from __future__ import annotations

import logging
import os
import shutil
import importlib
from urllib.parse import urlparse

from modules import shared
from modules.upscaler import Upscaler, UpscalerLanczos, UpscalerNearest, UpscalerNone
from modules.paths import script_path, models_path


logger = logging.getLogger(__name__)


def load_file_from_url(
    url: str,
    *,
    model_dir: str,
    progress: bool = True,
    file_name: str | None = None,
) -> str:
    """Download a file from `url` into `model_dir`, using the file present if possible.

    Returns the path to the downloaded file.
    """
    os.makedirs(model_dir, exist_ok=True)
    if not file_name:
        parts = urlparse(url)
        file_name = os.path.basename(parts.path)
    cached_file = os.path.abspath(os.path.join(model_dir, file_name))
    if not os.path.exists(cached_file):
        print(f'Downloading: "{url}" to {cached_file}\n')
        from torch.hub import download_url_to_file
        download_url_to_file(url, cached_file, progress=progress)
    return cached_file


def load_models(model_path: str, model_url: str = None, command_path: str = None, ext_filter=None, download_name=None, ext_blacklist=None) -> list:
    """
    A one-and done loader to try finding the desired models in specified directories.

    @param download_name: Specify to download from model_url immediately.
    @param model_url: If no other models are found, this will be downloaded on upscale.
    @param model_path: The location to store/find models in.
    @param command_path: A command-line argument to search for models in first.
    @param ext_filter: An optional list of filename extensions to filter by
    @return: A list of paths containing the desired model(s)
    """
    output = []

    try:
        places = []

        if command_path is not None and command_path != model_path:
            pretrained_path = os.path.join(command_path, 'experiments/pretrained_models')
            if os.path.exists(pretrained_path):
                print(f"Appending path: {pretrained_path}")
                places.append(pretrained_path)
            elif os.path.exists(command_path):
                places.append(command_path)

        places.append(model_path)

        for place in places:
            for full_path in shared.walk_files(place, allowed_extensions=ext_filter):
                if os.path.islink(full_path) and not os.path.exists(full_path):
                    print(f"Skipping broken symlink: {full_path}")
                    continue
                if ext_blacklist is not None and any(full_path.endswith(x) for x in ext_blacklist):
                    continue
                if full_path not in output:
                    output.append(full_path)

        if model_url is not None and len(output) == 0:
            if download_name is not None:
                output.append(load_file_from_url(model_url, model_dir=places[0], file_name=download_name))
            else:
                output.append(model_url)

    except Exception:
        pass

    return output


def friendly_name(file: str):
    if file.startswith("http"):
        file = urlparse(file).path

    file = os.path.basename(file)
    model_name, extension = os.path.splitext(file)
    return model_name


def cleanup_models():
    # This code could probably be more efficient if we used a tuple list or something to store the src/destinations
    # and then enumerate that, but this works for now. In the future, it'd be nice to just have every "model" scaler
    # somehow auto-register and just do these things...
    root_path = script_path
    src_path = models_path
    dest_path = os.path.join(models_path, "Stable-diffusion")
    move_files(src_path, dest_path, ".ckpt")
    move_files(src_path, dest_path, ".safetensors")
    src_path = os.path.join(root_path, "ESRGAN")
    dest_path = os.path.join(models_path, "ESRGAN")
    move_files(src_path, dest_path)
    src_path = os.path.join(models_path, "BSRGAN")
    dest_path = os.path.join(models_path, "ESRGAN")
    move_files(src_path, dest_path, ".pth")
    src_path = os.path.join(root_path, "gfpgan")
    dest_path = os.path.join(models_path, "GFPGAN")
    move_files(src_path, dest_path)
    src_path = os.path.join(root_path, "SwinIR")
    dest_path = os.path.join(models_path, "SwinIR")
    move_files(src_path, dest_path)
    src_path = os.path.join(root_path, "repositories/latent-diffusion/experiments/pretrained_models/")
    dest_path = os.path.join(models_path, "LDSR")
    move_files(src_path, dest_path)


def move_files(src_path: str, dest_path: str, ext_filter: str = None):
    try:
        os.makedirs(dest_path, exist_ok=True)
        if os.path.exists(src_path):
            for file in os.listdir(src_path):
                fullpath = os.path.join(src_path, file)
                if os.path.isfile(fullpath):
                    if ext_filter is not None:
                        if ext_filter not in file:
                            continue
                    print(f"Moving {file} from {src_path} to {dest_path}.")
                    try:
                        shutil.move(fullpath, dest_path)
                    except Exception:
                        pass
            if len(os.listdir(src_path)) == 0:
                print(f"Removing empty folder: {src_path}")
                shutil.rmtree(src_path, True)
    except Exception:
        pass


def load_upscalers():
    # We can only do this 'magic' method to dynamically load upscalers if they are referenced,
    # so we'll try to import any _model.py files before looking in __subclasses__
    modules_dir = os.path.join(shared.script_path, "modules")
    for file in os.listdir(modules_dir):
        if "_model.py" in file:
            model_name = file.replace("_model.py", "")
            full_model = f"modules.{model_name}_model"
            try:
                importlib.import_module(full_model)
            except Exception:
                pass

    datas = []
    commandline_options = vars(shared.cmd_opts)

    # some of upscaler classes will not go away after reloading their modules, and we'll end
    # up with two copies of those classes. The newest copy will always be the last in the list,
    # so we go from end to beginning and ignore duplicates
    used_classes = {}
    for cls in reversed(Upscaler.__subclasses__()):
        classname = str(cls)
        if classname not in used_classes:
            used_classes[classname] = cls

    for cls in reversed(used_classes.values()):
        name = cls.__name__
        cmd_name = f"{name.lower().replace('upscaler', '')}_models_path"
        commandline_model_path = commandline_options.get(cmd_name, None)
        scaler = cls(commandline_model_path)
        scaler.user_path = commandline_model_path
        scaler.model_download_path = commandline_model_path or scaler.model_path
        datas += scaler.scalers

    shared.sd_upscalers = sorted(
        datas,
        # Special case for UpscalerNone keeps it at the beginning of the list.
        key=lambda x: x.name.lower() if not isinstance(x.scaler, (UpscalerNone, UpscalerLanczos, UpscalerNearest)) else ""
    )


def load_spandrel_model(path, *, device, half: bool = False, dtype=None):
    import spandrel
    model = spandrel.ModelLoader(device=device).load_from_file(path)
    if half:
        model = model.model.half()
    if dtype:
        model = model.model.to(dtype=dtype)
    model.eval()
    logger.debug("Loaded %s from %s (device=%s, half=%s, dtype=%s)", model, path, device, half, dtype)
    return model