'use client';

import Link from 'next/link';
import { usePathname } from 'next/navigation';
import { Fragment } from 'react';
import { ChevronRight } from 'lucide-react';

import {
  Breadcrumb,
  BreadcrumbItem,
  BreadcrumbLink,
  BreadcrumbList,
  BreadcrumbPage,
  BreadcrumbSeparator,
} from '@/components/ui/breadcrumb';
import { useUIStore } from '@/stores/ui-store';
import { useBreadcrumbStore } from '@/stores/breadcrumb-store';

// Human-readable labels for route segments
const SEGMENT_LABELS: Record<string, string> = {
  dashboard: 'Dashboard',
  clients: 'Clients',
  interests: 'Interests',
  berths: 'Berths',
  documents: 'Documents',
  files: 'Files',
  expenses: 'Expenses',
  invoices: 'Invoices',
  email: 'Email',
  reminders: 'Reminders',
  settings: 'Settings',
  admin: 'Administration',
  reports: 'Reports',
  new: 'New',
  edit: 'Edit',
  profile: 'Profile',
};

// UUID v4-ish (or any 36-char hex+dash) - used to skip entity-id segments
// from the breadcrumbs since the page H1 already shows the entity name.
const UUID_RE = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;

function isIdSegment(segment: string): boolean {
  return UUID_RE.test(segment);
}

function formatSegment(segment: string): string {
  return (
    SEGMENT_LABELS[segment] ?? segment.replace(/-/g, ' ').replace(/\b\w/g, (c) => c.toUpperCase())
  );
}

export function Breadcrumbs() {
  const pathname = usePathname();
  const currentPortSlug = useUIStore((s) => s.currentPortSlug);
  const hint = useBreadcrumbStore((s) => s.hints[pathname]);

  // Split pathname and filter empty segments
  const rawSegments = pathname.split('/').filter(Boolean);

  // Remove the portSlug segment and any UUID-ish entity-id segments - the
  // page H1 already shows the entity name, no need to leak the raw id.
  const segments = (
    currentPortSlug ? rawSegments.filter((seg) => seg !== currentPortSlug) : rawSegments
  ).filter((seg) => !isIdSegment(seg));

  if (segments.length === 0) return null;

  // Build href for each segment from the URL.
  const urlCrumbs = segments.map((segment, index) => {
    const segmentsUpToHere = rawSegments.slice(0, rawSegments.indexOf(segment, index) + 1);
    const href = '/' + segmentsUpToHere.join('/');
    const label = formatSegment(segment);
    const isLast = index === segments.length - 1;

    return { label, href, isLast };
  });

  // When a detail page registered a hint, splice in the parent crumbs
  // (e.g. the parent client name) and replace the trailing label with
  // the entity's actual name (e.g. "B17"). This turns the URL-only
  // "Clients › Interests" into "Clients › Mary Smith › Interest › B17"
  // when the rep clicked from a client page. URL-only renders untouched
  // when no hint is registered.
  const crumbs = (() => {
    if (!hint) return urlCrumbs;
    const head = urlCrumbs.slice(0, -1).map((c) => ({ ...c, isLast: false }));
    const parents = hint.parents.map((p) => ({
      label: p.label,
      href: p.href ?? pathname,
      isLast: false,
    }));
    const lastUrlCrumb = urlCrumbs[urlCrumbs.length - 1];
    const tail = {
      label: hint.current,
      href: lastUrlCrumb?.href ?? pathname,
      isLast: true,
    };
    return [...head, ...parents, tail];
  })();

  return (
    <Breadcrumb>
      <BreadcrumbList className="text-sm gap-1.5">
        {crumbs.map((crumb, _index) => (
          <Fragment key={crumb.href}>
            <BreadcrumbItem>
              {crumb.isLast ? (
                <BreadcrumbPage className="font-medium text-foreground truncate max-w-[160px]">
                  {crumb.label}
                </BreadcrumbPage>
              ) : (
                <BreadcrumbLink asChild>
                  <Link
                    // eslint-disable-next-line @typescript-eslint/no-explicit-any
                    href={crumb.href as any}
                    className="text-muted-foreground hover:text-foreground transition-colors rounded px-1 -mx-1 truncate max-w-[160px]"
                  >
                    {crumb.label}
                  </Link>
                </BreadcrumbLink>
              )}
            </BreadcrumbItem>
            {!crumb.isLast && (
              <BreadcrumbSeparator className="text-muted-foreground/40">
                <ChevronRight className="w-3 h-3" />
              </BreadcrumbSeparator>
            )}
          </Fragment>
        ))}
      </BreadcrumbList>
    </Breadcrumb>
  );
}
