"use client";

// components/TaxRepresentativeSection.tsx
// Single-director picker for the company's SARS tax representative.
// Pattern mirrors LinkEntityModal: search-as-you-type via /api/pb/records/list,
// click to select. The selection is saved directly on the company via PATCH
// (no junction table — one tax rep per company, by design). Added 2026-09-16.

import { useEffect, useRef, useState } from "react";
import Link from "next/link";
import { useRouter } from "next/navigation";
import { pbPatch } from "@/lib/api";
import { text, number } from "@/lib/format";

interface DirectorHit {
  id: string;
  first_names: string | null;
  surname: string | null;
  id_no: string | null;
  tax_reference_no: number | null;
}

interface Props {
  companyId: string;
  /** Currently-linked director ID, or empty string. */
  initialDirectorId: string;
  /** Expanded payload for the currently-linked director. May be undefined
   *  if the server-side expand wasn't populated. */
  initialDirector?: DirectorHit;
}

export default function TaxRepresentativeSection({
  companyId,
  initialDirectorId,
  initialDirector,
}: Props) {
  const router = useRouter();
  const [picking, setPicking] = useState(false);
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState<string | null>(null);

  // Search state — only active when picking=true
  const [query, setQuery] = useState("");
  const [results, setResults] = useState<DirectorHit[]>([]);
  const [searching, setSearching] = useState(false);
  const debounceRef = useRef<ReturnType<typeof setTimeout>>();

  // Optimistic local state for instant feedback after PATCH
  const [directorId, setDirectorId] = useState(initialDirectorId);
  const [director, setDirector] = useState<DirectorHit | undefined>(
    initialDirector,
  );

  // Search-as-you-type, debounced 300ms (same as LinkEntityModal)
  useEffect(() => {
    if (!picking) return;
    clearTimeout(debounceRef.current);
    if (!query.trim()) {
      setResults([]);
      return;
    }
    debounceRef.current = setTimeout(async () => {
      setSearching(true);
      setError(null);
      try {
        const q = query.trim().replace(/'/g, "''");
        const filter = `(surname ~ '${q}' || first_names ~ '${q}' || id_no ~ '${q}')`;
        const res = await fetch(
          `/api/pb/records/list?collection=ysterbaard_directors&filter=${encodeURIComponent(filter)}&perPage=20&fields=id,first_names,surname,id_no,tax_reference_no`,
        );
        const data = await res.json();
        const items: DirectorHit[] = (data.items ?? []).map(
          (it: Record<string, unknown>) => ({
            id: it.id as string,
            first_names: (it.first_names as string | null) ?? null,
            surname: (it.surname as string | null) ?? null,
            id_no: (it.id_no as string | null) ?? null,
            tax_reference_no:
              (it.tax_reference_no as number | null) ?? null,
          }),
        );
        setResults(items);
      } catch {
        setError("Search failed. Try again.");
      } finally {
        setSearching(false);
      }
    }, 300);
    return () => clearTimeout(debounceRef.current);
  }, [query, picking]);

  async function choose(d: DirectorHit) {
    setSaving(true);
    setError(null);
    try {
      await pbPatch({
        collection: "ysterbaard_companies",
        id: companyId,
        fields: { tax_representative: d.id },
      });
      setDirectorId(d.id);
      setDirector(d);
      setPicking(false);
      setQuery("");
      setResults([]);
      router.refresh();
    } catch (e: unknown) {
      setError(e instanceof Error ? e.message : "Could not save");
    } finally {
      setSaving(false);
    }
  }

  async function unlink() {
    if (
      !confirm(
        "Remove the tax representative? The director will remain in the database.",
      )
    )
      return;
    setSaving(true);
    setError(null);
    try {
      await pbPatch({
        collection: "ysterbaard_companies",
        id: companyId,
        fields: { tax_representative: "" },
      });
      setDirectorId("");
      setDirector(undefined);
      router.refresh();
    } catch (e: unknown) {
      setError(e instanceof Error ? e.message : "Could not save");
    } finally {
      setSaving(false);
    }
  }

  const linked = directorId && director;
  const displayName = (d: DirectorHit) =>
    `${text(d.first_names)} ${text(d.surname)}`.trim();

  return (
    <section className="bg-surface border border-border rounded-lg p-6 md:p-8 flex flex-col gap-4">
      <div className="flex items-baseline justify-between gap-3 flex-wrap">
        <div>
          <h2 className="text-xl font-semibold text-fg">Tax representative</h2>
          <p className="text-sm text-muted mt-1">
            Director who acts as the SARS tax representative for this company.
          </p>
        </div>
        {!picking ? (
          <div className="flex items-center gap-2">
            <button
              type="button"
              onClick={() => setPicking(true)}
              disabled={saving}
              className="px-3 py-1.5 rounded-md bg-accent text-accent-on text-xs font-bold hover:bg-accent-hover transition-colors disabled:opacity-50"
            >
              {linked ? "Change" : "+ Link tax representative"}
            </button>
            {linked ? (
              <button
                type="button"
                onClick={unlink}
                disabled={saving}
                className="text-xs px-2.5 py-1 rounded border border-red-500/30 bg-red-500/10 text-red-400 hover:bg-red-500/20 transition-colors disabled:opacity-40"
              >
                Remove
              </button>
            ) : null}
          </div>
        ) : null}
      </div>

      {error ? (
        <div className="px-4 py-2.5 rounded-lg bg-red-500/10 border border-red-500/30 text-red-400 text-sm">
          {error}
        </div>
      ) : null}

      {linked ? (
        <div className="border-t border-border-soft pt-4 grid grid-cols-1 sm:grid-cols-3 gap-px bg-border border border-border rounded-md overflow-hidden">
          <div className="bg-surface p-4">
            <p className="text-xs uppercase tracking-[0.08em] text-muted font-semibold mb-1">
              Name
            </p>
            <p className="text-base font-bold text-fg">
              {text(director.surname) || "—"}
            </p>
            {text(director.first_names) ? (
              <p className="text-xs text-muted mt-0.5">
                {text(director.first_names)}
              </p>
            ) : null}
          </div>
          <div className="bg-surface p-4">
            <p className="text-xs uppercase tracking-[0.08em] text-muted font-semibold mb-1">
              ID Number
            </p>
            <p className="text-base text-fg font-mono">{text(director.id_no)}</p>
          </div>
          <div className="bg-surface p-4">
            <p className="text-xs uppercase tracking-[0.08em] text-muted font-semibold mb-1">
              Tax reference
            </p>
            <p className="text-base text-fg font-mono">
              {director.tax_reference_no != null && director.tax_reference_no > 0
                ? number(director.tax_reference_no)
                : "—"}
            </p>
          </div>
          <div className="col-span-1 sm:col-span-3 bg-surface p-4 border-t border-border-soft">
            <Link
              href={`/directors/${director.id}`}
              className="text-xs font-semibold text-accent hover:underline"
            >
              View director profile →
            </Link>
          </div>
        </div>
      ) : !picking ? (
        <div className="border-t border-border-soft pt-4 text-sm text-muted">
          No tax representative assigned.
        </div>
      ) : null}

      {picking ? (
        <div className="border-t border-border-soft pt-4 flex flex-col gap-3">
          <label className="flex flex-col gap-1.5">
            <span className="text-xs uppercase tracking-[0.08em] text-muted font-semibold">
              Search directors
            </span>
            <input
              type="search"
              autoFocus
              value={query}
              onChange={(e) => setQuery(e.target.value)}
              placeholder="Type surname, first names, or ID no…"
              className="w-full border border-border rounded-lg bg-surface-warm px-3 py-2.5 text-sm text-fg outline-none focus:border-accent transition-colors"
            />
          </label>

          {searching ? (
            <p className="text-sm text-muted text-center py-3">Searching…</p>
          ) : !query.trim() ? (
            <p className="text-sm text-muted text-center py-3">Type to search…</p>
          ) : results.length === 0 ? (
            <p className="text-sm text-muted text-center py-3">No matches found.</p>
          ) : (
            <div className="flex flex-col gap-2">
              {results.map((d) => (
                <button
                  key={d.id}
                  type="button"
                  disabled={saving}
                  onClick={() => choose(d)}
                  className="w-full flex flex-col items-start gap-1 px-4 py-3 rounded-lg border border-border bg-surface-warm hover:border-accent transition-colors text-left disabled:opacity-50"
                >
                  <p className="font-semibold text-fg truncate w-full">
                    {displayName(d) || "—"}
                  </p>
                  <div className="flex flex-wrap items-center gap-x-4 gap-y-0.5 text-xs text-muted font-mono">
                    <span>ID {text(d.id_no)}</span>
                    {d.tax_reference_no != null && d.tax_reference_no > 0 ? (
                      <span>Tax ref {number(d.tax_reference_no)}</span>
                    ) : null}
                  </div>
                </button>
              ))}
            </div>
          )}

          <div className="flex items-center justify-end gap-2 pt-1">
            <button
              type="button"
              onClick={() => {
                setPicking(false);
                setQuery("");
                setResults([]);
                setError(null);
              }}
              disabled={saving}
              className="text-xs px-3 py-1.5 rounded-md border border-border bg-surface-warm text-fg hover:bg-surface transition-colors disabled:opacity-50"
            >
              Cancel
            </button>
          </div>
        </div>
      ) : null}
    </section>
  );
}