from datetime import timedelta
from logging import getLogger
from time import monotonic
from typing import Any, List, Optional, Protocol, Tuple

from PIL import Image

from ..output import save_image
from ..params import ImageParams, StageParams
from ..server import ServerContext
from ..utils import is_debug
from ..worker import ProgressCallback, WorkerContext
from .utils import process_tile_order

logger = getLogger(__name__)


class StageCallback(Protocol):
    def __call__(
        self,
        job: WorkerContext,
        ctx: ServerContext,
        stage: StageParams,
        params: ImageParams,
        source: Image.Image,
        **kwargs: Any
    ) -> Image.Image:
        pass


PipelineStage = Tuple[StageCallback, StageParams, Optional[dict]]


class ChainProgress:
    def __init__(self, parent: ProgressCallback, start=0) -> None:
        self.parent = parent
        self.step = start
        self.total = 0

    def __call__(self, step: int, timestep: int, latents: Any) -> None:
        if step < self.step:
            # accumulate on resets
            self.total += self.step

        self.step = step
        self.parent(self.get_total(), timestep, latents)

    def get_total(self) -> int:
        return self.step + self.total

    @classmethod
    def from_progress(cls, parent: ProgressCallback):
        start = parent.step if hasattr(parent, "step") else 0
        return ChainProgress(parent, start=start)


class ChainPipeline:
    """
    Run many stages in series, passing the image results from each to the next, and processing
    tiles as needed.
    """

    def __init__(
        self,
        stages: Optional[List[PipelineStage]] = None,
    ):
        """
        Create a new pipeline that will run the given stages.
        """
        self.stages = list(stages or [])

    def append(self, stage: PipelineStage):
        """
        Append an additional stage to this pipeline.
        """
        if stage is not None:
            self.stages.append(stage)

    def __call__(
        self,
        job: WorkerContext,
        server: ServerContext,
        params: ImageParams,
        source: Image.Image,
        callback: Optional[ProgressCallback] = None,
        **pipeline_kwargs
    ) -> Image.Image:
        """
        TODO: handle List[Image] inputs and outputs
        """
        if callback is not None:
            callback = ChainProgress.from_progress(callback)

        start = monotonic()
        logger.info(
            "running pipeline on source image with dimensions %sx%s",
            source.width,
            source.height,
        )
        image = source

        for stage_pipe, stage_params, stage_kwargs in self.stages:
            name = stage_params.name or stage_pipe.__name__
            kwargs = stage_kwargs or {}
            kwargs = {**pipeline_kwargs, **kwargs}

            logger.info(
                "running stage %s on image with dimensions %sx%s, %s",
                name,
                image.width,
                image.height,
                kwargs.keys(),
            )

            if (
                image.width > stage_params.tile_size
                or image.height > stage_params.tile_size
            ):
                logger.info(
                    "image larger than tile size of %s, tiling stage",
                    stage_params.tile_size,
                )

                def stage_tile(tile: Image.Image, _dims) -> Image.Image:
                    tile = stage_pipe(
                        job,
                        server,
                        stage_params,
                        params,
                        tile,
                        callback=callback,
                        **kwargs
                    )

                    if is_debug():
                        save_image(server, "last-tile.png", tile)

                    return tile

                image = process_tile_order(
                    stage_params.tile_order,
                    image,
                    stage_params.tile_size,
                    stage_params.outscale,
                    [stage_tile],
                )
            else:
                logger.info("image within tile size, running stage")
                image = stage_pipe(
                    job,
                    server,
                    stage_params,
                    params,
                    image,
                    callback=callback,
                    **kwargs
                )

            logger.info(
                "finished stage %s, result size: %sx%s", name, image.width, image.height
            )

            if is_debug():
                save_image(server, "last-stage.png", image)

        end = monotonic()
        duration = timedelta(seconds=(end - start))
        logger.info(
            "finished pipeline in %s, result size: %sx%s",
            duration,
            image.width,
            image.height,
        )
        return image