#!/usr/bin/env python3
"""Utility helpers for ad-hoc log analysis.

This module exposes small helper functions to inspect the ``ngxstat`` SQLite
database.  The intent is to allow quick queries from the command line or other
scripts without rewriting SQL each time.

Examples
--------
To list all domains present in the database::

    python scripts/analyze.py domains

The CLI is powered by :mod:`typer` and currently only offers a couple of
commands.  More analysis routines can be added over time.
"""
from __future__ import annotations

import sqlite3
from pathlib import Path
from typing import Dict, List, Optional

import typer

from scripts import nginx_config  # noqa: F401  # imported for side effects/usage

DB_PATH = Path("database/ngxstat.db")

app = typer.Typer(help="Ad-hoc statistics queries")


def _connect() -> sqlite3.Connection:
    """Return a new SQLite connection to :data:`DB_PATH`."""
    return sqlite3.connect(DB_PATH)


def load_domains_from_db() -> List[str]:
    """Return a sorted list of distinct domains from the ``logs`` table."""
    conn = _connect()
    cur = conn.cursor()
    cur.execute("SELECT DISTINCT host FROM logs ORDER BY host")
    domains = [row[0] for row in cur.fetchall()]
    conn.close()
    return domains


def get_hit_count(domain: Optional[str] = None) -> int:
    """Return total request count.

    Parameters
    ----------
    domain:
        Optional domain to filter on. If ``None`` the count includes all logs.
    """
    conn = _connect()
    cur = conn.cursor()
    if domain:
        cur.execute("SELECT COUNT(*) FROM logs WHERE host = ?", (domain,))
    else:
        cur.execute("SELECT COUNT(*) FROM logs")
    count = cur.fetchone()[0] or 0
    conn.close()
    return count


def get_cache_ratio(domain: Optional[str] = None) -> float:
    """Return the percentage of requests served from cache."""
    conn = _connect()
    cur = conn.cursor()
    if domain:
        cur.execute(
            "SELECT SUM(CASE WHEN cache_status = 'HIT' THEN 1 ELSE 0 END) * 1.0 / "
            "COUNT(*) FROM logs WHERE host = ?",
            (domain,),
        )
    else:
        cur.execute(
            "SELECT SUM(CASE WHEN cache_status = 'HIT' THEN 1 ELSE 0 END) * 1.0 / "
            "COUNT(*) FROM logs"
        )
    result = cur.fetchone()[0]
    conn.close()
    return float(result or 0.0)


@app.command()
def domains() -> None:
    """Print the list of domains discovered in the database."""
    for d in load_domains_from_db():
        typer.echo(d)


@app.command()
def hits(domain: Optional[str] = typer.Option(None, help="Filter by domain")) -> None:
    """Show request count."""
    count = get_hit_count(domain)
    if domain:
        typer.echo(f"{domain}: {count} hits")
    else:
        typer.echo(f"Total hits: {count}")


@app.command("cache-ratio")
def cache_ratio_cmd(domain: Optional[str] = typer.Option(None, help="Filter by domain")) -> None:
    """Display cache hit ratio as a percentage."""
    ratio = get_cache_ratio(domain) * 100
    if domain:
        typer.echo(f"{domain}: {ratio:.2f}% cached")
    else:
        typer.echo(f"Cache hit ratio: {ratio:.2f}%")


if __name__ == "__main__":
    app()