import copy
import ipaddress

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_host_overrides', __name__)

VIEW = '/view/view_host_overrides'


def _vlan_networks(cfg):
    nets = []
    for v in cfg.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, cfg):
    try:
        addr = ipaddress.IPv4Address(ip_str)
    except ValueError:
        return False
    nets = _vlan_networks(cfg)
    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_config_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)

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

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

    flash(save_config_with_snapshot(
        cfg,
        path='host_overrides', key=host, operation='add',
        before=None, after=entry,
        description=f'Added host override: {host} → {ip}',
    ), '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)

    cfg  = load_config()
    items = cfg.get('host_overrides', [])
    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)

    action = 'Enabled' if not old_enabled else 'Disabled'
    flash(save_config_with_snapshot(
        cfg,
        path='host_overrides', key=items[idx]['host'], operation='toggle',
        before={'enabled': old_enabled}, after={'enabled': not old_enabled},
        description=f'{action} host override: {items[idx]["host"]}',
    ), '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)

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

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

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

    flash(save_config_with_snapshot(
        cfg,
        path='host_overrides', key=host, operation='edit',
        before=before, after=copy.deepcopy(items[idx]),
        description=f'Edited host override: {host} → {ip}',
    ), '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)

    cfg  = load_config()
    items = cfg.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(cfg)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(VIEW)

    flash(save_config_with_snapshot(
        cfg,
        path='host_overrides', key=removed['host'], operation='delete',
        before=removed, after=None,
        description=f'Deleted host override: {removed["host"]}',
    ), 'success')
    return redirect(VIEW)