import os
from typing import List

from django.core.exceptions import PermissionDenied, SuspiciousOperation
from django.db import transaction
from django.shortcuts import get_object_or_404, redirect, render
from django.template.response import TemplateResponse
from django.urls import reverse
from django.utils.encoding import force_str
from django.utils.functional import cached_property
from django.utils.translation import gettext as _
from django.utils.translation import gettext_lazy, ngettext
from django.views.decorators.http import require_http_methods

from wagtail.admin import messages
from wagtail.admin.auth import PermissionPolicyChecker
from wagtail.admin.forms.search import SearchForm
from wagtail.admin.ui.tables import Column, StatusTagColumn, TitleColumn
from wagtail.admin.views import generic
from wagtail.admin.widgets.button import Button
from wagtail.contrib.redirects import models
from wagtail.contrib.redirects.filters import RedirectsReportFilterSet
from wagtail.contrib.redirects.forms import (
    ConfirmImportForm,
    ConfirmImportManagementForm,
    ImportForm,
    RedirectForm,
)
from wagtail.contrib.redirects.models import Redirect
from wagtail.contrib.redirects.permissions import permission_policy
from wagtail.contrib.redirects.utils import (
    get_file_storage,
    get_format_cls_by_extension,
    get_import_formats,
    get_supported_extensions,
    write_to_file_storage,
)
from wagtail.log_actions import log

permission_checker = PermissionPolicyChecker(permission_policy)


class RedirectTargetColumn(Column):
    cell_template_name = "wagtailredirects/redirect_target_cell.html"
    url_name = "wagtailadmin_pages:edit"

    def get_value(self, instance):
        if instance.redirect_page_id:
            return instance.redirect_page.get_admin_display_title()
        return instance.redirect_link

    def get_url(self, instance):
        if instance.redirect_page_id:
            return reverse(self.url_name, args=[instance.redirect_page_id])
        return None

    def get_cell_context_data(self, instance, parent_context):
        context = super().get_cell_context_data(instance, parent_context)
        context["url"] = self.get_url(instance)
        return context


class IndexView(generic.IndexView):
    template_name = "wagtailredirects/index.html"
    results_template_name = "wagtailredirects/index_results.html"
    permission_policy = permission_policy
    model = Redirect
    header_icon = "redirect"
    add_item_label = gettext_lazy("Add redirect")
    context_object_name = "redirects"
    index_url_name = "wagtailredirects:index"
    index_results_url_name = "wagtailredirects:index_results"
    add_url_name = "wagtailredirects:add"
    edit_url_name = "wagtailredirects:edit"
    delete_url_name = "wagtailredirects:delete"
    default_ordering = "old_path"
    paginate_by = 20
    page_title = gettext_lazy("Redirects")
    search_fields = ["old_path", "redirect_page__url_path", "redirect_link"]
    _show_breadcrumbs = True
    columns = [
        TitleColumn(
            "old_path",
            label=gettext_lazy("From"),
            url_name="wagtailredirects:edit",
            sort_key="old_path",
        ),
        Column(
            "site",
            label=gettext_lazy("Site"),
            width="25%",
            sort_key="site__site_name",
        ),
        RedirectTargetColumn(
            "redirect_page",
            label=gettext_lazy("To"),
            width="30%",
        ),
        StatusTagColumn(
            "is_permanent",
            accessor="get_is_permanent_display",
            label=gettext_lazy("Type"),
            width="10%",
            sort_key="is_permanent",
            primary=lambda r: r.is_permanent,
        ),
    ]
    filterset_class = RedirectsReportFilterSet
    list_export = [
        "old_path",
        "link",
        "get_is_permanent_display",
        "site",
    ]
    export_headings = {
        "old_path": _("From"),
        "site": _("Site"),
        "link": _("To"),
        "get_is_permanent_display": _("Type"),
    }

    def get_base_queryset(self):
        return super().get_base_queryset().select_related("redirect_page", "site")

    @cached_property
    def header_more_buttons(self) -> List[Button]:
        buttons = super().header_more_buttons.copy()
        buttons.append(
            Button(
                _("Import redirects"),
                url=reverse("wagtailredirects:start_import"),
                icon_name="doc-full-inverse",
                priority=50,
            )
        )
        return buttons


class EditView(generic.EditView):
    model = Redirect
    form_class = RedirectForm
    permission_policy = permission_policy
    template_name = "wagtailredirects/edit.html"
    index_url_name = "wagtailredirects:index"
    edit_url_name = "wagtailredirects:edit"
    delete_url_name = "wagtailredirects:delete"
    pk_url_kwarg = "redirect_id"
    error_message = gettext_lazy("The redirect could not be saved due to errors.")
    header_icon = "redirect"
    _show_breadcrumbs = True

    def get_success_message(self):
        return _("Redirect '%(redirect_title)s' updated.") % {
            "redirect_title": self.object.title
        }


@permission_checker.require("delete")
def delete(request, redirect_id):
    theredirect = get_object_or_404(models.Redirect, id=redirect_id)

    if not permission_policy.user_has_permission_for_instance(
        request.user, "delete", theredirect
    ):
        raise PermissionDenied

    if request.method == "POST":
        with transaction.atomic():
            log(instance=theredirect, action="wagtail.delete")
            theredirect.delete()
        messages.success(
            request,
            _("Redirect '%(redirect_title)s' deleted.")
            % {"redirect_title": theredirect.title},
        )
        return redirect("wagtailredirects:index")

    return TemplateResponse(
        request,
        "wagtailredirects/confirm_delete.html",
        {
            "redirect": theredirect,
        },
    )


@permission_checker.require("add")
def add(request):
    if request.method == "POST":
        form = RedirectForm(request.POST, request.FILES)
        if form.is_valid():
            with transaction.atomic():
                theredirect = form.save()
                log(instance=theredirect, action="wagtail.create")

            messages.success(
                request,
                _("Redirect '%(redirect_title)s' added.")
                % {"redirect_title": theredirect.title},
                buttons=[
                    messages.button(
                        reverse("wagtailredirects:edit", args=(theredirect.id,)),
                        _("Edit"),
                    )
                ],
            )
            return redirect("wagtailredirects:index")
        else:
            messages.error(
                request, _("The redirect could not be created due to errors.")
            )
    else:
        form = RedirectForm()

    return TemplateResponse(
        request,
        "wagtailredirects/add.html",
        {
            "form": form,
        },
    )


@permission_checker.require_any("add")
def start_import(request):
    supported_extensions = get_supported_extensions()
    from_encoding = "utf-8"

    query_string = request.GET.get("q", "")

    if request.POST or request.FILES:
        form_kwargs = {}
        form = ImportForm(
            supported_extensions,
            request.POST or None,
            request.FILES or None,
            **form_kwargs,
        )
    else:
        form = ImportForm(supported_extensions)

    if not request.FILES or not form.is_valid():
        return render(
            request,
            "wagtailredirects/choose_import_file.html",
            {
                "search_form": SearchForm(
                    data={"q": query_string} if query_string else None,
                    placeholder=_("Search redirects"),
                ),
                "form": form,
            },
        )

    import_file = form.cleaned_data["import_file"]

    _name, extension = os.path.splitext(import_file.name)
    extension = extension.lstrip(".")

    if extension not in supported_extensions:
        messages.error(
            request,
            _('File format of type "%(extension)s" is not supported')
            % {"extension": extension},
        )
        return redirect("wagtailredirects:start_import")

    import_format_cls = get_format_cls_by_extension(extension)
    input_format = import_format_cls()
    file_storage = write_to_file_storage(import_file, input_format)

    try:
        data = file_storage.read(input_format.get_read_mode())
        if not input_format.is_binary() and from_encoding:
            data = force_str(data, from_encoding)
        dataset = input_format.create_dataset(data)
    except UnicodeDecodeError as e:
        messages.error(
            request,
            _("Imported file has a wrong encoding: %(error_message)s")
            % {"error_message": e},
        )
        return redirect("wagtailredirects:start_import")
    except Exception as e:  # noqa: BLE001; pragma: no cover
        messages.error(
            request,
            _("%(error)s encountered while trying to read file: %(filename)s")
            % {"error": type(e).__name__, "filename": import_file.name},
        )
        return redirect("wagtailredirects:start_import")

    # This data is needed in the processing step, so it is stored in
    # hidden form fields as signed strings (signing happens in the form).
    initial = {
        "import_file_name": os.path.basename(file_storage.name),
        "input_format": get_import_formats().index(import_format_cls),
    }

    return render(
        request,
        "wagtailredirects/confirm_import.html",
        {
            "form": ConfirmImportForm(dataset.headers, initial=initial),
            "dataset": dataset,
        },
    )


@permission_checker.require_any("add")
@require_http_methods(["POST"])
def process_import(request):
    supported_extensions = get_supported_extensions()
    from_encoding = "utf-8"

    management_form = ConfirmImportManagementForm(request.POST)
    if not management_form.is_valid():
        # Unable to unsign the hidden form data, or the data is missing, that's suspicious.
        raise SuspiciousOperation(
            f"Invalid management form, data is missing or has been tampered with:\n"
            f"{management_form.errors.as_text()}"
        )

    input_format = get_import_formats()[
        int(management_form.cleaned_data["input_format"])
    ]()

    FileStorage = get_file_storage()
    file_storage = FileStorage(name=management_form.cleaned_data["import_file_name"])

    data = file_storage.read(input_format.get_read_mode())
    if not input_format.is_binary() and from_encoding:
        data = force_str(data, from_encoding)
    dataset = input_format.create_dataset(data)

    # Now check if the rest of the management form is valid
    form = ConfirmImportForm(
        dataset.headers,
        request.POST,
        request.FILES,
        initial=management_form.cleaned_data,
    )

    if not form.is_valid():
        return render(
            request,
            "wagtailredirects/confirm_import.html",
            {
                "form": form,
                "dataset": dataset,
            },
        )

    import_summary = create_redirects_from_dataset(
        dataset,
        {
            "from_index": int(form.cleaned_data["from_index"]),
            "to_index": int(form.cleaned_data["to_index"]),
            "permanent": form.cleaned_data["permanent"],
            "site": form.cleaned_data["site"],
        },
    )

    file_storage.remove()

    if import_summary["errors_count"] > 0:
        return render(
            request,
            "wagtailredirects/import_summary.html",
            {
                "form": ImportForm(supported_extensions),
                "import_summary": import_summary,
            },
        )

    total = import_summary["total"]
    messages.success(
        request,
        ngettext("Imported %(total)d redirect", "Imported %(total)d redirects", total)
        % {"total": total},
    )

    return redirect("wagtailredirects:index")


def create_redirects_from_dataset(dataset, config):
    errors = []
    successes = 0
    total = 0

    for row in dataset:
        total += 1

        from_link = row[config["from_index"]]
        to_link = row[config["to_index"]]

        data = {
            "old_path": from_link,
            "redirect_link": to_link,
            "is_permanent": config["permanent"],
        }

        if config["site"]:
            data["site"] = config["site"].pk

        form = RedirectForm(data)
        if not form.is_valid():
            error = to_readable_errors(form.errors.as_text())
            errors.append([from_link, to_link, error])
            continue

        with transaction.atomic():
            redirect = form.save()
            log(instance=redirect, action="wagtail.create")
        successes += 1

    return {
        "errors": errors,
        "errors_count": len(errors),
        "successes": successes,
        "total": total,
    }


def to_readable_errors(error):
    errors = error.split("\n")
    errors = errors[1::2]
    errors = [x.lstrip("* ") for x in errors]
    errors = ", ".join(errors)
    return errors