import 'package:e_receipt_mobile/presentation/login/login_form_providers.dart';
import 'package:e_receipt_mobile/presentation/login/login_state.dart';
import 'package:e_receipt_mobile/presentation/login/login_view_model.dart';
import 'package:e_receipt_mobile/presentation/login/widgets/login_background.dart';
import 'package:e_receipt_mobile/presentation/login/widgets/login_error_banner.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

class LoginPage extends ConsumerWidget {
  const LoginPage({super.key});

  void _submit({
    required WidgetRef ref,
    required LoginState state,
    required GlobalKey<FormState> formKey,
    required TextEditingController usernameController,
    required TextEditingController passwordController,
  }) {
    if (state.isLoading) {
      return;
    }

    ref.read(loginViewModelProvider.notifier).clearMessages();
    FocusManager.instance.primaryFocus?.unfocus();
    ref.read(loginAttemptedSubmitProvider.notifier).state = true;

    if (!(formKey.currentState?.validate() ?? false)) {
      return;
    }

    TextInput.finishAutofillContext();
    ref.read(loginViewModelProvider.notifier).login(
          username: usernameController.text,
          password: passwordController.text,
        );
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final state = ref.watch(loginViewModelProvider);
    final colorScheme = Theme.of(context).colorScheme;

    final formKey = ref.watch(loginFormKeyProvider);
    final usernameController = ref.watch(loginUsernameControllerProvider);
    final passwordController = ref.watch(loginPasswordControllerProvider);
    final usernameFocusNode = ref.watch(loginUsernameFocusNodeProvider);
    final passwordFocusNode = ref.watch(loginPasswordFocusNodeProvider);
    final obscurePassword = ref.watch(loginObscurePasswordProvider);
    final attemptedSubmit = ref.watch(loginAttemptedSubmitProvider);

    return Scaffold(
      body: AnnotatedRegion<SystemUiOverlayStyle>(
        value: Theme.of(context).brightness == Brightness.dark
            ? SystemUiOverlayStyle.light
            : SystemUiOverlayStyle.dark,
        child: LoginBackground(
          child: SafeArea(
            child: Center(
              child: SingleChildScrollView(
                padding: const EdgeInsets.symmetric(
                  horizontal: 20,
                  vertical: 24,
                ),
                child: ConstrainedBox(
                  constraints: const BoxConstraints(maxWidth: 440),
                  child: Card(
                    elevation: 0,
                    color: colorScheme.surface.withOpacity(
                      Theme.of(context).brightness == Brightness.dark
                          ? 0.75
                          : 0.92,
                    ),
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(28),
                      side: BorderSide(
                        color: colorScheme.outlineVariant.withOpacity(0.35),
                      ),
                    ),
                    child: Padding(
                      padding: const EdgeInsets.fromLTRB(20, 22, 20, 18),
                      child: AutofillGroup(
                        child: Form(
                          key: formKey,
                          autovalidateMode: attemptedSubmit
                              ? AutovalidateMode.onUserInteraction
                              : AutovalidateMode.disabled,
                          child: Column(
                            mainAxisSize: MainAxisSize.min,
                            crossAxisAlignment: CrossAxisAlignment.stretch,
                            children: [
                              Row(
                                children: [
                                  Container(
                                    height: 44,
                                    width: 44,
                                    decoration: BoxDecoration(
                                      borderRadius: BorderRadius.circular(14),
                                      gradient: LinearGradient(
                                        begin: Alignment.topLeft,
                                        end: Alignment.bottomRight,
                                        colors: [
                                          colorScheme.primary,
                                          colorScheme.tertiary,
                                        ],
                                      ),
                                    ),
                                    child: Icon(
                                      Icons.receipt_long,
                                      color: colorScheme.onPrimary,
                                    ),
                                  ),
                                  const SizedBox(width: 12),
                                  Expanded(
                                    child: Column(
                                      crossAxisAlignment:
                                          CrossAxisAlignment.start,
                                      children: [
                                        Text(
                                          'E-Receipt',
                                          style: Theme.of(context)
                                              .textTheme
                                              .titleLarge
                                              ?.copyWith(
                                                fontWeight: FontWeight.w700,
                                              ),
                                        ),
                                        Text(
                                          'Sign in to continue',
                                          style: Theme.of(context)
                                              .textTheme
                                              .bodyMedium
                                              ?.copyWith(
                                                color: colorScheme
                                                    .onSurfaceVariant,
                                              ),
                                        ),
                                      ],
                                    ),
                                  ),
                                ],
                              ),
                              const SizedBox(height: 18),
                              LoginErrorBanner(message: state.errorMessage),
                              if (state.errorMessage != null)
                                const SizedBox(height: 14),
                              TextFormField(
                                controller: usernameController,
                                focusNode: usernameFocusNode,
                                enabled: !state.isLoading,
                                textInputAction: TextInputAction.next,
                                autofillHints: const [AutofillHints.username],
                                onFieldSubmitted: (_) =>
                                    passwordFocusNode.requestFocus(),
                                validator: (value) {
                                  if ((value ?? '').trim().isEmpty) {
                                    return 'Username is required';
                                  }
                                  return null;
                                },
                                decoration: InputDecoration(
                                  labelText: 'Username',
                                  hintText: 'Enter your username',
                                  prefixIcon: const Icon(Icons.person_outline),
                                  filled: true,
                                  fillColor: colorScheme.surfaceContainerHighest
                                      .withOpacity(
                                    Theme.of(context).brightness ==
                                            Brightness.dark
                                        ? 0.55
                                        : 0.9,
                                  ),
                                  border: OutlineInputBorder(
                                    borderRadius: BorderRadius.circular(18),
                                  ),
                                ),
                              ),
                              const SizedBox(height: 12),
                              TextFormField(
                                controller: passwordController,
                                focusNode: passwordFocusNode,
                                enabled: !state.isLoading,
                                textInputAction: TextInputAction.done,
                                autofillHints: const [AutofillHints.password],
                                obscureText: obscurePassword,
                                onFieldSubmitted: (_) => _submit(
                                  ref: ref,
                                  state: state,
                                  formKey: formKey,
                                  usernameController: usernameController,
                                  passwordController: passwordController,
                                ),
                                validator: (value) {
                                  if ((value ?? '').isEmpty) {
                                    return 'Password is required';
                                  }
                                  if (value!.length < 6) {
                                    return 'Password must be at least 6 characters';
                                  }
                                  return null;
                                },
                                decoration: InputDecoration(
                                  labelText: 'Password',
                                  hintText: 'Enter your password',
                                  prefixIcon: const Icon(Icons.lock_outline),
                                  filled: true,
                                  fillColor: colorScheme.surfaceContainerHighest
                                      .withOpacity(
                                    Theme.of(context).brightness ==
                                            Brightness.dark
                                        ? 0.55
                                        : 0.9,
                                  ),
                                  border: OutlineInputBorder(
                                    borderRadius: BorderRadius.circular(18),
                                  ),
                                  suffixIcon: IconButton(
                                    tooltip: obscurePassword
                                        ? 'Show password'
                                        : 'Hide password',
                                    onPressed: state.isLoading
                                        ? null
                                        : () => ref
                                                .read(
                                                  loginObscurePasswordProvider
                                                      .notifier,
                                                )
                                                .state =
                                            !obscurePassword,
                                    icon: Icon(
                                      obscurePassword
                                          ? Icons.visibility_outlined
                                          : Icons.visibility_off_outlined,
                                    ),
                                  ),
                                ),
                              ),
                              const SizedBox(height: 16),
                              FilledButton.icon(
                                onPressed: state.isLoading
                                    ? null
                                    : () => _submit(
                                        ref: ref,
                                        state: state,
                                        formKey: formKey,
                                        usernameController: usernameController,
                                        passwordController: passwordController,
                                      ),
                                icon: state.isLoading
                                    ? const SizedBox(
                                        height: 18,
                                        width: 18,
                                        child: CircularProgressIndicator(
                                          strokeWidth: 2,
                                        ),
                                      )
                                    : const Icon(Icons.login),
                                label: Padding(
                                  padding: const EdgeInsets.symmetric(
                                    vertical: 12,
                                  ),
                                  child: Text(
                                    state.isLoading
                                        ? 'Signing in...'
                                        : 'Sign in',
                                    style: const TextStyle(
                                      fontWeight: FontWeight.w600,
                                    ),
                                  ),
                                ),
                              ),
                              const SizedBox(height: 12),
                              Text(
                                "By continuing, you agree to your organization's policies.",
                                textAlign: TextAlign.center,
                                style: Theme.of(context).textTheme.bodySmall
                                    ?.copyWith(
                                      color: colorScheme.onSurfaceVariant,
                                    ),
                              ),
                            ],
                          ),
                        ),
                      ),
                    ),
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}