"""
Google Cloud Storage utilities for centralized client access and common operations.
"""
from typing import Optional
import asyncio
import os
import uuid
from src.logger_config import logger
from .gcloud_wrapper import get_default_wrapper
from src.file_downloader import get_file_downloader
from src.config import get_config_value

def _upload_to_drive(local_path: str, filename: str = None, account_name: str = "test_data") -> dict:
    """
    Helper to upload file to Google Drive.
    Returns dict with url, file_id, and storage_type.
    
    Args:
        local_path: Path to local file.
        filename: Optional filename to use in Drive (for consistency with GCS).
        account_name: Account to use.
    """
    from .drive_utils import upload_file_to_drive
    drive_result = upload_file_to_drive(local_path, filename=filename, account_name=account_name)
    drive_result["storage_type"] = "drive"
    return drive_result


def get_gcs_client(account_name: str = "final_data"):
    """
    Get a configured GCS client for the specified account.
    Defaults to 'final_data' which is the main account for production.
    Uses cached singleton wrapper - auth happens only once.
    """
    return get_default_wrapper().get_storage_client(account_name)

def get_gcs_credentials(account_name: str = "final_data"):
    """
    Get credentials for the specified account.
    Useful for initializing other clients (like TTS) with the same credentials.
    Uses cached singleton wrapper - auth happens only once.
    """
    return get_default_wrapper()._get_credentials(account_name)

def delete_gcs_file(filename: str, bucket_name: Optional[str] = None, account_name: str = "final_data") -> bool:
    """
    Delete a file from GCS.
    
    Args:
        filename: Name/path of the blob to delete.
        bucket_name: Name of the bucket. If None, tries to infer from filename or env.
        account_name: Account to use (default: final_data).
        
    Returns:
        bool: True if deleted or didn't exist, False if error.
    """
    try:
        client = get_gcs_client(account_name)
        
        # Determine bucket name
        target_bucket = bucket_name
        blob_name = filename
        
        # Handle cases where filename contains full GCS path or URL?
        # Assuming filename is relative path in bucket, but let's check config if bucket_name missing
        # For now, simplest implementation relying on caller providing correct relative path 
        # or checking env if bucket_name is None
        
        if not target_bucket:
            target_bucket = get_config_value("GCS_BUCKET_NAME", "elvoro-assets")

        bucket = client.bucket(target_bucket)
        blob = bucket.blob(blob_name)
        
        if blob.exists():
            blob.delete()
            logger.debug(f"🗑️ Deleted GCS file: gs://{target_bucket}/{blob_name}")
        else:
            logger.debug(f"⚠️ File not found (already deleted?): gs://{target_bucket}/{blob_name}")
            
        return True


    except Exception as e:
        logger.error(f"❌ Failed to delete GCS file {filename}: {e}")
        return False

def upload_file_to_gcs(
    local_path: str,
    folder: str = None,
    destination_blob_name: str = None,
    account_name: str = "final_data",
    bucket_name: str = get_config_value("GCS_BUCKET_NAME"),
    generate_signed_url: bool = True,
    fallback_to_drive: bool = True,
    save_in_drive_also: bool = True,  # Uploads to Shared Drive (service account must be contributor)
) -> dict:
    """
    Upload a local file to GCS.
    
    Args:
        local_path: Path to local file.
        destination_blob_name: Path in the bucket (e.g. 'folder/file.mp4').
        bucket_name: Target bucket name.
        account_name: Account to use.
        generate_signed_url: Whether to generate a signed URL.
        fallback_to_drive: If True, fallback to Google Drive upload on GCS failure.
        
    Returns:
        dict: {
            "gcs_filename": str,
            "url": str (signed or public),
            "public_url": str,
            "storage_type": str ("gcs" or "drive")
        }
    """
    from datetime import timedelta
    
    file_ext = os.path.splitext(local_path)[1].lower()
    
    # Determine folder based on file type
    if folder is None:
        folder = "others"
        if file_ext in [".mp4", ".mov", ".avi", ".mkv"]:
            folder = get_config_value("gcs_bucket_folder_name")
        elif file_ext in [".mp3", ".wav", ".aac", ".m4a"]:
            folder = "audio"
        elif file_ext in [".png", ".jpg", ".jpeg", ".gif", ".webp"]:
            folder = "image"
        
    setup_type = get_config_value("setup_type", "")
    setup_prefix = f"{setup_type}_" if setup_type else ""
    
    if destination_blob_name:
        blob_name = f"{folder}/{destination_blob_name}{file_ext}"
    else:
        blob_name = f"{folder}/{setup_prefix}{uuid.uuid4().hex}{file_ext}"
    
    try:
        client = get_gcs_client(account_name)

        # Lazy bucket creation
        create_bucket_if_not_exists(client, bucket_name)

        bucket = client.bucket(bucket_name)
        blob = bucket.blob(blob_name)
        
        # Check if file exists and retry with unique name if so
        if blob.exists():
            logger.warning(f"⚠️ File already exists in GCS: {blob_name}")
            # Insert a short UUID before extension to make it unique
            unique_suffix = uuid.uuid4().hex[:6]
            if destination_blob_name:
                blob_name = f"{folder}/{destination_blob_name}_{unique_suffix}{file_ext}"
            else:
                # Should rarely happen for UUIDs but good practice
                blob_name = f"{folder}/{setup_prefix}{uuid.uuid4().hex}{file_ext}"
            
            blob = bucket.blob(blob_name)
            logger.debug(f"🔄 Renamed to unique path: {blob_name}")

        # Determine content type
        content_types = {
            ".mp4": "video/mp4",
            ".mp3": "audio/mpeg",
            ".wav": "audio/wav",
            ".png": "image/png",
            ".jpg": "image/jpeg",
            ".jpeg": "image/jpeg",
            ".json": "application/json",
            ".txt": "text/plain",
            ".srt": "text/plain" 
        }
        
        blob.content_type = content_types.get(file_ext, "application/octet-stream")
        
        logger.debug(f"☁️ Uploading {os.path.basename(local_path)} to gs://{bucket_name}/{blob_name}")
        blob.upload_from_filename(local_path)
        
        public_url = f"https://storage.googleapis.com/{bucket_name}/{blob_name}"
        result = {
            "gcs_filename": blob_name,
            "public_url": public_url,
            "url": public_url,
            "storage_type": "gcs"
        }
        
        if generate_signed_url:
            try:
                # Note: signing requires service account credentials with signing capability
                signed_url = blob.generate_signed_url(
                    version="v4", 
                    expiration=timedelta(days=7), 
                    method="GET",
                    service_account_email=client.get_service_account_email()
                )
                logger.debug(f"✅ Signed URL generated")
                result["url"] = signed_url
                result["signed_url"] = signed_url
            except Exception as e:
                logger.warning(f"⚠️ Failed to generate signed URL (using public URL): {e}")
        
        # Also upload to Google Drive if requested
        if save_in_drive_also:
            try:
                drive_result = _upload_to_drive(local_path, filename=blob_name)
                result["drive_url"] = drive_result.get("url")
                result["drive_file_id"] = drive_result.get("file_id")
                logger.debug(f"✅ Also uploaded to Drive: {drive_result.get('url')}")
            except Exception as drive_error:
                logger.warning(f"⚠️ Failed to upload to Drive (GCS upload still successful): {drive_error}")
                
        return result

    except Exception as e:
        logger.error(f"❌ Failed to upload to GCS: {e}")
        
        # Fallback to Google Drive if enabled
        if fallback_to_drive:
            logger.debug("🔄 Falling back to Google Drive upload...")
            try:
                drive_result = _upload_to_drive(local_path, filename=blob_name)
                drive_result["gcs_filename"] = blob_name
                logger.debug(f"✅ Fallback to Drive successful: {drive_result['url']}")
                return drive_result
            except Exception as drive_error:
                logger.error(f"❌ Drive fallback also failed: {drive_error}")
                raise e  # Re-raise original GCS error
        
        # Re-raise to let caller handle critical failure
        raise e

def list_gcs_files(prefix: str = None, account_name: str = "final_data") -> list[str]:
    """
    List all files in the bucket, optionally filtered by prefix.
    Returns files sorted by creation time (newest first).
    """
    try:
        if prefix is None:
            prefix = get_config_value("gcs_bucket_folder_name")

        client = get_gcs_client(account_name)
        bucket_name = get_config_value("GCS_BUCKET_NAME")
        bucket = client.bucket(bucket_name)

        blobs = list(client.list_blobs(bucket, prefix=prefix))
        
        # Sort by creation time (newest first)
        blobs_sorted = sorted(
            blobs,
            key=lambda b: b.time_created,
            reverse=True,
        )
        
        file_names = [blob.name for blob in blobs_sorted]
        logger.debug(f"📂 Found {len(file_names)} files under '{prefix}'.")
        return file_names
        
    except Exception as e:
        logger.error(f"❌ Failed to list files: {e}")
        return []

def create_bucket_if_not_exists(client, bucket_name: str, location: str = "us-central1") -> bool:
    """
    Create a GCS bucket if it doesn't already exist.
    """
    try:
        bucket = client.bucket(bucket_name)
        
        if bucket.exists():
            logger.debug(f"✓ Bucket already exists: gs://{bucket_name}")
            return True
        
        # Bucket doesn't exist, create it
        # We need a project ID for creation.
        project_id = client.project
        if not project_id:
            logger.debug("No project ID found in client, trying to get from env.")
            project_id = os.environ.get("GOOGLE_CLOUD_PROJECT") or os.environ.get("GCP_PROJECT") or os.environ.get("GCP_PROJECT_ID")
        
        if not project_id:
            logger.warning(f"⚠️ Cannot create bucket '{bucket_name}': No project ID found in client or env.")
            return False

        logger.debug(f"📦 Creating new bucket: gs://{bucket_name} in {location} (Project: {project_id})")
        
        # Pass project explicitly if creating
        new_bucket = client.create_bucket(bucket_name, location=location, project=project_id)
        logger.debug(f"✅ Bucket created successfully: gs://{new_bucket.name}")
        return True
        
    except Exception as e:
        logger.error(f"❌ Failed to create bucket {bucket_name}: {e}")
        return False

def find_and_download_gcs_file(tts_script: str, local_dir: str = "/tmp", account_name: str = "final_data") -> Optional[str]:
    """
    Find and download a file from GCS whose name contains part of the TTS script.
    Useful when filenames are generated dynamically based on the script text.
    Replaces APIClients.download_from_gcs.

    Args:
        tts_script: Text content used to search for the file name in GCS
        local_dir: Local directory to save the downloaded file
        account_name: GCS account to use

    Returns:
        Local path to downloaded file, or None on failure.
    """
    try:
        if get_config_value("test_automation"):
            return f"{get_config_value('TEST_DATA_DIRECTORY')}/{uuid.uuid4().hex}.mp4"

        # Prepare a safe pattern to search by
        safe_name_50 = "".join(c for c in tts_script[:50] if c.isalnum())
        safe_name_10 = "".join(c for c in tts_script[:10] if c.isalnum())
        
        all_files = list_gcs_files(prefix="", account_name=account_name)

        # Try to find a matching file name
        blob_name = next((f for f in all_files if tts_script in f), None)
        if not blob_name:
            blob_name = next((f for f in all_files if safe_name_50 in f), None)
        if not blob_name:
            blob_name = next((f for f in all_files if safe_name_10 in f), None)

        if not blob_name:
            logger.error(f"❌ No matching file found in GCS for script: {tts_script[:50]}...")
            return None

        client = get_gcs_client(account_name)
        bucket_name = get_config_value("GCS_BUCKET_NAME")
        
        logger.debug(f"☁️ Found matching file: gs://{bucket_name}/{blob_name}")

        # Use authenticated download via GCloudWrapper
        local_path = os.path.join(local_dir, os.path.basename(blob_name))
        
        try:
            # Download using authenticated GCS client
            bucket = client.bucket(bucket_name)
            blob = bucket.blob(blob_name)
            blob.download_to_filename(local_path)
            
            file_size = os.path.getsize(local_path)
            logger.debug(f"✅ Downloaded {blob_name} → {local_path} ({file_size/1024:.1f} KB)")
            return str(local_path)
        except Exception as download_error:
            logger.error(f"❌ GCS authenticated download failed: {download_error}")
            return None

    except Exception as e:
        logger.error(f"❌ GCS download failed: {e}")
        return None