.labels = labels
        self.default_resource = resource

    @property
    def client(self):
        """Clent bound to the logger."""
        return self._client

    @property
    def project(self):
        """Project bound to the logger."""
        return self._client.project

    @property
    def full_name(self):
        """Fully-qualified name used in logging APIs"""
        return f"projects/{self.project}/logs/{self.name}"

    @property
    def path(self):
        """URI path for use in logging APIs"""
        return f"/{self.full_name}"

    def _require_client(self, client):
        """Check client or verify over-ride. Also sets ``parent``.

        Args:
            client (Union[None, ~logging_v2.client.Client]):
                The client to use.  If not passed, falls back to the
                ``client`` stored on the current sink.

        Returns:
            ~logging_v2.client.Client: The client passed in
                or the currently bound client.
        """
        if client is None:
            client = self._client
        return client

    def batch(self, *, client=None):
        """Return a batch to use as a context manager.

        Args:
            client (Union[None, ~logging_v2.client.Client]):
                The client to use.  If not passed, falls back to the
                ``client`` stored on the current sink.

        Returns:
            Batch: A batch to use as a context manager.
        """
        client = self._require_client(client)
        return Batch(self, client)

    def _do_log(self, client, _entry_class, payload=None, **kw):
        """Helper for :meth:`log_empty`, :meth:`log_text`, etc."""
        client = self._require_client(client)

        # Apply defaults
        kw["log_name"] = kw.pop("log_name", self.full_name)
        kw["labels"] = kw.pop("labels", self.labels)
        kw["resource"] = kw.pop("resource", self.default_resource)

        severity = kw.get("severity", None)
        if isinstance(severity, str):
            # convert severity to upper case, as expected by enum definition
            kw["severity"] = severity.upper()

        if isinstance(kw["resource"], collections.abc.Mapping):
            # if resource was passed as a dict, attempt to parse it into a
            # Resource object
            try:
                kw["resource"] = Resource(**kw["resource"])
            except TypeError as e:
                # dict couldn't be parsed as a Resource
                raise TypeError("invalid resource dict") from e

        if payload is not None:
            entry = _entry_class(payload=payload, **kw)
        else:
            entry = _entry_class(**kw)

        api_repr = entry.to_api_repr()
        entries = [api_repr]

        if google.cloud.logging_v2._instrumentation_emitted is False:
            entries = _add_instrumentation(entries, **kw)
            google.cloud.logging_v2._instrumentation_emitted = True
        # partial_success is true to avoid dropping instrumentation logs
        client.logging_api.write_entries(entries, partial_success=True)

    def log_empty(self, *, client=None, **kw):
        """Log an empty message

        See
        https://cloud.google.com/logging/docs/reference/v2/rest/v2/entries/write

        Args:
            client (Optional[~logging_v2.client.Client]):
                The client to use.  If not passed, falls back to the
                ``client`` stored on the current sink.
            kw (Optional[dict]): additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.
        """
        self._do_log(client, LogEntry, **kw)

    def log_text(self, text, *, client=None, **kw):
        """Log a text message

        See
        https://cloud.google.com/logging/docs/reference/v2/rest/v2/entries/write

        Args:
            text (str): the log message
            client (Optional[~logging_v2.client.Client]):
                The client to use.  If not passed, falls back to the
                ``client`` stored on the current sink.
            kw (Optional[dict]): additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.
        """
        self._do_log(client, TextEntry, text, **kw)

    def log_struct(self, info, *, client=None, **kw):
        """Logs a dictionary message.

        See
        https://cloud.google.com/logging/docs/reference/v2/rest/v2/entries/write

        The message must be able to be serializable to a Protobuf Struct.
        It must be a dictionary of strings to one of the following:

            - :class:`str`
            - :class:`int`
            - :class:`float`
            - :class:`bool`
            - :class:`list[str|float|int|bool|list|dict|None]`
            - :class:`dict[str, str|float|int|bool|list|dict|None]`

        For more details on Protobuf structs, see https://protobuf.dev/reference/protobuf/google.protobuf/#value.
        If the provided dictionary cannot be serialized into a Protobuf struct,
        it will not be logged, and a :class:`ValueError` will be raised.

        Args:
            info (dict[str, str|float|int|bool|list|dict|None]):
                the log entry information.
            client (Optional[~logging_v2.client.Client]):
                The client to use.  If not passed, falls back to the
                ``client`` stored on the current sink.
            kw (Optional[dict]): additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.

        Raises:
            ValueError:
                if the dictionary message provided cannot be serialized into a Protobuf
                struct.
        """
        for field in _STRUCT_EXTRACTABLE_FIELDS:
            # attempt to copy relevant fields from the payload into the LogEntry body
            if field in info and field not in kw:
                kw[field] = info[field]
        self._do_log(client, StructEntry, info, **kw)

    def log_proto(self, message, *, client=None, **kw):
        """Log a protobuf message

        See
        https://cloud.google.com/logging/docs/reference/v2/rest/v2/entries/list

        Args:
            message (google.protobuf.message.Message):
                The protobuf message to be logged.
            client (Optional[~logging_v2.client.Client]):
                The client to use.  If not passed, falls back to the
                ``client`` stored on the current sink.
            kw (Optional[dict]): additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.
        """
        self._do_log(client, ProtobufEntry, message, **kw)

    def log(self, message=None, *, client=None, **kw):
        """Log an arbitrary message. Type will be inferred based on the input.

        See
        https://cloud.google.com/logging/docs/reference/v2/rest/v2/entries/list

        Args:
            message (Optional[str or dict or google.protobuf.Message]): The message. to log
            client (Optional[~logging_v2.client.Client]):
                The client to use.  If not passed, falls back to the
                ``client`` stored on the current sink.
            kw (Optional[dict]): additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.
        """
        if isinstance(message, google.protobuf.message.Message):
            self.log_proto(message, client=client, **kw)
        elif isinstance(message, collections.abc.Mapping):
            self.log_struct(message, client=client, **kw)
        elif isinstance(message, str):
            self.log_text(message, client=client, **kw)
        else:
            self._do_log(client, LogEntry, message, **kw)

    def delete(self, logger_name=None, *, client=None):
        """Delete all entries in a logger via a DELETE request

        See
        https://cloud.google.com/logging/docs/reference/v2/rest/v2/projects.logs/delete

        Args:
            logger_name (Optional[str]):  The resource name of the log to delete:

                ::

                    "projects/[PROJECT_ID]/logs/[LOG_ID]"
                    "organizations/[ORGANIZATION_ID]/logs/[LOG_ID]"
                    "billingAccounts/[BILLING_ACCOUNT_ID]/logs/[LOG_ID]"
                    "folders/[FOLDER_ID]/logs/[LOG_ID]"

                ``[LOG_ID]`` must be URL-encoded. For example,
                ``"projects/my-project-id/logs/syslog"``,
                ``"organizations/1234567890/logs/cloudresourcemanager.googleapis.com%2Factivity"``.
                If not passed, defaults to the project bound to the client.
            client (Optional[~logging_v2.client.Client]):
                The client to use.  If not passed, falls back to the
                ``client`` stored on the current logger.
        """
        client = self._require_client(client)
        if logger_name is None:
            logger_name = self.full_name
        client.logging_api.logger_delete(logger_name)

    def list_entries(
        self,
        *,
        resource_names=None,
        filter_=None,
        order_by=None,
        max_results=None,
        page_size=None,
        page_token=None,
    ):
        """Return a generator of log entry resources.

        See
        https://cloud.google.com/logging/docs/reference/v2/rest/v2/entries/list

        Args:
            resource_names (Optional[Sequence[str]]): Names of one or more parent resources
                from which to retrieve log entries:

                ::

                    "projects/[PROJECT_ID]"
                    "organizations/[ORGANIZATION_ID]"
                    "billingAccounts/[BILLING_ACCOUNT_ID]"
                    "folders/[FOLDER_ID]"

                If not passed, defaults to the project bound to the client.
            filter_ (Optional[str]): a filter expression. See
                https://cloud.google.com/logging/docs/view/advanced_filters
                By default, a 24 hour filter is applied.
            order_by (Optional[str]): One of :data:`~logging_v2.ASCENDING`
                or :data:`~logging_v2.DESCENDING`.
            max_results (Optional[int]):
                Optional. The maximum number of entries to return.
                Non-positive values are treated as 0. If None, uses API defaults.
            page_size (int): number of entries to fetch in each API call. Although
                requests are paged internally, logs are returned by the generator
                one at a time. If not passed, defaults to a value set by the API.
            page_token (str): opaque marker for the starting "page" of entries. If not
                passed, the API will return the first page of entries.
        Returns:
            Generator[~logging_v2.LogEntry]
        """

        if resource_names is None:
            resource_names = [f"projects/{self.project}"]

        log_filter = f"logName={self.full_name}"
        if filter_ is not None:
            filter_ = f"{filter_} AND {log_filter}"
        else:
            filter_ = log_filter
        filter_ = _add_defaults_to_filter(filter_)
        return self.client.list_entries(
            resource_names=resource_names,
            filter_=filter_,
            order_by=order_by,
            max_results=max_results,
            page_size=page_size,
            page_token=page_token,
        )


class Batch(object):
    def __init__(self, logger, client, *, resource=None):
        """Context manager:  collect entries to log via a single API call.

        Helper returned by :meth:`Logger.batch`

        Args:
            logger (logging_v2.logger.Logger):
                the logger to which entries will be logged.
            client (~logging_V2.client.Client):
                The client to use.
            resource (Optional[~logging_v2.resource.Resource]):
                Monitored resource of the batch, defaults
                to None, which requires that every entry should have a
                resource specified. Since the methods used to write
                entries default the entry's resource to the global
                resource type, this parameter is only required
                if explicitly set to None. If no entries' resource are
                set to None, this parameter will be ignored on the server.
        """
        self.logger = logger
        self.entries = []
        self.client = client
        self.resource = resource

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        if exc_type is None:
            self.commit()

    def log_empty(self, **kw):
        """Add a entry without payload to be logged during :meth:`commit`.

        Args:
            kw (Optional[dict]): Additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.
        """
        self.entries.append(LogEntry(**kw))

    def log_text(self, text, **kw):
        """Add a text entry to be logged during :meth:`commit`.

        Args:
            text (str): the text entry
            kw (Optional[dict]): Additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.
        """
        self.entries.append(TextEntry(payload=text, **kw))

    def log_struct(self, info, **kw):
        """Add a struct entry to be logged during :meth:`commit`.

        The message must be able to be serializable to a Protobuf Struct.
        It must be a dictionary of strings to one of the following:

            - :class:`str`
            - :class:`int`
            - :class:`float`
            - :class:`bool`
            - :class:`list[str|float|int|bool|list|dict|None]`
            - :class:`dict[str, str|float|int|bool|list|dict|None]`

        For more details on Protobuf structs, see https://protobuf.dev/reference/protobuf/google.protobuf/#value.
        If the provided dictionary cannot be serialized into a Protobuf struct,
        it will not be logged, and a :class:`ValueError` will be raised during :meth:`commit`.

        Args:
            info (dict[str, str|float|int|bool|list|dict|None]): The struct entry,
            kw (Optional[dict]): Additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.
        """
        self.entries.append(StructEntry(payload=info, **kw))

    def log_proto(self, message, **kw):
        """Add a protobuf entry to be logged during :meth:`commit`.

        Args:
            message (google.protobuf.Message): The protobuf entry.
            kw (Optional[dict]): Additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.
        """
        self.entries.append(ProtobufEntry(payload=message, **kw))

    def log(self, message=None, **kw):
        """Add an arbitrary message to be logged during :meth:`commit`.
        Type will be inferred based on the input message.

        Args:
            message (Optional[str or dict or google.protobuf.Message]): The message. to log
            kw (Optional[dict]): Additional keyword arguments for the entry.
                See :class:`~logging_v2.entries.LogEntry`.
        """
        entry_type = LogEntry
        if isinstance(message, google.protobuf.message.Message):
            entry_type = ProtobufEntry
        elif isinstance(message, collections.abc.Mapping):
            entry_type = StructEntry
        elif isinstance(message, str):
            entry_type = TextEntry
        self.entries.append(entry_type(payload=message, **kw))

    def commit(self, *, client=None, partial_success=True):
        """Send saved log entries as a single API call.

        Args:
            client (Optional[~logging_v2.client.Client]):
                The client to use.  If not passed, falls back to the
                ``client`` stored on the current batch.
            partial_success (Optional[bool]):
                Whether a batch's valid entries should be written even
                if some other entry failed due to a permanent error such
                as INVALID_ARGUMENT or PERMISSION_DENIED.

        Raises:
            ValueError:
                if one of the messages in the batch cannot be successfully parsed.
        """
        if client is None:
            client = self.client

        kwargs = {"logger_name": self.logger.full_name}

        if self.resource is not None:
            kwargs["resource"] = self.resource._to_dict()

        if self.logger.labels is not None:
            kwargs["labels"] = self.logger.labels

        entries = [entry.to_api_repr() for entry in self.entries]
        try:
            client.logging_api.write_entries(
                entries, partial_success=partial_success, **kwargs
            )
        except InvalidArgument as e:
            # InvalidArgument is often sent when a log is too large
            # attempt to attach extra contex on which log caused error
            self._append_context_to_error(e)
            raise e
        del self.entries[:]

    def _append_context_to_error(self, err):
        """
        Attempts to Modify `write_entries` exception messages to contain
        context on which log in the batch caused the error.

        Best-effort basis. If another exception occurs while processing the
        input exception, the input will be left unmodified

        Args:
            err (~google.api_core.exceptions.InvalidArgument):
                The original exception object
        """
        try:
            # find debug info proto if in details
            debug_info = next(x for x in err.details if isinstance(x, DebugInfo))
            # parse out the index of the faulty entry
            error_idx = re.search("(?<=key: )[0-9]+", debug_info.detail).group(0)
            # find the faulty entry object
            found_entry = self.entries[int(error_idx)]
            str_entry = str(found_entry.to_api_repr())
            # modify error message to contain extra context
            err.message = f"{err.message}: {str_entry:.2000}..."
        except Exception:
            # if parsing fails, abort changes and leave err unmodified
            pass