from __future__ import annotations

from django.contrib import messages
from django.http import HttpResponseRedirect
from wagtail import hooks

from .types import format_issue, split_issues
from .validators.multilingual import validate_page, validate_posted_snippet, validate_snippet_instance


def _flash_issues(request, level, prefix: str, issues):
    preview = issues[:6]
    for issue in preview:
        messages.add_message(request, level, f"{prefix}: {format_issue(issue)}")
    remaining = len(issues) - len(preview)
    if remaining > 0:
        messages.add_message(request, level, f"{prefix}: {remaining} more issue(s) not shown.")


@hooks.register("before_publish_page")
def prevent_corrupt_multilingual_publish(request, page):
    issues = validate_page(page)
    blocking, warnings = split_issues(issues)
    if warnings:
        _flash_issues(request, messages.WARNING, "Content guard warning", warnings)
    if not blocking:
        return None
    _flash_issues(request, messages.ERROR, "Publishing blocked", blocking)
    return HttpResponseRedirect(request.path)


@hooks.register("after_edit_page")
def warn_on_corrupt_multilingual_draft(request, page):
    blocking, warnings = split_issues(validate_page(page))
    if blocking:
        _flash_issues(request, messages.WARNING, "Draft warning", blocking)
    if warnings:
        _flash_issues(request, messages.WARNING, "Draft warning", warnings)


def _snippet_locale_code(instance, request) -> str:
    posted_locale = request.POST.get("locale") if request.method == "POST" else None
    if posted_locale:
        return posted_locale
    locale = getattr(instance, "locale", None)
    if locale is not None and getattr(locale, "language_code", None):
        return locale.language_code
    return "nl"


def _validate_snippet_request(request, instance):
    if request.method != "POST":
        return None
    issues = validate_posted_snippet(_snippet_locale_code(instance, request), request.POST.dict())
    blocking, warnings = split_issues(issues)
    if warnings:
        _flash_issues(request, messages.WARNING, "Snippet warning", warnings)
    if not blocking:
        return None
    _flash_issues(request, messages.ERROR, "Snippet save blocked", blocking)
    return HttpResponseRedirect(request.path)


@hooks.register("before_create_snippet")
def prevent_corrupt_snippet_create(request, model):
    instance = model()
    posted_locale = request.GET.get("locale") or request.POST.get("locale")
    if posted_locale and hasattr(instance, "locale_id"):
        from wagtail.models import Locale

        instance.locale = Locale.objects.get(language_code=posted_locale)
    return _validate_snippet_request(request, instance)


@hooks.register("before_edit_snippet")
def prevent_corrupt_snippet_edit(request, instance):
    return _validate_snippet_request(request, instance)


def _warn_saved_snippet(request, instance):
    blocking, warnings = split_issues(validate_snippet_instance(instance))
    if blocking:
        _flash_issues(request, messages.WARNING, "Snippet integrity warning", blocking)
    if warnings:
        _flash_issues(request, messages.WARNING, "Snippet integrity warning", warnings)


@hooks.register("after_create_snippet")
def warn_on_saved_snippet_create(request, instance):
    _warn_saved_snippet(request, instance)


@hooks.register("after_edit_snippet")
def warn_on_saved_snippet_edit(request, instance):
    _warn_saved_snippet(request, instance)