import io
from datetime import datetime, timedelta

import random
import requests
from pystac_client import Client
import os 

from src.auth.auth import get_direct_access_token
from src.utils.image import extract_url_after_filename

class ProductDownloader:
    """
    Class for downloading products from Copernicus Data Space Ecosystem.
    
    This class provides methods to download products using an S3 client connection,
    either as in-memory content (bytes) or as files saved to disk.
    """
    
    def __init__(self, s3_client, bucket_name='eodata'):
        """
        Initialize the product downloader with an S3 client.
        
        Args:
            s3_client: The boto3 S3 client to use for downloads
            bucket_name (str): The S3 bucket name where products are stored (default: 'eodata')
        """
        
        self.s3_client = s3_client
        self.bucket_name = bucket_name
    
    
    def get_product_content(self, product_path):
        """
        Download a Sentinel-2 product directly from Copernicus Data Space Ecosystem as a bytes object.
        
        Args:
            product_path (str): S3 key or full S3 URI to the product
            
        Returns:
            bytes: The product content as bytes
            str: The filename of the product
        """
        # Extract S3 key if full URI is provided
        
        # Extract the filename from the path
        _, filename = os.path.split(product_path)
        
        # Download the file to a bytes buffer
        try:
            # Create a bytes buffer
            buffer = io.BytesIO()
            
            # Download the file to the buffer using the client
            self.s3_client.download_fileobj(self.bucket_name, product_path, buffer)
            
            # Reset buffer position to the start
            buffer.seek(0)
            
            # Get the bytes
            product_content = buffer.getvalue()
            
            print(f"Successfully downloaded product: {filename}")
            
            # Return both the bytes and the filename
            return product_content, filename
        except Exception as e:
            print(f"Error downloading product: {str(e)}")
            raise
    
    async def download_product(self, product_path, output_filename=None):
        """
        Download a Sentinel-2 product directly from Copernicus Data Space Ecosystem to disk.
        
        Args:
            product_path (str): S3 key or full S3 URI to the product
            output_filename (str, optional): Filename to save the product to.
                                              If None, uses the original filename.
            
        Returns:
            str: Path to the downloaded file
        """
        # Extract S3 key if full URI is provided
        if product_path.startswith('s3://'):
            product_path = self.get_s3_key_from_href(product_path)
        
        # Extract the filename from the path
        _, filename = os.path.split(product_path)
        
        # Use custom filename if provided, otherwise use the original
        if output_filename is None:
            output_filename = filename
        
        # Download the file using the client
        try:
            self.s3_client.download_file(self.bucket_name, product_path, output_filename)
            print(f"Successfully downloaded product {filename} to {output_filename}")
            return output_filename
        except Exception as e:
            print(f"Error downloading product: {str(e)}")
            raise

from src.auth.auth import get_direct_access_token
from src.utils.image import extract_url_after_filename

def download_sentinel_image(username, password, start_date, end_date,
                            bbox=[-180, -90, 180, 90], limit=10):
    """
    Download a random Sentinel-2 image based on criteria.
    
    Args:
        username (str): DESTINE username
        password (str): DESTINE password
        # date_range (str): Date range in format "YYYY-MM-DD/YYYY-MM-DD"
        cloud_cover (int, optional): Maximum cloud cover percentage
        bbox (list): Bounding box coordinates [west, south, east, north]
        limit (int): Maximum number of results to return
        
    Returns:
        tuple: (image_content or error_message, metadata)
    """
    # Get access token
    token_result = get_direct_access_token(username=username, password=password)
    if not token_result:
        return "Failed to authenticate", None

    access_token = token_result["access_token"]

    # Set up STAC API client
    stac_base_url = "https://cachea.destine.eu"
    stac_url = f"{stac_base_url}/stac/api"
    catalog = Client.open(stac_url)
    
    start_date = datetime.strptime(start_date, "%Y-%m-%d")
    end_date = datetime.strptime(end_date, "%Y-%m-%d")
    days_between = (end_date - start_date).days
    random_start_day = random.randint(0, days_between - 7)  # Ensure we have 7 days
    random_start_date = start_date + timedelta(days=random_start_day)
    random_end_date = random_start_date + timedelta(days=1)
    
    # Format dates for the API
    start_date_str = random_start_date.strftime("%Y-%m-%d")
    end_date_str = random_end_date.strftime("%Y-%m-%d")

    # Build search parameters
    search_params = {
        "method": "GET",
        "collections": ["SENTINEL-2"],
        "bbox": bbox,
        "datetime": f"{start_date_str}/{end_date_str}",
        "limit": limit
    }
    

    # Search for Sentinel-2 images
    search = catalog.search(**search_params)
    
    # Get a list of items
    items = list(search.items())
    if not items:
        return "No Sentinel-2 images found", None
    
    # Select a random item
    random_item = random.choice(items)
    
    # Get metadata for the selected item
    metadata = {
        "id": random_item.id,
        "datetime": random_item.datetime.strftime("%Y-%m-%d %H:%M:%S"),
        "bbox": random_item.bbox,
    }
    
    
    # Get the assets of the random item
    assets = random_item.assets
    asset_keys = list(assets.keys())
    
    # Filter the assets to get the one that ends with *_TCI_60m.jp2
    tci_assets = [assets[key].href for key in asset_keys if assets[key].href.endswith('_TCI_60m.jp2')]
    
    if not tci_assets:
        return "No TCI assets found in the selected image", None
    
    filepath = extract_url_after_filename(tci_assets[0])
    metadata["filename"] = os.path.basename(filepath)
    
    # Download the file
    url = f"{stac_base_url}/stac/download?filename={filepath}"
    
    headers = {
        'Authorization': f'Bearer {access_token}'
    }
    
    response = requests.post(url, headers=headers, data={})
    
    if response.status_code == 200:
        return response.content, metadata
    else:
        return f"Failed to download the file. Status code: {response.status_code}", None