import os

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,
                          flush_pending_to_queue, get_dashboard_pending,
                          _is_locked, _format_timing, _seconds_until_next_run)
import sanitize
import validation as validate

bp = Blueprint('action_general', __name__)

_VIEW = '/view/view_general'

_EXCLUDE_PREFIXES = ('lo', 'wg', 'docker', 'br-', 'veth',
                     'tun', 'tap', 'ppp', 'virbr',
                     'podman', 'vnet', 'macvtap', 'fc-')


def _get_system_interfaces():
    try:
        return {
            n for n in os.listdir('/sys/class/net')
            if not n.startswith(_EXCLUDE_PREFIXES)
            and os.path.exists(f'/sys/class/net/{n}/device')
        }
    except Exception:
        return set()


@bp.route('/action/general_cardnetworkinterface_save', methods=['POST'])
@require_level('administrator')
def general_cardnetworkinterface_save():
    wan = sanitize.interface_name(request.form.get('wan_interface', ''))
    lan = sanitize.interface_name(request.form.get('lan_interface', ''))

    if not wan or not lan:
        flash('Both WAN and LAN interfaces are required.', 'error')
        return redirect(_VIEW)

    if wan == lan:
        flash('WAN and LAN interfaces must be different.', 'error')
        return redirect(_VIEW)

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

    available = _get_system_interfaces()
    for iface in (wan, lan):
        if available and iface not in available:
            flash(f"Interface '{iface}' does not exist on this system.", 'error')
            return redirect(_VIEW)

    core = load_core()
    gen  = core.setdefault('general', {})
    gen['wan_interface'] = wan
    gen['lan_interface'] = lan
    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/general_cardupstreamdns_save', methods=['POST'])
@require_level('administrator')
def general_cardupstreamdns_save():
    strict_order   = 'strict_order' in request.form
    cache_size_raw = request.form.get('cache_size', '').strip()
    submitted      = request.form.getlist('upstream_servers')

    for s in submitted:
        if not s.strip():
            flash('Remove blank server entries before saving.', 'error')
            return redirect(_VIEW)

    upstream_servers = []
    for s in submitted:
        clean = sanitize.ip(s.strip())
        if not clean:
            flash(f"'{s.strip()}' is not a valid IP address.", 'error')
            return redirect(_VIEW)
        upstream_servers.append(clean)

    cache_size = validate.int_range(cache_size_raw, 0, None)
    if cache_size is None:
        flash('Cache Size must be a non-negative integer.', 'error')
        return redirect(_VIEW)

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

    core    = load_core()
    current = core.get('upstream_dns', {})
    if (strict_order   == bool(current.get('strict_order', False)) and
            cache_size == int(current.get('cache_size', 0)) and
            upstream_servers == current.get('upstream_servers', [])):
        flash('No changes detected.', 'info')
        return redirect(_VIEW)

    core.setdefault('upstream_dns', {}).update({
        'strict_order':     strict_order,
        'cache_size':       cache_size,
        'upstream_servers': upstream_servers,
    })
    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/general_cardlogging_save', methods=['POST'])
@require_level('administrator')
def general_cardlogging_save():
    log_max_kb_raw      = request.form.get('log_max_kb', '').strip()
    log_errors_only     = 'log_errors_only' in request.form
    dnsmasq_log_queries = 'dnsmasq_log_queries' in request.form

    log_max_kb = validate.int_range(log_max_kb_raw, 64, None)
    if log_max_kb is None:
        flash('Max Log Size must be a number >= 64.', 'error')
        return redirect(_VIEW)

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

    core = load_core()
    core.setdefault('general', {}).update({
        'log_max_kb':          log_max_kb,
        'log_errors_only':     log_errors_only,
        'dnsmasq_log_queries': dnsmasq_log_queries,
    })
    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/general_cardpendingchanges_save', methods=['POST'])
@require_level('administrator')
def general_cardpendingchanges_save():
    if not verify_core_hash(request.form.get('config_hash', '')):
        flash('Configuration was modified by another session. Please refresh and try again.', 'error')
        return redirect(_VIEW)

    core = load_core()
    core.setdefault('general', {})['apply_on_save'] = 'apply_on_save' in request.form
    save_core(core)

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


@bp.route('/action/general_cardpendingchanges_applyselected', methods=['POST'])
@require_level('administrator')
def general_cardpendingchanges_applyselected():
    items = get_dashboard_pending()
    if not items:
        flash('No pending changes to apply.', 'info')
        return redirect(_VIEW)
    flush_pending_to_queue()
    if _is_locked():
        msg = 'Changes queued. They are being applied now.'
    else:
        timing = _format_timing(_seconds_until_next_run())
        if timing:
            msg = f'Changes queued. They will be applied {timing}.'
        else:
            msg = 'Changes queued. The processing service is not running.'
    flash(msg, 'success')
    return redirect(_VIEW)


@bp.route('/action/general_cardpendingchanges_deleteselected', methods=['POST'])
@require_level('administrator')
def general_cardpendingchanges_deleteselected():
    flash('Not yet implemented.', 'info')
    return redirect(_VIEW)