# app_gradio.py
import os
import gradio as gr
from typing import Dict, Any
from pathlib import Path

from data_sources import google_books, openlibrary_enrich, normalize
from index_store_gradio import VectorStore
from utils import jaccard

# ----- locate catalog -----
BASE_DIR = Path(__file__).parent
CATALOG = BASE_DIR / "data" / "catalog.jsonl"
if not CATALOG.exists():
    raise RuntimeError("Missing data/catalog.jsonl. Commit it to the repo or mount it.")

# ----- load vector store once at startup -----
store = VectorStore(str(CATALOG))

def combo_tags(b: Dict[str, Any]) -> str:
    cats = (b.get("categories","") or "").strip()
    subs = (b.get("subjects","") or "").strip()
    return "; ".join([t for t in [cats, subs] if t])

def lookup_query_book(q: str) -> Dict[str, Any]:
    found = google_books(q, max_results=1)
    if not found:
        # Try Open Library fallback if Google misses (rare)
        # But simplest: just error out for now
        raise gr.Error("Book not found. Try a different title or add author.")
    qb = normalize(found[0], openlibrary_enrich(found[0]["title"]))
    return qb

def recommend(title: str, k: int = 8):
    title = (title or "").strip()
    if not title:
        raise gr.Error("Type a book title.")

    qb = lookup_query_book(title)
    pairs = store.similar(qb, k=min(k, len(store.books)))

    md_lines = []
    cards = []  # list of (image_url, caption) for the gallery

    for rank, (idx, sim) in enumerate(pairs, start=1):
        b = dict(store.books[idx])
        b["similarity"] = float(sim)
        b["tag_overlap"] = jaccard(combo_tags(qb), combo_tags(b))

        # Build markdown block with title, tags, and a real summary
        chips = "; ".join([t for t in [b.get('categories',''), b.get('subjects','')] if t])
        desc = (b.get("description") or "").strip()
        desc = desc[:600] + ("…" if len(desc) > 600 else "")

        md_lines.append(
            f"**{rank}. {b.get('title','(untitled)')}** — {b.get('authors','')}\n\n"
            + (f"*{chips}*\n\n" if chips else "")
            + (f"{desc}\n\n" if desc else "_No description available._\n\n")
            + f"Similarity: **{b['similarity']:.2f}** · Tag overlap: **{b['tag_overlap']:.2f}**\n\n---\n"
        )

        # Gallery still shows the cover; caption can be short
        cards.append((b.get("cover_url"), f"{rank}. {b.get('title','')}"))

    query_title_md = f"### Because you liked: **{qb.get('title','(unknown)')}**"
    query_auth_md  = f"*{qb.get('authors','')}*"
    md_text = "\n".join(md_lines)

    return query_title_md, query_auth_md, md_text, cards


STICKY_CSS = """
.sticky { 
  position: sticky; 
  top: 0; 
  z-index: 100; 
  background: white; 
  padding: 8px 0 12px 0; 
  border-bottom: 1px solid #eee;
}
"""

with gr.Blocks(title="BookRec (Gradio)", css=STICKY_CSS) as demo:
    # Sticky header + inputs
    with gr.Column(elem_classes=["sticky"]):
        gr.Markdown("# BookRec — because you loved…")
        with gr.Row():
            title_in = gr.Textbox(label="I liked…", placeholder="The Night Circus", scale=4)
            k_in = gr.Slider(3, 15, value=8, step=1, label="How many?", scale=1)
        with gr.Row():
            btn = gr.Button("Find similar", variant="primary", scale=1)
            clear_btn = gr.Button("Clear", scale=1)

    # Results area
    query_title = gr.Markdown()
    query_auth = gr.Markdown()
    results_md = gr.Markdown()  # full synopses
    gallery = gr.Gallery(label="Covers", columns=2, height=600, preview=True)

    # Wire actions
    btn.click(fn=recommend, inputs=[title_in, k_in], outputs=[query_title, query_auth, results_md, gallery])
    clear_btn.click(fn=lambda: ("", "", "", []), inputs=None, outputs=[query_title, query_auth, results_md, gallery])

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