"""Schema validator for DocumentMeta objects."""

from __future__ import annotations

from app.models.document import DocumentMeta, ValidationResult


class SchemaValidator:
    """Validates DocumentMeta structural integrity and mandatory attributes."""

    def validate(self, meta: DocumentMeta) -> ValidationResult:
        errors: list[str] = []
        warnings: list[str] = []

        if meta.pages < 1:
            errors.append(f"Invalid page count: {meta.pages}")

        if meta.file_size_bytes <= 0:
            errors.append(f"Invalid file size: {meta.file_size_bytes} bytes")

        if not meta.filename.endswith(".pdf"):
            errors.append(f"Filename does not end with .pdf: {meta.filename}")

        if meta.sha256 and len(meta.sha256) != 64:
            errors.append("sha256 hash must be 64 hexadecimal characters")

        if meta.language == "unknown":
            warnings.append("Document language is unknown")

        if meta.category == "other":
            warnings.append("Document category is generic 'other'")

        return ValidationResult(
            is_valid=len(errors) == 0,
            errors=errors,
            warnings=warnings,
        )