import os
from enum import Enum
from pathlib import Path
from typing import Literal, Optional

import torch

import invokeai.backend.util.logging as logger
from invokeai.app.services.config import InvokeAIAppConfig

from .base import (
    BaseModelType,
    EmptyConfigLoader,
    InvalidModelException,
    ModelBase,
    ModelConfigBase,
    ModelNotFoundException,
    ModelType,
    SubModelType,
    calc_model_size_by_data,
    calc_model_size_by_fs,
    classproperty,
)


class ControlNetModelFormat(str, Enum):
    Checkpoint = "checkpoint"
    Diffusers = "diffusers"


class ControlNetModel(ModelBase):
    # model_class: Type
    # model_size: int

    class DiffusersConfig(ModelConfigBase):
        model_format: Literal[ControlNetModelFormat.Diffusers]

    class CheckpointConfig(ModelConfigBase):
        model_format: Literal[ControlNetModelFormat.Checkpoint]
        config: str

    def __init__(self, model_path: str, base_model: BaseModelType, model_type: ModelType):
        assert model_type == ModelType.ControlNet
        super().__init__(model_path, base_model, model_type)

        try:
            config = EmptyConfigLoader.load_config(self.model_path, config_name="config.json")
            # config = json.loads(os.path.join(self.model_path, "config.json"))
        except Exception:
            raise Exception("Invalid controlnet model! (config.json not found or invalid)")

        model_class_name = config.get("_class_name", None)
        if model_class_name not in {"ControlNetModel"}:
            raise Exception(f"Invalid ControlNet model! Unknown _class_name: {model_class_name}")

        try:
            self.model_class = self._hf_definition_to_type(["diffusers", model_class_name])
            self.model_size = calc_model_size_by_fs(self.model_path)
        except Exception:
            raise Exception("Invalid ControlNet model!")

    def get_size(self, child_type: Optional[SubModelType] = None):
        if child_type is not None:
            raise Exception("There is no child models in controlnet model")
        return self.model_size

    def get_model(
        self,
        torch_dtype: Optional[torch.dtype],
        child_type: Optional[SubModelType] = None,
    ):
        if child_type is not None:
            raise Exception("There are no child models in controlnet model")

        model = None
        for variant in ["fp16", None]:
            try:
                model = self.model_class.from_pretrained(
                    self.model_path,
                    torch_dtype=torch_dtype,
                    variant=variant,
                )
                break
            except Exception:
                pass
        if not model:
            raise ModelNotFoundException()

        # calc more accurate size
        self.model_size = calc_model_size_by_data(model)
        return model

    @classproperty
    def save_to_config(cls) -> bool:
        return False

    @classmethod
    def detect_format(cls, path: str):
        if not os.path.exists(path):
            raise ModelNotFoundException()

        if os.path.isdir(path):
            if os.path.exists(os.path.join(path, "config.json")):
                return ControlNetModelFormat.Diffusers

        if os.path.isfile(path):
            if any([path.endswith(f".{ext}") for ext in ["safetensors", "ckpt", "pt", "pth"]]):
                return ControlNetModelFormat.Checkpoint

        raise InvalidModelException(f"Not a valid model: {path}")

    @classmethod
    def convert_if_required(
        cls,
        model_path: str,
        output_path: str,
        config: ModelConfigBase,
        base_model: BaseModelType,
    ) -> str:
        if cls.detect_format(model_path) == ControlNetModelFormat.Checkpoint:
            return _convert_controlnet_ckpt_and_cache(
                model_path=model_path,
                model_config=config.config,
                output_path=output_path,
                base_model=base_model,
            )
        else:
            return model_path


def _convert_controlnet_ckpt_and_cache(
    model_path: str,
    output_path: str,
    base_model: BaseModelType,
    model_config: str,
) -> str:
    """
    Convert the controlnet from checkpoint format to diffusers format,
    cache it to disk, and return Path to converted
    file. If already on disk then just returns Path.
    """
    print(f"DEBUG: controlnet config = {model_config}")
    app_config = InvokeAIAppConfig.get_config()
    weights = app_config.root_path / model_path
    output_path = Path(output_path)

    logger.info(f"Converting {weights} to diffusers format")
    # return cached version if it exists
    if output_path.exists():
        return output_path

    # to avoid circular import errors
    from ..convert_ckpt_to_diffusers import convert_controlnet_to_diffusers

    convert_controlnet_to_diffusers(
        weights,
        output_path,
        original_config_file=app_config.root_path / model_config,
        image_size=512,
        scan_needed=True,
        from_safetensors=weights.suffix == ".safetensors",
    )
    return output_path