import ipaddress

from flask import Blueprint, request, redirect, flash
from auth import require_level
from config_utils import load_core, save_core, verify_core_hash, queued_msg
import sanitize
import validation as validate

bp = Blueprint('action_apply_host_overrides', __name__)

VIEW   = '/view/view_host_overrides'


def _vlan_networks(core):
    nets = []
    for v in core.get('vlans', []):
        subnet = v.get('subnet', '')
        mask   = v.get('subnet_mask', '')
        if subnet and mask:
            try:
                nets.append(ipaddress.IPv4Network(f"{subnet}/{mask}", strict=False))
            except ValueError:
                pass
    return nets


def _ip_in_vlan(ip_str, core):
    """Return True if ip_str falls within at least one configured VLAN subnet."""
    try:
        addr = ipaddress.IPv4Address(ip_str)
    except ValueError:
        return False
    nets = _vlan_networks(core)
    return not nets or any(addr in net for net in nets)


def _row_index():
    try:
        return int(request.form.get('row_index', ''))
    except (ValueError, TypeError):
        return None


def _hash_ok():
    if not verify_core_hash(request.form.get('config_hash', '')):
        flash('Configuration was modified by another session. Please refresh and try again.', 'error')
        return False
    return True


@bp.route('/action/add_host_override', methods=['POST'])
@require_level('administrator')
def add_host_override():
    description = sanitize.text(request.form.get('description', ''))
    host        = validate.domainname(request.form.get('host', ''))
    ip          = sanitize.ip(request.form.get('ip', ''))

    if not host or not ip:
        flash('Hostname and IP address are required.', 'error')
        return redirect(VIEW)

    if not _hash_ok():
        return redirect(VIEW)

    core = load_core()
    if not _ip_in_vlan(ip, core):
        flash('IP address does not fall within any configured VLAN subnet.', 'error')
        return redirect(VIEW)

    core.setdefault('host_overrides', []).append({
        'description': description,
        'host':        host,
        'ip':          ip,
        'enabled':     True,
    })
    errors = validate.validate_config(core)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(VIEW)
    save_core(core)

    flash(queued_msg('core apply'), 'success')
    return redirect(VIEW)


@bp.route('/action/toggle_host_override', methods=['POST'])
@require_level('administrator')
def toggle_host_override():
    idx = _row_index()
    if idx is None:
        flash('Invalid request.', 'error')
        return redirect(VIEW)

    if not _hash_ok():
        return redirect(VIEW)

    core  = load_core()
    items = core.get('host_overrides', [])
    if idx < 0 or idx >= len(items):
        flash('Entry not found.', 'error')
        return redirect(VIEW)

    items[idx]['enabled'] = not items[idx].get('enabled', True)
    errors = validate.validate_config(core)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(VIEW)
    save_core(core)

    flash(queued_msg('core apply'), 'success')
    return redirect(VIEW)


@bp.route('/action/edit_host_override', methods=['POST'])
@require_level('administrator')
def edit_host_override():
    idx = _row_index()
    if idx is None:
        flash('Invalid request.', 'error')
        return redirect(VIEW)

    description = sanitize.text(request.form.get('description', ''))
    host        = validate.domainname(request.form.get('host', ''))
    ip          = sanitize.ip(request.form.get('ip', ''))
    enabled     = request.form.get('enabled') == 'on'

    if not host or not ip:
        flash('Hostname and IP address are required.', 'error')
        return redirect(VIEW)

    if not _hash_ok():
        return redirect(VIEW)

    core  = load_core()
    if not _ip_in_vlan(ip, core):
        flash('IP address does not fall within any configured VLAN subnet.', 'error')
        return redirect(VIEW)

    items = core.get('host_overrides', [])
    if idx < 0 or idx >= len(items):
        flash('Entry not found.', 'error')
        return redirect(VIEW)

    items[idx].update({'description': description, 'host': host, 'ip': ip, 'enabled': enabled})
    errors = validate.validate_config(core)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(VIEW)
    save_core(core)

    flash(queued_msg('core apply'), 'success')
    return redirect(VIEW)


@bp.route('/action/delete_host_override', methods=['POST'])
@require_level('administrator')
def delete_host_override():
    idx = _row_index()
    if idx is None:
        flash('Invalid request.', 'error')
        return redirect(VIEW)

    if not _hash_ok():
        return redirect(VIEW)

    core  = load_core()
    items = core.get('host_overrides', [])
    if idx < 0 or idx >= len(items):
        flash('Entry not found.', 'error')
        return redirect(VIEW)

    removed = items.pop(idx)
    errors = validate.validate_config(core)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(VIEW)
    save_core(core)

    flash(queued_msg('core apply'), 'success')
    return redirect(VIEW)