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
import re
import sanitize
import validation as validate

bp = Blueprint('action_apply_blocklists', __name__)

VIEW   = '/view/view_blocklists'

_VALID_FORMATS_STR = ', '.join(sorted(validate.VALID_BLOCKLIST_FORMATS))


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


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


def _save_as_from_name(name):
    slug = re.sub(r'[^a-z0-9_-]', '_', name.lower()).strip('_')
    return f'{slug}.conf'


def _parse_fields():
    """Parse and validate add/edit form fields. Returns (fields_dict, None) or (None, already_flashed)."""
    name        = sanitize.name(request.form.get('name', ''))
    description = sanitize.description(request.form.get('description', ''))
    fmt         = sanitize.filtervalue(request.form.get('format', ''), validate.VALID_BLOCKLIST_FORMATS)
    url         = sanitize.url(request.form.get('url', ''))

    if not name:
        flash('The configuration has not been saved because a name is required.', 'error')
        return None, True
    if not url:
        flash('The configuration has not been saved because a URL is required.', 'error')
        return None, True
    if not fmt:
        flash(f'The configuration has not been saved because the format is invalid. '
              f'Accepted formats: {_VALID_FORMATS_STR}.', 'error')
        return None, True

    return {'name': name, 'description': description, 'format': fmt, 'url': url}, None


@bp.route('/action/add_blocklist', methods=['POST'])
@require_level('administrator')
def add_blocklist():
    fields, err = _parse_fields()
    if err:
        return redirect(VIEW)

    if not _hash_ok():
        return redirect(VIEW)

    core       = load_core()
    blocklists = core.setdefault('blocklists', [])

    if any(b.get('name', '').lower() == fields['name'].lower() for b in blocklists):
        flash('The configuration has not been saved because a blocklist with that name already exists.', 'error')
        return redirect(VIEW)

    blocklists.append({
        'name':        fields['name'],
        'description': fields['description'],
        'format':      fields['format'],
        'url':         fields['url'],
        'save_as':     _save_as_from_name(fields['name']),
    })
    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/edit_blocklist', methods=['POST'])
@require_level('administrator')
def edit_blocklist():
    idx = _row_index()
    if idx is None:
        flash('Invalid request.', 'error')
        return redirect(VIEW)

    fields, err = _parse_fields()
    if err:
        return redirect(VIEW)

    if not _hash_ok():
        return redirect(VIEW)

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

    items[idx].update({
        'name':        fields['name'],
        'description': fields['description'],
        'format':      fields['format'],
        'url':         fields['url'],
    })
    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/delete_blocklist', methods=['POST'])
@require_level('administrator')
def delete_blocklist():
    idx = _row_index()
    if idx is None:
        flash('Invalid request.', 'error')
        return redirect(VIEW)

    if not _hash_ok():
        return redirect(VIEW)

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

    removed = items.pop(idx)
    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/update_blocklists', methods=['POST'])
@require_level('administrator')
def update_blocklists():
    flash(queued_msg('core update-blocklists'), 'success')
    return redirect(VIEW)