import Link from "next/link";
import { cn } from "@/lib/utils";

/**
 * Shared, server-safe building blocks of the master-data screens (customers, sites, teams,
 * documents). Controls are 44 px high (Brandbook §12.2 touch targets); colors only via tokens.
 */

export const controlClass =
  "h-11 w-full min-w-0 rounded-lg border border-input bg-card px-3 text-sm outline-none transition-colors focus-visible:border-ring focus-visible:ring-3 focus-visible:ring-ring/50 aria-invalid:border-destructive aria-invalid:ring-3 aria-invalid:ring-destructive/20 disabled:opacity-60";

export const textareaClass =
  "min-h-24 w-full rounded-lg border border-input bg-card px-3 py-2 text-sm outline-none transition-colors focus-visible:border-ring focus-visible:ring-3 focus-visible:ring-ring/50 aria-invalid:border-destructive";

export const buttonLinkClass =
  "inline-flex min-h-11 items-center justify-center gap-1.5 rounded-lg border border-border bg-background px-4 font-heading text-sm font-semibold transition-colors hover:bg-muted focus-visible:ring-3 focus-visible:ring-ring/50 outline-none";

export const primaryButtonClass =
  "inline-flex min-h-11 items-center justify-center gap-1.5 rounded-lg bg-[var(--ui-accent)] px-4 font-heading text-sm font-semibold text-[var(--ui-accent-foreground)] transition-opacity hover:opacity-90 focus-visible:ring-3 focus-visible:ring-ring/50 outline-none disabled:opacity-60";

export function Field({
  id,
  label,
  error,
  hint,
  required,
  className,
  children,
}: {
  id: string;
  label: string;
  error?: string;
  hint?: string;
  required?: boolean;
  className?: string;
  children: React.ReactNode;
}) {
  return (
    <div className={cn("flex flex-col gap-1", className)}>
      <label htmlFor={id} className="text-[12.5px] font-semibold text-foreground">
        {label}
        {required && <span aria-hidden className="text-[var(--risk)]"> *</span>}
      </label>
      {children}
      {hint && !error && <p className="text-[12px] text-muted-foreground">{hint}</p>}
      {error && (
        <p id={`${id}-error`} role="alert" className="text-[12px] font-semibold text-[var(--risk)]">
          {error}
        </p>
      )}
    </div>
  );
}

export function FormSection({ title, children, className }: { title: string; children: React.ReactNode; className?: string }) {
  return (
    <fieldset className={cn("grid gap-3 sm:grid-cols-2", className)}>
      <legend className="mb-2 font-heading text-[13px] font-semibold tracking-wide text-muted-foreground uppercase">{title}</legend>
      {children}
    </fieldset>
  );
}

export function TabNav({ tabs, active, label }: { tabs: { key: string; label: string; href: string; count?: number }[]; active: string; label: string }) {
  return (
    <nav aria-label={label} className="mb-4 flex gap-1 overflow-x-auto border-b">
      {tabs.map((tab) => {
        const isActive = tab.key === active;
        return (
          <Link
            key={tab.key}
            href={tab.href}
            aria-current={isActive ? "page" : undefined}
            className={cn(
              "-mb-px inline-flex min-h-11 items-center gap-1.5 border-b-2 px-3 text-[13.5px] font-semibold whitespace-nowrap transition-colors",
              isActive ? "border-[var(--ui-accent)] text-foreground" : "border-transparent text-muted-foreground hover:text-foreground",
            )}
          >
            {tab.label}
            {typeof tab.count === "number" && (
              <span className="rounded-full bg-muted px-1.5 text-[11px] font-bold text-muted-foreground">{tab.count}</span>
            )}
          </Link>
        );
      })}
    </nav>
  );
}

export function Pagination({
  page,
  pageSize,
  total,
  hrefFor,
  labels,
}: {
  page: number;
  pageSize: number;
  total: number;
  hrefFor: (page: number) => string;
  labels: { prev: string; next: string; summary: string };
}) {
  if (total <= pageSize && page === 1) return total > 0 ? <p className="mt-3 text-[12.5px] text-muted-foreground">{labels.summary}</p> : null;
  const last = Math.max(1, Math.ceil(total / pageSize));
  return (
    <div className="mt-3 flex flex-wrap items-center justify-between gap-3">
      <p className="text-[12.5px] text-muted-foreground">{labels.summary}</p>
      <div className="flex gap-2">
        {page > 1 ? (
          <Link href={hrefFor(page - 1)} className={buttonLinkClass} rel="prev">
            {labels.prev}
          </Link>
        ) : (
          <span aria-disabled className={cn(buttonLinkClass, "pointer-events-none opacity-50")}>{labels.prev}</span>
        )}
        {page < last ? (
          <Link href={hrefFor(page + 1)} className={buttonLinkClass} rel="next">
            {labels.next}
          </Link>
        ) : (
          <span aria-disabled className={cn(buttonLinkClass, "pointer-events-none opacity-50")}>{labels.next}</span>
        )}
      </div>
    </div>
  );
}

export function Banner({ tone, children }: { tone: "ok" | "warn" | "risk" | "info"; children: React.ReactNode }) {
  const tones = {
    ok: "border-[var(--ok)] text-[var(--ok)]",
    warn: "border-[var(--warn)] text-[var(--warn)]",
    risk: "border-[var(--risk)] text-[var(--risk)]",
    info: "border-[var(--info)] text-[var(--info)]",
  };
  return (
    <div role={tone === "risk" ? "alert" : "status"} className={cn("mb-4 rounded-lg border-l-4 bg-card px-4 py-3 text-[13px] font-semibold", tones[tone])}>
      {children}
    </div>
  );
}

/** Label/value list for read views. */
export function DefinitionList({ items }: { items: { label: string; value: React.ReactNode }[] }) {
  return (
    <dl className="grid gap-x-6 gap-y-3 sm:grid-cols-2">
      {items.map((it) => (
        <div key={it.label} className="min-w-0">
          <dt className="text-[12px] font-semibold text-muted-foreground">{it.label}</dt>
          <dd className="mt-0.5 text-sm break-words whitespace-pre-line">{it.value || "—"}</dd>
        </div>
      ))}
    </dl>
  );
}

export function Card({ children, className }: { children: React.ReactNode; className?: string }) {
  return <div className={cn("shadow-card rounded-xl border bg-card p-5", className)}>{children}</div>;
}

export function paginationSummary(page: number, pageSize: number, total: number) {
  const from = total === 0 ? 0 : (page - 1) * pageSize + 1;
  const to = Math.min(total, page * pageSize);
  return { from, to, total };
}

/** Build `path?…` from params, dropping empty values. */
export function hrefWith(path: string, params: Record<string, string | number | undefined | null>): string {
  const sp = new URLSearchParams();
  for (const [k, v] of Object.entries(params)) if (v !== undefined && v !== null && v !== "") sp.set(k, String(v));
  const qs = sp.toString();
  return qs ? `${path}?${qs}` : path;
}