"use client";

import { useState } from "react";
import { FLOCK_UI } from "@/lib/flock/ui-labels";
import type { FlockDisplayLine } from "@/modules/flock/quote-storage";
import type { FlockCheckoutTier } from "@/lib/flock/flock-checkout-selection";
import { validateFlockCheckoutSelection } from "@/lib/flock/flock-checkout-selection";
import { ErrorBanner } from "@/components/ui/error-banner";

export type FlockCheckoutIntent = {
  preferredTier: FlockCheckoutTier;
  line: FlockDisplayLine;
};

export interface FlockQuoteResultProps {
  lines: FlockDisplayLine[];
  reference?: string | null;
  onReset?: () => void;
  /** 登录态：允许选档结账 */
  checkoutEnabled?: boolean;
  checkoutBusy?: boolean;
  checkoutMessage?: string | null;
  onCheckout?: (intent: FlockCheckoutIntent) => void;
}

function formatUsd(n: number): string {
  return n.toLocaleString("en-US", {
    style: "currency",
    currency: "USD",
    maximumFractionDigits: 0,
  });
}

/** Flock 两档对比结果卡（中文）；登录态可选手选档结账 */
export function FlockQuoteResult({
  lines,
  reference,
  onReset,
  checkoutEnabled = false,
  checkoutBusy = false,
  checkoutMessage = null,
  onCheckout,
}: FlockQuoteResultProps) {
  const direct = lines.find((l) => l.tier === "flock_direct");
  const standard = lines.find((l) => l.tier === "standard");
  const [selectedTier, setSelectedTier] = useState<FlockCheckoutTier | null>(
    null,
  );
  const [localError, setLocalError] = useState<string | null>(null);

  const selectedLine =
    selectedTier === "flock_direct"
      ? direct
      : selectedTier === "standard"
        ? standard
        : null;

  if (!direct && !standard) {
    return (
      <div className="rounded-lg border border-border bg-surface p-5 text-sm text-text-secondary">
        {FLOCK_UI.emptyResult}
      </div>
    );
  }

  const selectTier = (tier: FlockCheckoutTier) => {
    if (!checkoutEnabled) return;
    setSelectedTier(tier);
    setLocalError(null);
  };

  return (
    <div className="space-y-4">
      <div className="flex flex-wrap items-end justify-between gap-2">
        <div>
          <h2 className="text-lg font-semibold text-text-primary">
            {FLOCK_UI.resultTitle}
          </h2>
          {reference && (
            <p className="mt-1 text-xs text-text-secondary">
              {FLOCK_UI.reference} #{reference}
            </p>
          )}
        </div>
        {onReset && (
          <button
            type="button"
            onClick={onReset}
            className="rounded-md border border-border bg-surface px-3 py-1.5 text-sm text-text-primary"
          >
            {FLOCK_UI.buildAnother}
          </button>
        )}
      </div>

      <div className="grid gap-4 md:grid-cols-2">
        {direct && (
          <article
            className={
              "rounded-lg border p-5 text-white shadow-card " +
              (checkoutEnabled
                ? "cursor-pointer " +
                  (selectedTier === "flock_direct"
                    ? "border-emerald-400 bg-[#1f2420] ring-2 ring-emerald-400/60"
                    : "border-primary/30 bg-[#1f2420] opacity-90 hover:opacity-100")
                : "border-primary/30 bg-[#1f2420]")
            }
            onClick={() => selectTier("flock_direct")}
            onKeyDown={(e) => {
              if (e.key === "Enter" || e.key === " ") {
                e.preventDefault();
                selectTier("flock_direct");
              }
            }}
            role={checkoutEnabled ? "button" : undefined}
            tabIndex={checkoutEnabled ? 0 : undefined}
            aria-pressed={
              checkoutEnabled ? selectedTier === "flock_direct" : undefined
            }
          >
            <div className="mb-1 text-xs uppercase tracking-wide text-emerald-300">
              {FLOCK_UI.directTag}
            </div>
            <h3 className="text-xl font-semibold">{FLOCK_UI.directName}</h3>
            <p className="mt-3 text-2xl font-bold">
              {FLOCK_UI.pricesFrom} {formatUsd(direct.final_total_usd)}
            </p>
            <p className="mt-1 text-sm text-white/80">
              {FLOCK_UI.transit}：{direct.transitDescription || direct.transitDays}
            </p>
            <ul className="mt-4 space-y-2 text-sm text-white/90">
              {FLOCK_UI.directFeatures.map((f) => (
                <li key={f}>✓ {f}</li>
              ))}
            </ul>
          </article>
        )}

        {standard && (
          <article
            className={
              "rounded-lg border bg-surface p-5 shadow-card " +
              (checkoutEnabled
                ? "cursor-pointer " +
                  (selectedTier === "standard"
                    ? "border-primary ring-2 ring-primary/40"
                    : "border-border hover:border-primary/40")
                : "border-border")
            }
            onClick={() => selectTier("standard")}
            onKeyDown={(e) => {
              if (e.key === "Enter" || e.key === " ") {
                e.preventDefault();
                selectTier("standard");
              }
            }}
            role={checkoutEnabled ? "button" : undefined}
            tabIndex={checkoutEnabled ? 0 : undefined}
            aria-pressed={
              checkoutEnabled ? selectedTier === "standard" : undefined
            }
          >
            <div className="mb-1 text-xs uppercase tracking-wide text-text-secondary">
              {FLOCK_UI.standardTag}
            </div>
            <h3 className="text-xl font-semibold text-text-primary">
              {FLOCK_UI.standardName}
            </h3>
            <p className="mt-3 text-2xl font-bold text-text-primary">
              {FLOCK_UI.pricesFrom} {formatUsd(standard.final_total_usd)}
            </p>
            <p className="mt-1 text-sm text-text-secondary">
              {FLOCK_UI.transit}：
              {standard.transitDescription || standard.transitDays}
            </p>
            <ul className="mt-4 space-y-2 text-sm text-text-secondary">
              {FLOCK_UI.standardFeatures.map((f, i) => (
                <li key={f}>
                  {i === 0 ? "✓" : "×"} {f}
                </li>
              ))}
            </ul>
            <p className="mt-3 text-xs text-text-secondary">
              {FLOCK_UI.standardNote}
            </p>
          </article>
        )}
      </div>

      {checkoutEnabled && (
        <div className="border-t border-border pt-4">
          {(localError || checkoutMessage) && (
            <div className="mb-3">
              <ErrorBanner>{localError || checkoutMessage}</ErrorBanner>
            </div>
          )}
          {selectedLine && selectedTier && (
            <p className="mb-2 text-center text-xs text-success">
              {FLOCK_UI.checkoutSelected}：
              {selectedTier === "flock_direct"
                ? FLOCK_UI.directName
                : FLOCK_UI.standardName}{" "}
              · {formatUsd(selectedLine.final_total_usd)}
            </p>
          )}
          <button
            type="button"
            disabled={
              !selectedTier || !selectedLine || checkoutBusy || !onCheckout
            }
            onClick={() => {
              if (!selectedTier || !selectedLine || !onCheckout) return;
              const err = validateFlockCheckoutSelection({
                preferredTier: selectedTier,
              });
              if (err) {
                setLocalError(err);
                return;
              }
              setLocalError(null);
              onCheckout({ preferredTier: selectedTier, line: selectedLine });
            }}
            className="flex h-12 w-full items-center justify-center rounded-md bg-success px-4 text-sm font-semibold text-white disabled:cursor-not-allowed disabled:opacity-50"
          >
            {checkoutBusy
              ? FLOCK_UI.checkoutSyncing
              : selectedLine
                ? `${FLOCK_UI.checkoutCta} — ${formatUsd(selectedLine.final_total_usd)}`
                : FLOCK_UI.checkoutCta}
          </button>
          {!selectedTier && (
            <p className="mt-2 text-center text-[11px] text-text-disabled">
              {FLOCK_UI.checkoutSelectHint}
            </p>
          )}
          <p className="mt-2 text-center text-[11px] text-text-disabled">
            {FLOCK_UI.checkoutFootnote}
          </p>
        </div>
      )}
    </div>
  );
}