"""
Custom exception types for the proof-of-existence system.
All agents raise these typed errors for consistent error handling.
"""

class ProofSystemError(Exception):
    """Base exception for all proof system errors."""
    pass


class ValidationError(ProofSystemError):
    """Raised when input validation fails."""
    pass


class HashingError(ProofSystemError):
    """Raised when hashing operation fails."""
    pass


class MetadataError(ProofSystemError):
    """Raised when metadata generation fails."""
    pass


class StorageError(ProofSystemError):
    """Raised when storage operations fail."""
    pass


class VerificationError(ProofSystemError):
    """Raised when proof verification fails."""
    pass


class ProofNotFoundError(ProofSystemError):
    """Raised when a proof cannot be found in storage."""
    pass


class OCRError(ProofSystemError):
    """Base exception for OCR-related errors."""
    pass


class OCRNotApplicableError(OCRError):
    """Raised when OCR is not applicable to the content type."""
    pass


class OCRProcessingError(OCRError):
    """Raised when OCR processing fails."""
    pass


class OCRDependencyMissingError(OCRError):
    """Raised when Tesseract OCR is not installed or not found."""
    pass