#
#  Copyright 2024 The InfiniFlow Authors. All Rights Reserved.
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#  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
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#      http://www.apache.org/licenses/LICENSE-2.0
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#  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.
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import operator
from functools import reduce

from playhouse.pool import PooledMySQLDatabase

from common.time_utils import current_timestamp, timestamp_to_date

from api.db.db_models import DB, DataBaseModel, is_gaussdb_compatible_database


def _gaussdb_replace_insert_by_id(model, batch, preserve):
    """Replace Peewee ``ON CONFLICT`` upserts on A/ORA-compatible GaussDB.

    Peewee's PostgreSQL dialect renders
    ``insert_many(...).on_conflict(conflict_target="id")`` as
    ``INSERT ... ON CONFLICT (...) DO UPDATE ... RETURNING``. A/ORA-compatible
    GaussDB rejects that syntax, which breaks APIs such as
    ``/datasets/{id}/documents/parse`` when they batch-write tasks.

    For ``DB_TYPE=gaussdb`` only, split this replace-by-id operation into two
    steps:

    * Query the IDs already present in the batch and update those rows using
      the same columns that Peewee's PostgreSQL path would preserve.
    * Insert rows with new IDs without generating unsupported ``ON CONFLICT``
      SQL.

    MySQL retains its on-duplicate-key behavior, and PostgreSQL/OceanBase retain
    Peewee's existing generation path. SQL for other databases is unchanged.
    """
    ids = [data.get("id") for data in batch if data.get("id") is not None]
    existing_ids = set()
    if ids:
        existing_ids = {row[0] for row in model.select(model.id).where(model.id.in_(ids)).tuples()}

    insert_rows = []
    update_columns = [column for column in preserve if column != "id"]
    for data in batch:
        row_id = data.get("id")
        if row_id in existing_ids:
            update_payload = {column: data[column] for column in update_columns if column in data}
            if update_payload:
                model.update(update_payload).where(model.id == row_id).execute()
        else:
            insert_rows.append(data)

    if insert_rows:
        model.insert_many(insert_rows).execute()


@DB.connection_context()
def bulk_insert_into_db(model, data_source, replace_on_conflict=False):
    DB.create_tables([model])

    for i, data in enumerate(data_source):
        current_time = current_timestamp() + i
        current_date = timestamp_to_date(current_time)
        if "create_time" not in data:
            data["create_time"] = current_time
        data["create_date"] = timestamp_to_date(data["create_time"])
        data["update_time"] = current_time
        data["update_date"] = current_date

    preserve = tuple(data_source[0].keys() - {"create_time", "create_date"})

    batch_size = 1000

    for i in range(0, len(data_source), batch_size):
        with DB.atomic():
            query = model.insert_many(data_source[i : i + batch_size])
            if replace_on_conflict:
                if isinstance(DB, PooledMySQLDatabase):
                    query = query.on_conflict(preserve=preserve)
                elif is_gaussdb_compatible_database():
                    # Peewee's PostgreSQL path emits `ON CONFLICT (...) DO
                    # UPDATE ... RETURNING`, which A/ORA-compatible GaussDB
                    # rejects. Query existing IDs first, then UPDATE or INSERT
                    # to preserve the operation without leaking PostgreSQL SQL.
                    _gaussdb_replace_insert_by_id(model, data_source[i : i + batch_size], preserve)
                    continue
                else:
                    query = query.on_conflict(conflict_target="id", preserve=preserve)
            query.execute()


def get_dynamic_db_model(base, job_id):
    return type(base.model(table_index=get_dynamic_tracking_table_index(job_id=job_id)))


def get_dynamic_tracking_table_index(job_id):
    return job_id[:8]


def fill_db_model_object(model_object, human_model_dict):
    for k, v in human_model_dict.items():
        attr_name = "f_%s" % k
        if hasattr(model_object.__class__, attr_name):
            setattr(model_object, attr_name, v)
    return model_object


# https://docs.peewee-orm.com/en/latest/peewee/query_operators.html
supported_operators = {
    "==": operator.eq,
    "<": operator.lt,
    "<=": operator.le,
    ">": operator.gt,
    ">=": operator.ge,
    "!=": operator.ne,
    "<<": operator.lshift,
    ">>": operator.rshift,
    "%": operator.mod,
    "**": operator.pow,
    "^": operator.xor,
    "~": operator.inv,
}


def query_dict2expression(model: type[DataBaseModel], query: dict[str, bool | int | str | list | tuple]):
    expression = []

    for field, value in query.items():
        if not isinstance(value, (list, tuple)):
            value = ("==", value)
        op, *val = value

        field = getattr(model, f"f_{field}")
        value = supported_operators[op](field, val[0]) if op in supported_operators else getattr(field, op)(*val)
        expression.append(value)

    return reduce(operator.iand, expression)


def query_db(model: type[DataBaseModel], limit: int = 0, offset: int = 0, query: dict = None, order_by: str | list | tuple | None = None):
    data = model.select()
    if query:
        data = data.where(query_dict2expression(model, query))
    count = data.count()

    if not order_by:
        order_by = "create_time"
    if not isinstance(order_by, (list, tuple)):
        order_by = (order_by, "asc")
    order_by, order = order_by
    order_by = getattr(model, f"f_{order_by}")
    order_by = getattr(order_by, order)()
    data = data.order_by(order_by)

    if limit > 0:
        data = data.limit(limit)
    if offset > 0:
        data = data.offset(offset)

    return list(data), count