import os
import shutil
import json
import logging
import re
from abc import ABC, abstractmethod
from typing import BinaryIO, Tuple, Dict

import boto3
from botocore.config import Config
from botocore.exceptions import ClientError
from open_webui.config import (
    S3_ACCESS_KEY_ID,
    S3_BUCKET_NAME,
    S3_ENDPOINT_URL,
    S3_KEY_PREFIX,
    S3_REGION_NAME,
    S3_SECRET_ACCESS_KEY,
    S3_USE_ACCELERATE_ENDPOINT,
    S3_ADDRESSING_STYLE,
    S3_ENABLE_TAGGING,
    GCS_BUCKET_NAME,
    GOOGLE_APPLICATION_CREDENTIALS_JSON,
    AZURE_STORAGE_ENDPOINT,
    AZURE_STORAGE_CONTAINER_NAME,
    AZURE_STORAGE_KEY,
    STORAGE_PROVIDER,
    UPLOAD_DIR,
)
from google.cloud import storage
from google.cloud.exceptions import GoogleCloudError, NotFound
from open_webui.constants import ERROR_MESSAGES
from azure.identity import DefaultAzureCredential
from azure.storage.blob import BlobServiceClient
from azure.core.exceptions import ResourceNotFoundError


log = logging.getLogger(__name__)


class StorageProvider(ABC):
    @abstractmethod
    def get_file(self, file_path: str) -> str:
        pass

    @abstractmethod
    def upload_file(
        self, file: BinaryIO, filename: str, tags: Dict[str, str]
    ) -> Tuple[bytes, str]:
        pass

    @abstractmethod
    def delete_all_files(self) -> None:
        pass

    @abstractmethod
    def delete_file(self, file_path: str) -> None:
        pass


class LocalStorageProvider(StorageProvider):
    @staticmethod
    def upload_file(
        file: BinaryIO, filename: str, tags: Dict[str, str]
    ) -> Tuple[bytes, str]:
        contents = file.read()
        if not contents:
            raise ValueError(ERROR_MESSAGES.EMPTY_CONTENT)
        file_path = f"{UPLOAD_DIR}/{filename}"
        with open(file_path, "wb") as f:
            f.write(contents)
        return contents, file_path

    @staticmethod
    def get_file(file_path: str) -> str:
        """Handles downloading of the file from local storage."""
        return file_path

    @staticmethod
    def delete_file(file_path: str) -> None:
        """Handles deletion of the file from local storage."""
        filename = file_path.split("/")[-1]
        file_path = f"{UPLOAD_DIR}/{filename}"
        if os.path.isfile(file_path):
            os.remove(file_path)
        else:
            log.warning(f"File {file_path} not found in local storage.")

    @staticmethod
    def delete_all_files() -> None:
        """Handles deletion of all files from local storage."""
        if os.path.exists(UPLOAD_DIR):
            for filename in os.listdir(UPLOAD_DIR):
                file_path = os.path.join(UPLOAD_DIR, filename)
                try:
                    if os.path.isfile(file_path) or os.path.islink(file_path):
                        os.unlink(file_path)  # Remove the file or link
                    elif os.path.isdir(file_path):
                        shutil.rmtree(file_path)  # Remove the directory
                except Exception as e:
                    log.exception(f"Failed to delete {file_path}. Reason: {e}")
        else:
            log.warning(f"Directory {UPLOAD_DIR} not found in local storage.")


class S3StorageProvider(StorageProvider):
    def __init__(self):
        config = Config(
            s3={
                "use_accelerate_endpoint": S3_USE_ACCELERATE_ENDPOINT,
                "addressing_style": S3_ADDRESSING_STYLE,
            },
            # KIT change - see https://github.com/boto/boto3/issues/4400#issuecomment-2600742103∆
            request_checksum_calculation="when_required",
            response_checksum_validation="when_required",
        )

        # If access key and secret are provided, use them for authentication
        if S3_ACCESS_KEY_ID and S3_SECRET_ACCESS_KEY:
            self.s3_client = boto3.client(
                "s3",
                region_name=S3_REGION_NAME,
                endpoint_url=S3_ENDPOINT_URL,
                aws_access_key_id=S3_ACCESS_KEY_ID,
                aws_secret_access_key=S3_SECRET_ACCESS_KEY,
                config=config,
            )
        else:
            # If no explicit credentials are provided, fall back to default AWS credentials
            # This supports workload identity (IAM roles for EC2, EKS, etc.)
            self.s3_client = boto3.client(
                "s3",
                region_name=S3_REGION_NAME,
                endpoint_url=S3_ENDPOINT_URL,
                config=config,
            )

        self.bucket_name = S3_BUCKET_NAME
        self.key_prefix = S3_KEY_PREFIX if S3_KEY_PREFIX else ""

    @staticmethod
    def sanitize_tag_value(s: str) -> str:
        """Only include S3 allowed characters."""
        return re.sub(r"[^a-zA-Z0-9 äöüÄÖÜß\+\-=\._:/@]", "", s)

    def upload_file(
        self, file: BinaryIO, filename: str, tags: Dict[str, str]
    ) -> Tuple[bytes, str]:
        """Handles uploading of the file to S3 storage."""
        _, file_path = LocalStorageProvider.upload_file(file, filename, tags)
        s3_key = os.path.join(self.key_prefix, filename)
        try:
            self.s3_client.upload_file(file_path, self.bucket_name, s3_key)
            if S3_ENABLE_TAGGING and tags:
                sanitized_tags = {
                    self.sanitize_tag_value(k): self.sanitize_tag_value(v)
                    for k, v in tags.items()
                }
                tagging = {
                    "TagSet": [
                        {"Key": k, "Value": v} for k, v in sanitized_tags.items()
                    ]
                }
                self.s3_client.put_object_tagging(
                    Bucket=self.bucket_name,
                    Key=s3_key,
                    Tagging=tagging,
                )
            return (
                open(file_path, "rb").read(),
                f"s3://{self.bucket_name}/{s3_key}",
            )
        except ClientError as e:
            raise RuntimeError(f"Error uploading file to S3: {e}")

    def get_file(self, file_path: str) -> str:
        """Handles downloading of the file from S3 storage."""
        try:
            s3_key = self._extract_s3_key(file_path)
            local_file_path = self._get_local_file_path(s3_key)
            self.s3_client.download_file(self.bucket_name, s3_key, local_file_path)
            return local_file_path
        except ClientError as e:
            raise RuntimeError(f"Error downloading file from S3: {e}")

    def delete_file(self, file_path: str) -> None:
        """Handles deletion of the file from S3 storage."""
        try:
            s3_key = self._extract_s3_key(file_path)
            self.s3_client.delete_object(Bucket=self.bucket_name, Key=s3_key)
        except ClientError as e:
            raise RuntimeError(f"Error deleting file from S3: {e}")

        # Always delete from local storage
        LocalStorageProvider.delete_file(file_path)

    def delete_all_files(self) -> None:
        """Handles deletion of all files from S3 storage."""
        try:
            response = self.s3_client.list_objects_v2(Bucket=self.bucket_name)
            if "Contents" in response:
                for content in response["Contents"]:
                    # Skip objects that were not uploaded from open-webui in the first place
                    if not content["Key"].startswith(self.key_prefix):
                        continue

                    self.s3_client.delete_object(
                        Bucket=self.bucket_name, Key=content["Key"]
                    )
        except ClientError as e:
            raise RuntimeError(f"Error deleting all files from S3: {e}")

        # Always delete from local storage
        LocalStorageProvider.delete_all_files()

    # The s3 key is the name assigned to an object. It excludes the bucket name, but includes the internal path and the file name.
    def _extract_s3_key(self, full_file_path: str) -> str:
        return "/".join(full_file_path.split("//")[1].split("/")[1:])

    def _get_local_file_path(self, s3_key: str) -> str:
        return f"{UPLOAD_DIR}/{s3_key.split('/')[-1]}"


class GCSStorageProvider(StorageProvider):
    def __init__(self):
        self.bucket_name = GCS_BUCKET_NAME

        if GOOGLE_APPLICATION_CREDENTIALS_JSON:
            self.gcs_client = storage.Client.from_service_account_info(
                info=json.loads(GOOGLE_APPLICATION_CREDENTIALS_JSON)
            )
        else:
            # if no credentials json is provided, credentials will be picked up from the environment
            # if running on local environment, credentials would be user credentials
            # if running on a Compute Engine instance, credentials would be from Google Metadata server
            self.gcs_client = storage.Client()
        self.bucket = self.gcs_client.bucket(GCS_BUCKET_NAME)

    def upload_file(
        self, file: BinaryIO, filename: str, tags: Dict[str, str]
    ) -> Tuple[bytes, str]:
        """Handles uploading of the file to GCS storage."""
        contents, file_path = LocalStorageProvider.upload_file(file, filename, tags)
        try:
            blob = self.bucket.blob(filename)
            blob.upload_from_filename(file_path)
            return contents, "gs://" + self.bucket_name + "/" + filename
        except GoogleCloudError as e:
            raise RuntimeError(f"Error uploading file to GCS: {e}")

    def get_file(self, file_path: str) -> str:
        """Handles downloading of the file from GCS storage."""
        try:
            filename = file_path.removeprefix("gs://").split("/")[1]
            local_file_path = f"{UPLOAD_DIR}/{filename}"
            blob = self.bucket.get_blob(filename)
            blob.download_to_filename(local_file_path)

            return local_file_path
        except NotFound as e:
            raise RuntimeError(f"Error downloading file from GCS: {e}")

    def delete_file(self, file_path: str) -> None:
        """Handles deletion of the file from GCS storage."""
        try:
            filename = file_path.removeprefix("gs://").split("/")[1]
            blob = self.bucket.get_blob(filename)
            blob.delete()
        except NotFound as e:
            raise RuntimeError(f"Error deleting file from GCS: {e}")

        # Always delete from local storage
        LocalStorageProvider.delete_file(file_path)

    def delete_all_files(self) -> None:
        """Handles deletion of all files from GCS storage."""
        try:
            blobs = self.bucket.list_blobs()

            for blob in blobs:
                blob.delete()

        except NotFound as e:
            raise RuntimeError(f"Error deleting all files from GCS: {e}")

        # Always delete from local storage
        LocalStorageProvider.delete_all_files()


class AzureStorageProvider(StorageProvider):
    def __init__(self):
        self.endpoint = AZURE_STORAGE_ENDPOINT
        self.container_name = AZURE_STORAGE_CONTAINER_NAME
        storage_key = AZURE_STORAGE_KEY

        if storage_key:
            # Configure using the Azure Storage Account Endpoint and Key
            self.blob_service_client = BlobServiceClient(
                account_url=self.endpoint, credential=storage_key
            )
        else:
            # Configure using the Azure Storage Account Endpoint and DefaultAzureCredential
            # If the key is not configured, then the DefaultAzureCredential will be used to support Managed Identity authentication
            self.blob_service_client = BlobServiceClient(
                account_url=self.endpoint, credential=DefaultAzureCredential()
            )
        self.container_client = self.blob_service_client.get_container_client(
            self.container_name
        )

    def upload_file(
        self, file: BinaryIO, filename: str, tags: Dict[str, str]
    ) -> Tuple[bytes, str]:
        """Handles uploading of the file to Azure Blob Storage."""
        contents, file_path = LocalStorageProvider.upload_file(file, filename, tags)
        try:
            blob_client = self.container_client.get_blob_client(filename)
            blob_client.upload_blob(contents, overwrite=True)
            return contents, f"{self.endpoint}/{self.container_name}/{filename}"
        except Exception as e:
            raise RuntimeError(f"Error uploading file to Azure Blob Storage: {e}")

    def get_file(self, file_path: str) -> str:
        """Handles downloading of the file from Azure Blob Storage."""
        try:
            filename = file_path.split("/")[-1]
            local_file_path = f"{UPLOAD_DIR}/{filename}"
            blob_client = self.container_client.get_blob_client(filename)
            with open(local_file_path, "wb") as download_file:
                download_file.write(blob_client.download_blob().readall())
            return local_file_path
        except ResourceNotFoundError as e:
            raise RuntimeError(f"Error downloading file from Azure Blob Storage: {e}")

    def delete_file(self, file_path: str) -> None:
        """Handles deletion of the file from Azure Blob Storage."""
        try:
            filename = file_path.split("/")[-1]
            blob_client = self.container_client.get_blob_client(filename)
            blob_client.delete_blob()
        except ResourceNotFoundError as e:
            raise RuntimeError(f"Error deleting file from Azure Blob Storage: {e}")

        # Always delete from local storage
        LocalStorageProvider.delete_file(file_path)

    def delete_all_files(self) -> None:
        """Handles deletion of all files from Azure Blob Storage."""
        try:
            blobs = self.container_client.list_blobs()
            for blob in blobs:
                self.container_client.delete_blob(blob.name)
        except Exception as e:
            raise RuntimeError(f"Error deleting all files from Azure Blob Storage: {e}")

        # Always delete from local storage
        LocalStorageProvider.delete_all_files()


def get_storage_provider(storage_provider: str):
    if storage_provider == "local":
        Storage = LocalStorageProvider()
    elif storage_provider == "s3":
        Storage = S3StorageProvider()
    elif storage_provider == "gcs":
        Storage = GCSStorageProvider()
    elif storage_provider == "azure":
        Storage = AzureStorageProvider()
    else:
        raise RuntimeError(f"Unsupported storage provider: {storage_provider}")
    return Storage


Storage = get_storage_provider(STORAGE_PROVIDER)
