// RunTab — the third tab. Shows:
//
//   1. A form for the flow's declared inputs (one field per
//      `inputs:` entry). Text inputs use a TextField; bytes
//      inputs use a "Choose file…" button + filename badge.
//
//   2. A Start button that calls the host's FlowRunDriver
//      with the collected inputs.
//
//   3. A live step list driven by the driver's event stream,
//      identical visually to the CLI's `fai run` block:
//      ◻ pending, · running, ✔ done + duration, ✗ failed,
//      ⏸ awaiting approval.
//
//   4. The flow's outputs once the run resolves.
//
// The tab requires the file to be saved on disk — the hub's
// runSavedFlow reads from `~/.fai/data/flows/<name>.yaml`,
// not from the in-memory buffer. The dirty banner reminds
// the operator to save before running so they don't run a
// stale version by surprise.

import 'dart:async';
import 'dart:io';
import 'dart:typed_data';

import 'package:flutter/material.dart';

import '../editor_controller.dart';
import '../l10n.dart';
import '../model/flow_graph.dart';
import '../run_driver.dart';
import '../tokens.dart';

class RunTab extends StatefulWidget {
  final FlowEditorController controller;
  final FlowEditorStrings strings;
  final FlowRunDriver? driver;
  const RunTab({
    super.key,
    required this.controller,
    required this.strings,
    this.driver,
  });

  @override
  State<RunTab> createState() => _RunTabState();
}

class _RunTabState extends State<RunTab> {
  final Map<String, TextEditingController> _textInputs = {};
  final Map<String, _FilePick> _fileInputs = {};

  StreamSubscription<FlowRunEvent>? _eventSub;
  bool _running = false;
  Map<String, FlowOutputValue>? _outputs;
  Object? _error;
  // Insertion-ordered: shows steps in the order the hub
  // actually started them, matching the CLI rendering.
  final Map<String, _StepState> _liveSteps = {};
  String? _runFlowName;

  @override
  void initState() {
    super.initState();
    widget.controller.addListener(_onControllerChanged);
    _syncInputs();
  }

  @override
  void dispose() {
    widget.controller.removeListener(_onControllerChanged);
    _eventSub?.cancel();
    for (final c in _textInputs.values) {
      c.dispose();
    }
    super.dispose();
  }

  void _onControllerChanged() {
    if (!mounted) return;
    _syncInputs();
    setState(() {});
  }

  void _syncInputs() {
    final graph = widget.controller.graph;
    final keep = <String>{};
    for (final entry in graph.inputs.entries) {
      keep.add(entry.key);
      if (entry.value.type == 'bytes' || entry.value.type == 'file') {
        // bytes input — keep its file pick if already chosen.
        _fileInputs.putIfAbsent(entry.key, () => const _FilePick.empty());
      } else {
        _textInputs.putIfAbsent(
          entry.key,
          () => TextEditingController(text: entry.value.defaultValue ?? ''),
        );
      }
    }
    // Drop controllers for inputs that no longer exist.
    _textInputs.removeWhere((k, c) {
      if (keep.contains(k)) return false;
      c.dispose();
      return true;
    });
    _fileInputs.removeWhere((k, _) => !keep.contains(k));
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final controller = widget.controller;
    final strings = widget.strings;
    if (controller.activeName == null) {
      return _empty(theme, strings.runNoFlow);
    }
    final graph = controller.graph;
    return Container(
      color: theme.colorScheme.surface,
      child: ListView(
        padding: const EdgeInsets.all(FaiSpace.lg),
        children: [
          _titleRow(theme),
          const SizedBox(height: FaiSpace.md),
          if (controller.isDirty)
            Container(
              padding: const EdgeInsets.all(FaiSpace.sm),
              margin: const EdgeInsets.only(bottom: FaiSpace.md),
              decoration: BoxDecoration(
                color: theme.colorScheme.tertiaryContainer,
                borderRadius: BorderRadius.circular(FaiRadius.sm),
              ),
              child: Row(
                children: [
                  Icon(
                    Icons.info_outline,
                    size: 16,
                    color: theme.colorScheme.onTertiaryContainer,
                  ),
                  const SizedBox(width: FaiSpace.sm),
                  Expanded(
                    child: Text(
                      strings.runUnsavedBanner,
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: theme.colorScheme.onTertiaryContainer,
                      ),
                    ),
                  ),
                ],
              ),
            ),
          _section(theme, strings.runInputs),
          if (graph.inputs.isEmpty)
            Padding(
              padding: const EdgeInsets.symmetric(vertical: FaiSpace.sm),
              child: Text(
                '—',
                style: theme.textTheme.bodySmall?.copyWith(
                  color: theme.colorScheme.onSurfaceVariant,
                ),
              ),
            )
          else
            for (final entry in graph.inputs.entries)
              _inputField(theme, entry.key, entry.value),
          const SizedBox(height: FaiSpace.md),
          FilledButton.icon(
            onPressed: _running || widget.driver == null ? null : _start,
            icon: _running
                ? const SizedBox(
                    width: 14,
                    height: 14,
                    child: CircularProgressIndicator(strokeWidth: 2),
                  )
                : const Icon(Icons.play_arrow, size: 18),
            label: Text(strings.runStart),
          ),
          if (_liveSteps.isNotEmpty || _running) ...[
            const SizedBox(height: FaiSpace.lg),
            _section(
              theme,
              _running ? strings.runTitleRunning : strings.runTitleDone,
            ),
            _stepList(theme),
          ],
          if (_outputs != null) ...[
            const SizedBox(height: FaiSpace.lg),
            _section(theme, strings.runOutputs),
            for (final entry in _outputs!.entries)
              _outputRow(theme, entry.key, entry.value),
          ],
          if (_error != null) ...[
            const SizedBox(height: FaiSpace.lg),
            _section(theme, strings.runTitleFailed),
            Container(
              padding: const EdgeInsets.all(FaiSpace.sm),
              decoration: BoxDecoration(
                color: theme.colorScheme.errorContainer,
                borderRadius: BorderRadius.circular(FaiRadius.sm),
              ),
              child: Text(
                _error.toString(),
                style: TextStyle(
                  fontFamily: 'monospace',
                  fontSize: 12,
                  color: theme.colorScheme.onErrorContainer,
                ),
              ),
            ),
          ],
        ],
      ),
    );
  }

  Widget _titleRow(ThemeData theme) {
    final title = _running
        ? widget.strings.runTitleRunning
        : _error != null
        ? widget.strings.runTitleFailed
        : _outputs != null
        ? widget.strings.runTitleDone
        : widget.strings.runTitleIdle;
    return Text(
      title,
      style: theme.textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w600),
    );
  }

  Widget _section(ThemeData theme, String label) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 4),
      child: Text(
        label,
        style: theme.textTheme.labelSmall?.copyWith(
          color: theme.colorScheme.onSurfaceVariant,
          letterSpacing: 0.6,
        ),
      ),
    );
  }

  Widget _empty(ThemeData theme, String hint) {
    return Container(
      color: theme.colorScheme.surface,
      padding: const EdgeInsets.all(FaiSpace.lg),
      child: Center(
        child: Text(
          hint,
          textAlign: TextAlign.center,
          style: theme.textTheme.bodySmall?.copyWith(
            color: theme.colorScheme.onSurfaceVariant,
          ),
        ),
      ),
    );
  }

  Widget _inputField(ThemeData theme, String name, FlowInput input) {
    final type = input.type;
    if (type == 'bytes' || type == 'file') {
      final pick = _fileInputs[name] ?? const _FilePick.empty();
      return Padding(
        padding: const EdgeInsets.symmetric(vertical: FaiSpace.xs),
        child: Row(
          children: [
            SizedBox(
              width: 140,
              child: Text(
                '$name ($type)',
                style: const TextStyle(fontFamily: 'monospace'),
              ),
            ),
            const SizedBox(width: FaiSpace.sm),
            OutlinedButton.icon(
              onPressed: () => _pickFile(name),
              icon: const Icon(Icons.attach_file, size: 16),
              label: Text(
                pick.fileName ?? widget.strings.runChooseFile,
                overflow: TextOverflow.ellipsis,
              ),
            ),
          ],
        ),
      );
    }
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: FaiSpace.xs),
      child: Row(
        children: [
          SizedBox(
            width: 140,
            child: Text(
              '$name ($type)',
              style: const TextStyle(fontFamily: 'monospace'),
            ),
          ),
          const SizedBox(width: FaiSpace.sm),
          Expanded(
            child: TextField(
              controller: _textInputs[name],
              style: const TextStyle(fontFamily: 'monospace', fontSize: 13),
              decoration: InputDecoration(
                hintText: input.hint,
                isDense: true,
                border: const OutlineInputBorder(),
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _stepList(ThemeData theme) {
    final entries = _liveSteps.entries.toList();
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        for (final entry in entries) _stepRow(theme, entry.key, entry.value),
      ],
    );
  }

  Widget _stepRow(ThemeData theme, String id, _StepState state) {
    final IconData glyph;
    final Color color;
    String suffix = '';
    switch (state.kind) {
      case _StepKind.running:
        glyph = Icons.refresh;
        color = theme.colorScheme.primary;
      case _StepKind.done:
        glyph = Icons.check;
        color = Colors.green.shade600;
        suffix = '  ${(state.durationMs ?? 0) / 1000.0}s';
      case _StepKind.error:
        glyph = Icons.close;
        color = theme.colorScheme.error;
        if (state.error != null && state.error!.isNotEmpty) {
          suffix = '  — ${state.error}';
        }
      case _StepKind.awaiting:
        glyph = Icons.pause_circle_outline;
        color = theme.colorScheme.tertiary;
        suffix = '  awaiting approval';
    }
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 2),
      child: Row(
        children: [
          Icon(glyph, size: 16, color: color),
          const SizedBox(width: FaiSpace.sm),
          Flexible(
            child: Text(
              '$id$suffix',
              style: TextStyle(
                fontFamily: 'monospace',
                fontSize: 13,
                color: color,
              ),
              overflow: TextOverflow.ellipsis,
            ),
          ),
        ],
      ),
    );
  }

  Widget _outputRow(ThemeData theme, String name, FlowOutputValue value) {
    return Padding(
      padding: const EdgeInsets.only(bottom: FaiSpace.sm),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            name.toUpperCase(),
            style: theme.textTheme.labelSmall?.copyWith(
              color: theme.colorScheme.onSurfaceVariant,
              letterSpacing: 0.6,
            ),
          ),
          const SizedBox(height: 2),
          _outputBody(theme, value),
        ],
      ),
    );
  }

  Widget _outputBody(ThemeData theme, FlowOutputValue value) {
    if (value is FlowOutputText) {
      return SelectableText(
        value.value,
        style: const TextStyle(fontFamily: 'monospace', fontSize: 12),
      );
    }
    if (value is FlowOutputJson) {
      return SelectableText(
        value.value.toString(),
        style: const TextStyle(fontFamily: 'monospace', fontSize: 12),
      );
    }
    if (value is FlowOutputBytes) {
      return Text(
        '${value.value.length} bytes · ${value.mimeType}',
        style: theme.textTheme.bodySmall,
      );
    }
    return const SizedBox.shrink();
  }

  Future<void> _pickFile(String name) async {
    // For 0.2.0 the editor relies on the host to inject a
    // file-picker via callback; minimal version uses
    // dart:io directly for desktop. Studio uses file_picker;
    // we fall back to a manual path entry dialog if no host
    // picker is available.
    final controller = TextEditingController();
    final ctx = context;
    final result = await showDialog<String>(
      context: ctx,
      builder: (_) => AlertDialog(
        title: Text(widget.strings.runChooseFile),
        content: TextField(
          controller: controller,
          decoration: const InputDecoration(
            hintText: '/path/to/file',
            border: OutlineInputBorder(),
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, null),
            child: Text(widget.strings.newDialogCancel),
          ),
          TextButton(
            onPressed: () => Navigator.pop(ctx, controller.text.trim()),
            child: const Text('OK'),
          ),
        ],
      ),
    );
    if (result == null || result.isEmpty || !mounted) return;
    try {
      final file = File(result);
      if (!file.existsSync()) return;
      final bytes = await file.readAsBytes();
      setState(() {
        _fileInputs[name] = _FilePick(
          fileName: file.uri.pathSegments.last,
          bytes: Uint8List.fromList(bytes),
        );
      });
    } catch (_) {
      // swallow — file unreadable, leave the pick empty
    }
  }

  Future<void> _start() async {
    final driver = widget.driver;
    if (driver == null) return;
    final flowName = widget.controller.activeName;
    if (flowName == null) return;
    setState(() {
      _running = true;
      _outputs = null;
      _error = null;
      _liveSteps.clear();
      _runFlowName = flowName;
    });
    widget.controller.running = true;
    // Subscribe BEFORE submitting so the first event isn't
    // lost to the broadcast's dead-letter.
    _eventSub?.cancel();
    _eventSub = driver.events().listen(_onEvent);
    final textInputs = <String, String>{
      for (final entry in _textInputs.entries) entry.key: entry.value.text,
    };
    final fileInputs = <String, Uint8List>{};
    final fileMimes = <String, String>{};
    for (final entry in _fileInputs.entries) {
      final bytes = entry.value.bytes;
      if (bytes == null) continue;
      fileInputs[entry.key] = bytes;
      fileMimes[entry.key] = _mimeFor(entry.value.fileName ?? '');
    }
    try {
      final outputs = await driver.runFlow(
        flowName: flowName,
        textInputs: textInputs,
        fileInputs: fileInputs,
        fileMimes: fileMimes,
      );
      if (!mounted) return;
      setState(() {
        _running = false;
        _outputs = outputs;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _running = false;
        _error = e;
      });
    } finally {
      widget.controller.running = false;
      _eventSub?.cancel();
      _eventSub = null;
    }
  }

  void _onEvent(FlowRunEvent event) {
    final flowName = _runFlowName;
    if (flowName == null) return;
    if (event.flowName != flowName) return;
    if (!mounted) return;
    setState(() {
      switch (event) {
        case StepStarted():
          _liveSteps[event.stepId] = const _StepState(kind: _StepKind.running);
          widget.controller.updateStepStatus(
            event.stepId,
            StepRunStatus.running,
          );
        case StepCompleted():
          _liveSteps[event.stepId] = _StepState(
            kind: _StepKind.done,
            durationMs: event.durationMs,
          );
          widget.controller.updateStepStatus(event.stepId, StepRunStatus.done);
        case StepFailed():
          _liveSteps[event.stepId] = _StepState(
            kind: _StepKind.error,
            error: event.error,
          );
          widget.controller.updateStepStatus(
            event.stepId,
            StepRunStatus.failed,
          );
        case StepAwaitingApproval():
          _liveSteps[event.stepId] = const _StepState(kind: _StepKind.awaiting);
          widget.controller.updateStepStatus(
            event.stepId,
            StepRunStatus.awaiting,
          );
      }
    });
  }

  String _mimeFor(String name) {
    final lower = name.toLowerCase();
    if (lower.endsWith('.pdf')) return 'application/pdf';
    if (lower.endsWith('.docx')) {
      return 'application/vnd.openxmlformats-officedocument.wordprocessingml.document';
    }
    if (lower.endsWith('.txt')) return 'text/plain';
    if (lower.endsWith('.json')) return 'application/json';
    return 'application/octet-stream';
  }
}

class _FilePick {
  final String? fileName;
  final Uint8List? bytes;
  const _FilePick({this.fileName, this.bytes});
  const _FilePick.empty() : fileName = null, bytes = null;
}

enum _StepKind { running, done, error, awaiting }

class _StepState {
  final _StepKind kind;
  final int? durationMs;
  final String? error;
  const _StepState({required this.kind, this.durationMs, this.error});
}