import os
import sys
import traceback

import torch
import tqdm
import html
import datetime
import csv
import numpy as np

import torchvision.transforms
from PIL import Image, PngImagePlugin
from torch.utils.tensorboard import SummaryWriter
from modules import shared, devices, sd_hijack, processing, sd_models
import modules.textual_inversion.dataset
from modules.textual_inversion.learn_schedule import LearnRateScheduler

from modules.textual_inversion.image_embedding import (embedding_to_b64, embedding_from_b64,
                                                       insert_image_data_embed, extract_image_data_embed,
                                                       caption_image_overlay)

class Embedding:
    def __init__(self, vec, name, step=None):
        self.vec = vec
        self.name = name
        self.step = step
        self.cached_checksum = None
        self.sd_checkpoint = None
        self.sd_checkpoint_name = None

    def save(self, filename):
        embedding_data = {
            "string_to_token": {"*": 265},
            "string_to_param": {"*": self.vec},
            "name": self.name,
            "step": self.step,
            "sd_checkpoint": self.sd_checkpoint,
            "sd_checkpoint_name": self.sd_checkpoint_name,
        }

        torch.save(embedding_data, filename)

    def checksum(self):
        if self.cached_checksum is not None:
            return self.cached_checksum

        def const_hash(a):
            r = 0
            for v in a:
                r = (r * 281 ^ int(v) * 997) & 0xFFFFFFFF
            return r

        self.cached_checksum = f'{const_hash(self.vec.reshape(-1) * 100) & 0xffff:04x}'
        return self.cached_checksum


class EmbeddingDatabase:
    def __init__(self, embeddings_dir):
        self.ids_lookup = {}
        self.word_embeddings = {}
        self.dir_mtime = None
        self.embeddings_dir = embeddings_dir

    def register_embedding(self, embedding, model):

        self.word_embeddings[embedding.name] = embedding

        ids = model.cond_stage_model.tokenizer([embedding.name], add_special_tokens=False)['input_ids'][0]

        first_id = ids[0]
        if first_id not in self.ids_lookup:
            self.ids_lookup[first_id] = []

        self.ids_lookup[first_id] = sorted(self.ids_lookup[first_id] + [(ids, embedding)], key=lambda x: len(x[0]), reverse=True)

        return embedding

    def load_textual_inversion_embeddings(self):
        mt = os.path.getmtime(self.embeddings_dir)
        if self.dir_mtime is not None and mt <= self.dir_mtime:
            return

        self.dir_mtime = mt
        self.ids_lookup.clear()
        self.word_embeddings.clear()

        def process_file(path, filename):
            name = os.path.splitext(filename)[0]

            data = []

            if os.path.splitext(filename.upper())[-1] in ['.PNG', '.WEBP', '.JXL', '.AVIF']:
                embed_image = Image.open(path)
                if hasattr(embed_image, 'text') and 'sd-ti-embedding' in embed_image.text:
                    data = embedding_from_b64(embed_image.text['sd-ti-embedding'])
                    name = data.get('name', name)
                else:
                    data = extract_image_data_embed(embed_image)
                    name = data.get('name', name)
            else:
                data = torch.load(path, map_location="cpu")

            # textual inversion embeddings
            if 'string_to_param' in data:
                param_dict = data['string_to_param']
                if hasattr(param_dict, '_parameters'):
                    param_dict = getattr(param_dict, '_parameters')  # fix for torch 1.12.1 loading saved file from torch 1.11
                assert len(param_dict) == 1, 'embedding file has multiple terms in it'
                emb = next(iter(param_dict.items()))[1]
            # diffuser concepts
            elif type(data) == dict and type(next(iter(data.values()))) == torch.Tensor:
                assert len(data.keys()) == 1, 'embedding file has multiple terms in it'

                emb = next(iter(data.values()))
                if len(emb.shape) == 1:
                    emb = emb.unsqueeze(0)
            else:
                raise Exception(f"Couldn't identify {filename} as neither textual inversion embedding nor diffuser concept.")

            vec = emb.detach().to(devices.device, dtype=torch.float32)
            embedding = Embedding(vec, name)
            embedding.step = data.get('step', None)
            embedding.sd_checkpoint = data.get('hash', None)
            embedding.sd_checkpoint_name = data.get('sd_checkpoint_name', None)
            self.register_embedding(embedding, shared.sd_model)

        for fn in os.listdir(self.embeddings_dir):
            try:
                fullfn = os.path.join(self.embeddings_dir, fn)

                if os.stat(fullfn).st_size == 0:
                    continue

                process_file(fullfn, fn)
            except Exception:
                print(f"Error loading emedding {fn}:", file=sys.stderr)
                print(traceback.format_exc(), file=sys.stderr)
                continue

        print(f"Loaded a total of {len(self.word_embeddings)} textual inversion embeddings.")
        print("Embeddings:", ', '.join(self.word_embeddings.keys()))

    def find_embedding_at_position(self, tokens, offset):
        token = tokens[offset]
        possible_matches = self.ids_lookup.get(token, None)

        if possible_matches is None:
            return None, None

        for ids, embedding in possible_matches:
            if tokens[offset:offset + len(ids)] == ids:
                return embedding, len(ids)

        return None, None


def create_embedding(name, num_vectors_per_token, init_text='*'):
    cond_model = shared.sd_model.cond_stage_model
    embedding_layer = cond_model.wrapped.transformer.text_model.embeddings

    ids = cond_model.tokenizer(init_text, max_length=num_vectors_per_token, return_tensors="pt", add_special_tokens=False)["input_ids"]
    embedded = embedding_layer.token_embedding.wrapped(ids.to(devices.device)).squeeze(0)
    vec = torch.zeros((num_vectors_per_token, embedded.shape[1]), device=devices.device)

    for i in range(num_vectors_per_token):
        vec[i] = embedded[i * int(embedded.shape[0]) // num_vectors_per_token]

    fn = os.path.join(shared.cmd_opts.embeddings_dir, f"{name}.pt")
    assert not os.path.exists(fn), f"file {fn} already exists"

    embedding = Embedding(vec, name)
    embedding.step = 0
    embedding.save(fn)

    return fn


def write_loss(log_directory, filename, step, epoch_len, values):
    if shared.opts.training_write_csv_every == 0:
        return

    if step % shared.opts.training_write_csv_every != 0:
        return

    write_csv_header = False if os.path.exists(os.path.join(log_directory, filename)) else True

    with open(os.path.join(log_directory, filename), "a+", newline='') as fout:
        csv_writer = csv.DictWriter(fout, fieldnames=["step", "epoch", "epoch_step", *(values.keys())])

        if write_csv_header:
            csv_writer.writeheader()

        epoch = step // epoch_len
        epoch_step = step - epoch * epoch_len

        csv_writer.writerow({
            "step": step + 1,
            "epoch": epoch + 1,
            "epoch_step": epoch_step + 1,
            **values,
        })

def tensorboard_add_scaler(tensorboard_writer, tag, value, step):
    if shared.opts.training_enable_tensorboard:
        tensorboard_writer.add_scalar(tag=tag, 
            scalar_value=value, global_step=step)

def tensorboard_add_image(tensorboard_writer, tag, pil_image, step):
    if shared.opts.training_enable_tensorboard:
        # Convert a pil image to a torch tensor
        img_tensor = torch.as_tensor(np.array(pil_image, copy=True))
        img_tensor = img_tensor.view(pil_image.size[1], pil_image.size[0], len(pil_image.getbands()))
        img_tensor = img_tensor.permute((2, 0, 1))
                
        tensorboard_writer.add_image(tag, img_tensor, global_step=step)

def train_embedding(embedding_name, learn_rate, batch_size, data_root, log_directory, training_width, training_height, steps, create_image_every, save_embedding_every, template_file, save_image_with_stored_embedding, preview_from_txt2img, preview_prompt, preview_negative_prompt, preview_steps, preview_sampler_index, preview_cfg_scale, preview_seed, preview_width, preview_height):
    assert embedding_name, 'embedding not selected'

    shared.state.textinfo = "Initializing textual inversion training..."
    shared.state.job_count = steps

    filename = os.path.join(shared.cmd_opts.embeddings_dir, f'{embedding_name}.pt')

    log_directory = os.path.join(log_directory, datetime.datetime.now().strftime("%Y-%m-%d"), embedding_name)

    if save_embedding_every > 0:
        embedding_dir = os.path.join(log_directory, "embeddings")
        os.makedirs(embedding_dir, exist_ok=True)
    else:
        embedding_dir = None

    if create_image_every > 0:
        images_dir = os.path.join(log_directory, "images")
        os.makedirs(images_dir, exist_ok=True)
    else:
        images_dir = None

    if create_image_every > 0 and save_image_with_stored_embedding:
        images_embeds_dir = os.path.join(log_directory, "image_embeddings")
        os.makedirs(images_embeds_dir, exist_ok=True)
    else:
        images_embeds_dir = None
        
    cond_model = shared.sd_model.cond_stage_model

    shared.state.textinfo = f"Preparing dataset from {html.escape(data_root)}..."
    with torch.autocast("cuda"):
        ds = modules.textual_inversion.dataset.PersonalizedBase(data_root=data_root, width=training_width, height=training_height, repeats=shared.opts.training_image_repeats_per_epoch, placeholder_token=embedding_name, model=shared.sd_model, device=devices.device, template_file=template_file, batch_size=batch_size)

    hijack = sd_hijack.model_hijack

    embedding = hijack.embedding_db.word_embeddings[embedding_name]
    embedding.vec.requires_grad = True

    losses = torch.zeros((32,))

    last_saved_file = "<none>"
    last_saved_image = "<none>"
    embedding_yet_to_be_embedded = False

    ititial_step = embedding.step or 0
    if ititial_step > steps:
        return embedding, filename

    scheduler = LearnRateScheduler(learn_rate, steps, ititial_step)
    optimizer = torch.optim.AdamW([embedding.vec], lr=scheduler.learn_rate)

    if shared.opts.training_enable_tensorboard:
        os.makedirs(os.path.join(log_directory, "tensorboard"), exist_ok=True)
        tensorboard_writer = SummaryWriter(
                log_dir=os.path.join(log_directory, "tensorboard"),
                flush_secs=shared.opts.training_tensorboard_flush_every)

    pbar = tqdm.tqdm(enumerate(ds), total=steps-ititial_step)
    for i, entries in pbar:
        embedding.step = i + ititial_step

        scheduler.apply(optimizer, embedding.step)
        if scheduler.finished:
            break

        if shared.state.interrupted:
            break

        with torch.autocast("cuda"):
            c = cond_model([entry.cond_text for entry in entries])
            x = torch.stack([entry.latent for entry in entries]).to(devices.device)
            loss = shared.sd_model(x, c)[0]
            del x

            losses[embedding.step % losses.shape[0]] = loss.item()
            

            optimizer.zero_grad()
            loss.backward()
            optimizer.step()

        epoch_num = embedding.step // len(ds)
        epoch_step = embedding.step - (epoch_num * len(ds)) + 1

        pbar.set_description(f"[Epoch {epoch_num}: {epoch_step}/{len(ds)}]loss: {losses.mean():.7f}")

        if embedding.step > 0 and embedding_dir is not None and embedding.step % save_embedding_every == 0:
            last_saved_file = os.path.join(embedding_dir, f'{embedding_name}-{embedding.step}.pt')
            embedding.save(last_saved_file)
            embedding_yet_to_be_embedded = True

        if shared.opts.training_enable_tensorboard:
            tensorboard_add_scaler(tensorboard_writer, "Loss/train", losses.mean(), embedding.step)
            tensorboard_add_scaler(tensorboard_writer, f"Loss/train/epoch-{epoch_num}", losses.mean(), epoch_step)
            tensorboard_add_scaler(tensorboard_writer, "Learn rate/train", scheduler.learn_rate, embedding.step)
            tensorboard_add_scaler(tensorboard_writer, f"Learn rate/train/epoch-{epoch_num}", scheduler.learn_rate, epoch_step)

        write_loss(log_directory, "textual_inversion_loss.csv", embedding.step, len(ds), {
            "loss": f"{losses.mean():.7f}",
            "learn_rate": scheduler.learn_rate
        })

        if embedding.step > 0 and images_dir is not None and embedding.step % create_image_every == 0:
            last_saved_image = os.path.join(images_dir, f'{embedding_name}-{embedding.step}.png')

            p = processing.StableDiffusionProcessingTxt2Img(
                sd_model=shared.sd_model,
                do_not_save_grid=True,
                do_not_save_samples=True,
                do_not_reload_embeddings=True,
            )

            if preview_from_txt2img:
                p.prompt = preview_prompt
                p.negative_prompt = preview_negative_prompt
                p.steps = preview_steps
                p.sampler_index = preview_sampler_index
                p.cfg_scale = preview_cfg_scale
                p.seed = preview_seed
                p.width = preview_width
                p.height = preview_height
            else:
                p.prompt = entries[0].cond_text
                p.steps = 20
                p.width = training_width
                p.height = training_height

            preview_text = p.prompt

            processed = processing.process_images(p)
            image = processed.images[0]

            shared.state.current_image = image

            if save_image_with_stored_embedding and os.path.exists(last_saved_file) and embedding_yet_to_be_embedded:

                last_saved_image_chunks = os.path.join(images_embeds_dir, f'{embedding_name}-{embedding.step}.png')

                info = PngImagePlugin.PngInfo()
                data = torch.load(last_saved_file)
                info.add_text("sd-ti-embedding", embedding_to_b64(data))

                title = "<{}>".format(data.get('name', '???'))

                try:
                    vectorSize = list(data['string_to_param'].values())[0].shape[0]
                except Exception as e:
                    vectorSize = '?'

                checkpoint = sd_models.select_checkpoint()
                footer_left = checkpoint.model_name
                footer_mid = '[{}]'.format(checkpoint.hash)
                footer_right = '{}v {}s'.format(vectorSize, embedding.step)

                captioned_image = caption_image_overlay(image, title, footer_left, footer_mid, footer_right)
                captioned_image = insert_image_data_embed(captioned_image, data)

                captioned_image.save(last_saved_image_chunks, "PNG", pnginfo=info)
                embedding_yet_to_be_embedded = False

            image.save(last_saved_image)
            tensorboard_add_image(tensorboard_writer, f"Validation at epoch {epoch_num}", image, embedding.step)

            last_saved_image += f", prompt: {preview_text}"

        shared.state.job_no = embedding.step

        shared.state.textinfo = f"""
<p>
Loss: {losses.mean():.7f}<br/>
Step: {embedding.step}<br/>
Last prompt: {html.escape(entries[0].cond_text)}<br/>
Last saved embedding: {html.escape(last_saved_file)}<br/>
Last saved image: {html.escape(last_saved_image)}<br/>
</p>
"""

    checkpoint = sd_models.select_checkpoint()

    embedding.sd_checkpoint = checkpoint.hash
    embedding.sd_checkpoint_name = checkpoint.model_name
    embedding.cached_checksum = None
    embedding.save(filename)

    return embedding, filename