import 'package:flutter/material.dart';

import '../data/hub.dart';
import '../theme/theme.dart';
import '../theme/tokens.dart';
import '../widgets/widgets.dart';

class FlowsPage extends StatefulWidget {
  const FlowsPage({super.key});

  @override
  State<FlowsPage> createState() => _FlowsPageState();
}

class _FlowsPageState extends State<FlowsPage> {
  late Future<List<SavedFlow>> _future;

  @override
  void initState() {
    super.initState();
    _future = HubService.instance.listFlows();
  }

  void _refresh() => setState(() {
        _future = HubService.instance.listFlows();
      });

  Future<void> _runFlow(SavedFlow flow) async {
    final inputs = await _FlowInputDialog.show(context, flow);
    if (inputs == null) return;
    if (!mounted) return;
    showDialog<void>(
      context: context,
      barrierDismissible: false,
      builder: (_) => _FlowRunDialog(flow: flow, inputs: inputs),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Theme.of(context).scaffoldBackgroundColor,
      appBar: AppBar(
        title: const Text('Flows'),
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh, size: 18),
            tooltip: 'Reload',
            onPressed: _refresh,
          ),
          const SizedBox(width: FaiSpace.sm),
        ],
      ),
      body: FutureBuilder<List<SavedFlow>>(
        future: _future,
        builder: (context, snapshot) {
          if (snapshot.connectionState == ConnectionState.waiting) {
            return const Center(child: CircularProgressIndicator());
          }
          if (snapshot.hasError) {
            return FaiEmptyState(
              icon: Icons.cloud_off_outlined,
              iconColor: Theme.of(context).colorScheme.error,
              title: 'Hub unreachable',
              hint: 'Start the hub with `fai serve`.',
              action: FilledButton.tonal(
                onPressed: _refresh,
                child: const Text('Retry'),
              ),
            );
          }
          final flows = snapshot.data ?? [];
          if (flows.isEmpty) {
            return const FaiEmptyState(
              icon: Icons.account_tree_outlined,
              title: 'No saved flows',
              hint:
                  'Save a flow with `fai admin flows save <name> <flow.yaml>` and it shows up here.',
            );
          }
          return ListView.separated(
            padding: const EdgeInsets.all(FaiSpace.xl),
            itemCount: flows.length,
            separatorBuilder: (_, _) => const SizedBox(height: FaiSpace.md),
            itemBuilder: (context, i) =>
                _FlowCard(flow: flows[i], onRun: () => _runFlow(flows[i])),
          );
        },
      ),
    );
  }
}

class _FlowCard extends StatelessWidget {
  final SavedFlow flow;
  final VoidCallback onRun;

  const _FlowCard({required this.flow, required this.onRun});

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return FaiCard(
      child: Row(
        children: [
          Icon(
            Icons.account_tree_outlined,
            size: 20,
            color: theme.colorScheme.primary,
          ),
          const SizedBox(width: FaiSpace.md),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  flow.name,
                  style: theme.textTheme.titleMedium?.copyWith(
                    fontWeight: FontWeight.w600,
                  ),
                ),
                const SizedBox(height: 2),
                Text(
                  flow.path,
                  style: FaiTheme.mono(
                    size: 11,
                    color: theme.colorScheme.onSurfaceVariant,
                  ),
                ),
              ],
            ),
          ),
          FaiPill(
            label: '${flow.sizeBytes} B',
            tone: FaiPillTone.neutral,
            monospace: true,
          ),
          const SizedBox(width: FaiSpace.md),
          FilledButton.icon(
            onPressed: onRun,
            icon: const Icon(Icons.play_arrow, size: 16),
            label: const Text('Run'),
          ),
        ],
      ),
    );
  }
}

class _FlowInputDialog extends StatefulWidget {
  final SavedFlow flow;

  const _FlowInputDialog({required this.flow});

  static Future<Map<String, String>?> show(
    BuildContext context,
    SavedFlow flow,
  ) {
    return showDialog<Map<String, String>>(
      context: context,
      builder: (_) => _FlowInputDialog(flow: flow),
    );
  }

  @override
  State<_FlowInputDialog> createState() => _FlowInputDialogState();
}

class _FlowInputDialogState extends State<_FlowInputDialog> {
  // The hub does not yet expose the flow's input schema over
  // gRPC, so this dialog accepts free-form key=value pairs.
  // Operator pastes pairs separated by newlines; we split on
  // the first `=` per line.
  final _ctrl = TextEditingController();

  @override
  void dispose() {
    _ctrl.dispose();
    super.dispose();
  }

  Map<String, String> _parsePairs() {
    final out = <String, String>{};
    for (final raw in _ctrl.text.split('\n')) {
      final line = raw.trim();
      if (line.isEmpty) continue;
      final eq = line.indexOf('=');
      if (eq < 0) continue;
      out[line.substring(0, eq).trim()] = line.substring(eq + 1).trim();
    }
    return out;
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return AlertDialog(
      title: Text('Run ${widget.flow.name}'),
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(FaiRadius.md),
      ),
      content: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: 480, maxHeight: 360),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(
              'Inputs as key=value, one per line. All values are sent as text payloads. For binary inputs use the `fai run` CLI.',
              style: theme.textTheme.bodySmall?.copyWith(
                color: theme.colorScheme.onSurfaceVariant,
              ),
            ),
            const SizedBox(height: FaiSpace.md),
            Expanded(
              child: TextField(
                controller: _ctrl,
                maxLines: null,
                expands: true,
                textAlignVertical: TextAlignVertical.top,
                style: FaiTheme.mono(size: 12),
                decoration: const InputDecoration(
                  hintText:
                      'name=World\ntarget_language=English\nsummary_style=three bullet points',
                  border: OutlineInputBorder(),
                  isDense: true,
                ),
              ),
            ),
          ],
        ),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.pop(context, null),
          child: const Text('Cancel'),
        ),
        FilledButton.icon(
          icon: const Icon(Icons.play_arrow, size: 16),
          label: const Text('Run'),
          onPressed: () => Navigator.pop(context, _parsePairs()),
        ),
      ],
    );
  }
}

class _FlowRunDialog extends StatefulWidget {
  final SavedFlow flow;
  final Map<String, String> inputs;

  const _FlowRunDialog({required this.flow, required this.inputs});

  @override
  State<_FlowRunDialog> createState() => _FlowRunDialogState();
}

class _FlowRunDialogState extends State<_FlowRunDialog> {
  late final Future<Map<String, String>> _future;

  @override
  void initState() {
    super.initState();
    _future = HubService.instance.runSavedFlow(
      name: widget.flow.name,
      textInputs: widget.inputs,
    );
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return AlertDialog(
      title: Text('Running ${widget.flow.name}'),
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(FaiRadius.md),
      ),
      content: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: 560, maxHeight: 480),
        child: FutureBuilder<Map<String, String>>(
          future: _future,
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.waiting) {
              return Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  const SizedBox(height: FaiSpace.md),
                  const CircularProgressIndicator(),
                  const SizedBox(height: FaiSpace.md),
                  Text(
                    'Flow running…',
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: theme.colorScheme.onSurfaceVariant,
                    ),
                  ),
                ],
              );
            }
            if (snapshot.hasError) {
              return SingleChildScrollView(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    Icon(
                      Icons.error_outline,
                      color: theme.colorScheme.error,
                      size: 32,
                    ),
                    const SizedBox(height: FaiSpace.md),
                    SelectableText(
                      snapshot.error.toString(),
                      style: FaiTheme.mono(
                        size: 11,
                        color: theme.colorScheme.error,
                      ),
                    ),
                  ],
                ),
              );
            }
            final outputs = snapshot.data ?? const {};
            if (outputs.isEmpty) {
              return Text(
                'Flow completed with no declared outputs.',
                style: theme.textTheme.bodyMedium,
              );
            }
            return SingleChildScrollView(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                mainAxisSize: MainAxisSize.min,
                children: [
                  for (final entry in outputs.entries) ...[
                    Padding(
                      padding: const EdgeInsets.only(bottom: 4),
                      child: Text(
                        entry.key.toUpperCase(),
                        style: theme.textTheme.labelSmall?.copyWith(
                          color: theme.colorScheme.onSurfaceVariant,
                          letterSpacing: 0.6,
                        ),
                      ),
                    ),
                    Container(
                      width: double.infinity,
                      padding: const EdgeInsets.all(FaiSpace.md),
                      decoration: BoxDecoration(
                        color: theme.colorScheme.surfaceContainerHigh,
                        borderRadius: BorderRadius.circular(FaiRadius.sm),
                        border: Border.all(
                          color: theme.colorScheme.outlineVariant,
                        ),
                      ),
                      child: SelectableText(
                        entry.value,
                        style: FaiTheme.mono(size: 11),
                      ),
                    ),
                    const SizedBox(height: FaiSpace.md),
                  ],
                ],
              ),
            );
          },
        ),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text('Close'),
        ),
      ],
    );
  }
}