import os, re
import traceback
import torch
import numpy as np
from omegaconf import OmegaConf
from PIL import Image
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

# local
session_id = str(uuid.uuid4())[-8:]
stop_processing = False

ckpt_file = None
gfpgan_file = None
real_esrgan_file = None

model = None
modelCS = None
modelFS = None
model_gfpgan = None
model_real_esrgan = None

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

has_valid_gpu = False
force_full_precision = False
try:
    gpu = torch.cuda.current_device()
    gpu_name = torch.cuda.get_device_name(gpu)
    print('GPU detected: ', gpu_name)

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

    mem_free, mem_total = torch.cuda.mem_get_info(gpu)
    mem_total /= float(10**9)
    if mem_total < 3.0:
        print("GPUs with less than 3 GB of VRAM are not compatible with Stable Diffusion")
        raise Exception()

    has_valid_gpu = True
except:
    print('WARNING: No compatible GPU found. Using the CPU, but this will be very slow!')
    pass

def load_model_ckpt(ckpt_to_use, device_to_use='cuda', turbo=False, unet_bs_to_use=1, precision_to_use='autocast', half_model_fs=False):
    global ckpt_file, model, modelCS, modelFS, model_is_half, device, unet_bs, precision, model_fs_is_half

    ckpt_file = ckpt_to_use
    device = device_to_use if has_valid_gpu else 'cpu'
    precision = precision_to_use if not force_full_precision else 'full'
    unet_bs = unet_bs_to_use

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

    sd = load_model_from_config(f"{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 = device
    model.unet_bs = unet_bs
    model.turbo = turbo

    modelCS = instantiate_from_config(config.modelCondStage)
    _, _ = modelCS.load_state_dict(sd, strict=False)
    modelCS.eval()
    modelCS.cond_stage_model.device = device

    modelFS = instantiate_from_config(config.modelFirstStage)
    _, _ = modelFS.load_state_dict(sd, strict=False)
    modelFS.eval()
    del sd

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

    if half_model_fs:
        modelFS.half()
        model_fs_is_half = True
    else:
        model_fs_is_half = False

    print('loaded ', ckpt_file, 'to', device, 'precision', precision)

def load_model_gfpgan(gfpgan_to_use):
    global gfpgan_file, model_gfpgan

    if gfpgan_to_use is None:
        return

    gfpgan_file = gfpgan_to_use
    model_path = gfpgan_to_use + ".pth"

    if device == 'cpu':
        model_gfpgan = GFPGANer(model_path=model_path, upscale=1, arch='clean', channel_multiplier=2, bg_upsampler=None, device=torch.device('cpu'))
    else:
        model_gfpgan = GFPGANer(model_path=model_path, upscale=1, arch='clean', channel_multiplier=2, bg_upsampler=None, device=torch.device('cuda'))

    print('loaded ', gfpgan_to_use, 'to', device, 'precision', precision)

def load_model_real_esrgan(real_esrgan_to_use):
    global real_esrgan_file, model_real_esrgan

    if real_esrgan_to_use is None:
        return

    real_esrgan_file = real_esrgan_to_use
    model_path = real_esrgan_to_use + ".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[real_esrgan_to_use]

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

    model_real_esrgan.model.name = real_esrgan_to_use

    print('loaded ', real_esrgan_to_use, 'to', device, 'precision', precision)

def mk_img(req: Request):
    global modelFS, device
    global model_gfpgan, model_real_esrgan
    global stop_processing

    stop_processing = False

    res = Response()
    res.images = []

    model.turbo = req.turbo
    if req.use_cpu:
        if device != 'cpu':
            device = 'cpu'

            if model_is_half:
                load_model_ckpt(ckpt_file, device)

            load_model_gfpgan(gfpgan_file)
            load_model_real_esrgan(real_esrgan_file)
    else:
        if has_valid_gpu:
            prev_device = device
            device = 'cuda'

            if (precision == 'autocast' and (req.use_full_precision or not model_is_half)) or \
                (precision == 'full' and not req.use_full_precision and not force_full_precision) or \
                (req.init_image is None and model_fs_is_half) or \
                (req.init_image is not None and not model_fs_is_half and not force_full_precision):

                load_model_ckpt(ckpt_file, device, model.turbo, unet_bs, ('full' if req.use_full_precision else 'autocast'), half_model_fs=(req.init_image is not None and not req.use_full_precision))

                if prev_device != device:
                    load_model_gfpgan(gfpgan_file)
                    load_model_real_esrgan(real_esrgan_file)

    if req.use_face_correction != gfpgan_file:
        load_model_gfpgan(req.use_face_correction)

    if req.use_upscale != real_esrgan_file:
        load_model_real_esrgan(req.use_upscale)

    model.cdevice = device
    modelCS.cond_stage_model.device = device

    opt_prompt = req.prompt
    opt_seed = req.seed
    opt_n_samples = req.num_outputs
    opt_n_iter = 1
    opt_scale = req.guidance_scale
    opt_C = 4
    opt_H = req.height
    opt_W = req.width
    opt_f = 8
    opt_ddim_steps = req.num_inference_steps
    opt_ddim_eta = 0.0
    opt_strength = req.prompt_strength
    opt_save_to_disk_path = req.save_to_disk_path
    opt_init_img = req.init_image
    opt_use_face_correction = req.use_face_correction
    opt_use_upscale = req.use_upscale
    opt_show_only_filtered = req.show_only_filtered_image
    opt_format = 'png'

    print(req.to_string(), '\n    device', device)

    print('\n\n    Using precision:', precision)

    seed_everything(opt_seed)

    batch_size = opt_n_samples
    prompt = opt_prompt
    assert prompt is not None
    data = [batch_size * [prompt]]

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

    if req.init_image is None:
        handler = _txt2img

        init_latent = None
        t_enc = None
    else:
        handler = _img2img

        init_image = load_img(req.init_image)
        init_image = init_image.to(device)

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

        modelFS.to(device)

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

        if device != "cpu":
            mem = torch.cuda.memory_allocated() / 1e6
            modelFS.to("cpu")
            while torch.cuda.memory_allocated() / 1e6 >= mem:
                time.sleep(1)

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

    if opt_save_to_disk_path is not None:
        session_out_path = os.path.join(opt_save_to_disk_path, 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"):
                    modelCS.to(device)
                    uc = None
                    if opt_scale != 1.0:
                        uc = modelCS.get_learned_conditioning(batch_size * [""])
                    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, modelCS.get_learned_conditioning(subprompts[i]), alpha=weight)
                    else:
                        c = modelCS.get_learned_conditioning(prompts)

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

                        partial_x_samples = x_samples

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

                    # run the handler
                    try:
                        if handler == _txt2img:
                            x_samples = _txt2img(opt_W, opt_H, opt_n_samples, opt_ddim_steps, opt_scale, None, opt_C, opt_f, opt_ddim_eta, c, uc, opt_seed, img_callback)
                        else:
                            x_samples = _img2img(init_latent, t_enc, batch_size, opt_scale, c, uc, opt_ddim_steps, opt_ddim_eta, opt_seed, img_callback)
                    except UserInitiatedStop:
                        if partial_x_samples is None:
                            continue

                        x_samples = partial_x_samples

                    modelFS.to(device)

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

                        x_samples_ddim = 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)

                        if opt_save_to_disk_path is not None:
                            prompt_flattened = filename_regex.sub('_', prompts[0])
                            prompt_flattened = prompt_flattened[:50]

                            img_id = str(uuid.uuid4())[-8:]

                            file_path = f"{prompt_flattened}_{img_id}"
                            img_out_path = os.path.join(session_out_path, f"{file_path}.{opt_format}")
                            meta_out_path = os.path.join(session_out_path, f"{file_path}.txt")

                            if not opt_show_only_filtered:
                                save_image(img, img_out_path)

                            save_metadata(meta_out_path, prompts, opt_seed, opt_W, opt_H, opt_ddim_steps, opt_scale, opt_strength, opt_use_face_correction, opt_use_upscale)

                        if not opt_show_only_filtered:
                            img_data = img_to_base64_str(img)
                            res.images.append(ResponseImage(data=img_data, seed=opt_seed))

                        if (opt_use_face_correction is not None and opt_use_face_correction.startswith('GFPGAN')) or \
                            (opt_use_upscale is not None and opt_use_upscale.startswith('RealESRGAN')):

                            gc()
                            filters_applied = []

                            if opt_use_face_correction:
                                _, _, output = model_gfpgan.enhance(x_sample[:,:,::-1], has_aligned=False, only_center_face=False, paste_back=True)
                                x_sample = output[:,:,::-1]
                                filters_applied.append(opt_use_face_correction)

                            if opt_use_upscale:
                                output, _ = model_real_esrgan.enhance(x_sample[:,:,::-1])
                                x_sample = output[:,:,::-1]
                                filters_applied.append(opt_use_upscale)

                            filtered_image = Image.fromarray(x_sample)

                            filtered_img_data = img_to_base64_str(filtered_image)
                            res.images.append(ResponseImage(data=filtered_img_data, seed=opt_seed))

                            filters_applied = "_".join(filters_applied)

                            if opt_save_to_disk_path is not None:
                                filtered_img_out_path = os.path.join(session_out_path, f"{file_path}_{filters_applied}.{opt_format}")
                                save_image(filtered_image, filtered_img_out_path)

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

                    if device != "cpu":
                        mem = torch.cuda.memory_allocated() / 1e6
                        modelFS.to("cpu")
                        while torch.cuda.memory_allocated() / 1e6 >= mem:
                            time.sleep(1)
                    del x_samples
                    print("memory_final = ", torch.cuda.memory_allocated() / 1e6)

    return res

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, prompts, opt_seed, opt_W, opt_H, opt_ddim_steps, opt_scale, opt_prompt_strength, opt_correct_face, opt_upscale):
    metadata = f"{prompts[0]}\nWidth: {opt_W}\nHeight: {opt_H}\nSeed: {opt_seed}\nSteps: {opt_ddim_steps}\nGuidance Scale: {opt_scale}\nPrompt Strength: {opt_prompt_strength}\nUse Face Correction: {opt_correct_face}\nUse Upscaling: {opt_upscale}"

    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):
    shape = [opt_n_samples, opt_C, opt_H // opt_f, opt_W // opt_f]

    if device != "cpu":
        mem = torch.cuda.memory_allocated() / 1e6
        modelCS.to("cpu")
        while torch.cuda.memory_allocated() / 1e6 >= mem:
            time.sleep(1)

    samples_ddim = 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,
        sampler = 'plms',
    )

    return samples_ddim

def _img2img(init_latent, t_enc, batch_size, opt_scale, c, uc, opt_ddim_steps, opt_ddim_eta, opt_seed, img_callback):
    # encode (scaled latent)
    z_enc = model.stochastic_encode(
        init_latent,
        torch.tensor([t_enc] * batch_size).to(device),
        opt_seed,
        opt_ddim_eta,
        opt_ddim_steps,
    )
    # decode it
    samples_ddim = model.sample(
        t_enc,
        c,
        z_enc,
        unconditional_guidance_scale=opt_scale,
        unconditional_conditioning=uc,
        img_callback=img_callback,
        sampler = 'ddim'
    )

    return samples_ddim

def gc():
    if 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):
    image = base64_str_to_img(img_str).convert("RGB")
    w, h = image.size
    print(f"loaded input image of size ({w}, {h}) from base64")
    w, h = map(lambda x: x - x % 64, (w, h))  # resize to integer multiple of 64
    image = image.resize((w, h), resample=Image.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.

# https://stackoverflow.com/a/61114178
def img_to_base64_str(img):
    buffered = BytesIO()
    img.save(buffered, format="PNG")
    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