# api_clients/clinicaltrials_client.py
"""
Client for the ClinicalTrials.gov API (Version 2).
This client is optimized to find active, recruiting studies for a given condition,
which is the most relevant information for patients and caregivers.
"""
import aiohttp
from urllib.parse import quote_plus
from .config import CLINICALTRIALS_BASE_URL, REQUEST_HEADERS

async def find_trials(session: aiohttp.ClientSession, condition_query: str, max_results: int = 5) -> list[dict]:
    """
    Searches ClinicalTrials.gov for active, recruiting studies related to a condition.

    Args:
        session (aiohttp.ClientSession): The active HTTP session.
        condition_query (str): The medical condition to search for (e.g., "Type 2 Diabetes").
        max_results (int): The maximum number of trial results to return.

    Returns:
        list[dict]: A list of dictionaries, where each dictionary represents a clinical trial.
                    Returns an empty list if no trials are found or an error occurs.
    """
    if not condition_query:
        return []

    # The API is powerful. We will specifically query for trials that are currently recruiting,
    # as this is the most actionable information for a user.
    # The `quote_plus` function ensures the query is safely encoded for the URL.
    formatted_query = quote_plus(condition_query)
    
    # Construct the query parameters
    params = {
        'query.term': formatted_query,
        'filter.overallStatus': 'RECRUITING',  # The "wow" factor: finding ACTIONABLE trials
        'pageSize': max_results,
        'format': 'json'
    }

    url = f"{CLINICALTRIALS_BASE_URL}/studies"

    try:
        async with session.get(url, params=params, headers=REQUEST_HEADERS, timeout=15) as resp:
            # Raise an exception for bad status codes (4xx or 5xx)
            resp.raise_for_status()
            data = await resp.json()

            studies_list = data.get('studies', [])
            if not studies_list:
                return []

            # Parse the complex response into a simple, clean list of dictionaries
            parsed_trials = []
            for study in studies_list:
                # Use nested .get() calls to safely access potentially missing keys
                protocol = study.get('protocolSection', {})
                id_module = protocol.get('identificationModule', {})
                status_module = protocol.get('statusModule', {})
                
                nct_id = id_module.get('nctId', '')
                if not nct_id:
                    continue  # Skip if the trial has no ID

                parsed_trials.append({
                    "title": id_module.get('briefTitle', 'Title Not Available'),
                    "nct_id": nct_id,
                    "status": status_module.get('overallStatus', 'Status Unknown'),
                    "url": f"https://clinicaltrials.gov/study/{nct_id}",
                    "condition": ", ".join(protocol.get('conditionsModule', {}).get('conditions', ['N/A'])),
                    "intervention": ", ".join(i.get('name', 'N/A') for i in protocol.get('armsAndInterventionsModule', {}).get('interventions', []))
                })
            
            return parsed_trials

    except aiohttp.ClientError as e:
        print(f"An error occurred while fetching data from ClinicalTrials.gov: {e}")
        return []
    except Exception as e:
        print(f"A general error occurred in the clinicaltrials_client: {e}")
        return []