"""Flask CLI admin commands (factor 12).

process-logs is now OPTIONAL (Chapter 12 simplification, per project
owner request): file processing is triggered automatically in-app right
after upload (app/services/background.py), so cron is no longer required.
This command still exists for anyone who'd rather run it manually or via
cron — it shares the exact same processing code (app/services/
log_processor.py) as the automatic background trigger, so both paths
behave identically. cleanup (Chapter 06/12) enforces the retention
policy. create-admin (Chapter 12) bootstraps the single admin account.
"""
from __future__ import annotations

from datetime import date, datetime, timedelta

import click
from flask import Flask, current_app

from app.extensions import db
from app.models.ip_traffic_stats import IpPathStatsDaily, IpStatusStatsDaily
from app.models.log_entry import LogEntry
from app.models.log_file import LogFile
from app.models.request_stats import RequestStatsHourly
from app.models.user import User
from app.services import aggregator
from app.services.log_processor import process_one_batch
from app.utils.upload_paths import upload_path_for

# Chapter 06 retention policy — the constants `flask cleanup` enforces.
LOG_ENTRIES_RETENTION_DAYS = 30
HOURLY_STATS_RETENTION_DAYS = 90
IP_TRAFFIC_STATS_RETENTION_DAYS = 30


def register_commands(app: Flask) -> None:
    app.cli.add_command(process_logs)
    app.cli.add_command(rollup)
    app.cli.add_command(cleanup)
    app.cli.add_command(create_admin)


@click.command("process-logs")
@click.option("--batch-size", default=None, type=int, help="Override PARSE_BATCH_SIZE.")
def process_logs(batch_size: int | None) -> None:
    """Optional manual/cron fallback — processing now also runs
    automatically in-app after upload. Parses queued/processing
    log_files in bounded, checkpointed batches; one batch per file per
    invocation, same as before.
    """
    batch = batch_size or current_app.config["PARSE_BATCH_SIZE"]
    pending = LogFile.query.filter(LogFile.status.in_(["queued", "processing"])).all()
    for log_file in pending:
        process_one_batch(log_file, batch)


@click.command("rollup")
@click.option("--from", "from_date", required=True, help="ISO date, e.g. 2026-07-01")
@click.option("--to", "to_date", required=True, help="ISO date, e.g. 2026-07-26")
def rollup(from_date: str, to_date: str) -> None:
    """Manual rollup recompute for an explicit range (e.g. after a backfill).

    Requires an explicit range — no "all time" default, mirroring Ch03 rule 7
    even for an admin command, to avoid an unbounded scan on constrained hosting.
    """
    start = date.fromisoformat(from_date)
    end = date.fromisoformat(to_date)
    aggregator.compute_rollups_for_range(start, end)
    click.echo(f"Rolled up {start} .. {end}")


@click.command("cleanup")
def cleanup() -> None:
    """Enforce the Chapter 06 retention policy (Chapter 12).

    Previously a stub through every earlier chapter — implemented here as
    Chapter 12's non-functional/deployment concern. Cron-invoked (e.g.
    daily, off-peak), never a long-running daemon.
    """
    now = datetime.utcnow()
    deleted_entries = _delete_old_log_entries(now)
    deleted_hourly = _collapse_old_hourly_stats(now)
    deleted_ip_stats = _delete_old_ip_traffic_stats(now)
    archived_files = _delete_parsed_upload_files()
    click.echo(
        f"Cleanup complete: {deleted_entries} log_entries, {deleted_hourly} "
        f"request_stats_hourly, {deleted_ip_stats} ip traffic-rollup rows "
        f"deleted; {archived_files} parsed upload file(s) removed from disk."
    )


def _delete_old_log_entries(now: datetime) -> int:
    """Ch06: raw log_entries retained ~30 days, then deleted."""
    cutoff = now - timedelta(days=LOG_ENTRIES_RETENTION_DAYS)
    count = db.session.query(LogEntry).filter(LogEntry.timestamp < cutoff).delete(synchronize_session=False)
    db.session.commit()
    return count


def _collapse_old_hourly_stats(now: datetime) -> int:
    """Ch06: request_stats_hourly retained ~90 days, then collapsed into
    request_stats_daily only. request_stats_daily is already computed
    independently by the aggregator straight from raw log_entries, so
    "collapsing" here just means deleting the now-redundant hourly rows
    once the retention window passes — no data is lost, since the daily
    rollup for that period was already written when the file was parsed.
    """
    cutoff = now - timedelta(days=HOURLY_STATS_RETENTION_DAYS)
    count = db.session.query(RequestStatsHourly).filter(
        RequestStatsHourly.date_hour < cutoff
    ).delete(synchronize_session=False)
    db.session.commit()
    return count


def _delete_old_ip_traffic_stats(now: datetime) -> int:
    """The bounded per-IP rollup (added as a Ch10 follow-up) was designed
    for ~30-day retention, matching log_entries — see aggregator.py.
    """
    cutoff_date = (now - timedelta(days=IP_TRAFFIC_STATS_RETENTION_DAYS)).date()
    count = db.session.query(IpPathStatsDaily).filter(IpPathStatsDaily.date < cutoff_date).delete(synchronize_session=False)
    count += db.session.query(IpStatusStatsDaily).filter(IpStatusStatsDaily.date < cutoff_date).delete(synchronize_session=False)
    db.session.commit()
    return count


def _delete_parsed_upload_files() -> int:
    """Ch06: 'compress or delete after successful parse + rollup, rather
    than keeping both the raw file and a full raw-row copy.' Deletes
    (rather than compresses) — simpler, and avoids spending extra CPU/IOPS
    gzip-ing data that's already been fully parsed into the database.
    """
    done_files = LogFile.query.filter_by(status="done").all()
    removed = 0
    for log_file in done_files:
        path = upload_path_for(log_file)
        if path.exists():
            path.unlink()
            removed += 1
    return removed


@click.command("create-admin")
@click.option("--email", default=None, help="Defaults to the ADMIN_EMAIL env var.")
@click.password_option()
def create_admin(email: str | None, password: str) -> None:
    """Bootstrap the single admin account (Chapter 12).

    Interactive password prompt (via --password-option's confirmation
    prompt) keeps the raw credential out of process env/config, unlike an
    ADMIN_PASSWORD env var would — Chapter 12 doesn't specify a bootstrap
    mechanism beyond documenting ADMIN_EMAIL, so this is a flagged addition.
    """
    resolved_email = (email or current_app.config.get("ADMIN_EMAIL") or "").strip().lower()
    if not resolved_email:
        raise click.UsageError("No --email given and ADMIN_EMAIL is not set.")
    if User.query.filter_by(email=resolved_email).first():
        raise click.UsageError(f"User {resolved_email} already exists.")

    user = User(email=resolved_email)
    user.set_password(password)
    db.session.add(user)
    db.session.commit()
    click.echo(f"Created admin user {resolved_email}")