"""Deterministic interaction endpoints: no models, storage, or external calls."""
from __future__ import annotations

from django.contrib import messages
from django.core.paginator import Paginator
from django.http import HttpRequest, HttpResponse, HttpResponseBadRequest
from django.shortcuts import redirect, render
from django.urls import reverse
from django.utils.cache import patch_vary_headers
from django.utils.safestring import mark_safe
from django.utils.translation import gettext as _
from django.views.decorators.http import require_http_methods, require_POST

from .forms import FilterForm, LanguageForm, MessageForm, UploadForm

LANGUAGES = (("python", "Python"), ("django", "Django"), ("htmx", "HTMX"), ("alpine", "Alpine"))
ROWS = tuple({"name": name, "status": status} for name, status in (
    ("Modal response", "ready"), ("Combobox endpoint", "draft"), ("Toast delivery", "ready"),
    ("No-JavaScript floor", "draft"), ("Slide-over focus", "ready"), ("Tooltip focus", "draft"),
    ("Dropdown links", "ready"), ("Native disclosure", "draft"), ("Tag input carrier", "ready"),
    ("Dropzone metadata", "draft"), ("Table selection", "ready"), ("Search request", "draft"),
))


def _htmx(request: HttpRequest) -> bool:
    return request.headers.get("HX-Request") == "true"


def _branch(request: HttpRequest, partial: str, page: str, context: dict, status: int = 200) -> HttpResponse:
    response = render(request, partial if _htmx(request) else page, context, status=status)
    patch_vary_headers(response, ("HX-Request",))
    return response


def _page(request: HttpRequest, template: str, **context) -> HttpResponse:
    return render(request, template, context)


def index(request): return _page(request, "component_cookbook/index.html")
def dropdown(request):
    return _page(request, "component_cookbook/dropdown.html", items=[
        {"label": _("Open cookbook"), "url": reverse("component_cookbook:index"), "icon": "external-link"},
        {"divider": True}, {"label": _("Delete draft"), "url": "#delete", "variant": "danger", "icon": "trash"},
    ])
def tabs(request):
    active = request.GET.get("tab", "overview")
    if active not in {"overview", "api"}:
        return HttpResponseBadRequest("Unknown cookbook tab.")
    return _page(request, "component_cookbook/tabs.html", active=active, tabs=[{"key": "overview", "label": _("Overview")}, {"key": "api", "label": "API"}], overview=mark_safe("<p>Overview content comes from this consumer template.</p>"), api=mark_safe("<p>The API panel uses the same package tab relationship.</p>"))
def tooltip(request): return _page(request, "component_cookbook/tooltip.html", tooltip_id="cookbook-tooltip", text=_("Explains the button"), placement="top")
def disclosure(request): return _page(request, "component_cookbook/disclosure.html")
def tag_input(request): return _page(request, "component_cookbook/tag_input.html")


def modal(request):
    return _branch(request, "component_cookbook/partials/modal.html", "component_cookbook/modal.html", {"form": MessageForm(), "modal_id": "cookbook-message-modal", "close_href": reverse("component_cookbook:index")})


@require_POST
def modal_submit(request):
    form = MessageForm(request.POST)
    context = {"form": form, "modal_id": "cookbook-message-modal", "close_href": reverse("component_cookbook:index")}
    if not form.is_valid():
        return _branch(request, "component_cookbook/partials/modal.html", "component_cookbook/modal.html", context, 422 if _htmx(request) else 200)
    if _htmx(request):
        response = HttpResponse(status=204)
        response["HX-Trigger"] = '{"bw:modal:close": {"id": "cookbook-message-modal"}}'
        return response
    messages.success(request, _("The demo accepted your message without saving it."))
    return redirect("component_cookbook:modal")


def slide_over(request):
    size = request.GET.get("size", "md")
    placement = request.GET.get("placement", "end")
    if size not in {"sm", "md", "lg"} or placement not in {"start", "end"}:
        return HttpResponseBadRequest("Invalid slide-over options.")
    return _branch(request, "component_cookbook/partials/slide_over.html", "component_cookbook/slide_over.html", {"close_href": reverse("component_cookbook:index"), "size": size, "placement": placement})


@require_POST
def toggle(request):
    return _branch(request, "component_cookbook/partials/toggle_outcome.html", "component_cookbook/toggle.html", {"enabled": request.POST.get("notices") == "on"})


@require_POST
def toast(request):
    if not _htmx(request):
        messages.success(request, _("The server delivered this demonstration outcome."))
        response = redirect("component_cookbook:toast-page")
    else:
        response = render(request, "component_cookbook/partials/toast_oob.html")
    patch_vary_headers(response, ("HX-Request",))
    return response


def toast_page(request):
    return _page(request, "component_cookbook/toast_region.html")


def toast_region(request):
    return _page(request, "component_cookbook/toast_region.html")


def combobox(request): return _page(request, "component_cookbook/combobox.html", form=LanguageForm(), options_url=reverse("component_cookbook:combobox-options"))


def combobox_options(request):
    query = request.GET.get("q", "").strip().casefold()[:40]
    return render(request, "component_cookbook/partials/combobox_options.html", {"choices": [choice for choice in LANGUAGES if not query or query in choice[1].casefold()]})


@require_POST
def combobox_submit(request):
    form = LanguageForm(request.POST)
    context = {"form": form, "options_url": reverse("component_cookbook:combobox-options")}
    if form.is_valid():
        context["selected_label"] = dict(LANGUAGES)[form.cleaned_data["language"]]
    return _branch(request, "component_cookbook/partials/combobox_form.html", "component_cookbook/combobox.html", context, 422 if _htmx(request) and not form.is_valid() else 200)


def _rows(query: str, status: str):
    return [row for row in ROWS if (not query or query.casefold() in row["name"].casefold()) and (not status or row["status"] == status)]


def table(request):
    form = FilterForm(request.GET)
    query, status = (form.cleaned_data["q"], form.cleaned_data["status"]) if form.is_valid() else ("", "")
    context = {"filter_form": form, "page_obj": Paginator(_rows(query, status), 4).get_page(request.GET.get("page", 1)), "table_url": reverse("component_cookbook:table"), "form_invalid": not form.is_valid()}
    return _branch(request, "component_cookbook/partials/table_region.html", "component_cookbook/table.html", context)


def search(request):
    query = request.GET.get("q", "").strip()[:40]
    return _page(request, "component_cookbook/search.html", query=query, result_count=len(_rows(query, "")), search_url=reverse("component_cookbook:search"))


@require_http_methods(["GET", "POST"])
def upload(request):
    if request.method == "GET":
        return _page(request, "component_cookbook/upload.html", form=UploadForm())
    form = UploadForm(request.POST, request.FILES)
    context = {"form": form}
    if form.is_valid():
        uploaded = form.cleaned_data["file"]
        context["outcome"] = _("Validated %(name)s (%(size)s bytes). The application did not retain it.") % {"name": uploaded.name, "size": uploaded.size}
        context["form"] = UploadForm()
    return _branch(request, "component_cookbook/partials/upload_form.html", "component_cookbook/upload.html", context, 422 if _htmx(request) and not form.is_valid() else 200)