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#      http://www.apache.org/licenses/LICENSE-2.0
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from dataclasses import dataclass
from typing import List
from typing import ClassVar

from pypaimon.table.row.generic_row import GenericRow
from pypaimon.table.row.internal_row import InternalRow


@dataclass
class SimpleStats:
    min_values: InternalRow
    max_values: InternalRow
    null_counts: List[int]

    _empty_stats: ClassVar[object] = None

    @classmethod
    def empty_stats(cls):
        if cls._empty_stats is None:
            min_values = GenericRow([], [])
            max_values = GenericRow([], [])
            cls._empty_stats = cls(min_values, max_values, None)
        return cls._empty_stats


SIMPLE_STATS_FIELDS = [
    {"name": "_MIN_VALUES", "type": "bytes"},
    {"name": "_MAX_VALUES", "type": "bytes"},
    {"name": "_NULL_COUNTS",
     "type": [
         "null",
         {
             "type": "array",
             "items": ["null", "long"]
         }
     ],
     "default": None},
]

KEY_STATS_SCHEMA = {
    "type": "record",
    "name": "record_KEY_STATS",
    "fields": SIMPLE_STATS_FIELDS
}

VALUE_STATS_SCHEMA = {
    "type": "record",
    "name": "record_VALUE_STATS",
    "fields": SIMPLE_STATS_FIELDS
}

PARTITION_STATS_SCHEMA = {
    "type": "record",
    "name": "record_PARTITION_STATS",
    "fields": SIMPLE_STATS_FIELDS
}