"""
Streamlit front-end for the DREEF PUE report generator.

Upload a community master-sheet workbook, set the developer / date (and any
externally-supplied mini-grid capacities), and download a template-faithful
Word report. Optional AI narratives use Gemini and require GOOGLE_API_KEY.

Run locally:   streamlit run app.py
Deploy:        push this folder to a Hugging Face Space (SDK = Streamlit).
"""
from __future__ import annotations

import os
import tempfile
from io import BytesIO

import streamlit as st

from pue_report_agent import extract_master_sheet, recompute, validate

st.set_page_config(page_title="PUE Report Generator", page_icon="📄",
                   layout="centered")

st.title("📄 PUE Report Generator")
st.caption(
    "Turn a community PUE master-sheet workbook into a template-faithful Word "
    "report. Every number is recomputed from the sheet — the AI only ever "
    "touches prose, never figures."
)

# --------------------------------------------------------------------------- #
# Sidebar — options
# --------------------------------------------------------------------------- #
with st.sidebar:
    st.header("Report settings")
    developer = st.text_input("Mini-grid developer",
                              value="the mini-grid developer")
    report_date = st.text_input("Report date (title page)", value="")

    st.subheader("Mini-grid capacities")
    st.caption(
        "Developer-supplied; only fill these if they aren't already in the "
        "sheet's Key Findings."
    )
    solar_pv = st.text_input("Solar PV", value="", placeholder="e.g. 6.45 MWp")
    battery = st.text_input("Battery storage", value="", placeholder="e.g. 10 MWh")
    annual_consumption = st.text_input("Annual consumption", value="",
                                       placeholder="e.g. 5 MW")

    st.subheader("AI narratives")

    def _has_api_key() -> bool:
        if os.environ.get("GOOGLE_API_KEY"):
            return True
        try:
            return bool(st.secrets.get("GOOGLE_API_KEY"))
        except Exception:
            return False

    has_key = _has_api_key()
    want_narratives = st.toggle(
        "Generate AI prose sections (Gemini)", value=False,
        help="Needs GOOGLE_API_KEY in the Space secrets or environment. "
             "Without it, the three prose sections use a plain fallback.")
    if want_narratives and not has_key:
        st.warning("No GOOGLE_API_KEY found — narratives will be skipped.")

# --------------------------------------------------------------------------- #
# Main — upload & generate
# --------------------------------------------------------------------------- #
uploaded = st.file_uploader(
    "Upload the PUE master sheet (.xlsx)", type=["xlsx", "xlsm"])

if uploaded is None:
    st.info("Upload a master-sheet workbook to begin.")
    st.stop()

if st.button("Generate report", type="primary"):
    with st.spinner("Extracting, recomputing, validating…"):
        # extract_master_sheet expects a path, so spill the upload to a temp file.
        with tempfile.NamedTemporaryFile(suffix=".xlsx", delete=False) as tmp:
            tmp.write(uploaded.getvalue())
            xlsx_path = tmp.name
        try:
            data = extract_master_sheet(xlsx_path)
            data = recompute(data)

            # Merge any developer-supplied capacity overrides.
            if solar_pv:
                data.minigrid.solar_pv = solar_pv
            if battery:
                data.minigrid.battery_storage = battery
            if annual_consumption:
                data.minigrid.annual_consumption = annual_consumption

            data = validate(data)

            narrative_note = None
            if want_narratives:
                from pue_report_agent import generate_narratives
                if generate_narratives is None:
                    narrative_note = ("langchain isn't installed — prose "
                                      "sections used the fallback.")
                elif not has_key:
                    narrative_note = ("No API key — prose sections used the "
                                      "fallback.")
                else:
                    data = generate_narratives(data)

            # Render to a temp .docx and read the bytes back for download.
            from pue_report_agent.render import render
            out_path = os.path.join(tempfile.gettempdir(),
                                    "PUE_Report.docx")
            render(data, out_path, developer=developer,
                   report_date=report_date)
            with open(out_path, "rb") as fh:
                docx_bytes = fh.read()
        finally:
            try:
                os.unlink(xlsx_path)
            except OSError:
                pass

    st.success(f"Report generated for {data.community.name or 'the community'}.")
    if narrative_note:
        st.info(narrative_note)

    fname = f"{(data.community.name or 'Community').replace(' ', '_')}_PUE_Report.docx"
    st.download_button(
        "⬇️ Download Word report", data=docx_bytes, file_name=fname,
        mime="application/vnd.openxmlformats-officedocument.wordprocessingml.document",
        type="primary")

    # Quick at-a-glance summary.
    col1, col2, col3 = st.columns(3)
    col1.metric("Interviewed", data.interviews.total)
    col2.metric("Machines", len(data.processors.machinery))
    col3.metric("Equipment cost (₦)",
                f"{(data.budget.grand_total or 0):,.0f}")

    if data.warnings:
        with st.expander(f"⚠️ {len(data.warnings)} item(s) to review", expanded=True):
            for w in data.warnings:
                st.write("• " + w)
    else:
        st.caption("No validation warnings.")