/**
 * WizardShell — chrome for the multi-step new-project wizard.
 *
 * Renders the step indicator (numbered chips with completion
 * state), the page title for the current step, and the Back/Next
 * footer. The actual step body is passed in as `children`.
 *
 * Keyboard: Enter on the Next button submits; ESC is owned by the
 * surrounding host (back to landing).
 */

import React from "react";
import { Check, ChevronLeft, ChevronRight } from "lucide-react";
import { PrimaryButton } from "./ui";

export interface StepDef {
  key: string;
  label: string;
}

export interface WizardShellProps {
  steps: StepDef[];
  activeIndex: number;
  title: string;
  subtitle?: string;
  canGoBack: boolean;
  canGoNext: boolean;
  nextLabel?: string;
  submitting?: boolean;
  onBack: () => void;
  onNext: () => void;
  children: React.ReactNode;
}

export function WizardShell({
  steps, activeIndex, title, subtitle,
  canGoBack, canGoNext, nextLabel, submitting,
  onBack, onNext, children,
}: WizardShellProps) {
  // Three-row enterprise layout: stepper + title stay pinned at
  // the top, footer stays pinned at the bottom, and only the
  // middle content area scrolls. Follows the Linear / Stripe /
  // Notion wizard pattern so users never lose the Next button
  // regardless of viewport height or field length.
  return (
    <div className="flex flex-col h-full w-full">
      {/* ───── Row 1 — Fixed header (stepper + step title) ───── */}
      <header className="shrink-0 border-b border-[#2a2a2a]">
        <div className="max-w-3xl mx-auto px-6 pt-6 pb-4">
          <Stepper steps={steps} activeIndex={activeIndex} />
          <div className="mt-5">
            <h1 className="text-2xl font-medium">{title}</h1>
            {subtitle && <p className="text-sm text-[#aaa] mt-1">{subtitle}</p>}
          </div>
        </div>
      </header>

      {/* ───── Row 2 — Scrollable content (flex-1 + overflow) ─── */}
      <div className="flex-1 min-h-0 overflow-y-auto">
        <div className="max-w-3xl mx-auto px-6 py-6">{children}</div>
      </div>

      {/* ───── Row 3 — Fixed action bar (Back / Next) ───────── */}
      <footer className="shrink-0 border-t border-[#2a2a2a] bg-[#0f0f0f]">
        <div className="max-w-3xl mx-auto px-6 py-3 flex items-center justify-between gap-3">
          {/* Back — ghost/text button so visual weight sits on Next */}
          <button
            type="button"
            onClick={onBack}
            disabled={!canGoBack || submitting}
            className={[
              "inline-flex items-center gap-1.5",
              "px-2.5 py-2 text-sm font-medium rounded",
              "text-[#aaa] hover:text-[#f1f1f1]",
              "disabled:text-[#555] disabled:cursor-not-allowed",
              "transition-colors focus:outline-none",
              "focus-visible:ring-2 focus-visible:ring-[#3ea6ff]",
            ].join(" ")}
          >
            <ChevronLeft className="w-4 h-4" aria-hidden />
            Back
          </button>
          {/* Next — prominent primary with forward chevron after the label */}
          <PrimaryButton
            onClick={onNext}
            disabled={!canGoNext}
            loading={submitting}
            size="lg"
          >
            <span>{nextLabel || "Next"}</span>
            {!submitting && <ChevronRight className="w-4 h-4" aria-hidden />}
          </PrimaryButton>
        </div>
      </footer>
    </div>
  );
}

function Stepper({ steps, activeIndex }: { steps: StepDef[]; activeIndex: number }) {
  return (
    <ol
      aria-label="Wizard progress"
      className="flex items-center gap-2 overflow-x-auto"
    >
      {steps.map((s, i) => {
        const done = i < activeIndex;
        const active = i === activeIndex;
        return (
          <li key={s.key} className="flex items-center gap-2 shrink-0">
            <span
              aria-current={active ? "step" : undefined}
              className={[
                "w-7 h-7 rounded-full flex items-center justify-center text-xs font-semibold border",
                done && "bg-[#3ea6ff] border-[#3ea6ff] text-black",
                active && "bg-transparent border-[#3ea6ff] text-[#3ea6ff]",
                !done && !active && "bg-transparent border-[#3f3f3f] text-[#777]",
              ].filter(Boolean).join(" ")}
            >
              {done ? <Check className="w-3.5 h-3.5" aria-hidden /> : i + 1}
            </span>
            <span
              className={[
                "text-xs whitespace-nowrap",
                active ? "text-[#f1f1f1] font-medium" : "text-[#777]",
              ].join(" ")}
            >
              {s.label}
            </span>
            {i < steps.length - 1 && <span className="w-6 h-px bg-[#3f3f3f] mx-1" aria-hidden />}
          </li>
        );
      })}
    </ol>
  );
}