import json
import os
import shutil
import warnings
from datetime import datetime
from functools import cache
from pathlib import Path
from typing import Callable, Dict, List, Tuple
from uuid import uuid4

import gradio as gr
import numpy as np
import requests
from filelock import FileLock
from PIL.Image import Image


def setup(folder_path: str | Path | None = None) -> None:
    user_history = _UserHistory()
    user_history.folder_path = _resolve_folder_path(folder_path)
    user_history.initialized = True


def render() -> None:
    user_history = _UserHistory()

    # initialize with default config
    if not user_history.initialized:
        print("Initializing user history with default config. Use `user_history.setup(...)` to customize.")
        setup()

    # Render user history tab
    gr.Markdown(
        "## Your past generations\n\n(Log in to keep a gallery of your previous generations."
        " Your history will be saved and available on your next visit.)"
    )

    if os.getenv("SYSTEM") == "spaces" and not os.path.exists("/data"):
        gr.Markdown(
            "**⚠️ Persistent storage is disabled, meaning your history will be lost if the Space gets restarted."
            " Only the Space owner can setup a Persistent Storage. If you are not the Space owner, consider"
            " duplicating this Space to set your own storage.⚠️**"
        )

    with gr.Row():
        gr.LoginButton(min_width=250)
        gr.LogoutButton(min_width=250)
        refresh_button = gr.Button("Refresh", icon="./assets/icon_refresh.png")
        export_button = gr.Button("Export", icon="./assets/icon_download.png")
        delete_button = gr.Button("Delete history", icon="./assets/icon_delete.png")

    # "Export zip" row (hidden by default)
    with gr.Row():
        export_file = gr.File(file_count="single", file_types=[".zip"], label="Exported history", visible=False)

    # "Config deletion" row (hidden by default)
    with gr.Row():
        confirm_button = gr.Button("Confirm delete all history", variant="stop", visible=False)
        cancel_button = gr.Button("Cancel", visible=False)

    # Gallery
    gallery = gr.Gallery(
        label="Past images",
        show_label=True,
        elem_id="gallery",
        object_fit="contain",
        columns=5,
        height=600,
        preview=False,
        show_share_button=False,
        show_download_button=False,
    )
    gr.Markdown("Make sure to save your images from time to time, this gallery may be deleted in the future.")
    gallery.attach_load_event(_fetch_user_history, every=None)

    # Interactions
    refresh_button.click(fn=_fetch_user_history, inputs=[], outputs=[gallery], queue=False)
    export_button.click(fn=_export_user_history, inputs=[], outputs=[export_file], queue=False)

    # Taken from https://github.com/gradio-app/gradio/issues/3324#issuecomment-1446382045
    delete_button.click(
        lambda: [gr.update(visible=True), gr.update(visible=True)],
        outputs=[confirm_button, cancel_button],
        queue=False,
    )
    cancel_button.click(
        lambda: [gr.update(visible=False), gr.update(visible=False)],
        outputs=[confirm_button, cancel_button],
        queue=False,
    )
    confirm_button.click(_delete_user_history).then(
        lambda: [gr.update(visible=False), gr.update(visible=False)],
        outputs=[confirm_button, cancel_button],
        queue=False,
    )

    # Admin section (only shown locally or when logged in as Space owner)
    _admin_section()


def save_image(
    profile: gr.OAuthProfile | None,
    image: Image | np.ndarray | str | Path,
    label: str | None = None,
    metadata: Dict | None = None,
):
    # Ignore images from logged out users
    if profile is None:
        return
    username = profile["preferred_username"]

    # Ignore images if user history not used
    user_history = _UserHistory()
    if not user_history.initialized:
        warnings.warn(
            "User history is not set in Gradio demo. Saving image is ignored. You must use `user_history.render(...)`"
            " first."
        )
        return

    # Copy image to storage
    image_path = _copy_image(image, dst_folder=user_history._user_images_path(username))

    # Save new image + metadata
    if metadata is None:
        metadata = {}
    if "datetime" not in metadata:
        metadata["datetime"] = str(datetime.now())
    data = {"path": str(image_path), "label": label, "metadata": metadata}
    with user_history._user_lock(username):
        with user_history._user_jsonl_path(username).open("a") as f:
            f.write(json.dumps(data) + "\n")


#############
# Internals #
#############


class _UserHistory(object):
    _instance = None
    initialized: bool = False
    folder_path: Path

    def __new__(cls):
        # Using singleton pattern => we don't want to expose an object (more complex to use) but still want to keep
        # state between `render` and `save_image` calls.
        if cls._instance is None:
            cls._instance = super(_UserHistory, cls).__new__(cls)
        return cls._instance

    def _user_path(self, username: str) -> Path:
        path = self.folder_path / username
        path.mkdir(parents=True, exist_ok=True)
        return path

    def _user_lock(self, username: str) -> FileLock:
        """Ensure history is not corrupted if concurrent calls."""
        return FileLock(self.folder_path / f"{username}.lock")  # lock outside of folder => better when exporting ZIP

    def _user_jsonl_path(self, username: str) -> Path:
        return self._user_path(username) / "history.jsonl"

    def _user_images_path(self, username: str) -> Path:
        path = self._user_path(username) / "images"
        path.mkdir(parents=True, exist_ok=True)
        return path


def _fetch_user_history(profile: gr.OAuthProfile | None) -> List[Tuple[str, str]]:
    """Return saved history for that user, if it exists."""
    # Cannot load history for logged out users
    if profile is None:
        return []
    username = profile["preferred_username"]

    user_history = _UserHistory()
    if not user_history.initialized:
        warnings.warn("User history is not set in Gradio demo. You must use `user_history.render(...)` first.")
        return []

    with user_history._user_lock(username):
        # No file => no history saved yet
        jsonl_path = user_history._user_jsonl_path(username)
        if not jsonl_path.is_file():
            return []

        # Read history
        images = []
        for line in jsonl_path.read_text().splitlines():
            data = json.loads(line)
            images.append((data["path"], data["label"] or ""))
        return list(reversed(images))


def _export_user_history(profile: gr.OAuthProfile | None) -> Dict | None:
    """Zip all history for that user, if it exists and return it as a downloadable file."""
    # Cannot load history for logged out users
    if profile is None:
        return None
    username = profile["preferred_username"]

    user_history = _UserHistory()
    if not user_history.initialized:
        warnings.warn("User history is not set in Gradio demo. You must use `user_history.render(...)` first.")
        return None

    # Zip history
    with user_history._user_lock(username):
        path = shutil.make_archive(
            str(_archives_path() / f"history_{username}"), "zip", user_history._user_path(username)
        )

    return gr.update(visible=True, value=path)


def _delete_user_history(profile: gr.OAuthProfile | None) -> None:
    """Delete all history for that user."""
    # Cannot load history for logged out users
    if profile is None:
        return
    username = profile["preferred_username"]

    user_history = _UserHistory()
    if not user_history.initialized:
        warnings.warn("User history is not set in Gradio demo. You must use `user_history.render(...)` first.")
        return

    with user_history._user_lock(username):
        shutil.rmtree(user_history._user_path(username))


####################
# Internal helpers #
####################


def _copy_image(image: Image | np.ndarray | str | Path, dst_folder: Path) -> Path:
    """Copy image to the images folder."""
    # Already a path => copy it
    if isinstance(image, str):
        image = Path(image)
    if isinstance(image, Path):
        dst = dst_folder / f"{uuid4().hex}_{Path(image).name}"  # keep file ext
        shutil.copyfile(image, dst)
        return dst

    # Still a Python object => serialize it
    if isinstance(image, np.ndarray):
        image = Image.fromarray(image)
    if isinstance(image, Image):
        dst = dst_folder / f"{uuid4().hex}.png"
        image.save(dst)
        return dst

    raise ValueError(f"Unsupported image type: {type(image)}")


def _resolve_folder_path(folder_path: str | Path | None) -> Path:
    if folder_path is not None:
        return Path(folder_path).expanduser().resolve()

    if os.getenv("SYSTEM") == "spaces" and os.path.exists("/data"):  # Persistent storage is enabled!
        return Path("/data") / "_user_history"

    # Not in a Space or Persistent storage not enabled => local folder
    return Path(__file__).parent / "_user_history"


def _archives_path() -> Path:
    # Doesn't have to be on persistent storage as it's only used for download
    path = Path(__file__).parent / "_user_history_exports"
    path.mkdir(parents=True, exist_ok=True)
    return path


#################
# Admin section #
#################


def _admin_section() -> None:
    title = gr.Markdown()
    title.attach_load_event(_display_if_admin(), every=None)


def _display_if_admin() -> Callable:
    def _inner(profile: gr.OAuthProfile | None) -> str:
        if profile is None:
            return ""
        if profile["preferred_username"] in _fetch_admins():
            return _admin_content()
        return ""

    return _inner


def _admin_content() -> str:
    return f"""
## Admin section

Running on **{os.getenv("SYSTEM", "local")}** (id: {os.getenv("SPACE_ID")}). {_get_msg_is_persistent_storage_enabled()}

Admins: {', '.join(_fetch_admins())}

{_get_nb_users()} user(s), {_get_nb_images()} image(s)

### Configuration

History folder: *{_UserHistory().folder_path}*

Exports folder: *{_archives_path()}*

### Disk usage

{_disk_space_warning_message()}
"""


def _get_nb_users() -> int:
    user_history = _UserHistory()
    if not user_history.initialized:
        return 0
    if user_history.folder_path is not None:
        return len([path for path in user_history.folder_path.iterdir() if path.is_dir()])
    return 0


def _get_nb_images() -> int:
    user_history = _UserHistory()
    if not user_history.initialized:
        return 0
    if user_history.folder_path is not None:
        return len([path for path in user_history.folder_path.glob("*/images/*")])
    return 0


def _get_msg_is_persistent_storage_enabled() -> str:
    if os.getenv("SYSTEM") == "spaces":
        if os.path.exists("/data"):
            return "Persistent storage is enabled."
        else:
            return (
                "Persistent storage is not enabled. This means that user histories will be deleted when the Space is"
                " restarted. Consider adding a Persistent Storage in your Space settings."
            )
    return ""


def _disk_space_warning_message() -> str:
    user_history = _UserHistory()
    if not user_history.initialized:
        return ""

    message = ""
    if user_history.folder_path is not None:
        total, used, _ = _get_disk_usage(user_history.folder_path)
        message += f"History folder: **{used / 1e9 :.0f}/{total / 1e9 :.0f}GB** used ({100*used/total :.0f}%)."

    total, used, _ = _get_disk_usage(_archives_path())
    message += f"\n\nExports folder: **{used / 1e9 :.0f}/{total / 1e9 :.0f}GB** used ({100*used/total :.0f}%)."

    return f"{message.strip()}"


def _get_disk_usage(path: Path) -> Tuple[int, int, int]:
    for path in [path] + list(path.parents):  # first check target_dir, then each parents one by one
        try:
            return shutil.disk_usage(path)
        except OSError:  # if doesn't exist or can't read => fail silently and try parent one
            pass
    return 0, 0, 0


@cache
def _fetch_admins() -> List[str]:
    # Running locally => fake user is admin
    if os.getenv("SYSTEM") != "spaces":
        return ["FakeGradioUser"]

    # Running in Space but no space_id => ???
    space_id = os.getenv("SPACE_ID")
    if space_id is None:
        return ["Unknown"]

    # Running in Space => try to fetch organization members
    # Otherwise, it's not an organization => namespace is the user
    namespace = space_id.split("/")[0]
    response = requests.get("https://huggingface.co/api/organizations/{namespace}/members")
    if response.status_code == 200:
        return sorted(member["user"] for member in response.json())
    return [namespace]