"""
Pre-upload validation for files and metadata
"""

from typing import Tuple, List
from core.data_loader import DataLoader
from utils.file_handler import FileHandler


class UploadValidator:
    """Pre-upload validation to ensure data quality"""

    def __init__(self, data_loader: DataLoader, max_file_size_mb: int = 500):
        """
        Initialize validator

        Args:
            data_loader: DataLoader instance for validation
            max_file_size_mb: Maximum allowed file size in MB
        """
        self.data_loader = data_loader
        self.max_file_size_mb = max_file_size_mb

    def validate_file(self, file_path: str) -> Tuple[bool, List[str]]:
        """
        Validate file exists, is readable, and has supported format

        Args:
            file_path: Path to file

        Returns:
            tuple: (is_valid: bool, errors: List[str])
        """
        errors = []

        # Check file exists
        if not FileHandler.file_exists(file_path):
            errors.append(f"File not found: {file_path}")
            return False, errors

        # Check readable
        if not FileHandler.is_readable(file_path):
            errors.append(f"File not readable (permission denied): {file_path}")
            return False, errors

        # Check format
        if not FileHandler.is_supported_format(file_path):
            ext = FileHandler.get_file_extension(file_path)
            supported = (FileHandler.SUPPORTED_VIDEO_FORMATS +
                        FileHandler.SUPPORTED_IMAGE_FORMATS)
            errors.append(
                f"Unsupported file format: {ext}. "
                f"Supported formats: {', '.join(supported)}"
            )
            return False, errors

        # Check file size
        size_mb = FileHandler.get_file_size_mb(file_path)
        if size_mb > self.max_file_size_mb:
            errors.append(
                f"File too large: {size_mb:.2f}MB "
                f"(max: {self.max_file_size_mb}MB)"
            )
            return False, errors

        return True, []

    def validate_parsed_metadata(self, metadata: dict) -> Tuple[bool, List[str]]:
        """
        Validate all required fields are present and valid

        Args:
            metadata: Parsed metadata dict

        Returns:
            tuple: (is_valid: bool, errors: List[str])
        """
        errors = []

        # Check required fields
        required_fields = [
            'brand_code', 'brand_name',
            'subject',
            'asset_type',
            'aspect_ratio',
            'country_code', 'country_name',
            'language_code',
            'channel'
        ]

        for field in required_fields:
            if not metadata.get(field):
                errors.append(f"Missing required field: {field}")

        # Validate brand
        if metadata.get('brand_code') and not self.data_loader.validate_brand_code(metadata['brand_code']):
            errors.append(f"Invalid brand code: {metadata['brand_code']}")

        # Validate country
        if metadata.get('country_code') and not self.data_loader.validate_country_code(metadata['country_code']):
            errors.append(f"Invalid country code: {metadata['country_code']}")

        # Validate language
        if metadata.get('language_code') and not self.data_loader.validate_language_code(metadata['language_code']):
            errors.append(f"Invalid language code: {metadata['language_code']}")

        # Validate asset type
        if metadata.get('asset_type') and not self.data_loader.validate_asset_type(metadata['asset_type']):
            errors.append(f"Invalid asset type: {metadata['asset_type']}")

        # Validate social media (if present)
        if metadata.get('social_media'):
            if not self.data_loader.validate_social_code(metadata['social_media']):
                errors.append(f"Invalid social media code: {metadata['social_media']}")

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

    def get_content_type(self, file_path: str) -> str:
        """
        Get MIME content type for file

        Args:
            file_path: Path to file

        Returns:
            str: MIME type
        """
        return FileHandler.get_content_type(file_path)