"""
backend/workers/analytics_worker.py

Analytics & evaluation background tasks:
 - compute_daily_metrics: aggregates logs into per-tenant daily metrics
 - compute_rag_quality: synthetic RAG evaluation (precision@k style)
 - export_metrics_to_supabase: writes aggregated metrics to a supabase analytics table
"""

import os
import logging
import time
from typing import Dict, Any, List

try:
    from backend.workers.celeryconfig import celery_app
except Exception:
    celery_app = None

logger = logging.getLogger("analytics_worker")
logger.setLevel(os.getenv("LOG_LEVEL", "INFO"))

# Placeholder: hook to your logging/event store. Replace with concrete DB queries
def fetch_raw_logs(since_ts: int = 0) -> List[Dict[str, Any]]:
    """
    Fetch raw logs from the event store (Postgres / Supabase table).
    Here we return dummy data if no DB configured.
    """
    # In prod: query your events table for entries after since_ts
    return [
        {"tenant_id": "demo", "tool": "rag", "latency_ms": 120, "tokens": 12, "ts": since_ts + 10},
        {"tenant_id": "demo", "tool": "web", "latency_ms": 70, "tokens": 0, "ts": since_ts + 20},
        {"tenant_id": "demo", "tool": "llm", "latency_ms": 400, "tokens": 150, "ts": since_ts + 30},
    ]


def aggregate_logs(logs: List[Dict[str, Any]]) -> Dict[str, Dict[str, Any]]:
    """
    Simple aggregator by tenant: counts requests, tokens, latency per tool.
    Returns a dict keyed by tenant_id.
    """
    out = {}
    for e in logs:
        tid = e.get("tenant_id", "unknown")
        out.setdefault(tid, {"requests": 0, "tokens": 0, "tools": {}, "total_latency_ms": 0})
        out[tid]["requests"] += 1
        out[tid]["tokens"] += e.get("tokens", 0)
        out[tid]["total_latency_ms"] += e.get("latency_ms", 0)
        tool = e.get("tool", "unknown")
        out[tid]["tools"].setdefault(tool, {"count": 0, "latency_ms": 0})
        out[tid]["tools"][tool]["count"] += 1
        out[tid]["tools"][tool]["latency_ms"] += e.get("latency_ms", 0)
    return out


def write_metrics_supabase(metrics: Dict[str, Dict[str, Any]]):
    """
    Writes aggregated metrics to supabase analytics table. Falls back to logging if supabase not configured.
    """
    from backend.workers.ingestion_worker import SUPABASE
    if SUPABASE is None:
        logger.info("Supabase not configured; metrics:\n%s", metrics)
        return {"status": "logged", "metrics_count": len(metrics)}

    table = os.getenv("SUPABASE_ANALYTICS_TABLE", "analytics_daily")
    rows = []
    ts = int(time.time())
    for tenant_id, data in metrics.items():
        rows.append({
            "tenant_id": tenant_id,
            "date": time.strftime("%Y-%m-%d", time.gmtime(ts)),
            "requests": data["requests"],
            "tokens": data["tokens"],
            "total_latency_ms": data["total_latency_ms"],
            "tools": data["tools"],
        })
    try:
        res = SUPABASE.table(table).upsert(rows).execute()
        logger.info("Wrote %d metrics rows to supabase table %s", len(rows), table)
        return {"status": "ok", "count": len(rows), "result": res}
    except Exception as e:
        logger.exception("Failed to write metrics to supabase: %s", e)
        return {"status": "error", "error": str(e)}


# Celery decorator
def task_decorator(func):
    if celery_app is not None:
        return celery_app.task(func)
    else:
        def wrapper(*args, **kwargs):
            return func(*args, **kwargs)
        return wrapper


@task_decorator
def compute_daily_metrics(window_seconds: int = 86400):
    """
    Compute daily metrics by fetching raw logs and aggregating.
    """
    logger.info("compute_daily_metrics started; window=%s", window_seconds)
    since_ts = int(time.time()) - window_seconds
    logs = fetch_raw_logs(since_ts=since_ts)
    metrics = aggregate_logs(logs)
    res = write_metrics_supabase(metrics)
    logger.info("compute_daily_metrics finished; res=%s", res)
    return res


@task_decorator
def compute_rag_quality(sample_size: int = 20, top_k: int = 3):
    """
    Synthetic RAG evaluation:
     - sample random chunks (or seed queries)
     - ask the RAG server to search
     - compute simple precision@k using exact string matching heuristic
    """
    logger.info("compute_rag_quality started; sample_size=%d top_k=%d", sample_size, top_k)

    # In production: sample from DB. Here we simulate a simple check using mock data or minimal queries.
    try:
        # fake sample
        sample_queries = ["What is our HR policy?", "What is refund policy?"] * (sample_size // 2)
        results = []
        # Try to call rag MCP if available
        from backend.api.mcp_clients.rag_client import RagClient
        rag = RagClient()
        for q in sample_queries:
            try:
                r = rag.search({"tenant_id": "demo", "query": q})
                # r should contain scored results; we use heuristics: check if any item contains a keyword
                top_texts = [it.get("text", "") for it in r.get("results", [])[:top_k]]
                success = any("policy" in t.lower() for t in top_texts)
                results.append({"query": q, "success": success})
            except Exception:
                results.append({"query": q, "success": False})
        precision = sum(1 for r in results if r["success"]) / max(1, len(results))
        logger.info("compute_rag_quality precision=%.3f", precision)
        return {"precision_at_k": precision, "sample": len(results)}
    except Exception as e:
        logger.exception("compute_rag_quality failed: %s", e)
        return {"error": str(e)}