"use client";

import * as React from "react";
import { useParams } from "next/navigation";
import { History, Loader2, ScrollText, ShieldOff } from "lucide-react";

import { api } from "@/lib/trpc";
import { Button } from "@/components/ui/button";
import { Skeleton } from "@/components/ui/skeleton";

/**
 * Owner-only debugging view over `audit_log`. Intentionally dumb: no
 * filters, no search, no time-zone toggles. The job is "show me what
 * happened, most recent first." If we add filters later they should be
 * server-side keyset queries, not client-side slicing.
 */

const ACTION_LABELS: Record<string, string> = {
  "workspace.create": "Workspace created",
  "workspace.update": "Workspace updated",
  "workspace.archive": "Workspace archived",
  "workspace.restore": "Workspace restored",
  "member.role_change": "Role changed",
  "member.remove": "Member removed",
  "member.leave": "Member left",
  "invite.create": "Invite sent",
  "invite.revoke": "Invite revoked",
  "invite.accept": "Invite accepted",
};

function actionLabel(action: string): string {
  return ACTION_LABELS[action] ?? action;
}

function formatTimestamp(when: Date | string): string {
  const d = when instanceof Date ? when : new Date(when);
  return d.toLocaleString(undefined, {
    year: "numeric",
    month: "short",
    day: "numeric",
    hour: "2-digit",
    minute: "2-digit",
    second: "2-digit",
  });
}

function metadataSummary(metadata: Record<string, unknown> | null): string {
  if (!metadata || Object.keys(metadata).length === 0) return "—";
  // Truncate aggressively. The expanded raw JSON is one row away via the
  // <details> below; this is just the at-a-glance hint.
  const json = JSON.stringify(metadata);
  return json.length > 120 ? `${json.slice(0, 117)}…` : json;
}

export default function AuditLogPage() {
  const params = useParams();
  const workspaceSlug = params?.workspaceSlug as string | undefined;

  const [cursor, setCursor] = React.useState<string | undefined>(undefined);
  const auditQuery = api.audit.list.useQuery(
    { workspace: workspaceSlug ?? "", cursorCreatedAt: cursor, limit: 50 },
    { enabled: Boolean(workspaceSlug) },
  );

  const isForbidden = auditQuery.error?.data?.code === "FORBIDDEN";

  return (
    <div className="mx-auto max-w-5xl px-8 py-10">
      <div className="mb-8 flex items-center gap-3">
        <div className="flex h-10 w-10 items-center justify-center rounded-lg bg-primary/10">
          <ScrollText className="size-5 text-primary" />
        </div>
        <div>
          <h1 className="text-xl font-semibold">Audit log</h1>
          <p className="text-xs text-muted-foreground">
            Append-only record of meaningful actions in this workspace. Owner-only.
          </p>
        </div>
      </div>

      {isForbidden ? (
        <div className="flex flex-col items-center gap-3 rounded-lg border bg-muted/40 px-6 py-12 text-center">
          <ShieldOff className="size-6 text-muted-foreground" />
          <p className="text-sm font-medium">Owner-only view</p>
          <p className="max-w-sm text-xs text-muted-foreground">
            Only the workspace owner can read the audit log. Ask an owner to share
            specific events if you need them for support.
          </p>
        </div>
      ) : auditQuery.isLoading ? (
        <div className="space-y-2">
          {Array.from({ length: 6 }).map((_, i) => (
            <Skeleton key={i} className="h-12 w-full" />
          ))}
        </div>
      ) : auditQuery.error ? (
        <div className="rounded-lg border border-destructive/40 bg-destructive/5 px-4 py-3 text-sm text-destructive">
          Couldn&apos;t load the audit log: {auditQuery.error.message}
        </div>
      ) : !auditQuery.data || auditQuery.data.rows.length === 0 ? (
        <div className="flex flex-col items-center gap-3 rounded-lg border bg-muted/40 px-6 py-12 text-center">
          <History className="size-6 text-muted-foreground" />
          <p className="text-sm font-medium">No events yet</p>
          <p className="max-w-sm text-xs text-muted-foreground">
            Actions like creating invites, changing roles, or archiving the workspace
            will appear here.
          </p>
        </div>
      ) : (
        <>
          <div className="overflow-hidden rounded-lg border">
            <table className="w-full text-sm">
              <thead className="bg-muted/40 text-xs uppercase tracking-wide text-muted-foreground">
                <tr>
                  <th className="px-4 py-2 text-left font-medium">When</th>
                  <th className="px-4 py-2 text-left font-medium">Action</th>
                  <th className="px-4 py-2 text-left font-medium">Actor</th>
                  <th className="px-4 py-2 text-left font-medium">Target</th>
                  <th className="px-4 py-2 text-left font-medium">Details</th>
                </tr>
              </thead>
              <tbody className="divide-y">
                {auditQuery.data.rows.map((row) => (
                  <tr key={row.id} className="hover:bg-muted/30">
                    <td className="whitespace-nowrap px-4 py-2 text-xs tabular-nums text-muted-foreground">
                      {formatTimestamp(row.createdAt)}
                    </td>
                    <td className="px-4 py-2 font-medium">{actionLabel(row.action)}</td>
                    <td className="px-4 py-2 text-xs">
                      {row.actorUserId ? (
                        <span>
                          {row.actorName ?? row.actorEmail ?? row.actorUserId.slice(0, 8)}
                        </span>
                      ) : (
                        <span className="italic text-muted-foreground">
                          system
                          {row.metadata && typeof (row.metadata as { system_actor?: unknown }).system_actor === "string"
                            ? `: ${(row.metadata as { system_actor: string }).system_actor}`
                            : ""}
                        </span>
                      )}
                    </td>
                    <td className="px-4 py-2 text-xs text-muted-foreground">
                      <code className="rounded bg-muted px-1 py-0.5">{row.targetType}</code>
                      {row.targetId ? (
                        <span className="ml-1 font-mono text-[10px]">{row.targetId.slice(0, 8)}</span>
                      ) : null}
                    </td>
                    <td className="px-4 py-2">
                      {row.metadata && Object.keys(row.metadata).length > 0 ? (
                        <details className="text-xs">
                          <summary className="cursor-pointer text-muted-foreground hover:text-foreground">
                            {metadataSummary(row.metadata)}
                          </summary>
                          <pre className="mt-1 overflow-x-auto rounded bg-muted px-2 py-1 text-[10px]">
                            {JSON.stringify(row.metadata, null, 2)}
                          </pre>
                        </details>
                      ) : (
                        <span className="text-xs text-muted-foreground">—</span>
                      )}
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>

          {auditQuery.data.nextCursor ? (
            <div className="mt-4 flex justify-center">
              <Button
                variant="outline"
                size="sm"
                onClick={() => setCursor(auditQuery.data.nextCursor ?? undefined)}
                disabled={auditQuery.isFetching}
              >
                {auditQuery.isFetching ? (
                  <Loader2 className="size-3 animate-spin" />
                ) : (
                  "Load older"
                )}
              </Button>
            </div>
          ) : null}
        </>
      )}
    </div>
  );
}