"""Custom exception hierarchy and error code mapping.

Defines exception hierarchy for adjustment file pipeline, distinguishing between
permanent (non-retriable) and transient (retriable) errors for Lambda retry control.

Error Types:
    - PermanentError: Batch marked as ERROR, no retry (validation, missing data, logic errors)
    - TransientError: Lambda retries with backoff (network, throttling, temporary failures)
    - ERROR_CODE_MAP: Maps exceptions to BatchErrorCode for database tracking
"""

from src.enums import BatchErrorCode


class PermanentError(Exception):
    """Non-retriable errors that cause batch to be marked as ERROR."""


class ChecksumMismatchError(PermanentError):
    """Raised when file checksum verification fails."""


class EmptyFileError(PermanentError):
    """Raised when the file is empty (no data rows)."""


class FileParsingError(PermanentError):
    """Raised when the file cannot be parsed or processed."""


class FileSizeExceededError(PermanentError):
    """Raised when the file exceeds the maximum file size."""


class FileIntegrityError(PermanentError):
    """Raised when downloaded file fails integrity verification."""


class FileSystemError(PermanentError):
    """Raised when file system operations fail on downloaded file."""


class InvalidFileTypeError(PermanentError):
    """Raised when the file type is not supported."""


class MissingHeadersError(PermanentError):
    """Raised when the file is missing required headers."""


class RowCountExceededError(PermanentError):
    """Raised when the file exceeds the maximum row count."""


class S3FileNotFoundError(PermanentError):
    """Raised when S3 object is not found."""


class UpdateBatchError(PermanentError):
    """Raised when the batch is not in the expected state or does not exist."""


class TransientError(Exception):
    """Retriable errors that trigger Lambda automatic retry with backoff."""


ERROR_CODE_MAP: dict[type[Exception], BatchErrorCode] = {
    ChecksumMismatchError: BatchErrorCode.CHECKSUM_MISMATCH,
    EmptyFileError: BatchErrorCode.EMPTY_FILE,
    S3FileNotFoundError: BatchErrorCode.FILE_NOT_FOUND,
    FileParsingError: BatchErrorCode.FILE_PARSING_ERROR,
    FileSizeExceededError: BatchErrorCode.FILE_SIZE_EXCEEDED,
    FileIntegrityError: BatchErrorCode.FILE_INTEGRITY_ERROR,
    FileSystemError: BatchErrorCode.FILE_SYSTEM_ERROR,
    InvalidFileTypeError: BatchErrorCode.INVALID_FILE_TYPE,
    MissingHeadersError: BatchErrorCode.MISSING_HEADERS,
    RowCountExceededError: BatchErrorCode.ROW_COUNT_EXCEEDED,
    UpdateBatchError: BatchErrorCode.BATCH_STATE_ERROR,
}


def get_error_code(error: Exception) -> BatchErrorCode:
    """Map exception to BatchErrorCode, returning UNKNOWN_ERROR for unmapped exceptions.

    Args:
        error: The exception to map.

    Returns:
        The corresponding batch error code.
    """
    return ERROR_CODE_MAP.get(type(error), BatchErrorCode.UNKNOWN_ERROR)