from typing import Any, Dict, Optional

import aioboto3
from botocore.config import Config
from botocore.exceptions import ClientError

from .base import AsyncReadable, BaseFileSystem


class S3FileSystem(BaseFileSystem):
    """S3 implementation of the filesystem interface."""

    def __init__(
        self,
        bucket_name: str,
        region_name: str = "us-east-1",
        endpoint_url: Optional[str] = None,
        signature_version: Optional[str] = None,
        addressing_style: Optional[str] = None,
    ):
        """Initialize S3 filesystem.

        Args:
            bucket_name: Name of the S3 bucket
            region_name: AWS region name
            endpoint_url: Optional custom S3 endpoint (e.g. for MinIO/rustfs).
                ``None`` uses AWS's default endpoint resolution.
            signature_version: Optional botocore signature version (e.g.
                ``"s3v4"``). ``None`` keeps botocore's default signing behavior.
            addressing_style: Optional S3 addressing style (``"path"`` /
                ``"virtual"`` / ``"auto"``). ``None`` keeps botocore's default.
        """
        self.bucket_name = bucket_name
        self.region_name = region_name
        self.endpoint_url = endpoint_url
        self.session = aioboto3.Session()

        # Build a botocore Config only when an override is requested so that the
        # default behavior is byte-for-byte unchanged when no env vars are set.
        config_kwargs: Dict[str, Any] = {}
        if signature_version:
            config_kwargs["signature_version"] = signature_version
        if addressing_style:
            config_kwargs["s3"] = {"addressing_style": addressing_style}
        self._config = Config(**config_kwargs) if config_kwargs else None

    def _client_kwargs(self) -> Dict[str, Any]:
        """Common kwargs for every ``session.client("s3", ...)`` call.

        Only includes ``endpoint_url`` / ``config`` when configured, so default
        deployments behave exactly as before.
        """
        kwargs: Dict[str, Any] = {"region_name": self.region_name}
        if self.endpoint_url:
            kwargs["endpoint_url"] = self.endpoint_url
        if self._config is not None:
            kwargs["config"] = self._config
        return kwargs

    async def acreate_file(self, file_path: str, content: AsyncReadable) -> bool:
        try:
            async with self.session.client("s3", **self._client_kwargs()) as s3_client:
                await s3_client.put_object(
                    Bucket=self.bucket_name, Key=file_path, Body=await content.read()
                )
            return True
        except ClientError:
            return False

    async def aupload_file(self, local_path: str, destination_path: str) -> bool:
        try:
            async with self.session.client("s3", **self._client_kwargs()) as s3_client:
                await s3_client.upload_file(
                    local_path, self.bucket_name, destination_path
                )
            return True
        except ClientError:
            return False

    async def aget_signed_url(
        self,
        file_path: str,
        expiration: int = 3600,
        force_inline: bool = False,
        use_internal_endpoint: bool = False,
    ) -> Optional[str]:
        """Generate a presigned GET url for the given object.

        For transcript text files we force the response headers so that the
        browser renders the content **inline** instead of triggering a file
        download.  We do this by asking S3 to override the content type &
        disposition on the response.
        """
        try:
            async with self.session.client("s3", **self._client_kwargs()) as s3_client:
                params = {"Bucket": self.bucket_name, "Key": file_path}

                # Make artifacts viewable inline in the browser when requested
                if force_inline:
                    if file_path.endswith(".txt"):
                        params.update(
                            {
                                "ResponseContentType": "text/plain",
                                "ResponseContentDisposition": "inline",
                            }
                        )
                    elif file_path.endswith(".wav"):
                        params.update(
                            {
                                "ResponseContentType": "audio/wav",
                                "ResponseContentDisposition": "inline",
                            }
                        )
                    elif file_path.endswith(".mp3"):
                        params.update(
                            {
                                "ResponseContentType": "audio/mpeg",
                                "ResponseContentDisposition": "inline",
                            }
                        )

                url = await s3_client.generate_presigned_url(
                    "get_object",
                    Params=params,
                    ExpiresIn=expiration,
                )
            return url
        except ClientError:
            return None

    async def aget_file_metadata(self, file_path: str) -> Optional[Dict[str, Any]]:
        """Get S3 object metadata."""
        try:
            async with self.session.client("s3", **self._client_kwargs()) as s3_client:
                response = await s3_client.head_object(
                    Bucket=self.bucket_name, Key=file_path
                )
                return {
                    "size": response.get("ContentLength"),
                    "created_at": response.get("LastModified"),
                    "modified_at": response.get("LastModified"),
                    "etag": response.get("ETag", "").strip('"'),
                    "content_type": response.get("ContentType"),
                    "storage_class": response.get("StorageClass"),
                }
        except ClientError:
            return None

    async def aget_presigned_put_url(
        self,
        file_path: str,
        expiration: int = 900,
        content_type: str = "text/csv",
        max_size: int = 10_485_760,
    ) -> Optional[str]:
        """Generate a presigned PUT URL for direct file upload."""
        try:
            async with self.session.client("s3", **self._client_kwargs()) as s3_client:
                url = await s3_client.generate_presigned_url(
                    "put_object",
                    Params={
                        "Bucket": self.bucket_name,
                        "Key": file_path,
                        "ContentType": content_type,
                    },
                    ExpiresIn=expiration,
                )
            return url
        except ClientError:
            return None

    async def adownload_file(self, source_path: str, local_path: str) -> bool:
        """Download a file from S3 to local path."""
        try:
            async with self.session.client("s3", **self._client_kwargs()) as s3_client:
                await s3_client.download_file(self.bucket_name, source_path, local_path)
            return True
        except ClientError:
            return False

    async def acopy_file(self, source_path: str, destination_path: str) -> bool:
        """Copy a file within S3 (server-side copy)."""
        try:
            async with self.session.client("s3", **self._client_kwargs()) as s3_client:
                await s3_client.copy_object(
                    Bucket=self.bucket_name,
                    Key=destination_path,
                    CopySource={"Bucket": self.bucket_name, "Key": source_path},
                )
            return True
        except ClientError:
            return False