from __future__ import annotations

import os
import typing as T
import warnings

from datetime import datetime
from pathlib import Path

from pycs import db
from pycs.database.Collection import Collection
from pycs.database.Result import Result
from pycs.database.base import NamedBaseModel
from pycs.database.util import commit_on_return


class File(NamedBaseModel):
    """
    database class for files
    """

    # table columns
    uuid = db.Column(db.String, nullable=False)

    extension = db.Column(db.String, nullable=False)

    type = db.Column(db.String, nullable=False)

    size = db.Column(db.String, nullable=False)

    created = db.Column(db.DateTime, default=datetime.utcnow,
        index=True, nullable=False)

    path = db.Column(db.String, nullable=False)

    frames = db.Column(db.Integer)

    fps = db.Column(db.Float)

    project_id = db.Column(
        db.Integer,
        db.ForeignKey("project.id", ondelete="CASCADE"),
        nullable=False)

    collection_id = db.Column(
        db.Integer,
        db.ForeignKey("collection.id", ondelete="SET NULL"))

    # contraints
    __table_args__ = (
        db.UniqueConstraint('project_id', 'path'),
    )


    results = db.relationship("Result", backref="file",
        lazy="dynamic", passive_deletes=True)


    serialize_only = NamedBaseModel.serialize_only + (
        "uuid",
        "extension",
        "type",
        "size",
        "created",
        "path",
        "frames",
        "fps",
        "project_id",
        "collection_id",
    )

    @property
    def filename(self):
        return f"{self.name}{self.extension}"

    @property
    def absolute_path(self) -> str:
        path = Path(self.path)

        if path.is_absolute():
            return str(path)

        return str(Path.cwd() / path)

    def delete(self, commit: bool = True):
        super().delete(commit=commit)
        # remove file from folder
        os.remove(self.path)
        # TODO: remove temp files
        warnings.warn("Temporary files may still exist!")

    @commit_on_return
    def set_collection(self, collection_id: T.Optional[int]):
        """
        set this file's collection

        :param collection_id: new collection id
        :return:
        """

        self.collection_id = collection_id

    @commit_on_return
    def set_collection_by_reference(self, collection_reference: T.Optional[str]):
        """
        set this file's collection

        :param collection_reference: collection reference
        :return:
        """
        if self.collection_reference is None:
            self.set_collection(None)

        collection = Collection.query.filter_by(reference=collection_reference).one()
        self.collection_id = collection.id

    def _get_another_file(self, *query) -> T.Optional[File]:
        """
        get the first file matching the query ordered by descending id

        :return: another file or None
        """
        return File.query.filter(File.project_id == self.project_id, *query)

    def next(self) -> T.Optional[File]:
        """
        get the successor of this file

        :return: another file or None
        """

        return self._get_another_file(File.id > self.id)\
            .order_by(File.id).first()


    def previous(self) -> T.Optional[File]:
        """
        get the predecessor of this file

        :return: another file or None
        """

        return self._get_another_file(File.id < self.id)\
            .order_by(File.id.desc()).first()


    def next_in_collection(self) -> T.Optional[File]:
        """
        get the predecessor of this file

        :return: another file or None
        """
        return self._get_another_file(
            File.id > self.id, File.collection_id == self.collection_id)\
            .order_by(File.id).first()


    def previous_in_collection(self) -> T.Optional[File]:
        """
        get the predecessor of this file

        :return: another file or None
        """
        return self._get_another_file(
            File.id < self.id, File.collection_id == self.collection_id)\
            .order_by(File.id.desc()).first()


    def result(self, id: int) -> T.Optional[Result]:
        return self.results.get(id)


    @commit_on_return
    def create_result(self,
                      origin: str,
                      result_type: str,
                      label: T.Optional[T.Union[Label, int]] = None,
                      data: T.Optional[dict] = None) -> Result:

        result = Result.new(commit=False,
                            file_id=self.id,
                            origin=origin,
                            type=result_type)

        result.data = data

        if label is not None:
            assert isinstance(label, (int, Label)), f"Wrong label type: {type(label)}"

            if isinstance(label, Label):
                label = label.id

            result.label_id = label

        return result


    def remove_results(self, origin='pipeline') -> T.List[Result]:

        results = Result.query.filter(
            Result.file_id == self.id,
            Result.origin == origin)

        _results = results.all()
        results.delete()

        return _results