import { useCallback, useEffect, useState } from "react";
import type { FormEvent } from "react";
import { useParams } from "react-router-dom";
import { Link } from "react-router-dom";
import { Alert, Badge, Button, Card, Input, PageHeader, Select } from "@eden/ui";
import type { BadgeVariant } from "@eden/ui";
import { useAuth } from "../../lib/auth/AuthContext.js";
import { ApiError } from "../../lib/api/http.js";
import { closeQuoteDeal, decideQuoteApproval, getQuote } from "../../lib/api/quotes.js";
import type { ApprovalStatus, DealStatus, Quote } from "../../lib/api/quotes.js";
import { listResellers } from "../../lib/api/resellers.js";
import type { Reseller } from "../../lib/api/resellers.js";
import { listClientRegistrations } from "../../lib/api/client-registrations.js";
import type { ClientRegistration } from "../../lib/api/client-registrations.js";
import { formatCurrencyBRL, formatDateBR } from "../../lib/format.js";
import { PRIMARY_LINK_BUTTON_CLASS } from "../../components/linkButtonClasses.js";
import { Breadcrumb } from "../../components/Breadcrumb.js";

/**
 * Layout reference: DreamsERP theme `.tmp/theme-reference/sales/salesQuotesDetails.tsx`
 * (breadcrumb + title/status header, bill-to summary block, item table,
 * right-aligned financial totals) plus `.tmp/theme-reference/crm/dealsDetails.tsx`
 * (summary sidebar's `flex justify-between` key/value rows for the numbers
 * that don't fit an invoice-style table). Rebuilt with `@eden/ui` + plain
 * Tailwind — no antd/Preline dependency.
 */
const APPROVAL_LABEL: Record<ApprovalStatus, string> = {
  none: "Sem aprovação",
  pending: "Pendente",
  approved: "Aprovada",
  rejected: "Rejeitada",
};

const APPROVAL_VARIANT: Record<ApprovalStatus, BadgeVariant> = {
  none: "neutral",
  pending: "warning",
  approved: "success",
  rejected: "danger",
};

const DEAL_LABEL: Record<DealStatus, string> = {
  orcamento: "Orçamento",
  fechado: "Fechado",
  perdido: "Perdido",
};

const DEAL_VARIANT: Record<DealStatus, BadgeVariant> = {
  orcamento: "info",
  fechado: "success",
  perdido: "danger",
};

export function QuoteDetailPage() {
  const { id } = useParams<{ id: string }>();
  const { accessToken } = useAuth();

  const [quote, setQuote] = useState<Quote | null>(null);
  const [reseller, setReseller] = useState<Reseller | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  const load = useCallback(() => {
    if (!id || !accessToken) return;
    setLoading(true);
    setError(null);
    Promise.all([getQuote(id, accessToken), listResellers(accessToken)])
      .then(([quoteResult, resellers]) => {
        setQuote(quoteResult);
        setReseller(resellers.find((r) => r.id === quoteResult.reseller_id) ?? null);
      })
      .catch((err) => setError(err instanceof ApiError ? err.message : "Não foi possível carregar a oferta."))
      .finally(() => setLoading(false));
  }, [id, accessToken]);

  useEffect(() => {
    load();
  }, [load]);

  if (loading) {
    return (
      <div>
        <PageHeader title="Oferta" />
        <p className="text-sm text-default">Carregando oferta…</p>
      </div>
    );
  }

  if (error || !quote) {
    return (
      <div>
        <PageHeader title="Oferta" />
        <Alert variant="error">{error ?? "Oferta não encontrada."}</Alert>
      </div>
    );
  }

  return (
    <div>
      <Breadcrumb items={[{ label: "Ofertas", href: "/quotes" }, { label: quote.quote_number }]} />
      <PageHeader
        title={`Oferta ${quote.quote_number}`}
        actions={
          <div className="flex items-center gap-2">
            <Badge variant={APPROVAL_VARIANT[quote.approval_status]}>{APPROVAL_LABEL[quote.approval_status]}</Badge>
            <Badge variant={DEAL_VARIANT[quote.deal_status]}>{DEAL_LABEL[quote.deal_status]}</Badge>
            {quote.deal_status === "fechado" ? (
              <Link
                to={`/contracts/new?quoteId=${encodeURIComponent(quote.id)}${
                  quote.client_registration_id
                    ? `&clientRegistrationId=${encodeURIComponent(quote.client_registration_id)}`
                    : ""
                }`}
                className={PRIMARY_LINK_BUTTON_CLASS}
              >
                Criar contrato a partir desta oferta
              </Link>
            ) : null}
          </div>
        }
      />

      <div className="grid grid-cols-1 gap-4 lg:grid-cols-3">
        <div className="lg:col-span-1">
          <Card title="Cliente">
            <dl className="space-y-3 text-sm">
              <Row label="Nome" value={quote.client_name} />
              <Row label="Empresa" value={quote.client_company ?? "—"} />
              <Row label="E-mail" value={quote.client_email ?? "—"} />
              <Row label="Telefone" value={quote.client_phone} />
              <Row label="Revenda" value={reseller?.name ?? quote.reseller_id} />
              <Row
                label="Período de contrato"
                value={quote.contract_period === 0 ? "Sem fidelidade" : `${quote.contract_period} meses`}
              />
              <Row
                label="Fidelidade reduzida"
                value={quote.fidelity_period != null ? `${quote.fidelity_period} meses` : "—"}
              />
              <Row label="Condição de pagamento" value={quote.impl_payment_condition} />
              <Row label="Criada em" value={formatDateBR(quote.created_at)} />
            </dl>
          </Card>
        </div>

        <div className="space-y-4 lg:col-span-2">
          <Card title="Itens">
            <div className="overflow-x-auto">
              <table className="w-full text-sm">
                <thead>
                  <tr className="border-b border-border-color text-left">
                    <th className="py-2 pe-3 font-semibold text-title">Produto</th>
                    <th className="py-2 pe-3 text-right font-semibold text-title">Qtd.</th>
                    <th className="py-2 pe-3 text-right font-semibold text-title">Preço unit.</th>
                    <th className="py-2 pe-3 text-right font-semibold text-title">Total</th>
                    <th className="py-2 pe-3 text-right font-semibold text-title">Impl. unit.</th>
                    <th className="py-2 text-right font-semibold text-title">Impl. total</th>
                  </tr>
                </thead>
                <tbody>
                  {quote.items.map((item, index) => (
                    <tr key={`${item.productId}-${index}`} className="border-b border-border-color last:border-0">
                      <td className="py-2 pe-3 font-semibold text-title">{item.productName}</td>
                      <td className="py-2 pe-3 text-right text-default">{item.quantity}</td>
                      <td className="py-2 pe-3 text-right text-default">{formatCurrencyBRL(item.unitPrice)}</td>
                      <td className="py-2 pe-3 text-right text-default">{formatCurrencyBRL(item.total)}</td>
                      <td className="py-2 pe-3 text-right text-default">{formatCurrencyBRL(item.implUnitPrice)}</td>
                      <td className="py-2 text-right text-default">{formatCurrencyBRL(item.implTotal)}</td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          </Card>

          <Card title="Resumo financeiro">
            <div className="grid grid-cols-1 gap-3 sm:grid-cols-2">
              <SummaryRow label="Mensalidade calculada" value={formatCurrencyBRL(quote.monthly_total)} />
              {quote.proposed_monthly_total != null ? (
                <SummaryRow
                  label="Mensalidade proposta"
                  value={formatCurrencyBRL(quote.proposed_monthly_total)}
                  highlight
                />
              ) : null}
              <SummaryRow label="Implantação (produtos)" value={formatCurrencyBRL(quote.implementation_fee)} />
              <SummaryRow label="Implantação geral" value={formatCurrencyBRL(quote.impl_geral)} />
              <SummaryRow label="Total do contrato" value={formatCurrencyBRL(quote.contract_total)} highlight />
            </div>
            {quote.notes ? (
              <div className="mt-4 border-t border-border-color pt-4">
                <p className="text-xs font-semibold text-default">Notas</p>
                <p className="mt-1 text-sm text-title">{quote.notes}</p>
              </div>
            ) : null}
          </Card>

          {quote.approval_status === "pending" ? (
            <ApprovalCard quoteId={quote.id} accessToken={accessToken} onDecided={load} />
          ) : quote.approval_status !== "none" && quote.approval_notes ? (
            <Card title="Aprovação">
              <p className="text-sm text-default">{quote.approval_notes}</p>
            </Card>
          ) : null}

          {quote.deal_status === "orcamento" ? (
            <CloseDealCard quoteId={quote.id} accessToken={accessToken} onClosed={load} />
          ) : quote.client_registration_id ? (
            <Card title="Negócio">
              <div className="flex items-center justify-between gap-3">
                <dt className="text-sm text-default">Cadastro de cliente</dt>
                <dd>
                  <Link
                    to={`/client-registrations/${quote.client_registration_id}`}
                    className="text-sm font-semibold text-primary hover:underline"
                  >
                    Ver cadastro →
                  </Link>
                </dd>
              </div>
            </Card>
          ) : null}
        </div>
      </div>
    </div>
  );
}

function Row({ label, value }: { label: string; value: string }) {
  return (
    <div className="flex items-start justify-between gap-3">
      <dt className="text-default">{label}</dt>
      <dd className="text-right font-semibold text-title">{value}</dd>
    </div>
  );
}

function SummaryRow({ label, value, highlight }: { label: string; value: string; highlight?: boolean }) {
  return (
    <div className="flex items-center justify-between rounded-md border border-border-color p-3">
      <span className="text-sm text-default">{label}</span>
      <span className={highlight ? "text-base font-bold text-primary" : "text-sm font-semibold text-title"}>
        {value}
      </span>
    </div>
  );
}

function ApprovalCard({
  quoteId,
  accessToken,
  onDecided,
}: {
  quoteId: string;
  accessToken: string | null;
  onDecided: () => void;
}) {
  const [notes, setNotes] = useState("");
  const [submitting, setSubmitting] = useState<"approved" | "rejected" | null>(null);
  const [error, setError] = useState<string | null>(null);

  async function decide(decision: "approved" | "rejected") {
    if (!accessToken) return;
    setError(null);
    setSubmitting(decision);
    try {
      await decideQuoteApproval(quoteId, { decision, notes: notes || undefined }, accessToken);
      onDecided();
    } catch (err) {
      setError(err instanceof ApiError ? err.message : "Não foi possível registrar a decisão.");
    } finally {
      setSubmitting(null);
    }
  }

  return (
    <Card title="Aprovação pendente">
      {error ? (
        <Alert variant="error" className="mb-3">
          {error}
        </Alert>
      ) : null}
      <p className="mb-3 text-sm text-default">
        Esta oferta tem desconto e/ou fidelidade reduzida e precisa de aprovação antes de seguir.
      </p>
      <Input
        label="Observação (opcional)"
        value={notes}
        onChange={(e) => setNotes(e.target.value)}
        className="mb-3"
      />
      <div className="flex items-center gap-2">
        <Button type="button" onClick={() => decide("approved")} loading={submitting === "approved"}>
          Aprovar
        </Button>
        <Button type="button" variant="danger" onClick={() => decide("rejected")} loading={submitting === "rejected"}>
          Rejeitar
        </Button>
      </div>
    </Card>
  );
}

/**
 * Was a free-text UUID field the user had to paste manually — replaced with
 * a real `<select>` populated from `GET /v1/client-registrations` (name +
 * code), matching every other reference field in the app (e.g. Reseller in
 * the summary card above). When there's nothing to pick yet, a button
 * navigates to `/client-registrations/new` in a new tab so the in-progress
 * quote page isn't lost — the user comes back to this tab and reloads the
 * list once the cadastro exists.
 */
function CloseDealCard({
  quoteId,
  accessToken,
  onClosed,
}: {
  quoteId: string;
  accessToken: string | null;
  onClosed: () => void;
}) {
  const [registrations, setRegistrations] = useState<ClientRegistration[] | null>(null);
  const [loadError, setLoadError] = useState<string | null>(null);
  const [clientRegistrationId, setClientRegistrationId] = useState("");
  const [submitting, setSubmitting] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const loadRegistrations = useCallback(() => {
    if (!accessToken) return;
    setLoadError(null);
    listClientRegistrations(accessToken)
      .then(setRegistrations)
      .catch((err) =>
        setLoadError(err instanceof ApiError ? err.message : "Não foi possível carregar os cadastros de cliente."),
      );
  }, [accessToken]);

  useEffect(() => {
    loadRegistrations();
  }, [loadRegistrations]);

  async function handleSubmit(event: FormEvent) {
    event.preventDefault();
    if (!accessToken || !clientRegistrationId) return;
    setError(null);
    setSubmitting(true);
    try {
      await closeQuoteDeal(quoteId, { clientRegistrationId }, accessToken);
      onClosed();
    } catch (err) {
      setError(err instanceof ApiError ? err.message : "Não foi possível fechar o negócio.");
    } finally {
      setSubmitting(false);
    }
  }

  const registrationOptions = (registrations ?? []).map((registration) => {
    const name =
      (registration.person_type === "pf" ? registration.pf_full_name : registration.pj_company_name) ??
      "Sem nome preenchido";
    return { value: registration.id, label: `#${registration.client_code} — ${name}` };
  });

  return (
    <Card title="Fechar negócio">
      {error ? (
        <Alert variant="error" className="mb-3">
          {error}
        </Alert>
      ) : null}
      {loadError ? (
        <Alert variant="error" className="mb-3">
          {loadError}
        </Alert>
      ) : null}

      {registrations !== null && registrations.length === 0 ? (
        <div className="flex flex-wrap items-center justify-between gap-3">
          <p className="text-sm text-default">Nenhum cadastro de cliente encontrado ainda.</p>
          <Button type="button" variant="secondary" onClick={() => window.open("/client-registrations/new", "_blank")}>
            Criar novo cadastro de cliente
          </Button>
        </div>
      ) : (
        <form className="flex flex-wrap items-end gap-3" onSubmit={handleSubmit}>
          <Select
            label="Cadastro de cliente"
            options={registrationOptions}
            value={clientRegistrationId}
            onChange={(e) => setClientRegistrationId(e.target.value)}
            placeholder={registrations === null ? "Carregando cadastros…" : "Selecione um cadastro"}
            hint="Cadastro de cliente que receberá este negócio"
            className="min-w-72 flex-1"
            required
          />
          <Button type="submit" loading={submitting}>
            Fechar negócio
          </Button>
        </form>
      )}
    </Card>
  );
}