"use client";

import { useState, useTransition } from "react";
import { useRouter } from "next/navigation";
import { PASSWORD_MIN_LENGTH, PASSWORD_POLICY_MESSAGE } from "@capakraken/shared";
import { createFirstAdmin } from "./actions.js";

export function SetupClient() {
  const router = useRouter();

  const [name, setName] = useState("");
  const [email, setEmail] = useState("");
  const [password, setPassword] = useState("");
  const [confirmPassword, setConfirmPassword] = useState("");
  const [formError, setFormError] = useState<string | null>(null);
  const [done, setDone] = useState(false);

  const [isPending, startTransition] = useTransition();

  function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    setFormError(null);

    if (password.length < PASSWORD_MIN_LENGTH) {
      setFormError(PASSWORD_POLICY_MESSAGE);
      return;
    }
    if (password !== confirmPassword) {
      setFormError("Passwords do not match.");
      return;
    }

    startTransition(async () => {
      const result = await createFirstAdmin({ name, email, password });

      if ("success" in result) {
        setDone(true);
        router.push("/auth/signin?setup=done");
        return;
      }

      if (result.error === "alreadySetup") {
        setFormError("Setup already completed. Redirecting…");
        setTimeout(() => router.push("/auth/signin"), 2000);
        return;
      }

      if (result.error === "emailTaken") {
        setFormError("An account with this email already exists.");
        return;
      }

      if (result.error === "validation") {
        setFormError(result.message ?? "Validation error.");
        return;
      }
    });
  }

  if (done) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-gray-50 dark:bg-gray-950 p-4">
        <div className="w-full max-w-md rounded-2xl bg-white dark:bg-gray-900 shadow-lg p-8 text-center">
          <h1 className="text-lg font-semibold text-gray-900 dark:text-gray-100 mb-2">
            Admin account created
          </h1>
          <p className="text-sm text-gray-500">Redirecting to sign in…</p>
        </div>
      </div>
    );
  }

  return (
    <div className="min-h-screen flex items-center justify-center bg-gray-50 dark:bg-gray-950 p-4">
      <div className="w-full max-w-md rounded-2xl bg-white dark:bg-gray-900 shadow-lg p-8">
        <div className="mb-6">
          <h1 className="text-xl font-bold text-gray-900 dark:text-gray-100">First-run setup</h1>
          <p className="mt-1 text-sm text-gray-500">
            Create the initial administrator account for CapaKraken.
          </p>
        </div>

        <form onSubmit={handleSubmit} className="space-y-4">
          {formError && (
            <div className="rounded-lg bg-red-50 dark:bg-red-900/20 border border-red-200 dark:border-red-700 px-4 py-3 text-sm text-red-700 dark:text-red-400">
              {formError}
            </div>
          )}

          <div>
            <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
              Name
            </label>
            <input
              type="text"
              value={name}
              onChange={(e) => setName(e.target.value)}
              required
              placeholder="Your full name"
              className="w-full rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-900 px-3 py-2 text-sm text-gray-900 dark:text-gray-100 focus:outline-none focus:ring-2 focus:ring-brand-400"
            />
          </div>

          <div>
            <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
              Email
            </label>
            <input
              type="email"
              value={email}
              onChange={(e) => setEmail(e.target.value)}
              required
              placeholder="admin@example.com"
              className="w-full rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-900 px-3 py-2 text-sm text-gray-900 dark:text-gray-100 focus:outline-none focus:ring-2 focus:ring-brand-400"
            />
          </div>

          <div>
            <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
              Password
            </label>
            <input
              type="password"
              value={password}
              onChange={(e) => setPassword(e.target.value)}
              required
              minLength={PASSWORD_MIN_LENGTH}
              placeholder={`At least ${PASSWORD_MIN_LENGTH} characters`}
              className="w-full rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-900 px-3 py-2 text-sm text-gray-900 dark:text-gray-100 focus:outline-none focus:ring-2 focus:ring-brand-400"
            />
          </div>

          <div>
            <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
              Confirm password
            </label>
            <input
              type="password"
              value={confirmPassword}
              onChange={(e) => setConfirmPassword(e.target.value)}
              required
              placeholder="Repeat your password"
              className="w-full rounded-lg border border-gray-300 dark:border-gray-600 bg-white dark:bg-gray-900 px-3 py-2 text-sm text-gray-900 dark:text-gray-100 focus:outline-none focus:ring-2 focus:ring-brand-400"
            />
          </div>

          <button
            type="submit"
            disabled={isPending}
            className="w-full rounded-lg bg-brand-600 px-4 py-2 text-sm font-semibold text-white hover:bg-brand-700 transition-colors disabled:opacity-50"
          >
            {isPending ? "Creating account…" : "Create admin account"}
          </button>
        </form>
      </div>
    </div>
  );
}
