"use client";

import { useState, useEffect, useRef } from "react";
import { useRouter } from "next/navigation";
import { text } from "@/lib/format";

interface Props {
  /** "link-director-to-company" | "link-company-to-director" */
  mode: "link-director" | "link-company";
  /** PB id of the parent entity (company for director-mode, director for company-mode) */
  parentId: string;
  /** Display name of the parent entity, shown in the modal heading */
  parentName: string;
  /** Ids of entities already linked — excluded from the dropdown */
  alreadyLinkedIds: string[];
  open: boolean;
  onClose: () => void;
  /** Called after a successful link, so the parent page can refresh */
  onLinked: () => void;
}

interface SearchResult {
  id: string;
  label: string;
  sub: string;
}

export default function LinkEntityModal({
  mode,
  parentId,
  parentName,
  alreadyLinkedIds,
  open,
  onClose,
  onLinked,
}: Props) {
  const router = useRouter();
  const [query, setQuery] = useState("");
  const [results, setResults] = useState<SearchResult[]>([]);
  const [searching, setSearching] = useState(false);
  const [linking, setLinking] = useState<string | null>(null);
  const [error, setError] = useState<string | null>(null);
  const debounceRef = useRef<ReturnType<typeof setTimeout>>();

  // Search when query changes (debounced 300ms)
  useEffect(() => {
    if (!open) return;
    clearTimeout(debounceRef.current);
    if (!query.trim()) { setResults([]); return; }
    debounceRef.current = setTimeout(async () => {
      setSearching(true);
      setError(null);
      try {
        const collection = mode === "link-director" ? "ysterbaard_companies" : "ysterbaard_directors";
        const q = encodeURIComponent(query.trim().replace(/'/g, "''"));
        const filter = mode === "link-director"
          ? `(enterprise_name ~ '${q}' || enterprise_no ~ '${q}')`
          : `(surname ~ '${q}' || first_names ~ '${q}' || id_no ~ '${q}')`;
        const res = await fetch(
          `/api/pb/records/list?collection=${collection}&filter=${encodeURIComponent(filter)}&perPage=20&fields=id,enterprise_name,enterprise_no,first_names,surname,id_no`
        );
        const data = await res.json();
        const items: SearchResult[] = (data.items ?? []).map((item: Record<string, unknown>) => {
          if (mode === "link-director") {
            return {
              id: item.id as string,
              label: text(item.enterprise_name as string),
              sub: text(item.enterprise_no as string),
            };
          } else {
            return {
              id: item.id as string,
              label: `${text(item.first_names as string)} ${text(item.surname as string)}`.trim(),
              sub: text(item.id_no as string),
            };
          }
        }).filter((r: SearchResult) => !alreadyLinkedIds.includes(r.id));
        setResults(items);
      } catch {
        setError("Search failed. Try again.");
      } finally {
        setSearching(false);
      }
    }, 300);
    return () => clearTimeout(debounceRef.current);
  }, [query, open, mode, alreadyLinkedIds]);

  async function handleLink(targetId: string, targetLabel: string) {
    setLinking(targetId);
    setError(null);
    try {
      const body = mode === "link-director"
        ? { company: targetId, director: parentId, director_type: "Director" }
        : { director: targetId, company: parentId, director_type: "Director" };
      const res = await fetch("/api/pb/records/link", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(body),
      });
      if (!res.ok) {
        const err = await res.json();
        throw new Error(err.error ?? "Link failed");
      }
      setQuery("");
      setResults([]);
      onLinked();
      onClose();
      router.refresh();
    } catch (e: unknown) {
      setError((e instanceof Error ? e.message : "Link failed"));
    } finally {
      setLinking(null);
    }
  }

  if (!open) return null;

  const isDirectorMode = mode === "link-director";
  const heading = isDirectorMode
    ? `Link company to ${parentName}`
    : `Link director to ${parentName}`;
  const placeholder = isDirectorMode
    ? "Search companies by name or number…"
    : "Search directors by name or ID…";

  return (
    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50" onClick={onClose}>
      <div
        className="bg-surface border border-border rounded-xl shadow-2xl w-full max-w-lg mx-4 flex flex-col"
        style={{ maxHeight: "80vh" }}
        onClick={(e) => e.stopPropagation()}
      >
        {/* Header */}
        <div className="flex items-center justify-between px-6 py-4 border-b border-border shrink-0">
          <h2 className="text-lg font-semibold text-fg">{heading}</h2>
          <button
            onClick={onClose}
            className="text-muted hover:text-fg transition-colors p-1 rounded"
            aria-label="Close"
          >
            <svg viewBox="0 0 24 24" className="w-5 h-5" fill="none" stroke="currentColor" strokeWidth="2">
              <path d="M18 6L6 18M6 6l12 12"/>
            </svg>
          </button>
        </div>

        {/* Search input */}
        <div className="px-6 py-4 border-b border-border shrink-0">
          <input
            type="text"
            value={query}
            onChange={(e) => setQuery(e.target.value)}
            placeholder={placeholder}
            autoFocus
            className="w-full border border-border rounded-lg bg-surface-warm px-4 py-2.5 text-fg placeholder:text-meta outline-none focus:border-accent transition-colors"
          />
        </div>

        {/* Results */}
        <div className="flex-1 overflow-y-auto px-6 py-3">
          {error && (
            <div className="mb-3 px-4 py-2.5 rounded-lg bg-red-500/10 border border-red-500/30 text-red-400 text-sm">
              {error}
            </div>
          )}

          {searching && <p className="text-muted text-sm text-center py-4">Searching…</p>}
          {!searching && query && results.length === 0 && (
            <p className="text-muted text-sm text-center py-4">No matches found.</p>
          )}
          {!searching && !query && (
            <p className="text-muted text-sm text-center py-4">Type to search…</p>
          )}

          {results.map((r) => (
            <button
              key={r.id}
              onClick={() => handleLink(r.id, r.label)}
              disabled={linking !== null}
              className="w-full flex items-center justify-between gap-3 px-4 py-3 rounded-lg hover:bg-surface-warm transition-colors text-left disabled:opacity-50"
            >
              <div className="min-w-0">
                <p className="font-semibold text-fg truncate">{r.label}</p>
                <p className="text-sm text-muted font-mono truncate">{r.sub}</p>
              </div>
              <span className="shrink-0 text-xs font-semibold text-accent">
                {linking === r.id ? "…" : "Link →"}
              </span>
            </button>
          ))}
        </div>
      </div>
    </div>
  );
}