src/streamlit_app.py

import os
os.environ["HOME"] = "/tmp"  # ✅ Fix streamlit write permission on Hugging Face

import streamlit as st
import requests
import urllib.parse

st.set_page_config(page_title="WikiTrail", layout="wide")

st.title("📚 WikiTrail")
st.markdown("Explore Wikipedia topics visually and get a summarized journey.")

# 🌐 Language options
languages = {
    "English": "en",
    "Hindi (हिन्दी)": "hi",
    "Telugu (తెలుగు)": "te",
    "Tamil (தமிழ்)": "ta"
}
lang_name = st.selectbox("🌐 Select Language", list(languages.keys()))
lang_code = languages[lang_name]

# 🔍 Topic input
topic_input = st.text_input("🔍 Enter a topic (in English)", placeholder="e.g., India, Telangana, Gandhi")
topic_input = topic_input.strip()

# 🔧 Get title (fallbacks if search fails)
def get_translated_title(query, lang):
    try:
        search_url = f"https://{lang}.wikipedia.org/w/api.php"
        params = {
            "action": "query",
            "list": "search",
            "srsearch": query,
            "format": "json",
            "origin": "*"
        }
        res = requests.get(search_url, params=params)
        res.raise_for_status()
        data = res.json()
        results = data.get("query", {}).get("search", [])
        if results:
            return results[0]["title"]
        return query
    except:
        return query

# 🔍 Summary fetch
def fetch_summary(title, lang):
    title_encoded = urllib.parse.quote(title.replace(" ", "_"))
    url = f"https://{lang}.wikipedia.org/api/rest_v1/page/summary/{title_encoded}"
    res = requests.get(url)
    if res.status_code == 200:
        data = res.json()
        return {
            "title": data.get("title", ""),
            "summary": data.get("extract", ""),
            "link": data.get("content_urls", {}).get("desktop", {}).get("page")
        }
    return None

# 🔗 Related links
def fetch_related(title, lang):
    title_encoded = urllib.parse.quote(title.replace(" ", "_"))
    url = f"https://{lang}.wikipedia.org/w/api.php?action=query&format=json&origin=*&titles={title_encoded}&prop=links&pllimit=5"
    res = requests.get(url)
    if res.status_code == 200:
        data = res.json()
        pages = list(data["query"]["pages"].values())
        if pages and "links" in pages[0]:
            return [link["title"] for link in pages[0]["links"]]
    return []

# 🧠 Bullet summary
def summarize_bullets(summaries, limit=3):
    full = ' '.join(set(summaries))
    sentences = full.replace("।", ".").replace("!", ".").replace("?", ".").split(".")
    clean = [s.strip() for s in sentences if s.strip()]
    return ["• " + s + "." for s in clean[:limit]] if clean else ["No summary available."]

# 🔍 Main logic
if topic_input:
    with st.spinner("🔍 Searching Wikipedia..."):
        all_text = ""
        summaries = []

        title = get_translated_title(topic_input, lang_code)
        st.caption(f"📄 Fetched title: {title}")

        main = fetch_summary(title, lang_code)
        if not main:
            st.error(f"No matching page found in {lang_name} for '{topic_input}'")
            st.stop()

        st.subheader("🔷 Main Topic")
        st.markdown(f"### {main['title']}")
        st.write(main["summary"])
        st.markdown(f"[Read More →]({main['link']})", unsafe_allow_html=True)

        summaries.append(main["summary"])
        all_text += f"{main['title']} ({lang_name})\n\n{main['summary']}\n\n"

        st.subheader("🔗 Related Topics")
        related = fetch_related(title, lang_code)
        if related:
            for r in related:
                sub = fetch_summary(r, lang_code)
                if sub and sub["summary"] not in summaries:
                    summaries.append(sub["summary"])
                    all_text += f"{sub['title']}\n{sub['summary']}\n\n"
                    with st.expander(sub["title"]):
                        st.write(sub["summary"])
                        st.markdown(f"[Read More →]({sub['link']})", unsafe_allow_html=True)
        else:
            st.info("No related topics found.")

        st.subheader("🧠 Combined Summary")
        for bullet in summarize_bullets(summaries):
            st.markdown(bullet)

        st.download_button(
            label="📥 Download Summary",
            data=all_text,
            file_name=f"{main['title']}_summary.txt",
            mime="text/plain"
        )