Finizi B4B MCP Server

"""Input validation utilities."""

import re
from uuid import UUID

from .errors import MCPValidationError


def validate_uuid(value: str, field_name: str = "id") -> str:
    """
    Validate that a string is a valid UUID.

    Args:
        value: The string to validate
        field_name: Name of the field for error messages

    Returns:
        The validated UUID string in standard format

    Raises:
        MCPValidationError: If the value is not a valid UUID
    """
    if not value:
        raise MCPValidationError(
            message=f"{field_name} cannot be empty",
            field=field_name,
        )

    try:
        # Parse and normalize the UUID
        uuid_obj = UUID(value)
        return str(uuid_obj)
    except ValueError as e:
        raise MCPValidationError(
            message=f"Invalid UUID format: {str(e)}",
            field=field_name,
        ) from e


def validate_page_params(page: int, per_page: int) -> tuple[int, int]:
    """
    Validate pagination parameters.

    Args:
        page: Page number (1-indexed)
        per_page: Number of items per page

    Returns:
        Tuple of (validated_page, validated_per_page)

    Raises:
        MCPValidationError: If parameters are invalid
    """
    if page < 1:
        raise MCPValidationError(
            message="Page number must be greater than 0",
            field="page",
        )

    if per_page < 1:
        raise MCPValidationError(
            message="Items per page must be greater than 0",
            field="per_page",
        )

    if per_page > 100:
        raise MCPValidationError(
            message="Items per page cannot exceed 100",
            field="per_page",
        )

    return page, per_page


def validate_phone(phone: str) -> str:
    """
    Validate Vietnamese phone number format.

    Expected format: +84XXXXXXXXX (10-11 digits after +84)

    Args:
        phone: Phone number to validate

    Returns:
        The validated phone number

    Raises:
        MCPValidationError: If phone format is invalid
    """
    if not phone:
        raise MCPValidationError(
            message="Phone number cannot be empty",
            field="phone",
        )

    # Remove all spaces and dashes for validation
    cleaned = re.sub(r"[\s-]", "", phone)

    # Vietnamese phone pattern: +84 followed by 9-10 digits
    pattern = r"^\+84[0-9]{9,10}$"

    if not re.match(pattern, cleaned):
        raise MCPValidationError(
            message=(
                "Invalid Vietnamese phone format. "
                "Expected format: +84XXXXXXXXX (9-10 digits after +84)"
            ),
            field="phone",
        )

    return cleaned