"use client";

import { useState } from "react";
import Link from "next/link";
import { useRouter } from "next/navigation";
import { toast } from "sonner";
import type { WikiRevision } from "@/payload-types";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import { Card, CardContent } from "@/components/ui/card";
import { restoreWikiRevision } from "@/app/(frontend)/wiki/actions";

export interface WikiRevisionSummary {
  readonly id: number;
  readonly revisionNumber: number;
  readonly titleSnapshot: string;
  readonly editorName: string;
  readonly summary: string;
  readonly type: WikiRevision["type"];
  readonly restoredFromRevision: number | null;
  readonly createdAt: string;
}

interface RevisionListProps {
  readonly pageId: number;
  readonly slug: string;
  readonly revisions: readonly WikiRevisionSummary[];
  readonly isModerator: boolean;
}

const REVISION_TYPE_META: Record<WikiRevision["type"], { label: string; className: string }> = {
  create: {
    label: "Create",
    className: "border-emerald-500/40 text-emerald-400",
  },
  edit: {
    label: "Edit",
    className: "border-blue-500/40 text-blue-400",
  },
  restore: {
    label: "Restore",
    className: "border-amber-500/40 text-amber-400",
  },
};

function timeAgo(iso: string): string {
  const diff = Math.max(0, Date.now() - new Date(iso).getTime());
  const minutes = Math.floor(diff / 60000);
  if (minutes < 1) return "just now";
  if (minutes < 60) return `${minutes}m ago`;
  const hours = Math.floor(minutes / 60);
  if (hours < 24) return `${hours}h ago`;
  const days = Math.floor(hours / 24);
  return `${days}d ago`;
}

export function RevisionList({ pageId, slug, revisions, isModerator }: RevisionListProps) {
  const router = useRouter();
  const [restoring, setRestoring] = useState<number | null>(null);

  async function handleRestore(revisionNumber: number) {
    setRestoring(revisionNumber);
    const result = await restoreWikiRevision({ id: pageId, revisionNumber });
    setRestoring(null);

    if (!result.success) {
      toast.error(result.error ?? "Could not restore the revision.");
      return;
    }

    toast.success(`Restored revision ${revisionNumber}`);
    router.refresh();
  }

  if (revisions.length === 0) {
    return (
      <Card>
        <CardContent className="p-6">
          <p className="text-sm italic text-muted-foreground">No revisions recorded yet.</p>
        </CardContent>
      </Card>
    );
  }

  return (
    <div className="flex flex-col gap-3">
      {revisions.map((revision) => {
        const typeMeta = REVISION_TYPE_META[revision.type];
        return (
          <Card key={revision.id}>
            <CardContent className="flex flex-col gap-3 p-4 sm:flex-row sm:items-start sm:justify-between">
              <div className="flex min-w-0 flex-col gap-2">
                <div className="flex flex-wrap items-center gap-2">
                  <span className="font-mono text-sm font-semibold">
                    Revision {revision.revisionNumber}
                  </span>
                  <Badge variant="outline" className={typeMeta.className}>
                    {typeMeta.label}
                  </Badge>
                  {revision.restoredFromRevision !== null && (
                    <span className="text-xs text-muted-foreground">
                      from revision {revision.restoredFromRevision}
                    </span>
                  )}
                </div>
                <p className="truncate text-sm font-medium">{revision.titleSnapshot}</p>
                <p className="text-sm italic text-muted-foreground">
                  {revision.summary || "No summary provided."}
                </p>
                <div className="flex flex-wrap gap-x-3 gap-y-1 text-xs text-muted-foreground">
                  <span>Edited by {revision.editorName}</span>
                  <time dateTime={revision.createdAt}>{timeAgo(revision.createdAt)}</time>
                </div>
              </div>
              <div className="flex shrink-0 items-center gap-2">
                <Button asChild size="sm" variant="ghost">
                  <Link href={`/wiki/${slug}?revision=${revision.revisionNumber}`}>
                    View revision
                  </Link>
                </Button>
                {isModerator && (
                  <Button
                    type="button"
                    size="sm"
                    variant="outline"
                    onClick={() => void handleRestore(revision.revisionNumber)}
                    disabled={restoring !== null}
                  >
                    {restoring === revision.revisionNumber ? "Restoring..." : "Restore"}
                  </Button>
                )}
              </div>
            </CardContent>
          </Card>
        );
      })}
    </div>
  );
}