// FlowsPage — Studio's flow surface. Thin host wrapper around
// the swappable chain_studio_flow_editor package: loads the
// hub's installed capabilities, hands them + a Studio-side
// FlowRunDriver to the editor, and lets the editor own
// everything else (file list, three-tab body, properties
// panel, run progress, …).
//
// Pre-0.52 versions split file-listing and run-dialog state
// across this page. v0.52 moves all of that into the editor
// package so a swap is one pubspec change — Studio doesn't
// need to know what's inside the editor any more.

import 'dart:async' show unawaited;

import 'package:chain_studio_flow_editor/chain_studio_flow_editor.dart';
import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';

import '../data/error_presentation.dart';
import '../data/flow_run_driver.dart';
import '../data/hub.dart';
import '../data/store_caps.dart';
import '../data/workspace.dart';
import '../l10n/app_localizations.dart';
import '../widgets/chain_install_confirm.dart';
import '../widgets/chain_workspace_switcher.dart';

class FlowsPage extends StatefulWidget {
  /// Pre-load this flow when the editor first builds. Studio
  /// keeps the parameter so the Cmd+K palette + welcome page
  /// can deep-link straight into a specific flow.
  final String? initialFlowName;

  const FlowsPage({super.key, this.initialFlowName});

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

class _FlowsPageState extends State<FlowsPage> {
  late Future<List<String>> _capabilities;
  late final StudioFlowRunDriver _driver;

  /// Snapshot of bare capability names the public store can
  /// install; null while the store state is UNKNOWN (not yet
  /// loaded / search failed) so the editor claims neither
  /// "installable" nor "not in store". Refreshed at open, after
  /// an install and on a connection switch.
  List<String>? _storeCaps;

  /// Which hub connection the snapshots were loaded against —
  /// the sealed-area slug, or empty for the shared hub. A sealed
  /// switch keeps this page mounted, so without the guard the
  /// editor would keep offering the OTHER hub's capabilities.
  String _connKey = Workspace.instance.activeSealed?.slug ?? '';

  @override
  void initState() {
    super.initState();
    _driver = StudioFlowRunDriver();
    _capabilities = _loadCapabilities();
    _loadStoreCapabilities();
    Workspace.instance.addListener(_onWorkspaceChanged);
  }

  @override
  void dispose() {
    Workspace.instance.removeListener(_onWorkspaceChanged);
    super.dispose();
  }

  /// Reload both capability snapshots when the CONNECTION target
  /// changes (entering/leaving a sealed area) — a plain project
  /// filter change stays cheap and reuses the loaded lists.
  void _onWorkspaceChanged() {
    final key = Workspace.instance.activeSealed?.slug ?? '';
    if (key == _connKey) return;
    _connKey = key;
    if (!mounted) return;
    setState(() {
      _storeCaps = null; // other hub — snapshot unknown again
      _capabilities = _loadCapabilities();
    });
    _loadStoreCapabilities();
  }

  Future<void> _loadStoreCapabilities() async {
    try {
      final items = await HubService.instance.searchStore(limit: 500);
      if (!mounted) return;
      // Only capabilities the store can actually install — the
      // editor's Install quick-fix and list badge promise exactly
      // what the hub's install resolver accepts. (This set used to
      // ingest requiresCapabilities too, which offered installs
      // that ended in "no store entry for '<name>'".)
      setState(
        () => _storeCaps = installableStoreCapabilities(items).toList()..sort(),
      );
    } catch (_) {
      // Soft-fail: keep the last snapshot for THIS connection if
      // one exists; otherwise stay in the honest "unknown" state
      // (no install offers, no not-in-store claims). Add-source
      // remains available either way.
    }
  }

  /// Pulls the capability identifiers the picker dialog
  /// offers when adding a step. `<capability>@<version>` so
  /// the operator can see exactly what they'll be wiring in,
  /// matching the format the `use:` field expects. Soft-fails
  /// to an empty list if the hub is unreachable — the editor
  /// falls back to a free-form text field in that case.
  Future<List<String>> _loadCapabilities() async {
    try {
      final caps = await HubService.instance.allCapabilities();
      final entries =
          caps.map((c) => '${c.capability}@${c.version}').toSet().toList()
            ..sort();
      return entries;
    } catch (_) {
      return const <String>[];
    }
  }

  /// Quick-fix handler — invoked when the operator clicks
  /// `Install <capability>` on an analyzer issue. Parses the
  /// editor-supplied `provider/name@version` spec into the
  /// Hub's install API and returns the refreshed capability
  /// list so the editor can re-analyze without waiting for the
  /// parent widget rebuild.
  /// Native picker for a flow file input. `withData` loads the
  /// bytes directly so the editor never touches the path itself
  /// (sandbox-friendly: the picker grants access to exactly the
  /// chosen file).
  Future<PickedFileData?> _pickFlowInputFile() async {
    final picked = await FilePicker.pickFiles(withData: true);
    final f = picked?.files.single;
    if (f == null || f.bytes == null) return null;
    return PickedFileData(fileName: f.name, bytes: f.bytes!);
  }

  Future<List<String>?> _onInstallCapability(String capability) async {
    // The analyzer hands us the full `use:` value (e.g. `debug.echo@^0`).
    // The hub resolves install sources by bare capability name; the
    // `@<constraint>` suffix would make the store lookup miss ("no store
    // entry for 'debug.echo@^0'"). Strip it — same as the Store page.
    final at = capability.indexOf('@');
    final bare = at < 0 ? capability : capability.substring(0, at);
    // The quick-fix install goes through the same trust dialog as
    // the Store page — no quieter direct path.
    final confirmed =
        await ChainInstallConfirmDialog.showForCapability(context, bare);
    if (!confirmed) return null;
    return _runInstall(source: bare);
  }

  /// `Add source for <cap>…` handler. Prompts the operator
  /// for a local path or URL, then routes through the same
  /// install RPC. Returns the refreshed capability list on
  /// success, null on cancel / failure.
  Future<List<String>?> _onAddModuleSource(String capability) async {
    final source = await _AddModuleSourceDialog.show(context, capability);
    if (source == null || source.isEmpty) return null;
    return _runInstall(source: source);
  }

  Future<List<String>?> _runInstall({required String source}) async {
    try {
      await HubService.instance.installModule(source: source);
      // The store snapshot may have moved too (an install can pull
      // in new entries / the operator refreshed a store) — keep the
      // badge's truth in step with the capability list.
      unawaited(_loadStoreCapabilities());
      final caps = await HubService.instance.allCapabilities();
      final updated = caps
          .map((c) => '${c.capability}@${c.version}')
          .toSet()
          .toList()
        ..sort();
      if (mounted) {
        setState(() => _capabilities = Future.value(updated));
      }
      return updated;
    } catch (e) {
      if (mounted) {
        final l = AppLocalizations.of(context);
        // Copyable error (was a plain SnackBar) — install failures
        // carry the real cause (network, signature, store lookup).
        showChainErrorSnack(
          context,
          'flows.install',
          e,
          title: l != null ? l.installFailed('') : 'Install failed',
        );
      }
      return null;
    }
  }

  @override
  Widget build(BuildContext context) {
    final locale = Localizations.localeOf(context);
    final editorLocale = locale.languageCode == 'de'
        ? FlowEditorLocale.de
        : FlowEditorLocale.en;
    // Rebuild the editor's project chip when the workspace changes,
    // so a mismatch banner appears/clears live.
    return ListenableBuilder(
      listenable: Workspace.instance,
      builder: (context, _) => FutureBuilder<List<String>>(
        future: _capabilities,
        builder: (context, snap) {
          final caps = snap.data ?? const <String>[];
          return FlowEditorPage(
            initialFlowName: widget.initialFlowName,
            locale: editorLocale,
            runDriver: _driver,
            availableCapabilities: caps,
            storeCapabilities: _storeCaps,
            onInstallCapability: _onInstallCapability,
            onAddModuleSource: _onAddModuleSource,
            activeProject: Workspace.instance.activeSlug,
            // Same switcher as Audit/Approvals/Runs, hosted in the
            // editor's toolbar (the page's single header): it
            // filters the flow list and is the project a new flow
            // gets stamped with.
            toolbarTrailing: const ChainWorkspaceSwitcher(),
            // Native file dialog for the Run tab's file inputs —
            // nobody should have to type an absolute path by hand.
            onPickFile: _pickFlowInputFile,
            // The file wins for the run; accepting the switch only
            // aligns the workspace view to the file's project.
            onSwitchToFileProject: (slug) =>
                Workspace.instance.setActive(slug),
          );
        },
      ),
    );
  }
}

/// Modal asking the operator where a missing capability can be
/// installed from — either a local module directory (the
/// `--link` install path) or a remote URL the hub can resolve.
/// Returns the typed source string on submit, null on cancel.
class _AddModuleSourceDialog extends StatefulWidget {
  final String capability;
  const _AddModuleSourceDialog({required this.capability});

  static Future<String?> show(BuildContext context, String capability) {
    return showDialog<String>(
      context: context,
      builder: (_) => _AddModuleSourceDialog(capability: capability),
    );
  }

  @override
  State<_AddModuleSourceDialog> createState() => _AddModuleSourceDialogState();
}

class _AddModuleSourceDialogState extends State<_AddModuleSourceDialog> {
  final TextEditingController _ctrl = TextEditingController();
  String _source = '';

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

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final l = AppLocalizations.of(context)!;
    return AlertDialog(
      title: Text(l.addSourceTitle),
      content: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: 520),
        child: SingleChildScrollView(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                l.addSourceIntro(widget.capability),
                style: theme.textTheme.bodySmall?.copyWith(
                  color: theme.colorScheme.onSurfaceVariant,
                ),
              ),
              const SizedBox(height: 16),
              TextField(
                controller: _ctrl,
                autofocus: true,
                onChanged: (v) => setState(() => _source = v.trim()),
                decoration: InputDecoration(
                  labelText: l.addSourceField,
                  hintText: l.addSourceHint,
                  border: const OutlineInputBorder(),
                  isDense: true,
                ),
              ),
              const SizedBox(height: 12),
              Container(
                padding: const EdgeInsets.all(12),
                decoration: BoxDecoration(
                  color: theme.colorScheme.surfaceContainerHigh,
                  borderRadius: BorderRadius.circular(6),
                ),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      l.addSourceHowItWorksTitle,
                      style: theme.textTheme.labelMedium?.copyWith(
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                    const SizedBox(height: 6),
                    Text(
                      l.addSourceHowItWorksBody,
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: theme.colorScheme.onSurfaceVariant,
                      ),
                    ),
                    const SizedBox(height: 6),
                    Container(
                      padding: const EdgeInsets.symmetric(
                        horizontal: 8,
                        vertical: 4,
                      ),
                      decoration: BoxDecoration(
                        color: theme.colorScheme.surface,
                        borderRadius: BorderRadius.circular(4),
                      ),
                      child: SelectableText(
                        l.addSourceCliExample,
                        style: TextStyle(
                          fontFamily: 'JetBrains Mono',
                          fontFamilyFallback: const [
                            'Menlo',
                            'Consolas',
                            'Courier New',
                            'monospace',
                          ],
                          fontSize: 11,
                          color: theme.colorScheme.onSurface,
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: Text(l.addSourceCancel),
        ),
        FilledButton(
          onPressed: _source.isEmpty
              ? null
              : () => Navigator.of(context).pop(_source),
          child: Text(l.addSourceInstallButton),
        ),
      ],
    );
  }
}