"""
ui.tabs.analytics_tab
=====================
Tab 3 — Analytics

Query analytics pulled from the SQLite audit log:
  - Summary stats: total queries, avg latency, avg citations (7-day window)
  - Queries by day (table)
  - KB inventory table with doc/chunk counts
"""

from __future__ import annotations

import logging
from pathlib import Path

import gradio as gr

logger = logging.getLogger(__name__)


def build_analytics_tab(kb_manager, db_path: Path) -> None:
    """
    Build and render the Analytics tab.

    Args:
        kb_manager: KBManager for KB stats.
        db_path:    Path to the central SQLite database for query stats.
    """
    gr.Markdown("## 📊 Analytics")
    gr.Markdown("*Query volume, latency breakdown, and knowledge base inventory.*")

    # ── Top-level metric cards ──────────────────────────────────────────
    with gr.Row():
        total_queries_label = gr.Label(label="Total Queries (7d)", value="—")
        avg_latency_label = gr.Label(label="Avg End-to-End Latency (ms)", value="—")
        avg_citations_label = gr.Label(label="Avg Citations per Answer", value="—")
        kb_count_label = gr.Label(label="Knowledge Bases", value="—")

    refresh_btn = gr.Button("🔄 Refresh Stats", variant="secondary")

    gr.Markdown("---")
    gr.Markdown("### Query Volume (last 7 days)")
    queries_by_day_df = gr.Dataframe(
        headers=["Date", "Queries"],
        value=[["—", "—"]],
        interactive=False,
    )

    gr.Markdown("### Knowledge Base Inventory")
    kb_inventory_df = gr.Dataframe(
        headers=["KB Name", "Display Name", "Documents", "Chunks", "Protected"],
        value=_get_kb_inventory(kb_manager),
        interactive=False,
    )

    # ── Load stats on refresh ───────────────────────────────────────────
    def _refresh_stats():
        from voicevault.storage import sqlite_store as db_mod

        try:
            stats = db_mod.get_query_stats(db_path, days=7)
        except Exception as exc:
            logger.warning("Could not load query stats: %s", exc)
            stats = {
                "total_queries": 0,
                "avg_latency_ms": 0,
                "avg_citation_count": 0.0,
                "queries_by_day": [],
            }

        total = str(stats.get("total_queries") or 0)
        latency = str(int(stats.get("avg_latency_ms") or 0)) + " ms"
        citations = f"{stats.get('avg_citation_count') or 0:.1f}"

        by_day = stats.get("queries_by_day") or []
        day_rows = [[r["date"], str(r["count"])] for r in by_day] or [["—", "—"]]

        kbs = _get_kb_inventory(kb_manager)
        kb_count = str(len(kbs))

        return (
            gr.update(value=total),
            gr.update(value=latency),
            gr.update(value=citations),
            gr.update(value=kb_count),
            gr.update(value=day_rows),
            gr.update(value=kbs if kbs else [["(none)", "—", "0", "0", "No"]]),
        )

    refresh_btn.click(
        fn=_refresh_stats,
        outputs=[
            total_queries_label,
            avg_latency_label,
            avg_citations_label,
            kb_count_label,
            queries_by_day_df,
            kb_inventory_df,
        ],
    )


def _get_kb_inventory(kb_manager) -> list[list]:
    """Return rows for the KB inventory dataframe."""
    try:
        kbs = kb_manager.list_kbs()
        if not kbs:
            return [["(none)", "—", "0", "0", "No"]]
        return [
            [
                kb.kb_name,
                kb.display_name,
                str(kb.doc_count),
                str(kb.chunk_count),
                "🔒 Yes" if kb.is_protected else "No",
            ]
            for kb in kbs
        ]
    except Exception:
        return [["(error)", "—", "—", "—", "—"]]