import streamlit as st
import pandas as pd
from app_core.services.mappings_service import MappingsService
from app_core.config.settings import STORES


def render_page():
    if st.session_state.get("auth_user") is None:
        st.warning("Please login to continue.")
        st.stop()

    st.markdown("""
        <style>
        .stApp { font-size: 1.05rem; }
        [data-testid="stDataEditor"] { font-size: 1.05rem !important; }
        h2 { font-weight: 700 !important; letter-spacing: -0.02em !important; }
        h3 { font-weight: 600 !important; color: #6366f1 !important; margin-top: 1.2rem !important; }
        .store-pill {
            display: inline-block;
            padding: 4px 14px;
            border-radius: 20px;
            font-size: 0.85rem;
            font-weight: 600;
            margin: 3px 4px;
            background: linear-gradient(135deg, #6366f1, #8b5cf6);
            color: white;
        }
        </style>
    """, unsafe_allow_html=True)

    st.markdown("## 📋 Triumph Debtor Mappings")
    st.caption("Manage POS account sale mappings to Triumph debtor codes — filtered by store.")

    service = MappingsService()
    all_mappings = service.get_all_mappings()

    # Store labels from config — used only for the "Add New" dropdown
    store_labels = [s["label"] for s in STORES]

    tab1, tab2 = st.tabs(["🔍 View & Search", "➕ Add New Mapping"])

    # ── TAB 1: View & Edit ────────────────────────────────────────────────────
    with tab1:
        st.markdown("### 🔍 Current Mappings")

        if not all_mappings:
            st.info("No mappings found. Use the '➕ Add New Mapping' tab to create one.")
        else:
            # Build dataframe from raw DB values
            data = [
                {
                    "ID": m.id,
                    "POS Code": m.code or "",
                    "Account Name": m.name or "",
                    "Triumph Code": m.dbmacc or "",
                    "Outlet": (m.outlet or "").strip(),
                    "Created At": m.created_at.strftime("%Y-%m-%d %H:%M") if m.created_at else "—",
                    "Updated At": m.updated_at.strftime("%Y-%m-%d %H:%M") if m.updated_at else "—",
                }
                for m in all_mappings
            ]
            df_full = pd.DataFrame(data)

            # Distinct outlet names actually in DB
            distinct_outlets = sorted([
                o for o in df_full["Outlet"].dropna().unique().tolist() if o.strip()
            ])

            f1, f2 = st.columns([1, 2])
            with f1:
                selected_store = st.selectbox(
                    "🏪 Filter by Store",
                    options=["All Stores"] + distinct_outlets,
                    index=0,
                )
            with f2:
                search_query = st.text_input(
                    "🔎 Search",
                    placeholder="POS Code, Account Name, or Triumph Code…",
                )

            df = df_full.copy()

            if selected_store != "All Stores":
                df = df[df["Outlet"] == selected_store]

            if search_query:
                q = search_query
                df = df[
                    df["POS Code"].str.contains(q, case=False, na=False) |
                    df["Account Name"].str.contains(q, case=False, na=False) |
                    df["Triumph Code"].str.contains(q, case=False, na=False)
                ]

            store_label = selected_store if selected_store != "All Stores" else "all stores"
            st.caption(f"Showing **{len(df)}** mapping(s) for **{store_label}**.")

            st.markdown("#### 📝 Edit Mappings")
            st.caption("Double-click any editable cell to modify. Changes are saved when you press Enter.")

            st.data_editor(
                df,
                hide_index=True,
                use_container_width=True,
                num_rows="dynamic",
                disabled=["ID", "Created At", "Updated At"],
                column_config={
                    "ID":           st.column_config.NumberColumn(format="%d", width="small"),
                    "POS Code":     st.column_config.TextColumn(max_chars=50,  width="medium"),
                    "Account Name": st.column_config.TextColumn(max_chars=255, width="large"),
                    "Triumph Code": st.column_config.TextColumn(max_chars=50,  width="medium"),
                    "Outlet":       st.column_config.TextColumn(max_chars=255, width="large"),
                    "Created At":   st.column_config.TextColumn(width="medium"),
                    "Updated At":   st.column_config.TextColumn(width="medium"),
                },
                key="mapping_editor_v2",
            )

            if st.session_state.get("mapping_editor_v2"):
                edited_rows = st.session_state.mapping_editor_v2.get("edited_rows", {})
                deleted_rows = st.session_state.mapping_editor_v2.get("deleted_rows", [])

                if edited_rows or deleted_rows:
                    changes_made = False

                    for idx, patch in edited_rows.items():
                        mapping_id  = df.iloc[idx]["ID"]
                        row         = df.iloc[idx]
                        new_code    = patch.get("POS Code",     row["POS Code"])
                        new_name    = patch.get("Account Name", row["Account Name"])
                        new_triumph = patch.get("Triumph Code", row["Triumph Code"])
                        new_outlet  = patch.get("Outlet",       row["Outlet"])
                        if service.update_mapping(mapping_id, new_code, new_name, new_triumph, new_outlet):
                            changes_made = True

                    for idx in deleted_rows:
                        if service.delete_mapping(df.iloc[idx]["ID"]):
                            changes_made = True

                    if changes_made:
                        st.toast("✅ Mappings updated and synced!", icon="🚀")
                        st.rerun()

    # ── TAB 2: Add New ────────────────────────────────────────────────────────
    with tab2:
        st.markdown("### ➕ Create New Mapping")
        st.caption("All fields are mandatory.")

        with st.form("new_mapping_form", clear_on_submit=True):
            c1, c2 = st.columns(2)
            with c1:
                new_code = st.text_input("POS Code", placeholder="e.g. 0273",
                                         help="Unique identifier from your POS system.")
                new_name = st.text_input("Account Sale Name", placeholder="e.g. Suriya",
                                         help="The name as it appears on account invoices.")
            with c2:
                new_triumph = st.text_input("Triumph Debtor Code (DBMACC#)", placeholder="e.g. SURI0273",
                                            help="The debtor code in Triumph ERP.")
                new_outlet = st.selectbox(
                    "Store / Outlet",
                    options=["Select a Store"] + store_labels,
                    index=0,
                    help="Select the store this mapping belongs to.",
                )

            st.markdown("<br>", unsafe_allow_html=True)
            if st.form_submit_button("Create Mapping", type="primary", use_container_width=True):
                if not all([new_code.strip(), new_name.strip(), new_triumph.strip()]) or new_outlet == "— Select a Store —":
                    st.error("⚠️ All fields are required — including selecting a store.")
                else:
                    service.create_mapping(new_code.strip(), new_name.strip(), new_triumph.strip(), new_outlet)
                    st.success(f"✅ Mapping for **{new_name}** created under **{new_outlet}**!")
                    st.balloons()
                    st.rerun()

    st.markdown("---")
    with st.expander("📖 Field definitions"):
        st.write("""
        - **POS Code** — Unique identifier from your POS system.
        - **Account Name** — Name used on account sales invoices.
        - **Triumph Code (DBMACC#)** — Corresponding debtor code in Triumph ERP.
        - **Store / Outlet** — Store this mapping is assigned to.

        *Any change here is immediately picked up by the background event processor.*
        """)


if __name__ == "__main__":
    render_page()