# mcp/clinicaltrials.py
import httpx, random

V2_URL = "https://clinicaltrials.gov/api/v2/studies"
V1_URL = "https://clinicaltrials.gov/api/query/study_fields"
UA_LIST = [
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64)…Chrome/125…",
    "Mozilla/5.0 (Macintosh)…Safari/605…",
    "Mozilla/5.0 (X11)…Firefox/126…"
]

async def search_trials(term: str, max_studies: int = 20) -> list[dict]:
    ua = random.choice(UA_LIST)
    try:
        async with httpx.AsyncClient(headers={"User-Agent": ua}, timeout=12) as c:
            r = await c.get(V2_URL, params={"query": term, "pageSize": max_studies})
            if r.status_code == 200:
                return r.json().get("studies", [])
            raise httpx.HTTPStatusError("v2 failed", request=r.request, response=r)
    except Exception:
        params = {
            "expr": term,
            "fields": "NCTId,BriefTitle,Phase,OverallStatus,StartDate",
            "max_rnk": max_studies,
            "min_rnk": 1,
            "fmt": "json"
        }
        async with httpx.AsyncClient(headers={"User-Agent": ua}, timeout=12) as c:
            r = await c.get(V1_URL, params=params)
            r.raise_for_status()
            return r.json().get("StudyFieldsResponse", {}).get("StudyFields", [])