utils/api_clients.py

"""
utils/api_clients.py
------------------------------------------------
Enhanced API clients for:
- PubMed (NCBI)
- ClinicalTrials.gov
- FDA Open Data
- WHO ICTRP
------------------------------------------------
Optimized for hybrid VAN-based query processing:
- Automatically truncates long queries (top keywords only)
- Resilient to API downtime or malformed responses
- HTML formatted results for Gradio rendering
"""

import requests
import html
import re
import traceback

# ============================================================
# 🔹 Query Normalization
# ============================================================
def _normalize_query(query: str, max_words: int = 5) -> str:
    """
    Cleans and shortens user query for API compatibility.
    Removes filler phrases and limits to key words.
    """
    q = query.lower()
    q = re.sub(
        r"(what is|define|explain|describe|in clinical trials|the meaning of|tell me about|explanation of|concept of)\b",
        "",
        q,
    )
    q = re.sub(r"[^a-z0-9\s]", "", q)
    q = re.sub(r"\s+", " ", q).strip()

    # limit to first few words (avoid 404s from overlong queries)
    words = q.split()
    q = " ".join(words[:max_words])
    return q or "clinical trial"

# ============================================================
# 🔹 PubMed API (NCBI E-Utilities)
# ============================================================
def fetch_pubmed(query: str, limit: int = 3) -> str:
    try:
        q = _normalize_query(query)
        base = "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/"
        esearch = f"{base}esearch.fcgi?db=pubmed&term={q}&retmax={limit}&retmode=json"
        res = requests.get(esearch, timeout=10)
        res.raise_for_status()

        ids = res.json().get("esearchresult", {}).get("idlist", [])
        if not ids:
            return f"<i>No PubMed results found for <b>{html.escape(q)}</b>.</i>"

        summaries = []
        for pmid in ids:
            summary_url = f"{base}esummary.fcgi?db=pubmed&id={pmid}&retmode=json"
            sres = requests.get(summary_url, timeout=10)
            sres.raise_for_status()
            doc = sres.json()["result"].get(pmid, {})
            title = html.escape(doc.get("title", "Untitled"))
            source = html.escape(doc.get("source", ""))
            pubdate = html.escape(doc.get("pubdate", ""))
            link = f"https://pubmed.ncbi.nlm.nih.gov/{pmid}/"
            summaries.append(
                f"<b>{title}</b><br>{source} ({pubdate})<br>"
                f"<a href='{link}' target='_blank'>[PubMed]</a>"
            )

        return "<br><br>".join(summaries)

    except Exception as e:
        traceback.print_exc()
        return f"<i>PubMed fetch failed for <b>{html.escape(query)}</b>: {e}</i>"

# ============================================================
# 🔹 ClinicalTrials.gov API
# ============================================================
def fetch_clinicaltrials(query: str, limit: int = 3) -> str:
    """
    Retrieves brief summaries of matching trials from ClinicalTrials.gov.
    Automatically truncates query to avoid 404s on long input.
    """
    try:
        q = _normalize_query(query)
        url = (
            f"https://clinicaltrials.gov/api/query/study_fields?"
            f"expr={q}&fields=NCTId,BriefTitle,Condition,OverallStatus"
            f"&max_rnk={limit}&fmt=json"
        )
        res = requests.get(url, timeout=10)
        res.raise_for_status()

        studies = res.json().get("StudyFieldsResponse", {}).get("StudyFields", [])
        if not studies:
            return f"<i>No trials found for <b>{html.escape(q)}</b>.</i>"

        formatted = []
        for s in studies:
            nct = s.get("NCTId", [""])[0]
            title = html.escape(s.get("BriefTitle", [""])[0])
            condition = html.escape(", ".join(s.get("Condition", [])))
            status = html.escape(s.get("OverallStatus", ["Unknown"])[0])
            link = f"https://clinicaltrials.gov/study/{nct}" if nct else "#"
            formatted.append(
                f"<b>{title}</b><br>"
                f"Condition: {condition or 'N/A'}<br>"
                f"Status: {status}<br>"
                f"<a href='{link}' target='_blank'>[ClinicalTrials.gov]</a>"
            )

        return "<br><br>".join(formatted)

    except Exception as e:
        traceback.print_exc()
        return f"<i>ClinicalTrials.gov fetch failed for <b>{html.escape(query)}</b>: {e}</i>"

# ============================================================
# 🔹 FDA Open Data API
# ============================================================
def fetch_fda(query: str, limit: int = 3) -> str:
    """
    Retrieves FDA label and safety data for a given compound/drug name.
    """
    try:
        q = _normalize_query(query)
        url = f"https://api.fda.gov/drug/label.json?search=openfda.brand_name:{q}&limit={limit}"
        res = requests.get(url, timeout=10)

        if res.status_code == 404:
            return f"<i>No FDA data found for <b>{html.escape(q)}</b>.</i>"

        res.raise_for_status()
        data = res.json().get("results", [])
        if not data:
            return f"<i>No FDA label results found for <b>{html.escape(q)}</b>.</i>"

        formatted = []
        for entry in data:
            brand = ", ".join(entry.get("openfda", {}).get("brand_name", []))
            generic = ", ".join(entry.get("openfda", {}).get("generic_name", []))
            purpose = html.escape(" ".join(entry.get("purpose", [])[:1]))
            warnings = html.escape(" ".join(entry.get("warnings", [])[:1]))
            link = "https://open.fda.gov/drug/label/"
            formatted.append(
                f"<b>{brand or q}</b> ({generic or 'N/A'})<br>"
                f"<u>Purpose:</u> {purpose or 'N/A'}<br>"
                f"<u>Warning:</u> {warnings or 'N/A'}<br>"
                f"<a href='{link}' target='_blank'>[FDA Label]</a>"
            )

        return "<br><br>".join(formatted)

    except Exception as e:
        traceback.print_exc()
        return f"<i>FDA fetch failed for <b>{html.escape(query)}</b>: {e}</i>"

# ============================================================
# 🔹 WHO ICTRP (Backup Trial Source)
# ============================================================
def fetch_who_trials(query: str, limit: int = 2) -> str:
    """
    Optional backup trial search from WHO ICTRP API.
    Returns simplified summaries for readability.
    """
    try:
        q = _normalize_query(query)
        url = f"https://trialsearch.who.int/api/TrialSearch?query={q}"
        res = requests.get(url, timeout=10)

        if res.status_code != 200:
            return "<i>WHO ICTRP API unavailable or throttled.</i>"

        trials = res.json().get("TrialSearchResult", [])
        if not trials:
            return f"<i>No WHO trials found for <b>{html.escape(q)}</b>.</i>"

        formatted = []
        for t in trials[:limit]:
            title = html.escape(t.get("Scientific_title", "Untitled"))
            registry = html.escape(t.get("Register", ""))
            country = html.escape(t.get("Recruitment_Country", ""))
            formatted.append(
                f"<b>{title}</b><br>{registry or 'Registry Unknown'} — {country or 'N/A'}"
            )

        return "<br><br>".join(formatted)

    except Exception as e:
        traceback.print_exc()
        return f"<i>WHO ICTRP fetch failed for <b>{html.escape(query)}</b>: {e}</i>"