import copy

from flask import Blueprint, request, redirect, flash
from auth import require_level
from config_utils import load_config, save_config_with_snapshot, verify_config_hash
import sanitize
import validation as validate

bp = Blueprint('action_apply_inter_vlan', __name__)

VIEW = '/view/view_inter_vlan'

_VALID_PROTOS_STR = ', '.join(sorted(validate.VALID_PROTOCOLS))


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


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


def _parse_entry():
    description  = sanitize.text(request.form.get('description', ''))
    protocol     = sanitize.filtervalue(request.form.get('protocol', ''), validate.VALID_PROTOCOLS)
    src_raw      = request.form.get('src_ip_or_subnet', '').strip()
    dst_raw      = request.form.get('dst_ip_or_subnet', '').strip()
    dst_port_raw = request.form.get('dst_port', '').strip()

    if not protocol:
        flash(f'The configuration has not been saved because the protocol is invalid. '
              f'Accepted values: {_VALID_PROTOS_STR}.', 'error')
        return None, True

    if not src_raw:
        flash('The configuration has not been saved because a source IP or subnet is required.', 'error')
        return None, True
    src = validate.ip_or_cidr(src_raw)
    if not src:
        flash(f'The configuration has not been saved because "{src_raw}" is not a valid IP address or subnet.', 'error')
        return None, True

    if not dst_raw:
        flash('The configuration has not been saved because a destination IP or subnet is required.', 'error')
        return None, True
    dst = validate.ip_or_cidr(dst_raw)
    if not dst:
        flash(f'The configuration has not been saved because "{dst_raw}" is not a valid IP address or subnet.', 'error')
        return None, True

    dst_port = ''
    if dst_port_raw:
        dst_port = validate.port(dst_port_raw)
        if not dst_port:
            flash(f'The configuration has not been saved because "{dst_port_raw}" is not a valid port number (1-65535).', 'error')
            return None, True

    return {
        'description':      description,
        'protocol':         protocol,
        'src_ip_or_subnet': src,
        'dst_ip_or_subnet': dst,
        'dst_port':         dst_port,
        'enabled':          True,
    }, None


def _entry_key(entry):
    port = f':{entry["dst_port"]}' if entry.get('dst_port') else ''
    return f'{entry["protocol"]}:{entry["src_ip_or_subnet"]}→{entry["dst_ip_or_subnet"]}{port}'


@bp.route('/action/add_inter_vlan', methods=['POST'])
@require_level('administrator')
def add_inter_vlan():
    entry, err = _parse_entry()
    if err:
        return redirect(VIEW)
    if not _hash_ok():
        return redirect(VIEW)

    cfg = load_config()
    cfg.setdefault('inter_vlan_exceptions', []).append(entry)
    errors = validate.validate_config(cfg)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(VIEW)

    key = _entry_key(entry)
    flash(save_config_with_snapshot(
        cfg,
        path='inter_vlan_exceptions', key=key, operation='add',
        before=None, after=entry,
        description=f'Added inter-VLAN rule: {key}',
    ), 'success')
    return redirect(VIEW)


@bp.route('/action/toggle_inter_vlan', methods=['POST'])
@require_level('administrator')
def toggle_inter_vlan():
    idx = _row_index()
    if idx is None:
        flash('Invalid request.', 'error')
        return redirect(VIEW)
    if not _hash_ok():
        return redirect(VIEW)

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

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

    key    = _entry_key(items[idx])
    action = 'Enabled' if not old_enabled else 'Disabled'
    flash(save_config_with_snapshot(
        cfg,
        path='inter_vlan_exceptions', key=key, operation='toggle',
        before={'enabled': old_enabled}, after={'enabled': not old_enabled},
        description=f'{action} inter-VLAN rule: {key}',
    ), 'success')
    return redirect(VIEW)


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

    entry, err = _parse_entry()
    if err:
        return redirect(VIEW)
    if not _hash_ok():
        return redirect(VIEW)

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

    before        = copy.deepcopy(items[idx])
    items[idx]    = entry
    items[idx]['enabled'] = request.form.get('enabled') == 'on'
    errors = validate.validate_config(cfg)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(VIEW)

    key = _entry_key(entry)
    flash(save_config_with_snapshot(
        cfg,
        path='inter_vlan_exceptions', key=key, operation='edit',
        before=before, after=copy.deepcopy(items[idx]),
        description=f'Edited inter-VLAN rule: {key}',
    ), 'success')
    return redirect(VIEW)


@bp.route('/action/delete_inter_vlan', methods=['POST'])
@require_level('administrator')
def delete_inter_vlan():
    idx = _row_index()
    if idx is None:
        flash('Invalid request.', 'error')
        return redirect(VIEW)
    if not _hash_ok():
        return redirect(VIEW)

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

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

    key = _entry_key(removed)
    flash(save_config_with_snapshot(
        cfg,
        path='inter_vlan_exceptions', key=key, operation='delete',
        before=removed, after=None,
        description=f'Deleted inter-VLAN rule: {key}',
    ), 'success')
    return redirect(VIEW)