"""

- handle_found_object: Called when an object is successfully found and downloaded. Here,
    the object has the same sha256 as the one that was downloaded with Objaverse-XL. If
    not specified, the object will be downloaded, but nothing will be done with it.

    Args:
        file (str): Local path to the downloaded 3D object.
        github_url (str): GitHub URL of the 3D object.
        sha256 (str): SHA256 of the contents of the 3D object.
        repo (str): Name of the GitHub repo where the 3D object comes from.
        organization (str): Name of the GitHub organization where the 3D object comes from.
    Returns: Any

- handle_new_object: Called when a new object is found. Here, the object is not used in
    Objaverse-XL, but is still downloaded with the repository. The object may have not
    been used because it does not successfully import into Blender. If not specified,
    the object will be downloaded, but nothing will be done with it.

    Args:
        file (str): Local path to the downloaded 3D object.
        github_url (str): GitHub URL of the 3D object.
        sha256 (str): SHA256 of the contents of the 3D object.
        repo (str): Name of the GitHub repo where the 3D object comes from.
        organization (str): Name of the GitHub organization where the 3D object comes from.
    Returns: Any

- handle_modified_object: Called when a modified object is found and downloaded. Here,
    the object is successfully downloaded, but it has a different sha256 than the one
    that was downloaded with Objaverse-XL. This is not expected to happen very often,
    because the same commit hash is used for each repo. If not specified, the object
    will be downloaded, but nothing will be done with it.

    Args:
        file (str): Local path to the downloaded 3D object.
        github_url (str): GitHub URL of the 3D object.
        sha256 (str): SHA256 of the contents of the 3D object.
        repo (str): Name of the GitHub repo where the 3D object comes from.
        organization (str): Name of the GitHub organization where the 3D object comes from.
    Returns: Any

- handle_missing_object: Called when an object that is in Objaverse-XL is not found.
    Here, it is likely that the repository was deleted or renamed. If not specified, the
    object will be downloaded, but nothing will be done with it.

    Args:
        github_url (str): GitHub URL of the 3D object.
        sha256 (str): SHA256 of the contents of the original 3D object.
        repo (str): Name of the GitHub repo where the 3D object comes from.
        organization (str): Name of the GitHub organization where the 3D object comes from.
    Returns: Any


Note: You'll likely find more objects by 

"""

import hashlib
import json
import multiprocessing
import os
import shutil
import subprocess
import tarfile
import tempfile
from multiprocessing import Pool
from typing import Callable, Dict, List, Literal, Optional

import fsspec
import pandas as pd
import requests
from loguru import logger
from tqdm import tqdm

FILE_EXTENSIONS = [
    ".obj",
    ".glb",
    ".gltf",
    ".usdz",
    ".usd",
    ".fbx",
    ".stl",
    ".usda",
    ".dae",
    ".ply",
    ".abc",
    ".blend",
]


def load_github_metadata(download_dir: str = "~/.objaverse") -> pd.DataFrame:
    """Loads the GitHub 3D object metadata as a Pandas DataFrame.

    Args:
        download_dir (str, optional): Directory to download the parquet metadata file.
            Supports all file systems supported by fsspec. Defaults to "~/.objaverse".

    Returns:
        pd.DataFrame: GitHub 3D object metadata as a Pandas DataFrame with columns for
            the object "githubUrl", "license", and "sha256".
    """
    filename = os.path.join(download_dir, "github", "github-urls.parquet")
    fs, path = fsspec.core.url_to_fs(filename)
    fs.makedirs(os.path.dirname(path), exist_ok=True)

    # download the parquet file if it doesn't exist
    if not fs.exists(path):
        url = "https://huggingface.co/datasets/allenai/objaverse-xl/resolve/main/github/github-urls.parquet"

        response = requests.get(url)
        response.raise_for_status()
        with fs.open(path, "wb") as file:
            file.write(response.content)

    # load the parquet file with fsspec
    with fs.open(path) as f:
        df = pd.read_parquet(f)

    return df


def _get_repo_id_with_hash(item: pd.Series) -> str:
    org, repo = item["githubUrl"].split("/")[3:5]
    commit_hash = item["githubUrl"].split("/")[6]
    return f"{org}/{repo}/{commit_hash}"


def _git_shallow_clone(repo_url: str, target_directory: str) -> bool:
    return _run_command_with_check(
        ["git", "clone", "--depth", "1", repo_url, target_directory],
    )


def _run_command_with_check(command: List[str], cwd: Optional[str] = None) -> bool:
    try:
        subprocess.run(
            command,
            cwd=cwd,
            check=True,
            stdout=subprocess.DEVNULL,
            stderr=subprocess.DEVNULL,
        )
        return True
    except subprocess.CalledProcessError as e:
        logger.error("Error:", e)
        logger.error(e.stdout)
        logger.error(e.stderr)
        return False


def get_file_hash(file_path: str) -> str:
    # Check if the path is a symbolic link
    if os.path.islink(file_path):
        # Resolve the symbolic link
        resolved_path = os.readlink(file_path)
        # Check if the resolved path exists
        if not os.path.exists(resolved_path):
            raise FileNotFoundError(
                f"The symbolic link points to a file that doesn't exist: {resolved_path}"
            )
    sha256 = hashlib.sha256()
    # Read the file from the path
    with open(file_path, "rb") as f:
        # Loop till the end of the file
        for byte_block in iter(lambda: f.read(4096), b""):
            sha256.update(byte_block)
    return sha256.hexdigest()


def _process_repo(
    repo_id: str,
    fs: fsspec.AbstractFileSystem,
    base_dir: str,
    save_repo_format: Optional[Literal["zip", "tar", "tar.gz", "files"]],
    expected_objects: Dict[str, str],
    handle_found_object: Optional[Callable],
    handle_modified_object: Optional[Callable],
    handle_missing_object: Optional[Callable],
    handle_new_object: Optional[Callable],
    commit_hash: Optional[str],
) -> List[Dict[str, str]]:
    """

    Args:
        expected_objects (Dict[str, str]): Dictionary of objects that one expects to
            find in the repo. Keys are the GitHub URLs and values are the sha256 of the
            objects.
    """
    # NOTE: assuming that the user has already checked that the repo doesn't exist,
    org, repo = repo_id.split("/")

    with tempfile.TemporaryDirectory() as temp_dir:
        # clone the repo to a temp directory
        target_directory = os.path.join(temp_dir, repo)
        successful_clone = _git_shallow_clone(
            f"https://github.com/{org}/{repo}.git", target_directory
        )
        if not successful_clone:
            logger.error(f"Could not clone {repo_id}")
            if handle_missing_object is not None:
                for github_url, sha256 in expected_objects.items():
                    handle_missing_object(
                        github_url=github_url,
                        sha256=sha256,
                        repo=repo,
                        organization=org,
                    )
            return []

        # use the commit hash if specified
        repo_commit_hash = _get_commit_hash_from_local_git_dir(target_directory)
        if commit_hash is not None:
            keep_going = True
            if repo_commit_hash != commit_hash:
                # run git reset --hard && git checkout 37f4d8d287e201ce52c048bf74d46d6a09d26b2c
                if not _run_command_with_check(
                    ["git", "fetch", "origin", commit_hash], target_directory
                ):
                    logger.error(
                        f"Error in git fetch! Sticking with {repo_commit_hash=} instead of {commit_hash=}"
                    )
                    keep_going = False

                if keep_going and not _run_command_with_check(
                    ["git", "reset", "--hard"], target_directory
                ):
                    logger.error(
                        f"Error in git reset! Sticking with {repo_commit_hash=} instead of {commit_hash=}"
                    )
                    keep_going = False

                if keep_going:
                    if _run_command_with_check(
                        ["git", "checkout", commit_hash], target_directory
                    ):
                        repo_commit_hash = commit_hash
                    else:
                        logger.error(
                            f"Error in git checkout! Sticking with {repo_commit_hash=} instead of {commit_hash=}"
                        )

        # pull the lfs files
        _pull_lfs_files(target_directory)

        # get all the files in the repo
        files = _list_files(target_directory)
        files_with_3d_extension = [
            file
            for file in files
            if any(file.lower().endswith(ext) for ext in FILE_EXTENSIONS)
        ]

        # get the sha256 for each file
        file_hashes = []
        for file in files_with_3d_extension:
            file_hash = get_file_hash(file)
            # remove the temp_dir from the file path
            github_url = file.replace(
                target_directory,
                f"https://github.com/{org}/{repo}/blob/{repo_commit_hash}",
            )
            file_hashes.append(dict(sha256=file_hash, githubUrl=github_url))

            # handle the object under different conditions
            if github_url in expected_objects:
                if expected_objects[github_url] == file_hash:
                    if handle_found_object is not None:
                        handle_found_object(
                            file=file,
                            github_url=github_url,
                            sha256=file_hash,
                            repo=repo,
                            organization=org,
                        )
                else:
                    if handle_modified_object is not None:
                        handle_modified_object(
                            file=file,
                            github_url=github_url,
                            sha256=file_hash,
                            repo=repo,
                            organization=org,
                        )
            elif handle_new_object is not None:
                handle_new_object(
                    file=file,
                    github_url=github_url,
                    sha256=file_hash,
                    repo=repo,
                    organization=org,
                )

        # save the file hashes to a json file
        with open(
            os.path.join(target_directory, ".objaverse-file-hashes.json"), "w"
        ) as f:
            json.dump(file_hashes, f, indent=2)

        # remove the .git directory
        shutil.rmtree(os.path.join(target_directory, ".git"))

        if save_repo_format is not None:
            logger.debug(f"Saving as {save_repo_format}")
            # save the repo to a zip file
            if save_repo_format == "zip":
                shutil.make_archive(target_directory, "zip", target_directory)
            elif save_repo_format == "tar":
                with tarfile.open(os.path.join(temp_dir, f"{repo}.tar"), "w") as tar:
                    tar.add(target_directory, arcname=repo)
            elif save_repo_format == "tar.gz":
                with tarfile.open(
                    os.path.join(temp_dir, f"{repo}.tar.gz"), "w:gz"
                ) as tar:
                    tar.add(target_directory, arcname=repo)
            elif save_repo_format == "files":
                pass
            else:
                raise ValueError(
                    f"save_repo_format must be one of zip, tar, tar.gz, files. Got {save_repo_format}"
                )

            dirname = os.path.join(base_dir, "repos", org)
            fs.makedirs(dirname, exist_ok=True)
            if save_repo_format != "files":
                # move the repo to the correct location (with put)
                fs.put(
                    os.path.join(temp_dir, f"{repo}.{save_repo_format}"),
                    os.path.join(dirname, f"{repo}.{save_repo_format}"),
                )
            else:
                # move the repo to the correct location (with put)
                fs.put(target_directory, dirname, recursive=True)

    # get each object that was missing from the expected objects
    if handle_missing_object is not None:
        obtained_urls = {x["githubUrl"] for x in file_hashes}
        for github_url, sha256 in expected_objects.items():
            if github_url not in obtained_urls:
                handle_missing_object(
                    github_url=github_url,
                    sha256=sha256,
                    repo=repo,
                    organization=org,
                )

    return file_hashes


def _list_files(root_dir: str) -> List[str]:
    return [
        os.path.join(root, f) for root, dirs, files in os.walk(root_dir) for f in files
    ]


def _pull_lfs_files(repo_dir: str) -> None:
    if _has_lfs_files(repo_dir):
        subprocess.run(["git", "lfs", "pull"], cwd=repo_dir)


def _has_lfs_files(repo_dir: str) -> bool:
    gitattributes_path = os.path.join(repo_dir, ".gitattributes")
    if not os.path.exists(gitattributes_path):
        return False
    with open(gitattributes_path, "r") as f:
        for line in f:
            if "filter=lfs" in line:
                return True
    return False


def _get_commit_hash_from_local_git_dir(local_git_dir: str) -> str:
    # get the git hash of the repo
    result = subprocess.run(
        ["git", "rev-parse", "HEAD"], cwd=local_git_dir, capture_output=True
    )
    commit_hash = result.stdout.strip().decode("utf-8")
    return commit_hash


def _parallel_process_repo(args) -> List[Dict[str, str]]:
    (
        repo_id_hash,
        fs,
        base_dir,
        save_repo_format,
        expected_objects,
        handle_found_object,
        handle_modified_object,
        handle_missing_object,
        handle_new_object,
    ) = args
    repo_id = "/".join(repo_id_hash.split("/")[:2])
    commit_hash = repo_id_hash.split("/")[2]
    return _process_repo(
        repo_id=repo_id,
        fs=fs,
        base_dir=base_dir,
        save_repo_format=save_repo_format,
        expected_objects=expected_objects,
        handle_found_object=handle_found_object,
        handle_modified_object=handle_modified_object,
        handle_missing_object=handle_missing_object,
        handle_new_object=handle_new_object,
        commit_hash=commit_hash,
    )


def _process_group(group):
    key, group_df = group
    return key, group_df.set_index("githubUrl")["sha256"].to_dict()


def download_github_objects(
    objects: pd.DataFrame,
    processes: Optional[int] = None,
    download_dir: str = "~/.objaverse",
    save_repo_format: Optional[Literal["zip", "tar", "tar.gz", "files"]] = None,
    handle_found_object: Optional[Callable] = None,
    handle_modified_object: Optional[Callable] = None,
    handle_missing_object: Optional[Callable] = None,
    handle_new_object: Optional[Callable] = None,
) -> List[Dict[str, str]]:
    """Download the specified GitHub objects.

    Args:
        objects (pd.DataFrmae): GitHub objects to download. Must have columns for the
            object "githubUrl" and "sha256". Use the load_github_metadata function to
            get the metadata.
        processes (Optional[int], optional): Number of processes to use for downloading.
            If None, will use the number of CPUs on the machine. Defaults to None.
        download_dir (str, optional): Directory to download the GitHub objects to.
            Supports all file systems supported by fsspec. Defaults to "~/.objaverse".

    Returns:
        List[Dict[str, str]]: List of dictionaries with the keys "githubUrl" and
            "sha256" for each downloaded object.
    """
    if processes is None:
        processes = multiprocessing.cpu_count()

    base_download_dir = os.path.join(download_dir, "github")
    fs, path = fsspec.core.url_to_fs(base_download_dir)
    fs.makedirs(path, exist_ok=True)

    # Getting immediate subdirectories of root_path
    if save_repo_format == "files":
        downloaded_repo_dirs = fs.glob(base_download_dir + "/repos/*/*/")
        downloaded_repo_ids = set(
            ["/".join(x.split("/")[-2:]) for x in downloaded_repo_dirs]
        )
    else:
        downloaded_repo_dirs = fs.glob(
            base_download_dir + f"/repos/*/*.{save_repo_format}"
        )
        downloaded_repo_ids = set()
        for x in downloaded_repo_dirs:
            org, repo = x.split("/")[-2:]
            repo = repo[: -len(f".{save_repo_format}")]
            repo_id = f"{org}/{repo}"
            downloaded_repo_ids.add(repo_id)

    # make copy of objects
    objects = objects.copy()

    # get the unique repoIds
    objects["repoIdHash"] = objects.apply(_get_repo_id_with_hash, axis=1)
    repo_id_hashes = set(objects["repoIdHash"].unique().tolist())
    repo_ids = set(
        ["/".join(repo_id_hash.split("/")[:2]) for repo_id_hash in repo_id_hashes]
    )
    assert len(repo_id_hashes) == len(repo_ids), (
        f"More than 1 commit hash per repoId!"
        f" {len(repo_id_hashes)=}, {len(repo_ids)=}"
    )

    logger.info(
        f"Provided {len(repo_ids)} repoIds with {len(objects)} objects to process."
    )

    # remove repoIds that have already been downloaded
    repo_ids_to_download = repo_ids - downloaded_repo_ids
    repo_id_hashes_to_download = [
        repo_id_hash
        for repo_id_hash in repo_id_hashes
        if "/".join(repo_id_hash.split("/")[:2]) in repo_ids_to_download
    ]

    logger.info(
        f"Found {len(repo_ids_to_download)} not yet downloaded. Downloading now..."
    )

    # get the objects to download
    groups = list(objects.groupby("repoIdHash"))
    with Pool(processes=processes) as pool:
        out_list = list(
            tqdm(
                pool.imap_unordered(_process_group, groups),
                total=len(groups),
                desc="Grouping objects by repository",
            )
        )
    objects_per_repo_id_hash = dict(out_list)

    all_args = [
        (
            repo_id_hash,
            fs,
            path,
            save_repo_format,
            objects_per_repo_id_hash[repo_id_hash],
            handle_found_object,
            handle_missing_object,
            handle_modified_object,
            handle_new_object,
        )
        for repo_id_hash in repo_id_hashes_to_download
    ]

    with Pool(processes=processes) as pool:
        # use tqdm to show progress
        out = list(
            tqdm(
                pool.imap_unordered(_parallel_process_repo, all_args),
                total=len(all_args),
            )
        )
    out_list = [item for sublist in out for item in sublist]
    return out_list