"use client";

/**
 * /settings — the top-level user-settings screen.
 *
 * Lives outside the /u/me profile layout so it doesn't carry the
 * ProfileHeader + tabs that frame the profile views. It sits directly
 * under (app)/, which gives it the default site chrome (sidebar, header,
 * etc.) without the profile-specific frame on top.
 *
 * Sections are stacked plain — no per-section card chrome — so the page
 * reads as a single ordered list of preferences rather than a dashboard
 * of widgets. To add a new section, drop another <Section> in the
 * `<main>` below.
 */

import { useState } from "react";
import Link from "next/link";
import { ChevronLeft, ChevronRight } from "lucide-react";
import { ChangePasswordModal } from "@/components/auth/change-password-modal";
import { ReadingSettings } from "@/components/reading-settings";

const BFF_BASE =
  process.env.NEXT_PUBLIC_BFF_URL || "http://localhost:8080";

export default function SettingsPage() {
  return (
    <main className="flex-1 max-w-3xl w-full mx-auto px-4 sm:px-6 py-6 space-y-10">
      <header className="space-y-1">
        <Link
          href="/u/me"
          className="inline-flex items-center gap-1 text-sm text-muted-foreground hover:text-foreground transition-colors"
        >
          <ChevronLeft className="size-4" />
          Back to profile
        </Link>
        <h1 className="font-[family-name:var(--font-title)] text-3xl font-semibold text-foreground pt-2">
          Settings
        </h1>
      </header>

      <Section
        title="Reading preferences"
        description="Theme, palette, font, and size — synced across your devices."
      >
        <ReadingSettings variant="bare" />
      </Section>

      <Section title="Authentication">
        <AuthenticationSection />
      </Section>

      <Section title="Legal">
        <LegalSection />
      </Section>
    </main>
  );
}

function Section({
  title,
  description,
  children,
}: {
  title: string;
  description?: string;
  children: React.ReactNode;
}) {
  return (
    <section className="space-y-4">
      <div className="border-b border-border pb-3">
        <h2 className="font-[family-name:var(--font-title)] text-xl font-semibold text-foreground">
          {title}
        </h2>
        {description ? (
          <p className="text-sm text-muted-foreground mt-1">{description}</p>
        ) : null}
      </div>
      <div>{children}</div>
    </section>
  );
}

// ─── Authentication ────────────────────────────────────────────────────

function AuthenticationSection() {
  const [pwModalOpen, setPwModalOpen] = useState(false);
  const next = "/settings";

  function startOAuth(provider: "facebook" | "google") {
    const u = new URL(`${BFF_BASE}/api/v1/auth/oauth/${provider}/start`);
    u.searchParams.set("next", next);
    return u.toString();
  }

  return (
    <>
      <ul className="divide-y divide-border">
        {/* Google sign-in — uncomment once the Google OAuth app clears review.
        <Row
          label="Connect your Google account"
          action={
            <a
              href={startOAuth("google")}
              className="text-sm font-medium text-primary hover:underline"
            >
              Connect
            </a>
          }
        />
        */}
        <Row
          icon={<FacebookGlyph />}
          label="Connect your Facebook account"
          action={
            <a
              href={startOAuth("facebook")}
              className="text-sm font-medium text-primary hover:underline"
            >
              Connect
            </a>
          }
        />
        <Row
          label="Change your password"
          description="Update the password you use to sign in."
          action={
            <button
              type="button"
              onClick={() => setPwModalOpen(true)}
              className="text-sm font-medium text-primary hover:underline"
            >
              Change
            </button>
          }
        />
      </ul>
      <ChangePasswordModal
        open={pwModalOpen}
        onClose={() => setPwModalOpen(false)}
      />
    </>
  );
}

// ─── Legal ─────────────────────────────────────────────────────────────

function LegalSection() {
  return (
    <ul className="divide-y divide-border">
      <LegalLink href="/terms" label="Terms of Service" />
      <LegalLink href="/privacy" label="Privacy Policy" />
      <LegalLink href="/data-deletion" label="Steps for data deletion" />
    </ul>
  );
}

function LegalLink({ href, label }: { href: string; label: string }) {
  return (
    <li>
      <Link
        href={href}
        className="flex items-center justify-between py-3 group"
      >
        <span className="text-sm text-foreground group-hover:text-primary transition-colors">
          {label}
        </span>
        <ChevronRight className="size-4 text-muted-foreground group-hover:text-foreground transition-colors" />
      </Link>
    </li>
  );
}

// ─── Row helper ────────────────────────────────────────────────────────

function FacebookGlyph() {
  return (
    <svg
      className="size-4"
      viewBox="0 0 24 24"
      xmlns="http://www.w3.org/2000/svg"
      aria-hidden
    >
      <path
        fill="#1877F2"
        d="M24 12a12 12 0 1 0-13.88 11.85V15.47H7.08V12h3.04V9.36c0-3 1.79-4.67 4.53-4.67 1.31 0 2.69.24 2.69.24v2.96H15.83c-1.49 0-1.95.92-1.95 1.87V12h3.32l-.53 3.47h-2.79v8.38A12 12 0 0 0 24 12Z"
      />
    </svg>
  );
}

function Row({
  icon,
  label,
  description,
  action,
}: {
  icon?: React.ReactNode;
  label: string;
  description?: string;
  action: React.ReactNode;
}) {
  return (
    <li className="flex items-center justify-between gap-4 py-3">
      <div className="min-w-0">
        <div className="flex items-center gap-2">
          {icon ? <span className="shrink-0">{icon}</span> : null}
          <span className="text-sm text-foreground truncate">{label}</span>
        </div>
        {description ? (
          <p className="text-xs text-muted-foreground mt-0.5">{description}</p>
        ) : null}
      </div>
      <div className="shrink-0">{action}</div>
    </li>
  );
}