"""
Chunker exception hierarchy.

Demonstrates: Managing exceptions and writing resilient code (Interview Topic 7).
"""


class PipelineError(Exception):
    """Base exception for all chunker pipeline errors."""
    pass


class ChunkError(PipelineError):
    """Errors related to chunk creation or validation."""
    pass


class ChunkReadError(ChunkError):
    """Failed to read chunk data from source file."""
    pass


class ChunkChecksumError(ChunkError):
    """Chunk data integrity validation failed."""

    def __init__(self, sequence: int, expected: str, actual: str):
        self.sequence = sequence
        self.expected = expected
        self.actual = actual
        super().__init__(
            f"Chunk {sequence}: checksum mismatch "
            f"(expected={expected}, actual={actual})"
        )


class ProcessingError(PipelineError):
    """Errors during chunk processing by workers."""
    pass


class ProcessorTimeoutError(ProcessingError):
    """Processor exceeded allowed time for a chunk."""

    def __init__(self, sequence: int, timeout: float):
        self.sequence = sequence
        self.timeout = timeout
        super().__init__(f"Chunk {sequence}: processor timed out after {timeout}s")


class ProcessorFailureError(ProcessingError):
    """Processor failed to process a chunk after all retries."""

    def __init__(self, sequence: int, retries: int, original_error: Exception):
        self.sequence = sequence
        self.retries = retries
        self.original_error = original_error
        super().__init__(
            f"Chunk {sequence}: failed after {retries} retries — {original_error}"
        )


class ReassemblyError(PipelineError):
    """Errors during result collection and ordering."""
    pass