"""Standard Gradio Blocks UI — the fallback frontend for the ZeroGPU Space.

The primary frontend is the React app served by ``webapp/server.py`` (gr.Server
Server mode). If that doesn't drive under ZeroGPU's runtime, point the Space's
``app_file`` at this module instead: it's a plain ``gr.Blocks`` UI over the exact
same ``webapp/backend.py`` functions, so parse/summarize/report still run in-process
on ZeroGPU (when ``LLM_BACKEND=local``).

The flow mirrors the React app: upload an agenda-packet PDF + give the agenda page
range, parse it into items, then summarize / report on an item / view its pages /
ask the agent.

Run: ``python -m webapp.app_blocks``  (or set it as the Space app_file).
"""

from __future__ import annotations

import os

import gradio as gr

from webapp import backend


def _item_titles(items: list[dict]) -> list[str]:
    """Every item's ``"<number> <name>"`` line, in agenda order — the anchors the
    backend uses to locate and bound each item's section in the packet."""
    return [f"{it['number']} {it['name']}".strip() for it in items]


def _upload(file_path, agenda_pages):
    """Parse an uploaded packet into agenda items and populate the item picker."""
    blank = gr.update(choices=[], value=None)
    if not file_path:
        return "_Upload an agenda-packet PDF to begin._", blank, None
    try:
        with open(file_path, "rb") as fh:
            data = fh.read()
        name = os.path.basename(file_path)
        res = backend.upload_packet(data, name, (agenda_pages or "").strip())
    except Exception as e:  # noqa: BLE001
        return f"_Could not parse the packet: {type(e).__name__}: {e}_", blank, None

    items = res.get("items", [])
    if not items:
        return ("_No agenda items were parsed — check the agenda page range._", blank, None)

    lines, choices = [], []
    for i, it in enumerate(items):
        label = f"{it['number']} {it['name']}".strip() or "(untitled item)"
        indent = "&nbsp;" * (4 * int(it.get("level", 0)))
        if it.get("is_section"):
            lines.append(f"{indent}**{label}**")
        else:
            tag = f" · pp. {it['pages']}" if it.get("has_pages") else " · _no pages_"
            lines.append(f"{indent}{label}{tag}")
            choices.append((label[:90], i))

    md = (f"### Agenda items\n_{len(choices)} reportable item(s) · {res.get('page_count')} "
          f"packet pages · parsed from the {res.get('source')}_\n\n" + "  \n".join(lines))
    state = {"upload_id": res["upload_id"], "items": items}
    return md, gr.update(choices=choices, value=None), state


def _view_pages(state, item_idx):
    if not state or item_idx is None:
        return [], "_Pick an agenda item, then view its packet pages._"
    items = state["items"]
    if item_idx < 0 or item_idx >= len(items):
        return [], "_That item is no longer available — re-parse the packet._"
    from webapp import pdf_view

    it = items[item_idx]
    try:
        images, caption = pdf_view.render_item_pages(
            state["upload_id"], _item_titles(items), item_idx,
            int(it.get("start") or 0), int(it.get("end") or 0),
        )
    except Exception as e:  # noqa: BLE001
        return [], f"_Couldn't render the packet pages: {type(e).__name__}: {e}_"
    return images, caption


def _summarize(state, model):
    if not state:
        yield "_Upload a packet, then click Summarize._"
        return
    head = "## Agenda summary\n\n"
    for frame in backend.summarize_agenda(state["upload_id"], model):
        if frame["stage"] == "error":
            yield head + f"❌ {frame['message']}"
        elif frame["stage"] == "working":
            yield head + f"⏳ {frame['message']}"
        else:
            meta = f"_Summarized by `{frame['model']}` · {frame['message']}_\n\n"
            yield head + meta + frame["summary"]


def _item_report(state, item_idx, question, thoroughness, engine, model):
    """Generate a report scoped to the selected agenda item."""
    if not state or item_idx is None:
        yield "_Pick an agenda item, enter a question, then Generate item report._"
        return
    items = state["items"]
    if item_idx < 0 or item_idx >= len(items):
        yield "_That item is no longer available — re-parse the packet._"
        return
    it = items[item_idx]
    item_label = f"{it['number']} {it['name']}".strip() or "(untitled item)"
    head = f"## {item_label}\n\n**Question:** {question}\n\n"
    for frame in backend.generate_agenda_item_report(
        state["upload_id"], _item_titles(items), item_idx, question,
        int(it.get("start") or 0), int(it.get("end") or 0),
        int(thoroughness), engine, model,
    ):
        if frame["stage"] == "error":
            yield head + f"❌ {frame['message']}"
        elif frame["stage"] == "working":
            pct = int(frame.get("frac", 0) * 100)
            yield head + f"⏳ [{pct}%] {frame['message']}"
        else:
            meta = f"_Reported by `{frame['model']}` · {frame['message']}_\n\n"
            yield head + meta + frame["report"]


def _agent(state, question, model):
    """Stream one Agent Mode turn as a running markdown transcript (single-turn)."""
    if not state:
        yield "_Upload a packet first._"
        return
    q = (question or "").strip()
    if not q:
        yield "_Ask a question to begin._"
        return

    head = f"**You:** {q}\n\n---\n"
    body = ""
    yield head + "_⏳ reading the agenda…_"
    for fr in backend.agent_chat(state["upload_id"], [{"role": "user", "content": q}], model):
        st = fr["stage"]
        if st == "thinking":
            body += f"\n*§ {fr['text']}*\n"
        elif st == "tool_call":
            args = ", ".join(f"{k}={v}" for k, v in (fr["args"] or {}).items())
            body += f"\n`→ {fr['tool']}({args})`\n"
        elif st == "tool_result":
            body += f"\n<sub>↳ {fr['result'][:160]}…</sub>\n"
        elif st == "answer":
            body += f"\n\n**Agent:** {fr['text']}\n\n_— {fr['model']}_"
        elif st == "error":
            body += f"\n\n❌ {fr['text']}"
        yield head + body


def build_demo() -> gr.Blocks:
    model_choices = [("Gemma 4 E4B — fast", "e4b"), ("Gemma 4 26B — detailed", "26b")]

    with gr.Blocks(title="Agenda Parser") as demo:
        doc_state = gr.State(None)

        gr.Markdown(
            "# Agenda Parser\n"
            "Upload a meeting **agenda-packet PDF**, give the agenda (table-of-contents) "
            "page range, and parse it into items mapped to their backup pages — then "
            "summarize, report on an item, view its pages, or ask the agent. Model runs "
            "in-process on ZeroGPU."
        )

        with gr.Row():
            with gr.Column(scale=2):
                gr.Markdown("### 📄 Upload")
                file_in = gr.File(label="Agenda packet PDF", file_types=[".pdf"], type="filepath")
                pages_in = gr.Textbox(label="Agenda pages", value="1-3", placeholder="e.g. 1-3")
                model = gr.Dropdown(choices=model_choices, value="e4b", label="Model")
                upload_btn = gr.Button("Upload & parse", variant="primary")
                items_md = gr.Markdown("_Upload a packet to load its agenda items._")
                item_dd = gr.Dropdown(choices=[], label="Agenda item")

            with gr.Column(scale=3):
                with gr.Tab("Summarize"):
                    sum_btn = gr.Button("Summarize agenda", variant="primary")
                    sum_md = gr.Markdown("_Upload a packet, then click Summarize._")
                with gr.Tab("Agenda Item Report"):
                    report_q = gr.Textbox(
                        label="Your question", lines=2,
                        placeholder="e.g. What is being approved, and what does it cost?",
                    )
                    rep_engine = gr.Dropdown(
                        choices=[("Semantic search — fastest", "single"),
                                 ("Full read — every section", "mapreduce")],
                        value="single", label="Reading method",
                    )
                    thoroughness = gr.Slider(
                        10, 120, value=50, step=10,
                        label="Thoroughness (context fed / sections mined)",
                    )
                    rep_btn = gr.Button("Generate item report", variant="primary")
                    rep_md = gr.Markdown(
                        "_Pick an agenda item, ask a question, then Generate item report._"
                    )
                    gr.Markdown("---\n#### 📄 Packet pages for this item")
                    pages_btn = gr.Button("View packet pages for this item")
                    pages_info = gr.Markdown(
                        "_Pick an agenda item, then view its packet pages._"
                    )
                    pages_gallery = gr.Gallery(
                        label="Agenda packet pages", columns=2, height=520,
                        object_fit="contain", show_label=False,
                    )
                with gr.Tab("Agent"):
                    gr.Markdown(
                        "Ask in plain language — the agent reads this agenda packet "
                        "and shows its work."
                    )
                    agent_q = gr.Textbox(
                        label="Your question", lines=2,
                        placeholder="e.g. What's on this agenda? · "
                        "Search the packet for the budget.",
                    )
                    agent_btn = gr.Button("Ask the agent", variant="primary")
                    agent_md = gr.Markdown("_Upload a packet, then ask._")

        upload_btn.click(_upload, [file_in, pages_in], [items_md, item_dd, doc_state])
        sum_btn.click(_summarize, [doc_state, model], sum_md)
        rep_btn.click(_item_report,
                      [doc_state, item_dd, report_q, thoroughness, rep_engine, model],
                      rep_md)
        pages_btn.click(_view_pages, [doc_state, item_dd], [pages_gallery, pages_info])
        agent_btn.click(_agent, [doc_state, agent_q, model], agent_md)

    return demo


# Module-level Blocks so HF's Gradio SDK can auto-detect `demo` when this file is
# the Space app_file. Cheap to build (no model load).
demo = build_demo()


def main() -> None:
    if os.getenv("LLM_BACKEND", "remote").strip().lower() == "local":
        from webapp import local_llm

        local_llm.prefetch_models()
        print("[startup] models ready.", flush=True)
    demo.launch(
        server_name=os.getenv("GRADIO_SERVER_NAME", "0.0.0.0"),
        server_port=int(os.getenv("GRADIO_SERVER_PORT", "7860")),
    )


if __name__ == "__main__":
    main()