import os, requests
import gradio as gr
from pypdf import PdfReader

OPENAI_API_KEY = os.getenv("OPENAI_API_KEY")
OPENAI_URL = "https://api.openai.com/v1/chat/completions"
MODEL = "gpt-4o-mini"
MAX_PAGES, MAX_CHARS = 15, 10000

def extract_text(pdf_file):
    try:
        reader = PdfReader(pdf_file)
        pages = min(len(reader.pages), MAX_PAGES)
        text = "\n".join((reader.pages[i].extract_text() or "") for i in range(pages))
        lines = [ln.strip() for ln in text.splitlines() if ln.strip()]
        return "\n".join(lines)[:MAX_CHARS]
    except Exception:
        return ""

def call_openai(system_prompt, user_content):
    if not OPENAI_API_KEY:
        raise RuntimeError("Missing OPENAI_API_KEY (set it in Space → Settings → Secrets).")
    headers = {"Authorization": f"Bearer {OPENAI_API_KEY}", "Content-Type": "application/json"}
    body = {
        "model": MODEL,
        "messages": [
            {"role": "system", "content": system_prompt},
            {"role": "user", "content": user_content}
        ],
        "temperature": 0.2
    }
    r = requests.post(OPENAI_URL, headers=headers, json=body, timeout=60)
    r.raise_for_status()
    return r.json()["choices"][0]["message"]["content"]

def summarize(content, length):
    sys = ("You are a precise study assistant for MBA-level students. "
           "Summarize in clean bullet points; short=5 bullets, medium=8-10, long=12-15.")
    usr = f"Length: {length}\n\nCONTENT:\n{content[:MAX_CHARS]}"
    return call_openai(sys, usr)

def mcqs(content):
    sys = ("Create 10 single-answer MCQs from the content. "
           "Each item: question + 4 options labeled A)–D), then a line 'Answer: X' "
           "and a one-sentence explanation.")
    usr = f"CONTENT:\n{content[:8000]}"
    return call_openai(sys, usr)

def generate(pasted_text, pdf_file, length):
    source = ""
    if pdf_file is not None:
        source = extract_text(pdf_file)
    if not source and pasted_text:
        source = pasted_text.strip()[:MAX_CHARS]
    if not source:
        return "❌ Paste text or upload a PDF.", ""
    if len(source) < 200:
        return "❌ Input too short.", ""

    try:
        summary_md = summarize(source, length)
    except Exception as e:
        return f"❌ Summarization failed: {e}", ""
    try:
        mcq_md = mcqs(source)
    except Exception as e:
        mcq_md = f"❌ MCQ generation failed: {e}"

    summary_md = f"### 📄 Summary\n\n{summary_md}"
    mcq_md = f"### 🧠 Practice — 10 MCQs\n\n{mcq_md}"
    return summary_md, mcq_md

with gr.Blocks(title="StudySnap — Summaries + MCQs") as demo:
    gr.Markdown("# 📚 StudySnap\nUpload a PDF or paste text. Get a clean summary + 10 MCQs.")
    with gr.Row():
        pasted = gr.Textbox(label="Paste Text", lines=10, placeholder="Paste your lecture notes or article here…")
        pdf = gr.File(label="Upload PDF (first 15 pages)", file_types=[".pdf"])
    length = gr.Radio(["short", "medium", "long"], value="medium", label="Output length")
    btn = gr.Button("Generate", variant="primary")
    out_summary = gr.Markdown()
    out_mcq = gr.Markdown()
    btn.click(fn=generate, inputs=[pasted, pdf, length], outputs=[out_summary, out_mcq])

if __name__ == "__main__":
    demo.launch()