import contextlib
import os
import sys
import traceback
from collections import namedtuple
import re

import torch

from torchvision import transforms
from torchvision.transforms.functional import InterpolationMode

import modules.shared as shared
from modules import devices, paths

blip_image_eval_size = 384
blip_model_url = 'https://storage.googleapis.com/sfr-vision-language-research/BLIP/models/model_base_caption_capfilt_large.pth'
clip_model_name = 'ViT-L/14'

Category = namedtuple("Category", ["name", "topn", "items"])

re_topn = re.compile(r"\.top(\d+)\.")

class InterrogateModels:
    blip_model = None
    clip_model = None
    clip_preprocess = None
    categories = None
    dtype = None

    def __init__(self, content_dir):
        self.categories = []

        if os.path.exists(content_dir):
            for filename in os.listdir(content_dir):
                m = re_topn.search(filename)
                topn = 1 if m is None else int(m.group(1))

                with open(os.path.join(content_dir, filename), "r", encoding="utf8") as file:
                    lines = [x.strip() for x in file.readlines()]

                self.categories.append(Category(name=filename, topn=topn, items=lines))

    def load_blip_model(self):
        import models.blip

        blip_model = models.blip.blip_decoder(pretrained=blip_model_url, image_size=blip_image_eval_size, vit='base', med_config=os.path.join(paths.paths["BLIP"], "configs", "med_config.json"))
        blip_model.eval()

        return blip_model

    def load_clip_model(self):
        import clip

        model, preprocess = clip.load(clip_model_name)
        model.eval()
        model = model.to(shared.device)

        return model, preprocess

    def load(self):
        if self.blip_model is None:
            self.blip_model = self.load_blip_model()
            if not shared.cmd_opts.no_half:
                self.blip_model = self.blip_model.half()

        self.blip_model = self.blip_model.to(shared.device)

        if self.clip_model is None:
            self.clip_model, self.clip_preprocess = self.load_clip_model()
            if not shared.cmd_opts.no_half:
                self.clip_model = self.clip_model.half()

        self.clip_model = self.clip_model.to(shared.device)

        self.dtype = next(self.clip_model.parameters()).dtype

    def unload(self):
        if not shared.opts.interrogate_keep_models_in_memory:
            if self.clip_model is not None:
                self.clip_model = self.clip_model.to(devices.cpu)

            if self.blip_model is not None:
                self.blip_model = self.blip_model.to(devices.cpu)

            devices.torch_gc()

    def rank(self, image_features, text_array, top_count=1):
        import clip

        top_count = min(top_count, len(text_array))
        text_tokens = clip.tokenize([text for text in text_array]).to(shared.device)
        text_features = self.clip_model.encode_text(text_tokens).type(self.dtype)
        text_features /= text_features.norm(dim=-1, keepdim=True)

        similarity = torch.zeros((1, len(text_array))).to(shared.device)
        for i in range(image_features.shape[0]):
            similarity += (100.0 * image_features[i].unsqueeze(0) @ text_features.T).softmax(dim=-1)
        similarity /= image_features.shape[0]

        top_probs, top_labels = similarity.cpu().topk(top_count, dim=-1)
        return [(text_array[top_labels[0][i].numpy()], (top_probs[0][i].numpy()*100)) for i in range(top_count)]

    def generate_caption(self, pil_image):
        gpu_image = transforms.Compose([
            transforms.Resize((blip_image_eval_size, blip_image_eval_size), interpolation=InterpolationMode.BICUBIC),
            transforms.ToTensor(),
            transforms.Normalize((0.48145466, 0.4578275, 0.40821073), (0.26862954, 0.26130258, 0.27577711))
        ])(pil_image).unsqueeze(0).type(self.dtype).to(shared.device)

        with torch.no_grad():
            caption = self.blip_model.generate(gpu_image, sample=False, num_beams=shared.opts.interrogate_clip_num_beams, min_length=shared.opts.interrogate_clip_min_length, max_length=shared.opts.interrogate_clip_max_length)

        return caption[0]

    def interrogate(self, pil_image):
        res = None

        try:
            self.load()

            caption = self.generate_caption(pil_image)
            res = caption

            images = self.clip_preprocess(pil_image).unsqueeze(0).type(self.dtype).to(shared.device)

            precision_scope = torch.autocast if shared.cmd_opts.precision == "autocast" else contextlib.nullcontext
            with torch.no_grad(), precision_scope("cuda"):
                image_features = self.clip_model.encode_image(images).type(self.dtype)

                image_features /= image_features.norm(dim=-1, keepdim=True)

                if shared.opts.interrogate_use_builtin_artists:
                    artist = self.rank(image_features, ["by " + artist.name for artist in shared.artist_db.artists])[0]

                    res += ", " + artist[0]

                for name, topn, items in self.categories:
                    matches = self.rank(image_features, items, top_count=topn)
                    for match, score in matches:
                        res += ", " + match

        except Exception:
            print(f"Error interrogating", file=sys.stderr)
            print(traceback.format_exc(), file=sys.stderr)

        self.unload()

        return res