from __future__ import annotations

import csv
from dataclasses import dataclass


@dataclass(frozen=True)
class Column:
    name: str
    source_type: str
    nullable: bool = True
    precision: int | None = None
    scale: int | None = None
    primary_key: bool = False


@dataclass(frozen=True, order=True)
class TableName:
    source_schema: str
    source_table: str

    @classmethod
    def from_qualified(cls, value: str) -> TableName:
        text = value.strip()
        if not text:
            raise ValueError("must be a non-empty source table identifier")
        source_schema, source_table = _parse_qualified_table_name(text)
        return cls(source_schema=source_schema, source_table=source_table)

    @property
    def quoted(self) -> str:
        return f"`{quote_table_identifier(self.source_schema)}`.`{quote_table_identifier(self.source_table)}`"

    def __str__(self) -> str:
        return self.quoted


@dataclass(frozen=True)
class Table:
    name: TableName
    primary_key: tuple[str, ...]
    columns: tuple[Column, ...]

    @property
    def source_schema(self) -> str:
        return self.name.source_schema

    @property
    def source_table(self) -> str:
        return self.name.source_table

    @property
    def quoted(self) -> str:
        return self.name.quoted

    def __str__(self) -> str:
        return self.quoted

    @property
    def column_names(self) -> list[str]:
        return [column.name for column in self.columns]

    def column(self, name: str) -> Column:
        for column in self.columns:
            if column.name == name:
                return column
        raise KeyError(name)


def quote_table_identifier(value: str) -> str:
    return value.replace("`", "``")


def _parse_qualified_table_name(value: str) -> tuple[str, str]:
    try:
        parts = next(csv.reader([value], delimiter=".", quotechar="`", doublequote=True, strict=True))
    except csv.Error as exc:
        raise ValueError("must contain exactly one schema/table separator") from exc
    if len(parts) != 2:
        raise ValueError("must contain exactly one schema/table separator")
    source_schema, source_table = (part.strip() for part in parts)
    if not source_schema or not source_table:
        raise ValueError("must contain non-empty schema and table identifiers")
    if "`" in value and value != TableName(source_schema, source_table).quoted:
        raise ValueError("quoted identifiers must wrap the complete schema and table identifiers")
    return source_schema, source_table


__all__ = [
    "Column",
    "Table",
    "TableName",
    "quote_table_identifier",
]