"""
Custom exception classes for the GradeM8 application.

This module defines a hierarchy of domain-specific exceptions that provide
better error handling and clearer failure modes throughout the application.
"""


class GradeM8Error(Exception):
    """Base exception for all GradeM8 application errors."""
    pass


# =============================================================================
# Document Processing Errors
# =============================================================================

class DocumentError(GradeM8Error):
    """Base exception for document processing errors."""
    pass


class DocumentExtractionError(DocumentError):
    """Raised when text extraction from a document fails."""
    pass


class UnsupportedFileTypeError(DocumentError):
    """Raised when an unsupported file type is encountered."""
    
    def __init__(self, filename: str, supported_types: list[str]) -> None:
        self.filename = filename
        self.supported_types = supported_types
        super().__init__(
            f"Unsupported file type for '{filename}'. "
            f"Supported types: {', '.join(supported_types)}"
        )


class CorruptedDocumentError(DocumentError):
    """Raised when a document is corrupted or cannot be read."""
    pass


class DocumentConversionError(DocumentError):
    """Raised when document conversion fails."""
    pass


# =============================================================================
# AI Grading Errors
# =============================================================================

class GradingError(GradeM8Error):
    """Base exception for AI grading errors."""
    pass


class ResponseParseError(GradingError):
    """Raised when the AI response cannot be parsed as valid JSON."""

    def __init__(self, message: str, raw_response: str | None = None) -> None:
        self.raw_response = raw_response
        super().__init__(message)


class InvalidResponseError(GradingError):
    """Raised when the AI response is valid JSON but missing required fields."""
    pass


class APIKeyError(GradingError):
    """Raised when the API key is missing or invalid."""
    pass


class AIServiceError(GradingError):
    """Raised when the AI service returns an error."""

    def __init__(self, message: str, status_code: int | None = None) -> None:
        self.status_code = status_code
        super().__init__(message)


# =============================================================================
# Configuration Errors
# =============================================================================

class ConfigurationError(GradeM8Error):
    """Raised when there's a configuration issue."""