import React, { useMemo, useState } from 'react';
import { useTranslation } from 'react-i18next';
import type { TFunction } from 'i18next';
import { ColumnDef } from '@tanstack/react-table';
import { Info, Trash2 } from 'lucide-react';
import { Link, useNavigate } from 'react-router-dom';
import { useTickets, useDeleteTicket, useTicketStats } from '@/hooks/useTickets';
import { useExploreView } from '@/hooks/useExploreView';
import { useAdmin } from '@/hooks/useAdmins';
import { Ticket, TicketListParams } from '@/types/api';
import { getSavedPageSize } from '@/utils/tablePagination';
import { formatStatusLabel } from '@/utils/statusLabels';
import { ExploreListShell } from '@/components/explore/ExploreListShell';
import { ExploreDataView } from '@/components/explore/ExploreDataView';
import { RowActionsMenu, type RowAction } from '@/components/explore/RowActionsMenu';
import type { DenseRowModel } from '@/components/explore/DenseRowList';
import { Button } from '@/components/ui/button';
import { Badge } from '@/components/ui/badge';
import {
    Dialog,
    DialogContent,
    DialogFooter,
    DialogHeader,
    DialogTitle,
} from '@/components/ui/dialog';
import { Skeleton } from '@/components/ui/skeleton';

const TABLE_KEY = 'tickets';

const isBadValue = (val: unknown) =>
    val === '-' || val === 'undefined' || val === '' || val === null || val === undefined;

const ticketStatusVariant = (status: string) => {
    if (status === 'open') return 'destructive' as const;
    if (status === 'in_progress') return 'default' as const;
    if (status === 'resolved') return 'secondary' as const;
    return 'outline' as const;
};

function ticketActions(
    handlers: { onOpen: () => void; onDelete: () => void },
    t: TFunction
): RowAction[] {
    return [
        { label: t('common.open'), icon: <Info className="h-4 w-4" />, onClick: handlers.onOpen },
        {
            label: t('common.delete'),
            icon: <Trash2 className="h-4 w-4" />,
            onClick: handlers.onDelete,
            destructive: true,
            separatorBefore: true,
        },
    ];
}

const AssignedCell: React.FC<{ adminId: string | null }> = ({ adminId }) => {
    const { data: admin, isLoading: loading } = useAdmin(adminId || '');
    if (!adminId || adminId === '-' || adminId === 'undefined') return <span>-</span>;
    if (loading) return <Skeleton className="h-4 w-20" />;
    if (!admin) return <span>{adminId}</span>;
    const name = !isBadValue(admin.nickname) ? admin.nickname : admin.email;
    return <Link to={`/admins/${admin.id}`}>{!isBadValue(name) ? name : admin.id}</Link>;
};

const TicketListPage: React.FC = () => {
    const { t } = useTranslation();
    const navigate = useNavigate();
    const { viewMode, setViewMode } = useExploreView();
    const [params, setParams] = useState<TicketListParams>({
        limit: getSavedPageSize(TABLE_KEY),
        offset: 0,
        sort: 'last_seen',
        order: 'desc',
    });
    const { data, isLoading } = useTickets(params);
    const deleteTicket = useDeleteTicket();
    const { data: stats } = useTicketStats();

    const [deleteConfirm, setDeleteConfirm] = useState<{ open: boolean; ticketId: string | null }>({
        open: false,
        ticketId: null,
    });

    const handleDelete = (id: string) => setDeleteConfirm({ open: true, ticketId: id });

    const confirmDelete = () => {
        if (!deleteConfirm.ticketId) return;
        deleteTicket.mutate(deleteConfirm.ticketId, {
            onSuccess: () => setDeleteConfirm({ open: false, ticketId: null }),
        });
    };

    const exploreStats = useMemo(() => {
        if (!stats) return [];
        return [
            { label: t('common.total'), value: stats.total_tickets },
            { label: formatStatusLabel('open'), value: stats.open },
            { label: formatStatusLabel('in_progress'), value: stats.in_progress },
            { label: formatStatusLabel('resolved'), value: stats.resolved },
        ];
    }, [stats, t]);

    const columns = useMemo<ColumnDef<Ticket>[]>(
        () => [
            {
                accessorKey: 'error_message',
                header: t('common.error'),
                enableSorting: true,
                cell: ({ getValue }) => {
                    const text = getValue<string>();
                    return isBadValue(text) ? '-' : text;
                },
            },
            {
                accessorKey: 'status',
                header: t('common.status'),
                size: 100,
                enableSorting: true,
                cell: ({ getValue }) => {
                    const status = getValue<string>();
                    return <Badge variant={ticketStatusVariant(status)}>{formatStatusLabel(status)}</Badge>;
                },
            },
            {
                accessorKey: 'assigned_to',
                header: t('common.assigned'),
                enableSorting: false,
                cell: ({ getValue }) => <AssignedCell adminId={getValue<string | null>()} />,
            },
            { accessorKey: 'count', header: t('common.count'), size: 80, enableSorting: true },
            { accessorKey: 'first_seen', header: t('common.firstSeen'), enableSorting: true },
            { accessorKey: 'last_seen', header: t('common.lastSeen'), enableSorting: true },
            {
                id: 'actions',
                header: '',
                size: 48,
                enableSorting: false,
                cell: ({ row }) => {
                    const record = row.original;
                    return (
                        <RowActionsMenu
                            actions={ticketActions({
                                onOpen: () => navigate(`/tickets/${record.id}`),
                                onDelete: () => handleDelete(record.id),
                            }, t)}
                        />
                    );
                },
            },
        ],
        [navigate, t]
    );

    const denseRows = useMemo<DenseRowModel[]>(() => {
        return (data?.data ?? []).map((record) => {
            const errorText = isBadValue(record.error_message) ? record.id : record.error_message;
            const title =
                typeof errorText === 'string' && errorText.length > 80
                    ? `${errorText.slice(0, 80)}…`
                    : errorText;
            return {
                id: record.id,
                title,
                subtitle: record.assigned_to && record.assigned_to !== '-' ? record.assigned_to : undefined,
                badges: (
                    <Badge variant={ticketStatusVariant(record.status)}>
                        {formatStatusLabel(record.status)}
                    </Badge>
                ),
                meta: `×${record.count} · ${record.last_seen}`,
                onActivate: () => navigate(`/tickets/${record.id}`),
                actions: ticketActions({
                    onOpen: () => navigate(`/tickets/${record.id}`),
                    onDelete: () => handleDelete(record.id),
                }, t),
            };
        });
    }, [data?.data, navigate, t]);

    return (
        <>
            <ExploreListShell
                title={t('tickets.title')}
                stats={exploreStats}
                viewMode={viewMode}
                onViewModeChange={setViewMode}
                banner={{
                    text: t('inbox.bannerTickets'),
                    to: '/inbox/tickets',
                    actionLabel: t('common.openInbox'),
                }}
            >
                <ExploreDataView
                    viewMode={viewMode}
                    columns={columns}
                    data={data?.data ?? []}
                    denseRows={denseRows}
                    total={data?.total}
                    isLoading={isLoading}
                    tableKey={TABLE_KEY}
                    params={params}
                    onParamsChange={setParams}
                />
            </ExploreListShell>

            <Dialog open={deleteConfirm.open} onOpenChange={(open) => !open && setDeleteConfirm({ open: false, ticketId: null })}>
                <DialogContent>
                    <DialogHeader>
                        <DialogTitle>{t('tickets.deleteTitle')}</DialogTitle>
                    </DialogHeader>
                    <p className="text-sm text-muted-foreground">{t('common.irreversible')}</p>
                    <DialogFooter>
                        <Button variant="outline" onClick={() => setDeleteConfirm({ open: false, ticketId: null })}>
                            {t('common.cancel')}
                        </Button>
                        <Button variant="destructive" onClick={confirmDelete} disabled={deleteTicket.isPending}>
                            {t('common.delete')}
                        </Button>
                    </DialogFooter>
                </DialogContent>
            </Dialog>
        </>
    );
};

export default TicketListPage;