"""Gandalf – Global Advanced Network Detection And Link Facilitator.

Flask web application serving the monitoring dashboard and suppression
management UI. Authentication via Authelia forward-auth headers.
All monitoring and alerting is handled by the separate monitor.py daemon.
"""
import ipaddress
import json
import logging
import re
import threading
import time
import uuid
from functools import wraps

from flask import Flask, jsonify, redirect, render_template, request, url_for

import db
import diagnose
from monitor import PulseClient

logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s %(levelname)s %(name)s %(message)s',
)
logger = logging.getLogger('gandalf.web')

app = Flask(__name__)

_cfg = None


@app.context_processor
def inject_config():
    """Inject safe config values into all templates."""
    cfg = _config()
    return {
        'config': {
            'ticket_api': {
                'web_url': cfg.get('ticket_api', {}).get('web_url', 'http://t.lotusguild.org/ticket/'),
            }
        }
    }

# In-memory diagnostic job store { job_id: { status, result, created_at } }
_diag_jobs: dict = {}
_diag_lock = threading.Lock()


_last_event_purge = [0.0]  # mutable container so the thread can update it


def _purge_old_jobs_loop():
    """Background thread: remove stale diag jobs and run daily event purge."""
    while True:
        time.sleep(120)
        cutoff = time.time() - 600
        stuck_cutoff = time.time() - 300  # 5 min: job still 'running' → thread must have crashed
        with _diag_lock:
            stale = [jid for jid, j in _diag_jobs.items() if j.get('created_at', 0) < cutoff]
            for jid in stale:
                del _diag_jobs[jid]
            for jid, j in _diag_jobs.items():
                if j['status'] == 'running' and j.get('created_at', 0) < stuck_cutoff:
                    j['status'] = 'done'
                    j['result'] = {'status': 'error', 'error': 'Diagnostic timed out (thread crash)'}
                    logger.error(f'Diagnostic job {jid} appeared stuck; marked as errored')

        # Purge old resolved events once per day
        now = time.time()
        if now - _last_event_purge[0] > 86400:
            try:
                db.purge_old_resolved_events(days=90)
            except Exception as e:
                logger.error(f'Daily event purge failed: {e}')
            _last_event_purge[0] = now


_purge_thread = threading.Thread(target=_purge_old_jobs_loop, daemon=True)
_purge_thread.start()


def _config() -> dict:
    global _cfg
    if _cfg is None:
        with open('config.json') as f:
            _cfg = json.load(f)
    return _cfg


# ---------------------------------------------------------------------------
# Auth helpers
# ---------------------------------------------------------------------------

def _get_user() -> dict:
    return {
        'username': request.headers.get('Remote-User', ''),
        'name': request.headers.get('Remote-Name', ''),
        'email': request.headers.get('Remote-Email', ''),
        'groups': [
            g.strip()
            for g in request.headers.get('Remote-Groups', '').split(',')
            if g.strip()
        ],
    }


def require_auth(f):
    @wraps(f)
    def wrapper(*args, **kwargs):
        user = _get_user()
        if not user['username']:
            return (
                '<h1>401 – Not authenticated</h1>'
                '<p>Please access Gandalf through '
                '<a href="https://auth.lotusguild.org">auth.lotusguild.org</a>.</p>',
                401,
            )
        allowed = _config().get('auth', {}).get('allowed_groups', ['admin'])
        if not any(g in allowed for g in user['groups']):
            return (
                f'<h1>403 – Access denied</h1>'
                f'<p>Your account ({user["username"]}) is not in an allowed group '
                f'({", ".join(allowed)}).</p>',
                403,
            )
        return f(*args, **kwargs)
    return wrapper


# ---------------------------------------------------------------------------
# Page routes
# ---------------------------------------------------------------------------

_PAGE_LIMIT = 200  # max events returned per request


@app.route('/')
@require_auth
def index():
    user = _get_user()
    events = db.get_active_events(limit=_PAGE_LIMIT)
    total_active = db.count_active_events()
    summary = db.get_status_summary()
    snapshot_raw = db.get_state('network_snapshot')
    last_check = db.get_state('last_check', 'Never')
    snapshot = json.loads(snapshot_raw) if snapshot_raw else {}
    suppressions = db.get_active_suppressions()
    recent_resolved = db.get_recent_resolved(hours=24, limit=10)
    return render_template(
        'index.html',
        user=user,
        events=events,
        total_active=total_active,
        summary=summary,
        snapshot=snapshot,
        last_check=last_check,
        suppressions=suppressions,
        recent_resolved=recent_resolved,
    )


@app.route('/links')
@require_auth
def links_page():
    user = _get_user()
    return render_template('links.html', user=user)


@app.route('/inspector')
@require_auth
def inspector():
    user = _get_user()
    return render_template('inspector.html', user=user)


@app.route('/suppressions')
@require_auth
def suppressions_page():
    user = _get_user()
    active = db.get_active_suppressions()
    history = db.get_suppression_history(limit=50)
    snapshot_raw = db.get_state('network_snapshot')
    snapshot = json.loads(snapshot_raw) if snapshot_raw else {}
    return render_template(
        'suppressions.html',
        user=user,
        active=active,
        history=history,
        snapshot=snapshot,
    )


# ---------------------------------------------------------------------------
# API routes
# ---------------------------------------------------------------------------

@app.route('/api/status')
@require_auth
def api_status():
    active = db.get_active_events(limit=_PAGE_LIMIT)
    return jsonify({
        'summary': db.get_status_summary(),
        'last_check': db.get_state('last_check', 'Never'),
        'events': active,
        'total_active': db.count_active_events(),
    })


@app.route('/api/network')
@require_auth
def api_network():
    raw = db.get_state('network_snapshot')
    if raw:
        try:
            return jsonify(json.loads(raw))
        except Exception:
            logger.error('Failed to parse network_snapshot JSON')
    return jsonify({'hosts': {}, 'unifi': [], 'updated': None})


@app.route('/api/links')
@require_auth
def api_links():
    raw = db.get_state('link_stats')
    if raw:
        try:
            return jsonify(json.loads(raw))
        except Exception:
            logger.error('Failed to parse link_stats JSON')
    return jsonify({'hosts': {}, 'updated': None})


@app.route('/api/events')
@require_auth
def api_events():
    try:
        limit = min(int(request.args.get('limit', _PAGE_LIMIT)), 1000)
        offset = max(int(request.args.get('offset', 0)), 0)
    except ValueError:
        return jsonify({'error': 'limit and offset must be integers'}), 400
    status_filter = request.args.get('status', 'active')
    if status_filter not in ('active', 'resolved', 'all'):
        return jsonify({'error': 'status must be active, resolved, or all'}), 400

    result: dict = {}
    if status_filter in ('active', 'all'):
        result['active'] = db.get_active_events(limit=limit, offset=offset)
        result['total_active'] = db.count_active_events()
    if status_filter in ('resolved', 'all'):
        result['resolved'] = db.get_recent_resolved(hours=24, limit=30)
    return jsonify(result)


@app.route('/api/suppressions', methods=['GET'])
@require_auth
def api_get_suppressions():
    return jsonify(db.get_active_suppressions())


@app.route('/api/suppressions', methods=['POST'])
@require_auth
def api_create_suppression():
    user = _get_user()
    data = request.get_json(silent=True) or {}

    target_type = data.get('target_type', 'host')
    target_name = (data.get('target_name') or '').strip()
    target_detail = (data.get('target_detail') or '').strip()
    reason = (data.get('reason') or '').strip()
    expires_minutes = data.get('expires_minutes')  # None = manual/permanent

    if target_type not in ('host', 'interface', 'unifi_device', 'all'):
        return jsonify({'error': 'Invalid target_type'}), 400
    if target_type != 'all' and not target_name:
        return jsonify({'error': 'target_name required'}), 400
    if not reason:
        return jsonify({'error': 'reason required'}), 400
    if len(reason) > 500:
        return jsonify({'error': 'reason must be 500 characters or fewer'}), 400
    if len(target_name) > 255:
        return jsonify({'error': 'target_name must be 255 characters or fewer'}), 400
    if len(target_detail) > 255:
        return jsonify({'error': 'target_detail must be 255 characters or fewer'}), 400

    sup_id = db.create_suppression(
        target_type=target_type,
        target_name=target_name,
        target_detail=target_detail,
        reason=reason,
        suppressed_by=user['username'],
        expires_minutes=int(expires_minutes) if expires_minutes else None,
    )
    logger.info(
        f'Suppression #{sup_id} created by {user["username"]}: '
        f'{target_type}/{target_name}/{target_detail} – {reason}'
    )
    return jsonify({'success': True, 'id': sup_id})


@app.route('/api/suppressions/<int:sup_id>', methods=['DELETE'])
@require_auth
def api_delete_suppression(sup_id: int):
    user = _get_user()
    db.deactivate_suppression(sup_id)
    logger.info(f'Suppression #{sup_id} removed by {user["username"]}')
    return jsonify({'success': True})


@app.route('/api/diagnose', methods=['POST'])
@require_auth
def api_diagnose_start():
    """Start a link diagnostic job. Returns {job_id}."""
    data = request.get_json(silent=True) or {}
    switch_name = (data.get('switch_name') or '').strip()
    try:
        port_idx = int(data.get('port_idx'))
    except (TypeError, ValueError):
        return jsonify({'error': 'port_idx must be an integer'}), 400

    if not switch_name:
        return jsonify({'error': 'switch_name and port_idx required'}), 400

    # Look up switch + port in cached link_stats
    raw = db.get_state('link_stats')
    if not raw:
        return jsonify({'error': 'No link_stats data available'}), 503
    try:
        link_data = json.loads(raw)
    except Exception:
        logger.error('Failed to parse link_stats JSON in /api/diagnose')
        return jsonify({'error': 'Internal data error'}), 500

    switches = link_data.get('unifi_switches', {})
    sw = switches.get(switch_name)
    if not sw:
        return jsonify({'error': f'Switch "{switch_name}" not found'}), 404

    # Find port by port_idx
    port_data = None
    for pname, pd in sw.get('ports', {}).items():
        if pd.get('port_idx') == port_idx:
            port_data = dict(pd)
            port_data['name'] = pname
            break
    if not port_data:
        return jsonify({'error': f'Port {port_idx} not found on switch "{switch_name}"'}), 404

    # LLDP neighbor required to know which host+iface to SSH into
    lldp = port_data.get('lldp')
    if not lldp or not lldp.get('system_name'):
        return jsonify({'error': 'No LLDP neighbor data for this port'}), 400

    server_name = lldp['system_name']
    lldp_port_id = lldp.get('port_id', '')

    # Find matching host + interface in link_stats hosts
    hosts = link_data.get('hosts', {})
    server_ifaces = hosts.get(server_name)
    if not server_ifaces:
        return jsonify({'error': f'Host "{server_name}" not in link stats'}), 404

    # Match interface by LLDP port_id (exact then fuzzy)
    matched_iface = None
    if lldp_port_id and lldp_port_id in server_ifaces:
        matched_iface = lldp_port_id
    if not matched_iface and lldp_port_id:
        matched_iface = next(
            (k for k in server_ifaces if lldp_port_id in k or k in lldp_port_id),
            None
        )
    if not matched_iface:
        matched_iface = next(iter(server_ifaces), None)
    if not matched_iface:
        return jsonify({'error': 'Cannot determine server interface'}), 400

    # Resolve host IP from link_stats host data
    host_ip = (server_ifaces.get(matched_iface) or {}).get('host_ip')
    if not host_ip:
        # Fallback: use LLDP mgmt IPs
        mgmt_ips = lldp.get('mgmt_ips') or []
        host_ip = mgmt_ips[0] if mgmt_ips else None
    if not host_ip:
        return jsonify({'error': 'Cannot determine host IP for SSH'}), 400

    # Validate resolved values before passing to SSH command builder
    try:
        ipaddress.ip_address(host_ip)
    except ValueError:
        logger.error(f'Refusing diagnostic: invalid host_ip "{host_ip}" for {server_name}')
        return jsonify({'error': 'Resolved host IP is not a valid IP address'}), 400
    if not re.fullmatch(r'[a-zA-Z0-9._-]+', matched_iface):
        logger.error(f'Refusing diagnostic: invalid iface "{matched_iface}" for {server_name}')
        return jsonify({'error': 'Resolved interface name contains invalid characters'}), 400

    job_id = str(uuid.uuid4())
    with _diag_lock:
        _diag_jobs[job_id] = {'status': 'running', 'result': None, 'created_at': time.time()}

    def _run():
        try:
            cfg = _config()
            pulse = PulseClient(cfg)
            runner = diagnose.DiagnosticsRunner(pulse)
            result = runner.run(host_ip, server_name, matched_iface, port_data)
        except Exception as e:
            logger.error(f'Diagnostic job {job_id} failed: {e}', exc_info=True)
            result = {'status': 'error', 'error': str(e)}
        with _diag_lock:
            if job_id in _diag_jobs:
                _diag_jobs[job_id]['status'] = 'done'
                _diag_jobs[job_id]['result'] = result

    t = threading.Thread(target=_run, daemon=True)
    t.start()

    return jsonify({'job_id': job_id})


@app.route('/api/diagnose/<job_id>', methods=['GET'])
@require_auth
def api_diagnose_poll(job_id: str):
    """Poll a diagnostic job. Returns {status, result}."""
    with _diag_lock:
        job = _diag_jobs.get(job_id)
    if not job:
        return jsonify({'error': 'Job not found'}), 404
    return jsonify({'status': job['status'], 'result': job.get('result')})


@app.route('/health')
def health():
    """Health check endpoint (no auth). Checks DB and monitor freshness."""
    checks = {}
    overall = 'ok'

    # DB connectivity
    try:
        db.get_state('last_check')
        checks['db'] = 'ok'
    except Exception as e:
        checks['db'] = f'error: {e}'
        overall = 'degraded'

    # Monitor freshness: fail if last_check is older than 20 minutes
    try:
        last_check = db.get_state('last_check', '')
        if last_check:
            from datetime import datetime, timezone
            ts = datetime.strptime(last_check, '%Y-%m-%d %H:%M:%S UTC').replace(tzinfo=timezone.utc)
            age_s = (datetime.now(timezone.utc) - ts).total_seconds()
            if age_s > 1200:
                checks['monitor'] = f'stale ({int(age_s)}s since last check)'
                overall = 'degraded'
            else:
                checks['monitor'] = f'ok ({int(age_s)}s ago)'
        else:
            checks['monitor'] = 'no data yet'
    except Exception as e:
        checks['monitor'] = f'error: {e}'
        overall = 'degraded'

    status_code = 200 if overall == 'ok' else 503
    return jsonify({'status': overall, 'service': 'gandalf', 'checks': checks}), status_code


if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0', port=5000)