# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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.
"""Defines the templating context for SQL Lab"""
import json
import re
from functools import partial
from typing import (
    Any,
    Callable,
    cast,
    Dict,
    List,
    Optional,
    Tuple,
    TYPE_CHECKING,
    Union,
)

from flask import current_app, g, request
from flask_babel import gettext as _
from jinja2 import DebugUndefined
from jinja2.sandbox import SandboxedEnvironment
from typing_extensions import TypedDict

from superset.exceptions import SupersetTemplateException
from superset.extensions import feature_flag_manager
from superset.utils.core import convert_legacy_filters_into_adhoc, merge_extra_filters
from superset.utils.memoized import memoized

if TYPE_CHECKING:
    from superset.connectors.sqla.models import SqlaTable
    from superset.models.core import Database
    from superset.models.sql_lab import Query

NONE_TYPE = type(None).__name__
ALLOWED_TYPES = (
    NONE_TYPE,
    "bool",
    "str",
    "unicode",
    "int",
    "long",
    "float",
    "list",
    "dict",
    "tuple",
    "set",
)
COLLECTION_TYPES = ("list", "dict", "tuple", "set")


@memoized
def context_addons() -> Dict[str, Any]:
    return current_app.config.get("JINJA_CONTEXT_ADDONS", {})


class Filter(TypedDict):
    op: str  # pylint: disable=C0103
    col: str
    val: Union[None, Any, List[Any]]


class ExtraCache:
    """
    Dummy class that exposes a method used to store additional values used in
    calculation of query object cache keys.
    """

    # Regular expression for detecting the presence of templated methods which could
    # be added to the cache key.
    regex = re.compile(
        r"\{\{.*("
        r"current_user_id\(.*\)|"
        r"current_username\(.*\)|"
        r"cache_key_wrapper\(.*\)|"
        r"url_param\(.*\)"
        r").*\}\}"
    )

    def __init__(
        self,
        extra_cache_keys: Optional[List[Any]] = None,
        removed_filters: Optional[List[str]] = None,
    ):
        self.extra_cache_keys = extra_cache_keys
        self.removed_filters = removed_filters if removed_filters is not None else []

    def current_user_id(self, add_to_cache_keys: bool = True) -> Optional[int]:
        """
        Return the user ID of the user who is currently logged in.

        :param add_to_cache_keys: Whether the value should be included in the cache key
        :returns: The user ID
        """

        if hasattr(g, "user") and g.user:
            if add_to_cache_keys:
                self.cache_key_wrapper(g.user.get_id())
            return g.user.get_id()
        return None

    def current_username(self, add_to_cache_keys: bool = True) -> Optional[str]:
        """
        Return the username of the user who is currently logged in.

        :param add_to_cache_keys: Whether the value should be included in the cache key
        :returns: The username
        """

        if g.user and hasattr(g.user, "username"):
            if add_to_cache_keys:
                self.cache_key_wrapper(g.user.username)
            return g.user.username
        return None

    def cache_key_wrapper(self, key: Any) -> Any:
        """
        Adds values to a list that is added to the query object used for calculating a
        cache key.

        This is needed if the following applies:
            - Caching is enabled
            - The query is dynamically generated using a jinja template
            - A `JINJA_CONTEXT_ADDONS` or similar is used as a filter in the query

        :param key: Any value that should be considered when calculating the cache key
        :return: the original value ``key`` passed to the function
        """
        if self.extra_cache_keys is not None:
            self.extra_cache_keys.append(key)
        return key

    def url_param(
        self, param: str, default: Optional[str] = None, add_to_cache_keys: bool = True
    ) -> Optional[str]:
        """
        Read a url or post parameter and use it in your SQL Lab query.

        When in SQL Lab, it's possible to add arbitrary URL "query string" parameters,
        and use those in your SQL code. For instance you can alter your url and add
        `?foo=bar`, as in `{domain}/superset/sqllab?foo=bar`. Then if your query is
        something like SELECT * FROM foo = '{{ url_param('foo') }}', it will be parsed
        at runtime and replaced by the value in the URL.

        As you create a visualization form this SQL Lab query, you can pass parameters
        in the explore view as well as from the dashboard, and it should carry through
        to your queries.

        Default values for URL parameters can be defined in chart metadata by adding the
        key-value pair `url_params: {'foo': 'bar'}`

        :param param: the parameter to lookup
        :param default: the value to return in the absence of the parameter
        :param add_to_cache_keys: Whether the value should be included in the cache key
        :returns: The URL parameters
        """

        from superset.views.utils import get_form_data

        if request.args.get(param):
            return request.args.get(param, default)
        form_data, _ = get_form_data()
        url_params = form_data.get("url_params") or {}
        result = url_params.get(param, default)
        if add_to_cache_keys:
            self.cache_key_wrapper(result)
        return result

    def filter_values(
        self, column: str, default: Optional[str] = None, remove_filter: bool = False
    ) -> List[Any]:
        """Gets a values for a particular filter as a list

        This is useful if:
            - you want to use a filter component to filter a query where the name of
             filter component column doesn't match the one in the select statement
            - you want to have the ability for filter inside the main query for speed
            purposes

        Usage example::

            SELECT action, count(*) as times
            FROM logs
            WHERE
                action in ({{ "'" + "','".join(filter_values('action_type')) + "'" }})
            GROUP BY action

        :param column: column/filter name to lookup
        :param default: default value to return if there's no matching columns
        :param remove_filter: When set to true, mark the filter as processed,
            removing it from the outer query. Useful when a filter should
            only apply to the inner query
        :return: returns a list of filter values
        """
        return_val: List[Any] = []
        filters = self.get_filters(column, remove_filter)
        for flt in filters:
            val = flt.get("val")
            if isinstance(val, list):
                return_val.extend(val)
            elif val:
                return_val.append(val)

        if (not return_val) and default:
            # If no values are found, return the default provided.
            return_val = [default]

        return return_val

    def get_filters(self, column: str, remove_filter: bool = False) -> List[Filter]:
        """Get the filters applied to the given column. In addition
           to returning values like the filter_values function
           the get_filters function returns the operator specified in the explorer UI.

        This is useful if:
            - you want to handle more than the IN operator in your SQL clause
            - you want to handle generating custom SQL conditions for a filter
            - you want to have the ability for filter inside the main query for speed
            purposes

        Usage example::


            WITH RECURSIVE
                superiors(employee_id, manager_id, full_name, level, lineage) AS (
                SELECT
                    employee_id,
                    manager_id,
                    full_name,
                1 as level,
                employee_id as lineage
                FROM
                    employees
                WHERE
                1=1
                {# Render a blank line #}
                {%- for filter in get_filters('full_name', remove_filter=True) -%}
                {%- if filter.get('op') == 'IN' -%}
                    AND
                    full_name IN ( {{ "'" + "', '".join(filter.get('val')) + "'" }} )
                {%- endif -%}
                {%- if filter.get('op') == 'LIKE' -%}
                    AND
                    full_name LIKE {{ "'" + filter.get('val') + "'" }}
                {%- endif -%}
                {%- endfor -%}
                UNION ALL
                    SELECT
                        e.employee_id,
                        e.manager_id,
                        e.full_name,
                s.level + 1 as level,
                s.lineage
                    FROM
                        employees e,
                    superiors s
                    WHERE s.manager_id = e.employee_id
            )


            SELECT
                employee_id, manager_id, full_name, level, lineage
            FROM
                superiors
            order by lineage, level

        :param column: column/filter name to lookup
        :param remove_filter: When set to true, mark the filter as processed,
            removing it from the outer query. Useful when a filter should
            only apply to the inner query
        :return: returns a list of filters
        """
        from superset.utils.core import FilterOperator
        from superset.views.utils import get_form_data

        form_data, _ = get_form_data()
        convert_legacy_filters_into_adhoc(form_data)
        merge_extra_filters(form_data)

        filters: List[Filter] = []

        for flt in form_data.get("adhoc_filters", []):
            val: Union[Any, List[Any]] = flt.get("comparator")
            op: str = flt["operator"].upper() if "operator" in flt else None
            # fltOpName: str = flt.get("filterOptionName")
            if (
                flt.get("expressionType") == "SIMPLE"
                and flt.get("clause") == "WHERE"
                and flt.get("subject") == column
                and val
            ):
                if remove_filter:
                    if column not in self.removed_filters:
                        self.removed_filters.append(column)
                if op in (
                    FilterOperator.IN.value,
                    FilterOperator.NOT_IN.value,
                ) and not isinstance(val, list):
                    val = [val]

                filters.append({"op": op, "col": column, "val": val})

        return filters


def safe_proxy(func: Callable[..., Any], *args: Any, **kwargs: Any) -> Any:
    return_value = func(*args, **kwargs)
    value_type = type(return_value).__name__
    if value_type not in ALLOWED_TYPES:
        raise SupersetTemplateException(
            _(
                "Unsafe return type for function %(func)s: %(value_type)s",
                func=func.__name__,
                value_type=value_type,
            )
        )
    if value_type in COLLECTION_TYPES:
        try:
            return_value = json.loads(json.dumps(return_value))
        except TypeError:
            raise SupersetTemplateException(
                _("Unsupported return value for method %(name)s", name=func.__name__,)
            )

    return return_value


def validate_context_types(context: Dict[str, Any]) -> Dict[str, Any]:
    for key in context:
        arg_type = type(context[key]).__name__
        if arg_type not in ALLOWED_TYPES and key not in context_addons():
            if arg_type == "partial" and context[key].func.__name__ == "safe_proxy":
                continue
            raise SupersetTemplateException(
                _(
                    "Unsafe template value for key %(key)s: %(value_type)s",
                    key=key,
                    value_type=arg_type,
                )
            )
        if arg_type in COLLECTION_TYPES:
            try:
                context[key] = json.loads(json.dumps(context[key]))
            except TypeError:
                raise SupersetTemplateException(
                    _("Unsupported template value for key %(key)s", key=key)
                )

    return context


def validate_template_context(
    engine: Optional[str], context: Dict[str, Any]
) -> Dict[str, Any]:
    if engine and engine in context:
        # validate engine context separately to allow for engine-specific methods
        engine_context = validate_context_types(context.pop(engine))
        valid_context = validate_context_types(context)
        valid_context[engine] = engine_context
        return valid_context

    return validate_context_types(context)


class BaseTemplateProcessor:  # pylint: disable=too-few-public-methods
    """
    Base class for database-specific jinja context
    """

    engine: Optional[str] = None

    # pylint: disable=too-many-arguments
    def __init__(
        self,
        database: "Database",
        query: Optional["Query"] = None,
        table: Optional["SqlaTable"] = None,
        extra_cache_keys: Optional[List[Any]] = None,
        removed_filters: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        self._database = database
        self._query = query
        self._schema = None
        if query and query.schema:
            self._schema = query.schema
        elif table:
            self._schema = table.schema
        self._extra_cache_keys = extra_cache_keys
        self._removed_filters = removed_filters
        self._context: Dict[str, Any] = {}
        self._env = SandboxedEnvironment(undefined=DebugUndefined)
        self.set_context(**kwargs)

    def set_context(self, **kwargs: Any) -> None:
        self._context.update(kwargs)
        self._context.update(context_addons())

    def process_template(self, sql: str, **kwargs: Any) -> str:
        """Processes a sql template

        >>> sql = "SELECT '{{ datetime(2017, 1, 1).isoformat() }}'"
        >>> process_template(sql)
        "SELECT '2017-01-01T00:00:00'"
        """
        template = self._env.from_string(sql)
        kwargs.update(self._context)

        context = validate_template_context(self.engine, kwargs)
        return template.render(context)


class JinjaTemplateProcessor(BaseTemplateProcessor):
    def set_context(self, **kwargs: Any) -> None:
        super().set_context(**kwargs)
        extra_cache = ExtraCache(self._extra_cache_keys, self._removed_filters)
        self._context.update(
            {
                "url_param": partial(safe_proxy, extra_cache.url_param),
                "current_user_id": partial(safe_proxy, extra_cache.current_user_id),
                "current_username": partial(safe_proxy, extra_cache.current_username),
                "cache_key_wrapper": partial(safe_proxy, extra_cache.cache_key_wrapper),
                "filter_values": partial(safe_proxy, extra_cache.filter_values),
                "get_filters": partial(safe_proxy, extra_cache.get_filters),
            }
        )


class NoOpTemplateProcessor(
    BaseTemplateProcessor
):  # pylint: disable=too-few-public-methods
    def process_template(self, sql: str, **kwargs: Any) -> str:
        """
        Makes processing a template a noop
        """
        return sql


class PrestoTemplateProcessor(JinjaTemplateProcessor):
    """Presto Jinja context

    The methods described here are namespaced under ``presto`` in the
    jinja context as in ``SELECT '{{ presto.some_macro_call() }}'``
    """

    engine = "presto"

    def set_context(self, **kwargs: Any) -> None:
        super().set_context(**kwargs)
        self._context[self.engine] = {
            "first_latest_partition": partial(safe_proxy, self.first_latest_partition),
            "latest_partitions": partial(safe_proxy, self.latest_partitions),
            "latest_sub_partition": partial(safe_proxy, self.latest_sub_partition),
            "latest_partition": partial(safe_proxy, self.latest_partition),
        }

    @staticmethod
    def _schema_table(
        table_name: str, schema: Optional[str]
    ) -> Tuple[str, Optional[str]]:
        if "." in table_name:
            schema, table_name = table_name.split(".")
        return table_name, schema

    def first_latest_partition(self, table_name: str) -> Optional[str]:
        """
        Gets the first value in the array of all latest partitions

        :param table_name: table name in the format `schema.table`
        :return: the first (or only) value in the latest partition array
        :raises IndexError: If no partition exists
        """

        latest_partitions = self.latest_partitions(table_name)
        return latest_partitions[0] if latest_partitions else None

    def latest_partitions(self, table_name: str) -> Optional[List[str]]:
        """
        Gets the array of all latest partitions

        :param table_name: table name in the format `schema.table`
        :return: the latest partition array
        """

        from superset.db_engine_specs.presto import PrestoEngineSpec

        table_name, schema = self._schema_table(table_name, self._schema)
        return cast(PrestoEngineSpec, self._database.db_engine_spec).latest_partition(
            table_name, schema, self._database
        )[1]

    def latest_sub_partition(self, table_name: str, **kwargs: Any) -> Any:
        table_name, schema = self._schema_table(table_name, self._schema)

        from superset.db_engine_specs.presto import PrestoEngineSpec

        return cast(
            PrestoEngineSpec, self._database.db_engine_spec
        ).latest_sub_partition(
            table_name=table_name, schema=schema, database=self._database, **kwargs
        )

    latest_partition = first_latest_partition


class HiveTemplateProcessor(PrestoTemplateProcessor):
    engine = "hive"


DEFAULT_PROCESSORS = {"presto": PrestoTemplateProcessor, "hive": HiveTemplateProcessor}


@memoized
def get_template_processors() -> Dict[str, Any]:
    processors = current_app.config.get("CUSTOM_TEMPLATE_PROCESSORS", {})
    for engine in DEFAULT_PROCESSORS:
        # do not overwrite engine-specific CUSTOM_TEMPLATE_PROCESSORS
        if not engine in processors:
            processors[engine] = DEFAULT_PROCESSORS[engine]

    return processors


def get_template_processor(
    database: "Database",
    table: Optional["SqlaTable"] = None,
    query: Optional["Query"] = None,
    **kwargs: Any,
) -> BaseTemplateProcessor:
    if feature_flag_manager.is_feature_enabled("ENABLE_TEMPLATE_PROCESSING"):
        template_processor = get_template_processors().get(
            database.backend, JinjaTemplateProcessor
        )
    else:
        template_processor = NoOpTemplateProcessor
    return template_processor(database=database, table=table, query=query, **kwargs)