import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../../core/providers/model_download_provider.dart';

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

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final scanState = ref.watch(modelScanProvider);

    return Scaffold(
      body: SafeArea(
        child: Padding(
          padding: const EdgeInsets.all(32),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              Icon(
                Icons.auto_awesome,
                size: 64,
                color: Theme.of(context).colorScheme.primary,
              ),
              const SizedBox(height: 24),
              Text(
                'On-device AI',
                style: Theme.of(context).textTheme.headlineSmall,
                textAlign: TextAlign.center,
              ),
              const SizedBox(height: 12),
              Text(
                'DailyYou uses an on-device AI model to spot patterns in your '
                'moods and behaviour. Your data never leaves your phone.',
                style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                      color: Theme.of(context).colorScheme.onSurfaceVariant,
                    ),
                textAlign: TextAlign.center,
              ),
              const SizedBox(height: 32),
              _InstructionCard(),
              const SizedBox(height: 24),
              if (scanState is AsyncLoading)
                const Center(child: CircularProgressIndicator())
              else ...[
                if (scanState is AsyncError)
                  Padding(
                    padding: const EdgeInsets.only(bottom: 12),
                    child: Text(
                      'Model not found at expected path.',
                      style: Theme.of(context).textTheme.bodySmall?.copyWith(
                            color: Theme.of(context).colorScheme.error,
                          ),
                      textAlign: TextAlign.center,
                    ),
                  ),
                FilledButton.icon(
                  onPressed: () =>
                      ref.read(modelScanProvider.notifier).scan(),
                  icon: const Icon(Icons.search),
                  label: const Text('Scan for model'),
                ),
                const SizedBox(height: 12),
                OutlinedButton(
                  onPressed: () => ref
                      .read(modelScanProvider.notifier)
                      .skipToApp(),
                  child: const Text('Continue without AI'),
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }
}

class _InstructionCard extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final cs = Theme.of(context).colorScheme;
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text('How to get the model',
                style: Theme.of(context).textTheme.titleSmall),
            const SizedBox(height: 10),
            _Step(
              n: '1',
              text: 'Download gemma-2b-it-cpu-int4.bin from Kaggle '
                  '(requires a free Google account and licence acceptance).',
            ),
            _Step(
              n: '2',
              text: 'Transfer the file to the device using adb:\n'
                  'adb push gemma-2b-it-cpu-int4.bin '
                  r'$(adb shell run-as net.stefwill.dailyou '
                  r'printenv DATA_DIR)/files/',
            ),
            _Step(
              n: '3',
              text: 'Tap "Scan for model" once the transfer is complete.',
            ),
            const SizedBox(height: 8),
            Text(
              'The model is ~1.3 GB and only needs to be transferred once.',
              style: Theme.of(context).textTheme.labelSmall?.copyWith(
                    color: cs.outline,
                  ),
            ),
          ],
        ),
      ),
    );
  }
}

class _Step extends StatelessWidget {
  const _Step({required this.n, required this.text});
  final String n;
  final String text;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 8),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          CircleAvatar(
            radius: 10,
            backgroundColor: Theme.of(context).colorScheme.primaryContainer,
            child: Text(n,
                style: Theme.of(context).textTheme.labelSmall?.copyWith(
                      color:
                          Theme.of(context).colorScheme.onPrimaryContainer,
                    )),
          ),
          const SizedBox(width: 10),
          Expanded(
            child: Text(text,
                style: Theme.of(context).textTheme.bodySmall),
          ),
        ],
      ),
    );
  }
}