'use client';

import { useState, useTransition, useEffect, useRef } from 'react';
import { useTranslations } from 'next-intl';
import {
  fetchCurrentUser,
  changePasswordAction,
  uploadAvatarAction,
  deleteAvatarAction,
  updateAccentColorAction,
} from '@/lib/auth-actions';
import { useAuthStore } from '@/lib/stores/auth-store';
import { BRAND_YELLOW } from '@/components/brand/brand';
import { normalizeHexColor } from '@/lib/color';

const DEFAULT_ACCENT = BRAND_YELLOW;

export function AccountSettingsForm() {
  const t = useTranslations('settings');
  const tAuth = useTranslations('auth');
  const { user, setUser, bumpAvatarVersion } = useAuthStore();

  const [isLocalUser, setIsLocalUser] = useState<boolean | null>(null);
  const [username, setUsername] = useState<string>('');
  const [hasAvatar, setHasAvatar] = useState(false);
  const [avatarKey, setAvatarKey] = useState(0);

  // Password change state
  const [pwError, setPwError] = useState<string | null>(null);
  const [pwSuccess, setPwSuccess] = useState(false);
  const [pwMismatch, setPwMismatch] = useState(false);
  const [isPwPending, startPwTransition] = useTransition();
  const pwFormRef = useRef<HTMLFormElement>(null);

  // Avatar upload/delete state
  const [avatarError, setAvatarError] = useState<string | null>(null);
  const [avatarSuccess, setAvatarSuccess] = useState(false);
  const [isAvatarPending, startAvatarTransition] = useTransition();

  // Accent color state
  const [accentColor, setAccentColor] = useState<string>(DEFAULT_ACCENT);
  const [hexInput, setHexInput] = useState<string>(DEFAULT_ACCENT);
  const isHexValid = normalizeHexColor(hexInput) !== null;
  const [accentSuccess, setAccentSuccess] = useState(false);
  const [accentError, setAccentError] = useState<string | null>(null);
  const [isAccentPending, startAccentTransition] = useTransition();

  useEffect(() => {
    fetchCurrentUser().then((u) => {
      if (u) {
        setIsLocalUser(u.isLocalUser ?? false);
        setUsername(u.displayName ?? u.username ?? '');
        setHasAvatar(!!u.hasAvatar);
        const c = u.accentColor ?? DEFAULT_ACCENT;
        setAccentColor(c);
        setHexInput(c);
      }
    });
  }, []);

  async function handlePasswordSubmit(e: React.FormEvent<HTMLFormElement>) {
    e.preventDefault();
    setPwError(null);
    setPwSuccess(false);
    setPwMismatch(false);

    const formData = new FormData(e.currentTarget);
    const currentPassword = formData.get('currentPassword') as string;
    const newPassword = formData.get('newPassword') as string;
    const confirmPassword = formData.get('confirmPassword') as string;

    if (newPassword !== confirmPassword) {
      setPwMismatch(true);
      return;
    }

    startPwTransition(async () => {
      const result = await changePasswordAction(currentPassword, newPassword);
      if (result) setPwError(result.error);
    });
  }

  async function handleAvatarUpload(e: React.ChangeEvent<HTMLInputElement>) {
    const file = e.target.files?.[0];
    if (!file) return;
    setAvatarError(null);
    setAvatarSuccess(false);
    const formData = new FormData();
    formData.append('file', file);
    startAvatarTransition(async () => {
      const result = await uploadAvatarAction(formData);
      if (result.success) {
        setAvatarSuccess(true);
        setHasAvatar(true);
        setAvatarKey((k) => k + 1);
        bumpAvatarVersion();
        if (user) setUser({ ...user, hasAvatar: true });
      } else {
        setAvatarError(result.error ?? 'uploadError');
      }
    });
  }

  function handleDeleteAvatar() {
    setAvatarError(null);
    setAvatarSuccess(false);
    startAvatarTransition(async () => {
      const result = await deleteAvatarAction();
      if (result.success) {
        setHasAvatar(false);
        setAvatarSuccess(true);
        setAvatarKey((k) => k + 1);
        if (user) setUser({ ...user, hasAvatar: false });
      } else {
        setAvatarError(result.error ?? 'deleteError');
      }
    });
  }

  function handleSaveAccentColor() {
    if (!isHexValid) return;
    setAccentSuccess(false);
    setAccentError(null);
    startAccentTransition(async () => {
      const result = await updateAccentColorAction(accentColor);
      if (result.success) {
        setAccentSuccess(true);
        if (user) setUser({ ...user, accentColor });
      } else {
        setAccentError(result.error ?? 'saveError');
      }
    });
  }

  function handleResetAccentColor() {
    setAccentColor(DEFAULT_ACCENT);
    setHexInput(DEFAULT_ACCENT);
    setAccentSuccess(false);
    setAccentError(null);
    startAccentTransition(async () => {
      const result = await updateAccentColorAction(null);
      if (result.success) {
        setAccentSuccess(true);
        if (user) setUser({ ...user, accentColor: null });
      }
    });
  }

  const userInitial = username.charAt(0).toUpperCase() || '?';

  return (
    <div className="space-y-8 max-w-lg">
      {/* ── Avatar section ─────────────────────────────────────── */}
      <section>
        <h2 className="text-sm font-semibold text-foreground mb-4">
          {t('account.avatarLabel')}
        </h2>
        <div className="flex items-center gap-4 mb-4">
          <div className="relative h-16 w-16 shrink-0">
            {hasAvatar ? (
              <img
                key={avatarKey}
                src={`/api-proxy/users/me/avatar?t=${avatarKey}`}
                alt=""
                aria-hidden="true"
                className="h-16 w-16 rounded-full object-cover"
                onError={() => setHasAvatar(false)}
              />
            ) : (
              <div className="h-16 w-16 rounded-full bg-primary flex items-center justify-center text-xl font-medium text-primary-foreground">
                {userInitial}
              </div>
            )}
          </div>
          <div className="text-sm text-muted-foreground">
            {t('account.avatarHelp')}
          </div>
        </div>

        {avatarSuccess && (
          <div className="rounded-md bg-green-50 dark:bg-green-900/20 border border-green-200 dark:border-green-800 px-4 py-3 text-sm text-green-800 dark:text-green-200 mb-3">
            {hasAvatar ? t('account.uploadSuccess') : t('account.deleteAvatarSuccess')}
          </div>
        )}
        {avatarError && (
          <div className="rounded-md bg-destructive/10 border border-destructive/20 px-4 py-3 text-sm text-destructive mb-3">
            {avatarError === 'deleteError' ? t('account.deleteAvatarError') : t('account.uploadError')}
          </div>
        )}

        <div className="flex items-center gap-2">
          <label className="inline-flex items-center gap-2 cursor-pointer">
            <input
              type="file"
              accept="image/png,image/jpeg,image/webp"
              className="sr-only"
              disabled={isAvatarPending}
              onChange={handleAvatarUpload}
            />
            <span className="btn btn-primary">
              {isAvatarPending ? '...' : t('account.uploadCta')}
            </span>
          </label>
          {hasAvatar && (
            <button
              type="button"
              disabled={isAvatarPending}
              onClick={handleDeleteAvatar}
              className="inline-flex items-center justify-center rounded-md border border-destructive/40 px-4 py-2 text-sm font-medium text-destructive hover:bg-destructive/10 transition-colors disabled:opacity-50"
            >
              {t('account.deleteAvatarCta')}
            </button>
          )}
        </div>
      </section>

      {/* ── Accent color section ────────────────────────────────── */}
      <section>
        <h2 className="text-sm font-semibold text-foreground mb-1">
          {t('account.accentColorLabel')}
        </h2>
        <p className="text-xs text-muted-foreground mb-4">{t('account.accentColorHelp')}</p>
        <div className="flex items-center gap-3 mb-1">
          <input
            type="color"
            value={accentColor}
            onChange={(e) => {
              setAccentColor(e.target.value);
              setHexInput(e.target.value);
            }}
            className="h-10 w-16 cursor-pointer rounded-md border border-input p-1"
          />
          <input
            id="accentColorHex"
            type="text"
            inputMode="text"
            autoComplete="off"
            spellCheck={false}
            maxLength={7}
            placeholder={DEFAULT_ACCENT}
            value={hexInput}
            aria-label={t('account.accentColorHex')}
            aria-invalid={!isHexValid}
            onChange={(e) => {
              const raw = e.target.value;
              setHexInput(raw);
              const n = normalizeHexColor(raw);
              if (n) setAccentColor(n);
            }}
            onBlur={() => {
              const n = normalizeHexColor(hexInput);
              if (n) setHexInput(n);
            }}
            className={`h-10 w-28 rounded-md border bg-background px-3 py-2 font-mono text-sm focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring ${
              isHexValid ? 'border-input' : 'border-destructive'
            }`}
          />
          <button
            type="button"
            onClick={handleResetAccentColor}
            disabled={isAccentPending}
            className="text-sm text-muted-foreground hover:text-foreground transition-colors disabled:opacity-50"
          >
            {t('account.accentColorReset')}
          </button>
        </div>
        {!isHexValid && (
          <p className="text-xs text-destructive mb-3">{t('account.accentColorHexInvalid')}</p>
        )}
        {accentSuccess && (
          <div className="rounded-md bg-green-50 dark:bg-green-900/20 border border-green-200 dark:border-green-800 px-4 py-3 text-sm text-green-800 dark:text-green-200 mb-3">
            {t('account.accentColorSuccess')}
          </div>
        )}
        {accentError && (
          <div className="rounded-md bg-destructive/10 border border-destructive/20 px-4 py-3 text-sm text-destructive mb-3">
            {t('account.accentColorError')}
          </div>
        )}
        <button
          type="button"
          onClick={handleSaveAccentColor}
          disabled={isAccentPending || !isHexValid}
          className="btn btn-primary"
        >
          {isAccentPending ? '...' : t('account.accentColorSave')}
        </button>
      </section>

      {/* ── Password section ────────────────────────────────────── */}
      <section>
        <h2 className="text-sm font-semibold text-foreground mb-4">
          {t('account.passwordSectionTitle')}
        </h2>

        {isLocalUser === false && (
          <div className="rounded-md bg-muted px-4 py-3 text-sm text-muted-foreground">
            {t('account.ldapManagedNotice')}
          </div>
        )}

        {isLocalUser === true && (
          <>
            {pwSuccess && (
              <div className="rounded-md bg-green-50 dark:bg-green-900/20 border border-green-200 dark:border-green-800 px-4 py-3 text-sm text-green-800 dark:text-green-200 mb-4">
                {tAuth('changePassword.success')}
              </div>
            )}
            {pwError && (
              <div className="rounded-md bg-destructive/10 border border-destructive/20 px-4 py-3 text-sm text-destructive mb-4">
                {tAuth(`changePassword.${pwError}`)}
              </div>
            )}
            {pwMismatch && (
              <div className="rounded-md bg-destructive/10 border border-destructive/20 px-4 py-3 text-sm text-destructive mb-4">
                {tAuth('changePassword.passwordMismatch')}
              </div>
            )}

            <form ref={pwFormRef} onSubmit={handlePasswordSubmit} className="space-y-4">
              <div className="space-y-2">
                <label htmlFor="currentPassword" className="text-sm font-medium text-foreground">
                  {tAuth('changePassword.currentPassword')}
                </label>
                <input
                  id="currentPassword"
                  name="currentPassword"
                  type="password"
                  required
                  autoComplete="current-password"
                  onChange={() => { setPwError(null); setPwMismatch(false); }}
                  className="flex h-10 w-full rounded-md border border-input bg-background px-3 py-2 text-sm focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
                />
              </div>
              <div className="space-y-2">
                <label htmlFor="newPassword" className="text-sm font-medium text-foreground">
                  {tAuth('changePassword.newPassword')}
                </label>
                <input
                  id="newPassword"
                  name="newPassword"
                  type="password"
                  required
                  minLength={8}
                  autoComplete="new-password"
                  onChange={() => { setPwError(null); setPwMismatch(false); }}
                  className="flex h-10 w-full rounded-md border border-input bg-background px-3 py-2 text-sm focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
                />
              </div>
              <div className="space-y-2">
                <label htmlFor="confirmPassword" className="text-sm font-medium text-foreground">
                  {tAuth('changePassword.confirmPassword')}
                </label>
                <input
                  id="confirmPassword"
                  name="confirmPassword"
                  type="password"
                  required
                  minLength={8}
                  autoComplete="new-password"
                  onChange={() => { setPwError(null); setPwMismatch(false); }}
                  className="flex h-10 w-full rounded-md border border-input bg-background px-3 py-2 text-sm focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
                />
              </div>
              <button
                type="submit"
                disabled={isPwPending}
                className="btn btn-primary"
              >
                {isPwPending ? (
                  <svg aria-hidden="true" className="animate-spin h-4 w-4" xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24">
                    <circle className="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" strokeWidth="4" />
                    <path className="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z" />
                  </svg>
                ) : (
                  tAuth('changePassword.submit')
                )}
              </button>
            </form>
          </>
        )}
      </section>
    </div>
  );
}