from pathlib import Path
import copy
from flask import Blueprint, request, redirect, flash
from auth import require_level
from config_utils import load_config, record_group, diff_fields, verify_config_hash
import sanitize
import mod_validation as validate

_PAGE = Path(__file__).parent.name

bp = Blueprint(_PAGE, __name__)

@bp.route('/action/dnsserver/upstreamdns_save', methods=['POST'])
@require_level('administrator')
def upstreamdns_save():
    strict_order = 'strict_order' in request.form
    submitted    = request.form.getlist('upstream_servers')

    for s in submitted:
        if not s.strip():
            flash('Remove blank server entries before saving.', 'error')
            return redirect(f'/{_PAGE}')

    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(f'/{_PAGE}')
        upstream_servers.append(clean)

    if not verify_config_hash(request.form.get('config_hash', '')):
        flash('Configuration was modified by another session. Please refresh and try again.', 'error')
        return redirect(f'/{_PAGE}')

    cfg    = load_config()
    before = copy.deepcopy(cfg.get('upstream_dns', {}))
    current = cfg.get('upstream_dns', {})
    if (strict_order == bool(current.get('strict_order', False)) and
            upstream_servers == current.get('upstream_servers', [])):
        flash('No changes detected.', 'info')
        return redirect(f'/{_PAGE}')

    cfg.setdefault('upstream_dns', {}).update({
        'strict_order':     strict_order,
        'upstream_servers': upstream_servers,
    })
    errors = validate.validate_config(cfg)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(f'/{_PAGE}')
    changes = diff_fields(before, cfg['upstream_dns'])
    flash(record_group(cfg, 'upstream_dns', None, None, changes, 'core apply'), 'success')
    return redirect(f'/{_PAGE}')


@bp.route('/action/dnsserver/dnsforwarding_save', methods=['POST'])
@require_level('administrator')
def dnsforwarding_save():
    cache_size = validate.int_range(request.form.get('cache_size', '').strip(), 0, None)
    if cache_size is None:
        flash('Cache Size must be a non-negative integer.', 'error')
        return redirect(f'/{_PAGE}')

    if not verify_config_hash(request.form.get('config_hash', '')):
        flash('Configuration was modified by another session. Please refresh and try again.', 'error')
        return redirect(f'/{_PAGE}')

    cfg    = load_config()
    before = copy.deepcopy(cfg.get('upstream_dns', {}))
    current = cfg.get('upstream_dns', {})
    if cache_size == int(current.get('cache_size', 0)):
        flash('No changes detected.', 'info')
        return redirect(f'/{_PAGE}')

    cfg.setdefault('upstream_dns', {})['cache_size'] = cache_size
    errors = validate.validate_config(cfg)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(f'/{_PAGE}')
    changes = diff_fields(before, cfg['upstream_dns'])
    flash(record_group(cfg, 'upstream_dns', None, None, changes, 'core apply'), 'success')
    return redirect(f'/{_PAGE}')