import json
import os, re
import traceback
import torch
import numpy as np
from omegaconf import OmegaConf
from PIL import Image, ImageOps
from tqdm import tqdm, trange
from itertools import islice
from einops import rearrange
import time
from pytorch_lightning import seed_everything
from torch import autocast
from contextlib import nullcontext
from einops import rearrange, repeat
from ldm.util import instantiate_from_config
from optimizedSD.optimUtils import split_weighted_subprompts
from transformers import logging

from gfpgan import GFPGANer
from basicsr.archs.rrdbnet_arch import RRDBNet
from realesrgan import RealESRGANer

import uuid

logging.set_verbosity_error()

# consts
config_yaml = "optimizedSD/v1-inference.yaml"
filename_regex = re.compile('[^a-zA-Z0-9]')

# api stuff
from . import Request, Response, Image as ResponseImage
import base64
from io import BytesIO
#from colorama import Fore

from threading import local as LocalThreadVars
thread_data = LocalThreadVars()

def device_would_fail(device):
    if device == 'cpu': return None
    # Returns None when no issues found, otherwise returns the detected error str.
    # Memory check
    try:
        mem_free, mem_total = torch.cuda.mem_get_info(device)
        mem_total /= float(10**9)
        if mem_total < 3.0:
            return 'GPUs with less than 3 GB of VRAM are not compatible with Stable Diffusion'
    except RuntimeError as e:
        return str(e) # Return cuda errors from mem_get_info as strings
    return None

def device_select(device):
    if device == 'cpu': return True
    if not torch.cuda.is_available(): return False
    failure_msg = device_would_fail(device)
    if failure_msg:
        if 'invalid device' in failure_msg:
            raise NameError(f'GPU "{device}" could not be found. Remove this device from config.render_devices or use one of "auto" or "cuda".')
        print(failure_msg)
        return False

    device_name = torch.cuda.get_device_name(device)

    # otherwise these NVIDIA cards create green images
    thread_data.force_full_precision = ('nvidia' in device_name.lower() or 'geforce' in device_name.lower()) and (' 1660' in device_name or ' 1650' in device_name)
    if thread_data.force_full_precision:
        print('forcing full precision on NVIDIA 16xx cards, to avoid green images. GPU detected: ', gpu_name)

    thread_data.device = device
    thread_data.has_valid_gpu = True
    return True

def device_init(device_selection=None):
    # Thread bound properties
    thread_data.stop_processing = False
    thread_data.temp_images = {}

    thread_data.ckpt_file = None
    thread_data.gfpgan_file = None
    thread_data.real_esrgan_file = None

    thread_data.model = None
    thread_data.modelCS = None
    thread_data.modelFS = None
    thread_data.model_gfpgan = None
    thread_data.model_real_esrgan = None

    thread_data.model_is_half = False
    thread_data.model_fs_is_half = False
    thread_data.device = None
    thread_data.unet_bs = 1
    thread_data.precision = 'autocast'
    thread_data.sampler_plms = None
    thread_data.sampler_ddim = None

    thread_data.turbo = False
    thread_data.has_valid_gpu = False
    thread_data.force_full_precision = False

    if device_selection.lower() == 'cpu':
        print('CPU requested, skipping gpu init.')
        thread_data.device = 'cpu'
        return
    if not torch.cuda.is_available():
        print('WARNING: torch.cuda is not available. Using the CPU, but this will be very slow!')
        return
    device_count = torch.cuda.device_count()
    if device_count <= 1 and device_selection == 'auto':
        device_selection = 'current' # Use 'auto' only when there is more than one compatible device found.
    if device_selection == 'auto':
        print('Autoselecting GPU. Using most free memory.')
        max_mem_free = 0
        best_device = None
        for device in range(device_count):
            mem_free, mem_total = torch.cuda.mem_get_info(device)
            mem_free /= float(10**9)
            mem_total /= float(10**9)
            device_name = torch.cuda.get_device_name(device)
            print(f'GPU:{device} detected: {device_name} - Memory: {round(mem_total - mem_free, 2)}Go / {round(mem_total, 2)}Go')
            if max_mem_free < mem_free:
                max_mem_free = mem_free
                best_device = device
        if best_device and device_select(device):
            print(f'Setting GPU:{device} as active')
            torch.cuda.device(device)
            return
    if isinstance(device_selection, str):
        device_selection = device_selection.lower()
        if device_selection.startswith('gpu:'):
            device_selection = int(device_selection[4:])
    if device_selection != 'cuda' and device_selection != 'current' and device_selection != 'gpu':
        if device_select(device_selection):
            if isinstance(device_selection, int):
                print(f'Setting GPU:{device_selection} as active')
            else:
                print(f'Setting {device_selection} as active')
            torch.cuda.device(device_selection)
            return
    # By default use current device.
    print('Checking current GPU...')
    device = torch.cuda.current_device()
    device_name = torch.cuda.get_device_name(device)
    print(f'GPU:{device} detected: {device_name}')
    if device_select(device):
        return
    print('WARNING: No compatible GPU found. Using the CPU, but this will be very slow!')
    thread_data.device = 'cpu'

def is_first_cuda_device(device):
    if device is None: return False
    if device == 0 or device == '0': return True
    if device == 'cuda' or device == 'cuda:0': return True
    if device == 'gpu' or device == 'gpu:0': return True
    if device == 'current': return True
    if device == torch.device(0): return True
    return False

def load_model_ckpt():
    if not thread_data.ckpt_file: raise ValueError(f'Thread ckpt_file is undefined.')
    if not os.path.exists(thread_data.ckpt_file + '.ckpt'): raise FileNotFoundError(f'Cannot find {thread_data.ckpt_file}.ckpt')

    if not thread_data.precision:
        thread_data.precision = 'full' if thread_data.force_full_precision else 'autocast'
    if not thread_data.unet_bs:
        thread_data.unet_bs = 1

    unload_model()

    if thread_data.device == 'cpu':
        thread_data.precision = 'full'

    print('loading', thread_data.ckpt_file, 'to', thread_data.device, 'using precision', thread_data.precision)
    sd = load_model_from_config(thread_data.ckpt_file + '.ckpt')
    li, lo = [], []
    for key, value in sd.items():
        sp = key.split(".")
        if (sp[0]) == "model":
            if "input_blocks" in sp:
                li.append(key)
            elif "middle_block" in sp:
                li.append(key)
            elif "time_embed" in sp:
                li.append(key)
            else:
                lo.append(key)
    for key in li:
        sd["model1." + key[6:]] = sd.pop(key)
    for key in lo:
        sd["model2." + key[6:]] = sd.pop(key)

    config = OmegaConf.load(f"{config_yaml}")

    model = instantiate_from_config(config.modelUNet)
    _, _ = model.load_state_dict(sd, strict=False)
    model.eval()
    model.cdevice = torch.device(thread_data.device)
    model.unet_bs = thread_data.unet_bs
    model.turbo = thread_data.turbo
    if thread_data.device != 'cpu':
        model.to(thread_data.device)
    thread_data.model = model

    modelCS = instantiate_from_config(config.modelCondStage)
    _, _ = modelCS.load_state_dict(sd, strict=False)
    modelCS.eval()
    modelCS.cond_stage_model.device = torch.device(thread_data.device)
    if thread_data.device != 'cpu':
        modelCS.to(thread_data.device)
    thread_data.modelCS = modelCS

    modelFS = instantiate_from_config(config.modelFirstStage)
    _, _ = modelFS.load_state_dict(sd, strict=False)
    modelFS.eval()
    if thread_data.device != 'cpu':
        modelFS.to(thread_data.device)
    thread_data.modelFS = modelFS
    del sd

    if thread_data.device != "cpu" and thread_data.precision == "autocast":
        thread_data.model.half()
        thread_data.modelCS.half()
        thread_data.modelFS.half()
        thread_data.model_is_half = True
        thread_data.model_fs_is_half = True
    else:
        thread_data.model_is_half = False
        thread_data.model_fs_is_half = False

    print('loaded', thread_data.ckpt_file, 'as', model.device, '->', modelCS.cond_stage_model.device, '->', thread_data.modelFS.device, 'using precision', thread_data.precision)

def unload_model():
    if thread_data.model is not None:
        print('Unloading models...')
        del thread_data.model
        del thread_data.modelCS
        del thread_data.modelFS
    thread_data.model = None
    thread_data.modelCS = None
    thread_data.modelFS = None

def load_model_gfpgan():
    if thread_data.gfpgan_file is None:
        print('load_model_gfpgan called without setting gfpgan_file')
        return
    if thread_data.device != 'cpu' and not is_first_cuda_device(thread_data.device):
        #TODO Remove when fixed - A bug with GFPGANer and facexlib needs to be fixed before use on other devices.
        raise Exception(f'Current device {torch.device(thread_data.device)} is not {torch.device(0)}.')
    model_path = thread_data.gfpgan_file + ".pth"
    thread_data.model_gfpgan = GFPGANer(device=torch.device(thread_data.device), model_path=model_path, upscale=1, arch='clean', channel_multiplier=2, bg_upsampler=None)
    print('loaded', thread_data.gfpgan_file, 'to', thread_data.model_gfpgan.device, 'precision', thread_data.precision)

def load_model_real_esrgan():
    if thread_data.real_esrgan_file is None:
        print('load_model_real_esrgan called without setting real_esrgan_file')
        return
    model_path = thread_data.real_esrgan_file + ".pth"

    RealESRGAN_models = {
        'RealESRGAN_x4plus': RRDBNet(num_in_ch=3, num_out_ch=3, num_feat=64, num_block=23, num_grow_ch=32, scale=4),
        'RealESRGAN_x4plus_anime_6B': RRDBNet(num_in_ch=3, num_out_ch=3, num_feat=64, num_block=6, num_grow_ch=32, scale=4)
    }

    model_to_use = RealESRGAN_models[thread_data.real_esrgan_file]

    if thread_data.device == 'cpu':
        thread_data.model_real_esrgan = RealESRGANer(device=torch.device(thread_data.device), scale=2, model_path=model_path, model=model_to_use, pre_pad=0, half=False) # cpu does not support half
        #thread_data.model_real_esrgan.device = torch.device(thread_data.device)
        thread_data.model_real_esrgan.model.to('cpu')
    else:
        thread_data.model_real_esrgan = RealESRGANer(device=torch.device(thread_data.device), scale=2, model_path=model_path, model=model_to_use, pre_pad=0, half=thread_data.model_is_half)

    thread_data.model_real_esrgan.model.name = thread_data.real_esrgan_file
    print('loaded ', thread_data.real_esrgan_file, 'to', thread_data.model_real_esrgan.device, 'precision', thread_data.precision)

def get_base_path(disk_path, session_id, prompt, ext, suffix=None):
    if disk_path is None: return None
    if session_id is None: return None
    if ext is None: raise Exception('Missing ext')

    session_out_path = os.path.join(disk_path, session_id)
    os.makedirs(session_out_path, exist_ok=True)

    prompt_flattened = filename_regex.sub('_', prompt)[:50]
    img_id = str(uuid.uuid4())[-8:]

    if suffix is not None:
        return os.path.join(session_out_path, f"{prompt_flattened}_{img_id}_{suffix}.{ext}")
    return os.path.join(session_out_path, f"{prompt_flattened}_{img_id}.{ext}")

def apply_filters(filter_name, image_data):
    print(f'Applying filter {filter_name}...')
    if isinstance(image_data, torch.Tensor):
        print(image_data)
        image_data.to(thread_data.device)

    gc()

    if filter_name == 'gfpgan':
        if thread_data.model_gfpgan is None: raise Exception('Model "gfpgan" not loaded.')
        print('enhance with', thread_data.gfpgan_file, 'on', thread_data.model_gfpgan.device, 'precision', thread_data.precision)
        _, _, output = thread_data.model_gfpgan.enhance(image_data[:,:,::-1], has_aligned=False, only_center_face=False, paste_back=True)
        image_data = output[:,:,::-1]

    if filter_name == 'real_esrgan':
        if thread_data.model_real_esrgan is None: raise Exception('Model "gfpgan" not loaded.')
        print('enhance with', thread_data.real_esrgan_file, 'on', thread_data.model_real_esrgan.device, 'precision', thread_data.precision)
        output, _ = thread_data.model_real_esrgan.enhance(image_data[:,:,::-1])
        image_data = output[:,:,::-1]

    return image_data

def mk_img(req: Request):
    try:
        yield from do_mk_img(req)
    except Exception as e:
        print(traceback.format_exc())

        gc()

        if thread_data.device != "cpu":
            thread_data.modelFS.to("cpu")
            thread_data.modelCS.to("cpu")

            thread_data.model.model1.to("cpu")
            thread_data.model.model2.to("cpu")

        gc()

        yield json.dumps({
            "status": 'failed',
            "detail": str(e)
        })

def do_mk_img(req: Request):
    thread_data.stop_processing = False

    res = Response()
    res.request = req
    res.images = []

    thread_data.temp_images.clear()

    # custom model support:
    #  the req.use_stable_diffusion_model needs to be a valid path
    #  to the ckpt file (without the extension).
    if not os.path.exists(req.use_stable_diffusion_model + '.ckpt'): raise FileNotFoundError(f'Cannot find {req.use_stable_diffusion_model}.ckpt')

    needs_model_reload = False
    if thread_data.ckpt_file != req.use_stable_diffusion_model:
        thread_data.ckpt_file = req.use_stable_diffusion_model
        needs_model_reload = True

    if req.use_cpu:
        if thread_data.device != 'cpu':
            thread_data.device = 'cpu'
            if thread_data.model_is_half:
                load_model_ckpt()
                needs_model_reload = False
            load_model_gfpgan()
            load_model_real_esrgan()
    else:
        if thread_data.has_valid_gpu:
            if (thread_data.precision == 'autocast' and (req.use_full_precision or not thread_data.model_is_half)) or \
                (thread_data.precision == 'full' and not req.use_full_precision and not thread_data.force_full_precision):
                thread_data.precision = 'full' if req.use_full_precision else 'autocast'
                load_model_ckpt()
                load_model_gfpgan()
                load_model_real_esrgan()
                needs_model_reload = False

    if needs_model_reload:
        load_model_ckpt()

    if req.use_face_correction != thread_data.gfpgan_file:
        thread_data.gfpgan_file = req.use_face_correction
        load_model_gfpgan()
    if req.use_upscale != thread_data.real_esrgan_file:
        thread_data.real_esrgan_file = req.use_upscale
        load_model_real_esrgan()

    if thread_data.turbo != req.turbo:
        thread_data.turbo = req.turbo
        thread_data.model.turbo = req.turbo

    opt_prompt = req.prompt
    opt_seed = req.seed
    opt_n_iter = 1
    opt_C = 4
    opt_f = 8
    opt_ddim_eta = 0.0
    opt_init_img = req.init_image

    print(req.to_string(), '\n    device', thread_data.device)
    print('\n\n    Using precision:', thread_data.precision)

    seed_everything(opt_seed)

    batch_size = req.num_outputs
    prompt = opt_prompt
    assert prompt is not None
    data = [batch_size * [prompt]]

    if thread_data.precision == "autocast" and thread_data.device != "cpu":
        precision_scope = autocast
    else:
        precision_scope = nullcontext

    mask = None

    if req.init_image is None:
        handler = _txt2img

        init_latent = None
        t_enc = None
    else:
        handler = _img2img

        init_image = load_img(req.init_image, req.width, req.height)
        init_image = init_image.to(thread_data.device)

        if thread_data.device != "cpu" and thread_data.precision == "autocast":
            init_image = init_image.half()

        thread_data.modelFS.to(thread_data.device)

        init_image = repeat(init_image, '1 ... -> b ...', b=batch_size)
        init_latent = thread_data.modelFS.get_first_stage_encoding(thread_data.modelFS.encode_first_stage(init_image))  # move to latent space

        if req.mask is not None:
            mask = load_mask(req.mask, req.width, req.height, init_latent.shape[2], init_latent.shape[3], True).to(thread_data.device)
            mask = mask[0][0].unsqueeze(0).repeat(4, 1, 1).unsqueeze(0)
            mask = repeat(mask, '1 ... -> b ...', b=batch_size)

            if thread_data.device != "cpu" and thread_data.precision == "autocast":
                mask = mask.half()

        move_fs_to_cpu()

        assert 0. <= req.prompt_strength <= 1., 'can only work with strength in [0.0, 1.0]'
        t_enc = int(req.prompt_strength * req.num_inference_steps)
        print(f"target t_enc is {t_enc} steps")

    if req.save_to_disk_path is not None:
        session_out_path = os.path.join(req.save_to_disk_path, req.session_id)
        os.makedirs(session_out_path, exist_ok=True)
    else:
        session_out_path = None

    seeds = ""
    with torch.no_grad():
        for n in trange(opt_n_iter, desc="Sampling"):
            for prompts in tqdm(data, desc="data"):

                with precision_scope("cuda"):
                    thread_data.modelCS.to(thread_data.device)
                    uc = None
                    if req.guidance_scale != 1.0:
                        uc = thread_data.modelCS.get_learned_conditioning(batch_size * [req.negative_prompt])
                    if isinstance(prompts, tuple):
                        prompts = list(prompts)

                    subprompts, weights = split_weighted_subprompts(prompts[0])
                    if len(subprompts) > 1:
                        c = torch.zeros_like(uc)
                        totalWeight = sum(weights)
                        # normalize each "sub prompt" and add it
                        for i in range(len(subprompts)):
                            weight = weights[i]
                            # if not skip_normalize:
                            weight = weight / totalWeight
                            c = torch.add(c, thread_data.modelCS.get_learned_conditioning(subprompts[i]), alpha=weight)
                    else:
                        c = thread_data.modelCS.get_learned_conditioning(prompts)

                    thread_data.modelFS.to(thread_data.device)

                    partial_x_samples = None
                    def img_callback(x_samples, i):
                        nonlocal partial_x_samples

                        partial_x_samples = x_samples

                        if req.stream_progress_updates:
                            n_steps = req.num_inference_steps if req.init_image is None else t_enc
                            progress = {"step": i, "total_steps": n_steps}

                            if req.stream_image_progress and i % 5 == 0:
                                partial_images = []

                                for i in range(batch_size):
                                    x_samples_ddim = thread_data.modelFS.decode_first_stage(x_samples[i].unsqueeze(0))
                                    x_sample = torch.clamp((x_samples_ddim + 1.0) / 2.0, min=0.0, max=1.0)
                                    x_sample = 255.0 * rearrange(x_sample[0].cpu().numpy(), "c h w -> h w c")
                                    x_sample = x_sample.astype(np.uint8)
                                    img = Image.fromarray(x_sample)
                                    buf = BytesIO()
                                    img.save(buf, format='JPEG')
                                    buf.seek(0)

                                    del img, x_sample, x_samples_ddim
                                    # don't delete x_samples, it is used in the code that called this callback

                                    thread_data.temp_images[str(req.session_id) + '/' + str(i)] = buf
                                    partial_images.append({'path': f'/image/tmp/{req.session_id}/{i}'})

                                progress['output'] = partial_images

                            yield json.dumps(progress)

                        if thread_data.stop_processing:
                            raise UserInitiatedStop("User requested that we stop processing")

                    # run the handler
                    try:
                        print('Running handler...')
                        if handler == _txt2img:
                            x_samples = _txt2img(req.width, req.height, req.num_outputs, req.num_inference_steps, req.guidance_scale, None, opt_C, opt_f, opt_ddim_eta, c, uc, opt_seed, img_callback, mask, req.sampler)
                        else:
                            x_samples = _img2img(init_latent, t_enc, batch_size, req.guidance_scale, c, uc, req.num_inference_steps, opt_ddim_eta, opt_seed, img_callback, mask)

                        yield from x_samples

                        x_samples = partial_x_samples
                    except UserInitiatedStop:
                        if partial_x_samples is None:
                            continue

                        x_samples = partial_x_samples

                    print("saving images")
                    for i in range(batch_size):

                        x_samples_ddim = thread_data.modelFS.decode_first_stage(x_samples[i].unsqueeze(0))
                        x_sample = torch.clamp((x_samples_ddim + 1.0) / 2.0, min=0.0, max=1.0)
                        x_sample = 255.0 * rearrange(x_sample[0].cpu().numpy(), "c h w -> h w c")
                        x_sample = x_sample.astype(np.uint8)
                        img = Image.fromarray(x_sample)

                        has_filters =   (req.use_face_correction is not None and req.use_face_correction.startswith('GFPGAN')) or \
                                        (req.use_upscale is not None and req.use_upscale.startswith('RealESRGAN'))

                        return_orig_img = not has_filters or not req.show_only_filtered_image

                        if thread_data.stop_processing:
                            return_orig_img = True

                        if req.save_to_disk_path is not None:
                            if return_orig_img:
                                img_out_path = get_base_path(req.save_to_disk_path, req.session_id, prompts[0], req.output_format)
                                save_image(img, img_out_path)
                            meta_out_path = get_base_path(req.save_to_disk_path, req.session_id, prompts[0], 'txt')
                            save_metadata(meta_out_path, req, prompts[0], opt_seed)

                        if return_orig_img:
                            img_data = img_to_base64_str(img, req.output_format)
                            res_image_orig = ResponseImage(data=img_data, seed=opt_seed)
                            res.images.append(res_image_orig)

                            if req.save_to_disk_path is not None:
                                res_image_orig.path_abs = img_out_path

                        del img

                        if has_filters and not thread_data.stop_processing:
                            filters_applied = []
                            if req.use_face_correction:
                                x_sample = apply_filters('gfpgan', x_sample)
                                filters_applied.append(req.use_face_correction)
                            if req.use_upscale:
                                x_sample = apply_filters('real_esrgan', x_sample)
                                filters_applied.append(req.use_upscale)
                            if (len(filters_applied) > 0):
                                filtered_image = Image.fromarray(x_sample)
                                filtered_img_data = img_to_base64_str(filtered_image, req.output_format)
                                response_image = ResponseImage(data=filtered_img_data, seed=req.seed)
                                res.images.append(response_image)
                                if req.save_to_disk_path is not None:
                                    filtered_img_out_path = get_base_path(req.save_to_disk_path, req.session_id, prompts[0], req.output_format, "_".join(filters_applied))
                                    save_image(filtered_image, filtered_img_out_path)
                                    response_image.path_abs = filtered_img_out_path
                                del filtered_image

                        seeds += str(opt_seed) + ","
                        opt_seed += 1

                    move_fs_to_cpu()
                    gc()
                    del x_samples, x_samples_ddim, x_sample
                    print(f'memory_final = {round(torch.cuda.memory_allocated(thread_data.device) / 1e6, 2)}Mo')

    print('Task completed')

    yield json.dumps(res.json())

def save_image(img, img_out_path):
    try:
        img.save(img_out_path)
    except:
        print('could not save the file', traceback.format_exc())

def save_metadata(meta_out_path, req, prompt, opt_seed):
    metadata = f'''{prompt}
Width: {req.width}
Height: {req.height}
Seed: {opt_seed}
Steps: {req.num_inference_steps}
Guidance Scale: {req.guidance_scale}
Prompt Strength: {req.prompt_strength}
Use Face Correction: {req.use_face_correction}
Use Upscaling: {req.use_upscale}
Sampler: {req.sampler}
Negative Prompt: {req.negative_prompt}
Stable Diffusion model: {req.use_stable_diffusion_model + '.ckpt'}
'''
    try:
        with open(meta_out_path, 'w') as f:
            f.write(metadata)
    except:
        print('could not save the file', traceback.format_exc())

def _txt2img(opt_W, opt_H, opt_n_samples, opt_ddim_steps, opt_scale, start_code, opt_C, opt_f, opt_ddim_eta, c, uc, opt_seed, img_callback, mask, sampler_name):
    shape = [opt_n_samples, opt_C, opt_H // opt_f, opt_W // opt_f]

    if thread_data.device != "cpu":
        mem = torch.cuda.memory_allocated(thread_data.device) / 1e6
        print('Device:', thread_data.device, 'CS_Model, Memory transfer starting. Memory Used:', round(mem, 2), 'Mo')
        thread_data.modelCS.to("cpu")
        while torch.cuda.memory_allocated(thread_data.device) / 1e6 >= mem and mem > 0:
            print('Device:', thread_data.device, 'Waiting Memory transfer. Memory Used:', round(mem, 2), 'Mo')
            time.sleep(1)
        print('Transfered', round(mem - torch.cuda.memory_allocated(thread_data.device) / 1e6, 2), 'Mo')

    if sampler_name == 'ddim':
        thread_data.model.make_schedule(ddim_num_steps=opt_ddim_steps, ddim_eta=opt_ddim_eta, verbose=False)

    samples_ddim = thread_data.model.sample(
        S=opt_ddim_steps,
        conditioning=c,
        seed=opt_seed,
        shape=shape,
        verbose=False,
        unconditional_guidance_scale=opt_scale,
        unconditional_conditioning=uc,
        eta=opt_ddim_eta,
        x_T=start_code,
        img_callback=img_callback,
        mask=mask,
        sampler = sampler_name,
    )
    yield from samples_ddim

def _img2img(init_latent, t_enc, batch_size, opt_scale, c, uc, opt_ddim_steps, opt_ddim_eta, opt_seed, img_callback, mask):
    # encode (scaled latent)
    z_enc = thread_data.model.stochastic_encode(
        init_latent,
        torch.tensor([t_enc] * batch_size).to(thread_data.device),
        opt_seed,
        opt_ddim_eta,
        opt_ddim_steps,
    )
    x_T = None if mask is None else init_latent

    # decode it
    samples_ddim = thread_data.model.sample(
        t_enc,
        c,
        z_enc,
        unconditional_guidance_scale=opt_scale,
        unconditional_conditioning=uc,
        img_callback=img_callback,
        mask=mask,
        x_T=x_T,
        sampler = 'ddim'
    )

    yield from samples_ddim

def move_fs_to_cpu():
    if thread_data.device != "cpu":
        mem = torch.cuda.memory_allocated(thread_data.device) / 1e6
        print('Device:', thread_data.device, 'FS_Model, Memory transfer starting. Memory Used:', round(mem, 2), 'Mo')
        thread_data.modelFS.to("cpu")
        while torch.cuda.memory_allocated(thread_data.device) / 1e6 >= mem and mem > 0:
            print('Device:', thread_data.device, 'Waiting for Memory transfer. Memory Used:', round(mem, 2), 'Mo')
            time.sleep(1)
        print('Transfered', round(mem - torch.cuda.memory_allocated(thread_data.device) / 1e6, 2), 'Mo')

def gc():
    #gc.collect()
    if thread_data.device == 'cpu':
        return
    torch.cuda.empty_cache()
    torch.cuda.ipc_collect()

# internal

def chunk(it, size):
    it = iter(it)
    return iter(lambda: tuple(islice(it, size)), ())

def load_model_from_config(ckpt, verbose=False):
    print(f"Loading model from {ckpt}")
    pl_sd = torch.load(ckpt, map_location="cpu")
    if "global_step" in pl_sd:
        print(f"Global Step: {pl_sd['global_step']}")
    sd = pl_sd["state_dict"]
    return sd

# utils
class UserInitiatedStop(Exception):
    pass

def load_img(img_str, w0, h0):
    image = base64_str_to_img(img_str).convert("RGB")
    w, h = image.size
    print(f"loaded input image of size ({w}, {h}) from base64")
    if h0 is not None and w0 is not None:
        h, w = h0, w0

    w, h = map(lambda x: x - x % 64, (w, h))  # resize to integer multiple of 64
    image = image.resize((w, h), resample=Image.Resampling.LANCZOS)
    image = np.array(image).astype(np.float32) / 255.0
    image = image[None].transpose(0, 3, 1, 2)
    image = torch.from_numpy(image)
    return 2.*image - 1.

def load_mask(mask_str, h0, w0, newH, newW, invert=False):
    image = base64_str_to_img(mask_str).convert("RGB")
    w, h = image.size
    print(f"loaded input mask of size ({w}, {h})")

    if invert:
        print("inverted")
        image = ImageOps.invert(image)
        # where_0, where_1 = np.where(image == 0), np.where(image == 255)
        # image[where_0], image[where_1] = 255, 0

    if h0 is not None and w0 is not None:
        h, w = h0, w0

    w, h = map(lambda x: x - x % 64, (w, h))  # resize to integer multiple of 64

    print(f"New mask size ({w}, {h})")
    image = image.resize((newW, newH), resample=Image.Resampling.LANCZOS)
    image = np.array(image)

    image = image.astype(np.float32) / 255.0
    image = image[None].transpose(0, 3, 1, 2)
    image = torch.from_numpy(image)
    return image

# https://stackoverflow.com/a/61114178
def img_to_base64_str(img, output_format="PNG"):
    buffered = BytesIO()
    img.save(buffered, format=output_format)
    buffered.seek(0)
    img_byte = buffered.getvalue()
    img_str = "data:image/png;base64," + base64.b64encode(img_byte).decode()
    return img_str

def base64_str_to_img(img_str):
    img_str = img_str[len("data:image/png;base64,"):]
    data = base64.b64decode(img_str)
    buffered = BytesIO(data)
    img = Image.open(buffered)
    return img