import Link from "next/link";
import {
  WifiIcon,
  BellIcon,
  ActivityIcon,
  CheckCircle2Icon,
  AlertTriangleIcon,
  XCircleIcon,
  MinusCircleIcon,
  Trash2Icon,
} from "lucide-react";
import { Button } from "@/components/ui/button";
import {
  Card,
  CardContent,
  CardHeader,
  CardTitle,
  CardDescription,
} from "@/components/ui/card";
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
  DialogTrigger,
} from "@/components/ui/dialog";
import { clearHistoryAction } from "@/actions/history";
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table";
import { Badge } from "@/components/ui/badge";
import { getSeededOperator } from "@/lib/operator";
import { getDashboardStats } from "@/lib/queries";
import { PageShell } from "@/components/page-shell";
import { EmptyState } from "@/components/empty-state";

// ---------------------------------------------------------------------------
// Time helpers (no external dep, server-safe)
// ---------------------------------------------------------------------------
function relativeTime(date: Date | string): string {
  const d = typeof date === "string" ? new Date(date) : date;
  const diffMs = Date.now() - d.getTime();
  const diffSec = Math.floor(diffMs / 1000);
  const rtf = new Intl.RelativeTimeFormat("en", { numeric: "auto" });

  if (diffSec < 60) return rtf.format(-diffSec, "second");
  if (diffSec < 3600) return rtf.format(-Math.floor(diffSec / 60), "minute");
  if (diffSec < 86400) return rtf.format(-Math.floor(diffSec / 3600), "hour");
  return rtf.format(-Math.floor(diffSec / 86400), "day");
}

/** Absolute-time fallback used as a tooltip on relative-time displays.
 *  12-hour format with AM/PM so the user can read it at a glance. */
function absoluteTime(date: Date | string): string {
  const d = typeof date === "string" ? new Date(date) : date;
  return new Intl.DateTimeFormat("en-GB", {
    day: "numeric",
    month: "short",
    year: "numeric",
    hour: "numeric",
    minute: "2-digit",
    hour12: true,
  }).format(d);
}

// ---------------------------------------------------------------------------
// Run-status pill
// ---------------------------------------------------------------------------
const RUN_STATUS_CONFIG: Record<
  string,
  { label: string; className: string; icon: React.ElementType }
> = {
  success: {
    label: "Success",
    className:
      "bg-emerald-500/15 text-emerald-700 dark:bg-emerald-500/20 dark:text-emerald-400 border-transparent",
    icon: CheckCircle2Icon,
  },
  partial: {
    label: "Partial",
    className:
      "bg-amber-500/15 text-amber-700 dark:bg-amber-500/20 dark:text-amber-400 border-transparent",
    icon: AlertTriangleIcon,
  },
  failed: {
    label: "Failed",
    className:
      "bg-red-500/15 text-red-600 dark:bg-red-500/20 dark:text-red-400 border-transparent",
    icon: XCircleIcon,
  },
  skipped: {
    label: "Skipped",
    className:
      "bg-slate-200/60 text-slate-500 dark:bg-slate-700/40 dark:text-slate-400 border-transparent",
    icon: MinusCircleIcon,
  },
};

function RunStatusBadge({ status }: { status: string }) {
  const cfg = RUN_STATUS_CONFIG[status] ?? {
    label: status,
    className: "bg-secondary text-secondary-foreground border-transparent",
    icon: ActivityIcon,
  };
  const Icon = cfg.icon;
  return (
    <Badge variant="secondary" className={cfg.className}>
      <Icon className="size-3 mr-0.5" />
      {cfg.label}
    </Badge>
  );
}

// ---------------------------------------------------------------------------
// Stat card — entire card is the link to its tab
// ---------------------------------------------------------------------------
function StatCard({
  title,
  value,
  icon: Icon,
  description,
  href,
}: {
  title: string;
  value: string | number;
  icon: React.ElementType;
  description?: string;
  href: string;
}) {
  return (
    <Link
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      href={href as any}
      className="block rounded-xl focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2"
    >
      <Card className="h-full transition-all hover:shadow-md hover:ring-primary/30 cursor-pointer">
        <CardHeader>
          <div className="flex items-center justify-between gap-2">
            <CardTitle className="text-sm font-medium text-muted-foreground">
              {title}
            </CardTitle>
            <Icon className="size-4 text-muted-foreground shrink-0" />
          </div>
        </CardHeader>
        <CardContent>
          <p className="text-2xl font-semibold tabular-nums">{value}</p>
          {description && (
            <CardDescription className="mt-1 text-xs">{description}</CardDescription>
          )}
        </CardContent>
      </Card>
    </Link>
  );
}

// ---------------------------------------------------------------------------
// Page
// ---------------------------------------------------------------------------
export default async function DashboardPage() {
  const op = await getSeededOperator();
  const stats = await getDashboardStats(op.id);

  const hasRuns = stats.recentRuns.length > 0;

  return (
    <PageShell title="Dashboard">
      {/* Stat cards — click to drill into the corresponding tab */}
      <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
        <StatCard
          title="WhatsApp accounts"
          value={`${stats.connectedAccounts} / ${stats.unpairedAccounts} / ${stats.totalAccounts}`}
          icon={WifiIcon}
          description="Connected / Unpaired / Total"
          href="/accounts"
        />
        <StatCard
          title="Reminders"
          value={`${stats.activeReminders} / ${stats.pausedReminders} / ${stats.inactiveReminders} / ${stats.totalReminders}`}
          icon={BellIcon}
          description="Active / Paused / Inactive / Total"
          href="/reminders"
        />
      </div>

      {/* Recent activity */}
      <section className="space-y-4">
        <div className="flex items-center justify-between gap-2">
          <h2 className="text-lg font-medium tracking-tight">Recent activity</h2>
          <div className="flex items-center gap-1">
            {hasRuns && (
              <Button asChild variant="ghost" size="sm" className="text-muted-foreground">
                {/* eslint-disable-next-line @typescript-eslint/no-explicit-any */}
                <Link href={"/activity" as any}>View all</Link>
              </Button>
            )}
            {hasRuns && (
            <Dialog>
              <DialogTrigger asChild>
                <Button variant="ghost" size="sm" className="text-muted-foreground hover:text-destructive">
                  <Trash2Icon />
                  Clear history
                </Button>
              </DialogTrigger>
              <DialogContent>
                <DialogHeader>
                  <DialogTitle>Clear all run history?</DialogTitle>
                  <DialogDescription>
                    This permanently removes every reminder run record, including
                    runs from reminders that have already been deleted. Reminders
                    themselves are not affected.
                  </DialogDescription>
                </DialogHeader>
                <DialogFooter showCloseButton>
                  <form action={clearHistoryAction}>
                    <Button type="submit" variant="destructive" size="sm">
                      <Trash2Icon />
                      Yes, clear history
                    </Button>
                  </form>
                </DialogFooter>
              </DialogContent>
            </Dialog>
            )}
          </div>
        </div>

        {hasRuns ? (
          <>
            {/* Mobile: card list — clickable when the reminder still exists */}
            <div className="flex flex-col gap-3 sm:hidden">
              {stats.recentRuns.map((run) => {
                const body = (
                  <Card size="sm" className={run.is_deleted ? undefined : "transition-all hover:shadow-md hover:ring-primary/30 cursor-pointer"}>
                    <CardContent className="flex items-center justify-between gap-3 py-3">
                      <div className="min-w-0">
                        <p className="text-sm font-medium truncate">
                          {run.name}
                          {run.is_deleted && (
                            <span className="ml-1.5 text-xs font-normal text-muted-foreground italic">
                              (deleted)
                            </span>
                          )}
                        </p>
                        <time
                          dateTime={new Date(run.fired_at).toISOString()}
                          title={absoluteTime(run.fired_at)}
                          className="text-xs text-muted-foreground mt-0.5 block"
                        >
                          {absoluteTime(run.fired_at)} · {relativeTime(run.fired_at)}
                        </time>
                      </div>
                      <RunStatusBadge status={run.status} />
                    </CardContent>
                  </Card>
                );
                return run.reminder_id && !run.is_deleted ? (
                  <Link
                    key={run.id}
                    // eslint-disable-next-line @typescript-eslint/no-explicit-any
                    href={`/reminders/${run.reminder_id}` as any}
                    className="block rounded-xl focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2"
                  >
                    {body}
                  </Link>
                ) : (
                  <div key={run.id}>{body}</div>
                );
              })}
            </div>

            {/* Desktop: table — rows are clickable when reminder still exists */}
            <div className="hidden sm:block">
              <Card>
                <CardContent className="p-0">
                  <Table>
                    <TableHeader>
                      <TableRow>
                        <TableHead>Reminder</TableHead>
                        <TableHead>Status</TableHead>
                        <TableHead className="text-right">Fired</TableHead>
                      </TableRow>
                    </TableHeader>
                    <TableBody>
                      {stats.recentRuns.map((run) => {
                        const clickable = run.reminder_id && !run.is_deleted;
                        return (
                          <TableRow
                            key={run.id}
                            className={clickable ? "cursor-pointer hover:bg-muted/50" : undefined}
                          >
                            <TableCell className="font-medium">
                              {clickable ? (
                                <Link
                                  // eslint-disable-next-line @typescript-eslint/no-explicit-any
                                  href={`/reminders/${run.reminder_id}` as any}
                                  className="block focus-visible:outline-none focus-visible:underline"
                                >
                                  {run.name}
                                </Link>
                              ) : (
                                <span className="text-muted-foreground italic">
                                  {run.name}
                                </span>
                              )}
                            </TableCell>
                            <TableCell>
                              <RunStatusBadge status={run.status} />
                            </TableCell>
                            <TableCell className="text-right text-muted-foreground text-xs">
                              <time
                                dateTime={new Date(run.fired_at).toISOString()}
                                title={absoluteTime(run.fired_at)}
                              >
                                {absoluteTime(run.fired_at)}
                              </time>
                              <span className="block text-[10px] opacity-75">
                                {relativeTime(run.fired_at)}
                              </span>
                            </TableCell>
                          </TableRow>
                        );
                      })}
                    </TableBody>
                  </Table>
                </CardContent>
              </Card>
            </div>
          </>
        ) : (
          <EmptyState
            icon={ActivityIcon}
            title="No reminders have fired yet."
            description="Schedule one to start sending WhatsApp messages."
            action={
              <Button asChild size="sm">
                {/* eslint-disable-next-line @typescript-eslint/no-explicit-any */}
                <Link href={"/reminders/new" as any}>Schedule a reminder</Link>
              </Button>
            }
          />
        )}
      </section>
    </PageShell>
  );
}