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__)

_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)
    dest_port_raw = request.form.get('dest_port', '').strip()
    nat_ip_raw    = request.form.get('nat_ip',    '').strip()
    nat_port_raw  = request.form.get('nat_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 dest_port_raw:
        flash('The configuration has not been saved because the external port is required.', 'error')
        return None, True
    dest_port = validate.port(dest_port_raw)
    if not dest_port:
        flash(f'The configuration has not been saved because "{dest_port_raw}" is not a valid port number (1-65535).', 'error')
        return None, True

    if not nat_ip_raw:
        flash('The configuration has not been saved because the NAT IP address is required.', 'error')
        return None, True
    nat_ip = validate.ip(nat_ip_raw)
    if not nat_ip:
        flash(f'The configuration has not been saved because "{nat_ip_raw}" is not a valid IP address.', 'error')
        return None, True

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

    return {
        'description': description,
        'protocol':    protocol,
        'dest_port':   dest_port,
        'nat_ip':      nat_ip,
        'nat_port':    nat_port,
        'enabled':     True,
    }, None


@bp.route('/action/portforwarding/addrule_add', methods=['POST'])
@require_level('administrator')
def addrule_add():
    entry, err = _parse_entry()
    if err:
        return redirect(f'/{_PAGE}')
    if not _hash_ok():
        return redirect(f'/{_PAGE}')

    cfg = load_config()
    cfg.setdefault('port_forwarding', []).append(entry)
    errors = validate.validate_config(cfg)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(f'/{_PAGE}')

    dest_port = entry.get('dest_port', '')
    changes = diff_fields(None, entry)
    flash(record_group(cfg, 'port_forwarding', 'dest_port', dest_port, changes, 'core apply'), 'success')
    return redirect(f'/{_PAGE}')


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

    cfg  = load_config()
    items = cfg.get('port_forwarding', [])
    if idx < 0 or idx >= len(items):
        flash('Entry not found.', 'error')
        return redirect(f'/{_PAGE}')

    old_enabled        = items[idx].get('enabled', True)
    before             = copy.deepcopy(items[idx])
    items[idx]['enabled'] = not old_enabled
    errors = validate.validate_config(cfg)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(f'/{_PAGE}')

    dest_port = items[idx].get('dest_port', '')
    changes = diff_fields(before, items[idx])
    flash(record_group(cfg, 'port_forwarding', 'dest_port', dest_port, changes, 'core apply'), 'success')
    return redirect(f'/{_PAGE}')


@bp.route('/action/portforwarding/rules_edit', methods=['POST'])
@require_level('administrator')
def rules_edit():
    idx = _row_index()
    if idx is None:
        flash('Invalid request.', 'error')
        return redirect(f'/{_PAGE}')

    entry, err = _parse_entry()
    if err:
        return redirect(f'/{_PAGE}')
    if not _hash_ok():
        return redirect(f'/{_PAGE}')

    cfg  = load_config()
    items = cfg.get('port_forwarding', [])
    if idx < 0 or idx >= len(items):
        flash('Entry not found.', 'error')
        return redirect(f'/{_PAGE}')

    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(f'/{_PAGE}')

    dest_port = items[idx].get('dest_port', '')
    changes = diff_fields(before, items[idx])
    flash(record_group(cfg, 'port_forwarding', 'dest_port', dest_port, changes, 'core apply'), 'success')
    return redirect(f'/{_PAGE}')


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

    cfg  = load_config()
    items = cfg.get('port_forwarding', [])
    if idx < 0 or idx >= len(items):
        flash('Entry not found.', 'error')
        return redirect(f'/{_PAGE}')

    removed = items.pop(idx)
    errors = validate.validate_config(cfg)
    if errors:
        for msg in errors:
            flash(msg, 'error')
        return redirect(f'/{_PAGE}')

    dest_port = removed.get('dest_port', '')
    changes = diff_fields(removed, None)
    flash(record_group(cfg, 'port_forwarding', 'dest_port', dest_port, changes, 'core apply'), 'success')
    return redirect(f'/{_PAGE}')