"""
Base class for invokeai.backend.generator.*
including img2img, txt2img, and inpaint
"""
from __future__ import annotations

import importlib
import itertools
import dataclasses
import diffusers
import os
import random
import traceback
from abc import ABCMeta, abstractmethod
from contextlib import nullcontext

import cv2
import numpy as np
import torch
from PIL import Image, ImageChops, ImageFilter
from accelerate.utils import set_seed
from diffusers import DiffusionPipeline
from tqdm import trange
from typing import List, Type, Iterator
from dataclasses import dataclass, field
from diffusers.schedulers import SchedulerMixin as Scheduler

from ..util.util import rand_perlin_2d
from ..safety_checker import SafetyChecker
from ..prompting.conditioning import get_uc_and_c_and_ec
from ..model_management.model_manager import ModelManager
from ..stable_diffusion.diffusers_pipeline import StableDiffusionGeneratorPipeline

downsampling = 8

@dataclass
class InvokeAIGeneratorBasicParams:
    seed: int=None
    width: int=512
    height: int=512
    cfg_scale: int=7.5
    steps: int=20
    ddim_eta: float=0.0
    model_name: str='stable-diffusion-1.5'
    scheduler: int='ddim'
    precision: str='float16'
    perlin: float=0.0
    threshold: int=0.0
    h_symmetry_time_pct: float=None
    v_symmetry_time_pct: float=None
    variation_amount: float = 0.0
    with_variations: list=field(default_factory=list)
    safety_checker: SafetyChecker=None

@dataclass
class InvokeAIGeneratorOutput:
    '''
    InvokeAIGeneratorOutput is a dataclass that contains the outputs of a generation
    operation, including the image, its seed, the model name used to generate the image
    and the model hash, as well as all the generate() parameters that went into 
    generating the image (in .params, also available as attributes)
    '''
    image: Image
    seed: int
    model_name: str
    model_hash: str
    params: dict

    def __getattribute__(self,name):
        try:
            return object.__getattribute__(self, name)
        except AttributeError:
            params = object.__getattribute__(self, 'params')
            if name in params:
                return params[name]
        raise AttributeError(f"'{self.__class__.__name__}' has no attribute '{name}'")

class InvokeAIGeneratorFactory(object):
    def __init__(self,
                 model_manager: ModelManager,
                 params: InvokeAIGeneratorBasicParams=InvokeAIGeneratorBasicParams(),
                 ):
        self.model_manager = model_manager
        self.params = params
                 
    def make_generator(self, generatorclass: Type[InvokeAIGenerator], **keyword_args)->InvokeAIGenerator:
        return generatorclass(self.model_manager,
                              self.params,
                              **keyword_args
                              )

    # getter and setter shortcuts for commonly used parameters
    @property
    def model_name(self)->str:
        return self.params.model_name

    @model_name.setter
    def model_name(self, model_name: str):
        self.params.model_name=model_name

# we are interposing a wrapper around the original Generator classes so that
# old code that calls Generate will continue to work.
class InvokeAIGenerator(metaclass=ABCMeta):
    scheduler_map = dict(
        ddim=diffusers.DDIMScheduler,
        dpmpp_2=diffusers.DPMSolverMultistepScheduler,
        k_dpm_2=diffusers.KDPM2DiscreteScheduler,
        k_dpm_2_a=diffusers.KDPM2AncestralDiscreteScheduler,
        k_dpmpp_2=diffusers.DPMSolverMultistepScheduler,
        k_euler=diffusers.EulerDiscreteScheduler,
        k_euler_a=diffusers.EulerAncestralDiscreteScheduler,
        k_heun=diffusers.HeunDiscreteScheduler,
        k_lms=diffusers.LMSDiscreteScheduler,
        plms=diffusers.PNDMScheduler,
    )

    def __init__(self,
                 model_manager: ModelManager,
                 params: InvokeAIGeneratorBasicParams,
                 ):
        self.model_manager=model_manager
        self.params=params

    def generate(self,
                 prompt: str='',
                 callback: callable=None,
                 step_callback: callable=None,
                 iterations: int=1,
                 **keyword_args,
                 )->Iterator[InvokeAIGeneratorOutput]:
        '''
        Return an iterator across the indicated number of generations.
        Each time the iterator is called it will return an InvokeAIGeneratorOutput
        object. Use like this:

           outputs = txt2img.generate(prompt='banana sushi', iterations=5)
           for result in outputs:
               print(result.image, result.seed)

        In the typical case of wanting to get just a single image, iterations
        defaults to 1 and do:

           output = next(txt2img.generate(prompt='banana sushi')

        Pass None to get an infinite iterator.

           outputs = txt2img.generate(prompt='banana sushi', iterations=None)
           for o in outputs:
               print(o.image, o.seed)
        
        '''
        model_name = self.params.model_name or self.model_manager.current_model
        model_info: dict = self.model_manager.get_model(model_name)
        model:StableDiffusionGeneratorPipeline = model_info['model']
        model_hash = model_info['hash']
        scheduler: Scheduler = self.get_scheduler(
            model=model,
            scheduler_name=self.params.scheduler
        )
        uc, c, extra_conditioning_info = get_uc_and_c_and_ec(prompt,model=model)
        generator = self.load_generator(model, self._generator_name())
        if self.params.variation_amount > 0:
            generator.set_variation(self.params.seed,
                                    self.params.variation_amount,
                                    self.params.with_variations)

        generator_args = dataclasses.asdict(self.params)
        generator_args.update(keyword_args)

        iteration_count = range(iterations) if iterations else itertools.count(start=0, step=1)
        for i in iteration_count:
            results = generator.generate(prompt,
                                         conditioning=(uc, c, extra_conditioning_info),
                                         sampler=scheduler,
                                         **generator_args,
                                         )
            output = InvokeAIGeneratorOutput(
                image=results[0][0],
                seed=results[0][1],
                model_name = model_name,
                model_hash = model_hash,
                params=generator_args,
            )
            if callback:
                callback(output)
            yield output
            
    @classmethod
    def schedulers(self)->List[str]:
        '''
        Return list of all the schedulers that we currently handle.
        '''
        return list(self.scheduler_map.keys())

    def load_generator(self, model: StableDiffusionGeneratorPipeline, class_name: str):
        module_name = f'invokeai.backend.generator.{class_name.lower()}'
        module = importlib.import_module(module_name)
        constructor = getattr(module, class_name)
        return constructor(model, self.params.precision)
               
    def get_scheduler(self, scheduler_name:str, model: StableDiffusionGeneratorPipeline)->Scheduler:
        scheduler_class = self.scheduler_map.get(scheduler_name,'ddim')
        scheduler = scheduler_class.from_config(model.scheduler.config)
        # hack copied over from generate.py
        if not hasattr(scheduler, 'uses_inpainting_model'):
            scheduler.uses_inpainting_model = lambda: False
        return scheduler
        
    @abstractmethod
    def _generator_name(self)->str:
        '''
        In derived classes will return the name of the generator to use.
        '''
        pass

# ------------------------------------
class Txt2Img(InvokeAIGenerator):
    def _generator_name(self)->str:
        return 'Txt2Img'

# ------------------------------------
class Img2Img(InvokeAIGenerator):
    def generate(self,
               init_image: Image | torch.FloatTensor,
               strength: float=0.75,
               **keyword_args
               )->List[InvokeAIGeneratorOutput]:
        return super().generate(init_image=init_image,
                                strength=strength,
                                **keyword_args
                                )

    def _generator_name(self)->str:
        return 'Img2Img'

# ------------------------------------
# Takes all the arguments of Img2Img and adds the mask image and the seam/infill stuff
class Inpaint(Img2Img):
    def generate(self,
                 mask_image: Image | torch.FloatTensor,
                 # Seam settings - when 0, doesn't fill seam
                 seam_size: int = 0,
                 seam_blur: int = 0,
                 seam_strength: float = 0.7,
                 seam_steps: int = 10,
                 tile_size: int = 32,
                 inpaint_replace=False,
                 infill_method=None,
                 inpaint_width=None,
                 inpaint_height=None,
                 inpaint_fill: tuple(int) = (0x7F, 0x7F, 0x7F, 0xFF),
                 **keyword_args
                 )->List[InvokeAIGeneratorOutput]:
        return super().generate(
            mask_image=mask_image,
            seam_size=seam_size,
            seam_blur=seam_blur,
            seam_strength=seam_strength,
            seam_steps=seam_steps,
            tile_size=tile_size,
            inpaint_replace=inpaint_replace,
            infill_method=infill_method,
            inpaint_width=inpaint_width,
            inpaint_height=inpaint_height,
            inpaint_fill=inpaint_fill,
            **keyword_args
        )

    def _generator_name(self)->str:
        return 'Inpaint'
    
class Generator:
    downsampling_factor: int
    latent_channels: int
    precision: str
    model: DiffusionPipeline

    def __init__(self, model: DiffusionPipeline, precision: str):
        self.model = model
        self.precision = precision
        self.seed = None
        self.latent_channels = model.channels
        self.downsampling_factor = downsampling  # BUG: should come from model or config
        self.safety_checker = None
        self.perlin = 0.0
        self.threshold = 0
        self.variation_amount = 0
        self.with_variations = []
        self.use_mps_noise = False
        self.free_gpu_mem = None

    # this is going to be overridden in img2img.py, txt2img.py and inpaint.py
    def get_make_image(self, prompt, **kwargs):
        """
        Returns a function returning an image derived from the prompt and the initial image
        Return value depends on the seed at the time you call it
        """
        raise NotImplementedError(
            "image_iterator() must be implemented in a descendent class"
        )

    def set_variation(self, seed, variation_amount, with_variations):
        self.seed = seed
        self.variation_amount = variation_amount
        self.with_variations = with_variations

    def generate(
        self,
        prompt,
        width,
        height,
        sampler,
        init_image=None,
        iterations=1,
        seed=None,
        image_callback=None,
        step_callback=None,
        threshold=0.0,
        perlin=0.0,
        h_symmetry_time_pct=None,
        v_symmetry_time_pct=None,
        safety_checker: SafetyChecker=None,
        free_gpu_mem: bool = False,
        **kwargs,
    ):
        scope = nullcontext
        self.safety_checker = safety_checker
        self.free_gpu_mem = free_gpu_mem
        attention_maps_images = []
        attention_maps_callback = lambda saver: attention_maps_images.append(
            saver.get_stacked_maps_image()
        )
        make_image = self.get_make_image(
            prompt,
            sampler=sampler,
            init_image=init_image,
            width=width,
            height=height,
            step_callback=step_callback,
            threshold=threshold,
            perlin=perlin,
            h_symmetry_time_pct=h_symmetry_time_pct,
            v_symmetry_time_pct=v_symmetry_time_pct,
            attention_maps_callback=attention_maps_callback,
            seed=seed,
            **kwargs,
        )
        results = []
        seed = seed if seed is not None and seed >= 0 else self.new_seed()
        first_seed = seed
        seed, initial_noise = self.generate_initial_noise(seed, width, height)

        # There used to be an additional self.model.ema_scope() here, but it breaks
        # the inpaint-1.5 model. Not sure what it did.... ?
        with scope(self.model.device.type):
            for n in trange(iterations, desc="Generating"):
                x_T = None
                if self.variation_amount > 0:
                    set_seed(seed)
                    target_noise = self.get_noise(width, height)
                    x_T = self.slerp(self.variation_amount, initial_noise, target_noise)
                elif initial_noise is not None:
                    # i.e. we specified particular variations
                    x_T = initial_noise
                else:
                    set_seed(seed)
                    try:
                        x_T = self.get_noise(width, height)
                    except:
                        print("** An error occurred while getting initial noise **")
                        print(traceback.format_exc())

                image = make_image(x_T)

                if self.safety_checker is not None:
                    image = self.safety_checker.check(image)

                results.append([image, seed])

                if image_callback is not None:
                    attention_maps_image = (
                        None
                        if len(attention_maps_images) == 0
                        else attention_maps_images[-1]
                    )
                    image_callback(
                        image,
                        seed,
                        first_seed=first_seed,
                        attention_maps_image=attention_maps_image,
                    )

                seed = self.new_seed()

                # Free up memory from the last generation.
                clear_cuda_cache = (
                    kwargs["clear_cuda_cache"] if "clear_cuda_cache" in kwargs else None
                )
                if clear_cuda_cache is not None:
                    clear_cuda_cache()

        return results

    def sample_to_image(self, samples) -> Image.Image:
        """
        Given samples returned from a sampler, converts
        it into a PIL Image
        """
        with torch.inference_mode():
            image = self.model.decode_latents(samples)
        return self.model.numpy_to_pil(image)[0]

    def repaste_and_color_correct(
        self,
        result: Image.Image,
        init_image: Image.Image,
        init_mask: Image.Image,
        mask_blur_radius: int = 8,
    ) -> Image.Image:
        if init_image is None or init_mask is None:
            return result

        # Get the original alpha channel of the mask if there is one.
        # Otherwise it is some other black/white image format ('1', 'L' or 'RGB')
        pil_init_mask = (
            init_mask.getchannel("A")
            if init_mask.mode == "RGBA"
            else init_mask.convert("L")
        )
        pil_init_image = init_image.convert(
            "RGBA"
        )  # Add an alpha channel if one doesn't exist

        # Build an image with only visible pixels from source to use as reference for color-matching.
        init_rgb_pixels = np.asarray(init_image.convert("RGB"), dtype=np.uint8)
        init_a_pixels = np.asarray(pil_init_image.getchannel("A"), dtype=np.uint8)
        init_mask_pixels = np.asarray(pil_init_mask, dtype=np.uint8)

        # Get numpy version of result
        np_image = np.asarray(result, dtype=np.uint8)

        # Mask and calculate mean and standard deviation
        mask_pixels = init_a_pixels * init_mask_pixels > 0
        np_init_rgb_pixels_masked = init_rgb_pixels[mask_pixels, :]
        np_image_masked = np_image[mask_pixels, :]

        if np_init_rgb_pixels_masked.size > 0:
            init_means = np_init_rgb_pixels_masked.mean(axis=0)
            init_std = np_init_rgb_pixels_masked.std(axis=0)
            gen_means = np_image_masked.mean(axis=0)
            gen_std = np_image_masked.std(axis=0)

            # Color correct
            np_matched_result = np_image.copy()
            np_matched_result[:, :, :] = (
                (
                    (
                        (
                            np_matched_result[:, :, :].astype(np.float32)
                            - gen_means[None, None, :]
                        )
                        / gen_std[None, None, :]
                    )
                    * init_std[None, None, :]
                    + init_means[None, None, :]
                )
                .clip(0, 255)
                .astype(np.uint8)
            )
            matched_result = Image.fromarray(np_matched_result, mode="RGB")
        else:
            matched_result = Image.fromarray(np_image, mode="RGB")

        # Blur the mask out (into init image) by specified amount
        if mask_blur_radius > 0:
            nm = np.asarray(pil_init_mask, dtype=np.uint8)
            nmd = cv2.erode(
                nm,
                kernel=np.ones((3, 3), dtype=np.uint8),
                iterations=int(mask_blur_radius / 2),
            )
            pmd = Image.fromarray(nmd, mode="L")
            blurred_init_mask = pmd.filter(ImageFilter.BoxBlur(mask_blur_radius))
        else:
            blurred_init_mask = pil_init_mask

        multiplied_blurred_init_mask = ImageChops.multiply(
            blurred_init_mask, self.pil_image.split()[-1]
        )

        # Paste original on color-corrected generation (using blurred mask)
        matched_result.paste(init_image, (0, 0), mask=multiplied_blurred_init_mask)
        return matched_result

    def sample_to_lowres_estimated_image(self, samples):
        # origingally adapted from code by @erucipe and @keturn here:
        # https://discuss.huggingface.co/t/decoding-latents-to-rgb-without-upscaling/23204/7

        # these updated numbers for v1.5 are from @torridgristle
        v1_5_latent_rgb_factors = torch.tensor(
            [
                #    R        G        B
                [0.3444, 0.1385, 0.0670],  # L1
                [0.1247, 0.4027, 0.1494],  # L2
                [-0.3192, 0.2513, 0.2103],  # L3
                [-0.1307, -0.1874, -0.7445],  # L4
            ],
            dtype=samples.dtype,
            device=samples.device,
        )

        latent_image = samples[0].permute(1, 2, 0) @ v1_5_latent_rgb_factors
        latents_ubyte = (
            ((latent_image + 1) / 2)
            .clamp(0, 1)  # change scale from -1..1 to 0..1
            .mul(0xFF)  # to 0..255
            .byte()
        ).cpu()

        return Image.fromarray(latents_ubyte.numpy())

    def generate_initial_noise(self, seed, width, height):
        initial_noise = None
        if self.variation_amount > 0 or len(self.with_variations) > 0:
            # use fixed initial noise plus random noise per iteration
            set_seed(seed)
            initial_noise = self.get_noise(width, height)
            for v_seed, v_weight in self.with_variations:
                seed = v_seed
                set_seed(seed)
                next_noise = self.get_noise(width, height)
                initial_noise = self.slerp(v_weight, initial_noise, next_noise)
            if self.variation_amount > 0:
                random.seed()  # reset RNG to an actually random state, so we can get a random seed for variations
                seed = random.randrange(0, np.iinfo(np.uint32).max)
        return (seed, initial_noise)

    def get_perlin_noise(self, width, height):
        fixdevice = "cpu" if (self.model.device.type == "mps") else self.model.device
        # limit noise to only the diffusion image channels, not the mask channels
        input_channels = min(self.latent_channels, 4)
        # round up to the nearest block of 8
        temp_width = int((width + 7) / 8) * 8
        temp_height = int((height + 7) / 8) * 8
        noise = torch.stack(
            [
                rand_perlin_2d(
                    (temp_height, temp_width), (8, 8), device=self.model.device
                ).to(fixdevice)
                for _ in range(input_channels)
            ],
            dim=0,
        ).to(self.model.device)
        return noise[0:4, 0:height, 0:width]

    def new_seed(self):
        self.seed = random.randrange(0, np.iinfo(np.uint32).max)
        return self.seed

    def slerp(self, t, v0, v1, DOT_THRESHOLD=0.9995):
        """
        Spherical linear interpolation
        Args:
            t (float/np.ndarray): Float value between 0.0 and 1.0
            v0 (np.ndarray): Starting vector
            v1 (np.ndarray): Final vector
            DOT_THRESHOLD (float): Threshold for considering the two vectors as
                                colineal. Not recommended to alter this.
        Returns:
            v2 (np.ndarray): Interpolation vector between v0 and v1
        """
        inputs_are_torch = False
        if not isinstance(v0, np.ndarray):
            inputs_are_torch = True
            v0 = v0.detach().cpu().numpy()
        if not isinstance(v1, np.ndarray):
            inputs_are_torch = True
            v1 = v1.detach().cpu().numpy()

        dot = np.sum(v0 * v1 / (np.linalg.norm(v0) * np.linalg.norm(v1)))
        if np.abs(dot) > DOT_THRESHOLD:
            v2 = (1 - t) * v0 + t * v1
        else:
            theta_0 = np.arccos(dot)
            sin_theta_0 = np.sin(theta_0)
            theta_t = theta_0 * t
            sin_theta_t = np.sin(theta_t)
            s0 = np.sin(theta_0 - theta_t) / sin_theta_0
            s1 = sin_theta_t / sin_theta_0
            v2 = s0 * v0 + s1 * v1

        if inputs_are_torch:
            v2 = torch.from_numpy(v2).to(self.model.device)

        return v2

    # this is a handy routine for debugging use. Given a generated sample,
    # convert it into a PNG image and store it at the indicated path
    def save_sample(self, sample, filepath):
        image = self.sample_to_image(sample)
        dirname = os.path.dirname(filepath) or "."
        if not os.path.exists(dirname):
            print(f"** creating directory {dirname}")
            os.makedirs(dirname, exist_ok=True)
        image.save(filepath, "PNG")

    def torch_dtype(self) -> torch.dtype:
        return torch.float16 if self.precision == "float16" else torch.float32

    # returns a tensor filled with random numbers from a normal distribution
    def get_noise(self, width, height):
        device = self.model.device
        # limit noise to only the diffusion image channels, not the mask channels
        input_channels = min(self.latent_channels, 4)
        if self.use_mps_noise or device.type == "mps":
            x = torch.randn(
                [
                    1,
                    input_channels,
                    height // self.downsampling_factor,
                    width // self.downsampling_factor,
                ],
                dtype=self.torch_dtype(),
                device="cpu",
            ).to(device)
        else:
            x = torch.randn(
                [
                    1,
                    input_channels,
                    height // self.downsampling_factor,
                    width // self.downsampling_factor,
                ],
                dtype=self.torch_dtype(),
                device=device,
            )
        if self.perlin > 0.0:
            perlin_noise = self.get_perlin_noise(
                width // self.downsampling_factor, height // self.downsampling_factor
            )
            x = (1 - self.perlin) * x + self.perlin * perlin_noise
        return x