from __future__ import annotations

from dataclasses import dataclass, field
from typing import Any


@dataclass(frozen=True)
class Column:
    name: str
    data_type: str
    column_type: str
    nullable: bool
    ordinal_position: int


@dataclass(frozen=True)
class Table:
    database: str
    name: str
    rows_estimate: int | None
    columns: list[Column]
    primary_key: list[str]
    watermark_candidates: list[str] = field(default_factory=list)
    classifications: list[str] = field(default_factory=list)

    @property
    def watermark_columns(self) -> list[str]:
        by_lower = {column.name.lower(): column.name for column in self.columns}
        return [by_lower[name.lower()] for name in self.watermark_candidates if name.lower() in by_lower]


def table_to_manifest(table: Table, classifications: list[str] | None = None) -> dict[str, Any]:
    return {
        "source_database": table.database,
        "table_name": table.name,
        "row_estimate": table.rows_estimate,
        "primary_key": table.primary_key,
        "watermark_columns": table.watermark_columns,
        "classifications": classifications if classifications is not None else table.classifications,
        "columns": [
            {
                "name": column.name,
                "data_type": column.data_type,
                "column_type": column.column_type,
                "nullable": column.nullable,
                "ordinal_position": column.ordinal_position,
            }
            for column in table.columns
        ],
    }