import copy
from typing import List, Literal, Optional, Union

from pydantic import BaseModel, Field

from ...backend.model_management import BaseModelType, ModelType, SubModelType
from .baseinvocation import (BaseInvocation, BaseInvocationOutput,
                             InvocationConfig, InvocationContext)


class ModelInfo(BaseModel):
    model_name: str = Field(description="Info to load submodel")
    base_model: BaseModelType = Field(description="Base model")
    model_type: ModelType = Field(description="Info to load submodel")
    submodel: Optional[SubModelType] = Field(
        default=None, description="Info to load submodel"
    )


class LoraInfo(ModelInfo):
    weight: float = Field(description="Lora's weight which to use when apply to model")


class UNetField(BaseModel):
    unet: ModelInfo = Field(description="Info to load unet submodel")
    scheduler: ModelInfo = Field(description="Info to load scheduler submodel")
    loras: List[LoraInfo] = Field(description="Loras to apply on model loading")


class ClipField(BaseModel):
    tokenizer: ModelInfo = Field(description="Info to load tokenizer submodel")
    text_encoder: ModelInfo = Field(description="Info to load text_encoder submodel")
    skipped_layers: int = Field(description="Number of skipped layers in text_encoder")
    loras: List[LoraInfo] = Field(description="Loras to apply on model loading")

class VaeField(BaseModel):
    # TODO: better naming?
    vae: ModelInfo = Field(description="Info to load vae submodel")


class ModelLoaderOutput(BaseInvocationOutput):
    """Model loader output"""

    # fmt: off
    type: Literal["model_loader_output"] = "model_loader_output"

    unet: UNetField = Field(default=None, description="UNet submodel")
    clip: ClipField = Field(default=None, description="Tokenizer and text_encoder submodels")
    vae: VaeField = Field(default=None, description="Vae submodel")
    # fmt: on

class MainModelField(BaseModel):
    """Main model field"""

    model_name: str = Field(description="Name of the model")
    base_model: BaseModelType = Field(description="Base model")


class LoRAModelField(BaseModel):
    """LoRA model field"""

    model_name: str = Field(description="Name of the LoRA model")
    base_model: BaseModelType = Field(description="Base model")

class MainModelLoaderInvocation(BaseInvocation):
    """Loads a main model, outputting its submodels."""

    type: Literal["main_model_loader"] = "main_model_loader"

    model: MainModelField = Field(description="The model to load")
    # TODO: precision?

    # Schema customisation
    class Config(InvocationConfig):
        schema_extra = {
            "ui": {
                "title": "Model Loader",
                "tags": ["model", "loader"],
                "type_hints": {"model": "model"},
            },
        }

    def invoke(self, context: InvocationContext) -> ModelLoaderOutput:
        base_model = self.model.base_model
        model_name = self.model.model_name
        model_type = ModelType.Main

        # TODO: not found exceptions
        if not context.services.model_manager.model_exists(
            model_name=model_name,
            base_model=base_model,
            model_type=model_type,
        ):
            raise Exception(f"Unknown {base_model} {model_type} model: {model_name}")

        """
        if not context.services.model_manager.model_exists(
            model_name=self.model_name,
            model_type=SDModelType.Diffusers,
            submodel=SDModelType.Tokenizer,
        ):
            raise Exception(
                f"Failed to find tokenizer submodel in {self.model_name}! Check if model corrupted"
            )

        if not context.services.model_manager.model_exists(
            model_name=self.model_name,
            model_type=SDModelType.Diffusers,
            submodel=SDModelType.TextEncoder,
        ):
            raise Exception(
                f"Failed to find text_encoder submodel in {self.model_name}! Check if model corrupted"
            )

        if not context.services.model_manager.model_exists(
            model_name=self.model_name,
            model_type=SDModelType.Diffusers,
            submodel=SDModelType.UNet,
        ):
            raise Exception(
                f"Failed to find unet submodel from {self.model_name}! Check if model corrupted"
            )
        """

        return ModelLoaderOutput(
            unet=UNetField(
                unet=ModelInfo(
                    model_name=model_name,
                    base_model=base_model,
                    model_type=model_type,
                    submodel=SubModelType.UNet,
                ),
                scheduler=ModelInfo(
                    model_name=model_name,
                    base_model=base_model,
                    model_type=model_type,
                    submodel=SubModelType.Scheduler,
                ),
                loras=[],
            ),
            clip=ClipField(
                tokenizer=ModelInfo(
                    model_name=model_name,
                    base_model=base_model,
                    model_type=model_type,
                    submodel=SubModelType.Tokenizer,
                ),
                text_encoder=ModelInfo(
                    model_name=model_name,
                    base_model=base_model,
                    model_type=model_type,
                    submodel=SubModelType.TextEncoder,
                ),
                loras=[],
                skipped_layers=0,
            ),
            clip2=ClipField(
                tokenizer=ModelInfo(
                    model_name=model_name,
                    base_model=base_model,
                    model_type=model_type,
                    submodel=SubModelType.Tokenizer2,
                ),
                text_encoder=ModelInfo(
                    model_name=model_name,
                    base_model=base_model,
                    model_type=model_type,
                    submodel=SubModelType.TextEncoder2,
                ),
                loras=[],
                skipped_layers=0,
            ),
            vae=VaeField(
                vae=ModelInfo(
                    model_name=model_name,
                    base_model=base_model,
                    model_type=model_type,
                    submodel=SubModelType.Vae,
                ),
            ),
        )

    
class LoraLoaderOutput(BaseInvocationOutput):
    """Model loader output"""

    # fmt: off
    type: Literal["lora_loader_output"] = "lora_loader_output"

    unet: Optional[UNetField] = Field(default=None, description="UNet submodel")
    clip: Optional[ClipField] = Field(default=None, description="Tokenizer and text_encoder submodels")
    # fmt: on


class LoraLoaderInvocation(BaseInvocation):
    """Apply selected lora to unet and text_encoder."""

    type: Literal["lora_loader"] = "lora_loader"

    lora: Union[LoRAModelField, None] = Field(
        default=None, description="Lora model name"
    )
    weight: float = Field(default=0.75, description="With what weight to apply lora")

    unet: Optional[UNetField] = Field(description="UNet model for applying lora")
    clip: Optional[ClipField] = Field(description="Clip model for applying lora")

    class Config(InvocationConfig):
        schema_extra = {
            "ui": {
                "title": "Lora Loader",
                "tags": ["lora", "loader"],
                "type_hints": {"lora": "lora_model"},
            },
        }

    def invoke(self, context: InvocationContext) -> LoraLoaderOutput:
        if self.lora is None:
            raise Exception("No LoRA provided")

        base_model = self.lora.base_model
        lora_name = self.lora.model_name

        if not context.services.model_manager.model_exists(
            base_model=base_model,
            model_name=lora_name,
            model_type=ModelType.Lora,
        ):
            raise Exception(f"Unkown lora name: {lora_name}!")

        if self.unet is not None and any(
            lora.model_name == lora_name for lora in self.unet.loras
        ):
            raise Exception(f'Lora "{lora_name}" already applied to unet')

        if self.clip is not None and any(
            lora.model_name == lora_name for lora in self.clip.loras
        ):
            raise Exception(f'Lora "{lora_name}" already applied to clip')

        output = LoraLoaderOutput()

        if self.unet is not None:
            output.unet = copy.deepcopy(self.unet)
            output.unet.loras.append(
                LoraInfo(
                    base_model=base_model,
                    model_name=lora_name,
                    model_type=ModelType.Lora,
                    submodel=None,
                    weight=self.weight,
                )
            )

        if self.clip is not None:
            output.clip = copy.deepcopy(self.clip)
            output.clip.loras.append(
                LoraInfo(
                    base_model=base_model,
                    model_name=lora_name,
                    model_type=ModelType.Lora,
                    submodel=None,
                    weight=self.weight,
                )
            )

        return output


class VAEModelField(BaseModel):
    """Vae model field"""

    model_name: str = Field(description="Name of the model")
    base_model: BaseModelType = Field(description="Base model")


class VaeLoaderOutput(BaseInvocationOutput):
    """Model loader output"""

    # fmt: off
    type: Literal["vae_loader_output"] = "vae_loader_output"

    vae: VaeField = Field(default=None, description="Vae model")
    # fmt: on


class VaeLoaderInvocation(BaseInvocation):
    """Loads a VAE model, outputting a VaeLoaderOutput"""

    type: Literal["vae_loader"] = "vae_loader"

    vae_model: VAEModelField = Field(description="The VAE to load")

    # Schema customisation
    class Config(InvocationConfig):
        schema_extra = {
            "ui": {
                "title": "VAE Loader",
                "tags": ["vae", "loader"],
                "type_hints": {"vae_model": "vae_model"},
            },
        }

    def invoke(self, context: InvocationContext) -> VaeLoaderOutput:
        base_model = self.vae_model.base_model
        model_name = self.vae_model.model_name
        model_type = ModelType.Vae

        if not context.services.model_manager.model_exists(
            base_model=base_model,
            model_name=model_name,
            model_type=model_type,
        ):
            raise Exception(f"Unkown vae name: {model_name}!")
        return VaeLoaderOutput(
            vae=VaeField(
                vae=ModelInfo(
                    model_name=model_name,
                    base_model=base_model,
                    model_type=model_type,
                )
            )
        )