import dataclasses
import json
from typing import Optional

from django.conf import settings

from paperless.models import ApplicationConfiguration


@dataclasses.dataclass
class BaseConfig:
    """
    Almost all parsers care about the chosen PDF output format
    """

    @staticmethod
    def _get_config_instance() -> ApplicationConfiguration:
        app_config = ApplicationConfiguration.objects.all().first()
        # Workaround for a test where the migration hasn't run to create the single model
        if app_config is None:
            ApplicationConfiguration.objects.create()
            app_config = ApplicationConfiguration.objects.all().first()
        return app_config


@dataclasses.dataclass
class OutputTypeConfig(BaseConfig):
    """
    Almost all parsers care about the chosen PDF output format
    """

    output_type: str = dataclasses.field(init=False)

    def __post_init__(self) -> None:
        app_config = self._get_config_instance()

        self.output_type = app_config.output_type or settings.OCR_OUTPUT_TYPE


@dataclasses.dataclass
class OcrConfig(OutputTypeConfig):
    """
    Specific settings for the Tesseract based parser.  Options generally
    correspond almost directly to the OCRMyPDF options
    """

    pages: Optional[int] = dataclasses.field(init=False)
    language: str = dataclasses.field(init=False)
    mode: str = dataclasses.field(init=False)
    skip_archive_file: str = dataclasses.field(init=False)
    image_dpi: Optional[int] = dataclasses.field(init=False)
    clean: str = dataclasses.field(init=False)
    deskew: bool = dataclasses.field(init=False)
    rotate: bool = dataclasses.field(init=False)
    rotate_threshold: float = dataclasses.field(init=False)
    max_image_pixel: Optional[float] = dataclasses.field(init=False)
    color_conversion_strategy: str = dataclasses.field(init=False)
    user_args: Optional[dict[str, str]] = dataclasses.field(init=False)

    def __post_init__(self) -> None:
        super().__post_init__()

        app_config = self._get_config_instance()

        self.pages = app_config.pages or settings.OCR_PAGES
        self.language = app_config.language or settings.OCR_LANGUAGE
        self.mode = app_config.mode or settings.OCR_MODE
        self.skip_archive_file = (
            app_config.skip_archive_file or settings.OCR_SKIP_ARCHIVE_FILE
        )
        self.image_dpi = app_config.image_dpi or settings.OCR_IMAGE_DPI
        self.clean = app_config.unpaper_clean or settings.OCR_CLEAN
        self.deskew = app_config.deskew or settings.OCR_DESKEW
        self.rotate = app_config.rotate_pages or settings.OCR_ROTATE_PAGES
        self.rotate_threshold = (
            app_config.rotate_pages_threshold or settings.OCR_ROTATE_PAGES_THRESHOLD
        )
        self.max_image_pixel = (
            app_config.max_image_pixels or settings.OCR_MAX_IMAGE_PIXELS
        )
        self.color_conversion_strategy = (
            app_config.color_conversion_strategy
            or settings.OCR_COLOR_CONVERSION_STRATEGY
        )

        user_args = None
        if app_config.user_args:
            user_args = app_config.user_args
        elif settings.OCR_USER_ARGS is not None:  # pragma: no cover
            try:
                user_args = json.loads(settings.OCR_USER_ARGS)
            except json.JSONDecodeError:
                user_args = {}

        self.user_args = user_args


@dataclasses.dataclass
class GeneralConfig(BaseConfig):
    """
    General application settings that require global scope
    """

    app_title: str = dataclasses.field(init=False)
    app_logo: str = dataclasses.field(init=False)

    def __post_init__(self) -> None:
        app_config = self._get_config_instance()

        self.app_title = app_config.app_title or None
        self.app_logo = app_config.app_logo.url if app_config.app_logo else None