// FlowYamlCodeController — CodeController subclass that adds
// F∆I-specific colouring on top of the stock YAML highlighter
// and routes analyzer-issue hovers + reanalyze cycles for the
// editor host.
//
// The base highlighter colours generic YAML structure (keys,
// strings, numbers, comments, anchors). On top of that, this
// subclass walks the rendered span tree once per build to
// recolour wire-typed values, lay wavy underlines on broken
// lines, and attach pointer-hover handlers so the editor host
// can pop a tooltip with the message + quick fixes.
//
// The lookup runs every keystroke (because TextField rebuilds
// the span on each change), but each pass is O(N) over the
// visible text — fast enough for the flow files we expect
// (hundreds of lines, not megabytes).

import 'dart:async';

import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter_code_editor/flutter_code_editor.dart';
import 'package:highlight/languages/yaml.dart';

import 'flow_analyzer.dart';
import 'quick_fix.dart';
import 'wire_colors.dart';

class FlowYamlCodeController extends CodeController {
  FlowYamlCodeController({
    List<String> Function()? availableCapabilities,
    List<String> Function()? storeCapabilities,
  }) : super(
         text: '',
         language: yaml,
         analyzer: FlowAnalyzer(
           availableCapabilities:
               availableCapabilities ?? (() => const <String>[]),
           storeCapabilities: storeCapabilities,
         ),
       );

  /// Set both capability providers in one go. Re-creating the
  /// analyzer is the simplest way to flip both closures without
  /// risking a stale storeCapabilities reference inside an old
  /// FlowAnalyzer instance.
  void setCapabilityProviders({
    required List<String> Function() available,
    List<String> Function()? store,
  }) {
    analyzer = FlowAnalyzer(
      availableCapabilities: available,
      storeCapabilities: store,
    );
  }

  /// Worst-severity per step / pseudo-node from the analyzer's
  /// last pass. Graph canvas reads this to decide which step
  /// nodes pulse red / amber. Returns an empty map when the
  /// active analyzer isn't a [FlowAnalyzer].
  Map<String, IssueType> get stepSeverity {
    final a = analyzer;
    return a is FlowAnalyzer ? a.stepSeverity : const {};
  }

  /// Published when the pointer enters a wavy-underlined range.
  /// The editor host (FlowEditorPage) listens and renders an
  /// overlay tooltip near the cursor. Reset to `null` once the
  /// pointer leaves both the range AND the tooltip.
  final ValueNotifier<IssueHoverRequest?> hoverRequest =
      ValueNotifier<IssueHoverRequest?>(null);

  Timer? _hideTimer;

  /// Cancel the pending hover-dismiss timer. The host calls
  /// this when the pointer enters the floating tooltip card so
  /// the operator can click an action button without the tip
  /// vanishing under them.
  void cancelHoverDismiss() {
    _hideTimer?.cancel();
    _hideTimer = null;
  }

  /// Schedule the hover tooltip to clear after a short grace
  /// period. Lets the operator slide from the underline into
  /// the tooltip without the latter snapping away.
  void scheduleHoverDismiss() {
    _hideTimer?.cancel();
    _hideTimer = Timer(const Duration(milliseconds: 220), () {
      hoverRequest.value = null;
      _hideTimer = null;
    });
  }

  /// Clear the hover tooltip immediately — used when the editor
  /// is being disposed or the host wants to dismiss the tip
  /// (e.g. after applying a quick fix).
  void clearHover() {
    _hideTimer?.cancel();
    _hideTimer = null;
    hoverRequest.value = null;
  }

  /// Replace the analyzer's capability provider. Called by the
  /// editor host when the installed-capability list changes —
  /// e.g. after `fai install` while the editor is open.
  void setAvailableCapabilities(List<String> Function() provider) {
    analyzer = FlowAnalyzer(availableCapabilities: provider);
  }

  /// Run the analyzer against the current buffer and publish
  /// the new result. The host calls this after a quick fix that
  /// changes external state (e.g. installing a module) so the
  /// strip + underlines update without waiting for the next
  /// keystroke.
  Future<void> reanalyze() async {
    final result = await analyzer.analyze(code);
    analysisResult = result;
    notifyListeners();
  }

  /// Read-only access to the quick fixes computed for an issue.
  /// Returns an empty list when the analyzer is the default
  /// `DefaultLocalAnalyzer` (i.e. no language host hooked up).
  List<QuickFix> fixesFor(Issue issue) {
    final a = analyzer;
    return a is FlowAnalyzer ? a.fixesFor(issue) : const <QuickFix>[];
  }

  @override
  void dispose() {
    _hideTimer?.cancel();
    hoverRequest.dispose();
    super.dispose();
  }

  // Matches an indented `key: value` line where the value is
  // one of our known type tokens. Covers both shapes the F∆I
  // YAML uses (`pdf: bytes` shorthand and the explicit
  // `type: bytes` row).
  static final RegExp _typeAssignment = RegExp(
    r'''^[ \t]+[A-Za-z_][\w-]*\s*:\s*(?:['"])?([A-Za-z_][\w-]*)(?:['"])?\s*(?:#.*)?$''',
    multiLine: true,
  );

  @override
  TextSpan buildTextSpan({
    required BuildContext context,
    TextStyle? style,
    bool? withComposing,
  }) {
    final base = super.buildTextSpan(
      context: context,
      style: style,
      withComposing: withComposing,
    );
    final theme = Theme.of(context);
    final overrides = <_Override>[];
    overrides.addAll(_collectOverrides(text, theme));
    overrides.addAll(_collectIssueOverrides(theme));
    if (overrides.isEmpty) return base;
    overrides.sort((a, b) => a.start.compareTo(b.start));
    return _applyOverrides(base, overrides);
  }

  /// Build wavy-underline overrides for every analyzer-reported
  /// issue. The underline spans from the first non-whitespace
  /// character to the end of the affected line, so a clean line
  /// stays clean and the diagnostic visually attaches to the
  /// content the operator wrote (not the indent).
  List<_Override> _collectIssueOverrides(ThemeData theme) {
    final issues = analysisResult.issues;
    if (issues.isEmpty) return const <_Override>[];
    final lines = code.lines.lines;
    final out = <_Override>[];
    for (final issue in issues) {
      if (issue.line < 0 || issue.line >= lines.length) continue;
      final line = lines[issue.line];
      final text = line.text;
      var endOffset = line.textRange.end;
      if (text.endsWith('\n')) endOffset -= 1;
      var startOffset = line.textRange.start;
      for (var i = 0; i < text.length; i++) {
        final c = text.codeUnitAt(i);
        if (c == 0x20 || c == 0x09) {
          startOffset++;
        } else {
          break;
        }
      }
      if (startOffset >= endOffset) continue;
      final color = switch (issue.type) {
        IssueType.error => theme.colorScheme.error,
        IssueType.warning => const Color(0xFFEF6C00),
        IssueType.info => theme.colorScheme.primary,
      };
      out.add(
        _Override(
          startOffset,
          endOffset,
          TextStyle(
            decoration: TextDecoration.underline,
            decorationStyle: TextDecorationStyle.wavy,
            decorationColor: color,
            decorationThickness: 1.5,
          ),
          issue: issue,
        ),
      );
    }
    return out;
  }

  List<_Override> _collectOverrides(String source, ThemeData theme) {
    final out = <_Override>[];
    for (final m in _typeAssignment.allMatches(source)) {
      final typeName = m.group(1);
      if (typeName == null || !kKnownTypes.contains(typeName)) continue;
      final whole = m.group(0)!;
      final nameStart = m.start + whole.indexOf(typeName);
      final nameEnd = nameStart + typeName.length;
      out.add(
        _Override(
          nameStart,
          nameEnd,
          TextStyle(
            color: wireColor(typeName, theme),
            fontWeight: FontWeight.w600,
          ),
        ),
      );
    }
    return out;
  }

  TextSpan _applyOverrides(InlineSpan span, List<_Override> overrides) {
    final leaves = <_Leaf>[];
    _flatten(span, null, leaves);

    final children = <InlineSpan>[];
    var globalCursor = 0;
    var ovIdx = 0;
    for (final leaf in leaves) {
      final localText = leaf.text;
      final leafStart = globalCursor;
      final leafEnd = leafStart + localText.length;
      var localCursor = 0;

      while (ovIdx < overrides.length && overrides[ovIdx].end <= leafStart) {
        ovIdx++;
      }

      var probe = ovIdx;
      while (probe < overrides.length && overrides[probe].start < leafEnd) {
        final ov = overrides[probe];
        final ovStart = ov.start < leafStart ? leafStart : ov.start;
        final ovEnd = ov.end > leafEnd ? leafEnd : ov.end;
        final before = ovStart - leafStart;
        if (before > localCursor) {
          children.add(
            TextSpan(
              text: localText.substring(localCursor, before),
              style: leaf.style,
            ),
          );
        }
        final overlap = ovEnd - leafStart;
        children.add(_buildOverrideSpan(localText, before, overlap, leaf, ov));
        localCursor = overlap;
        probe++;
      }

      if (localCursor < localText.length) {
        children.add(
          TextSpan(
            text: localText.substring(localCursor),
            style: leaf.style,
          ),
        );
      }
      globalCursor = leafEnd;
    }

    final rootStyle = (span is TextSpan) ? span.style : null;
    return TextSpan(style: rootStyle, children: children);
  }

  TextSpan _buildOverrideSpan(
    String localText,
    int before,
    int overlap,
    _Leaf leaf,
    _Override ov,
  ) {
    final mergedStyle = (leaf.style ?? const TextStyle()).merge(ov.style);
    final issue = ov.issue;
    if (issue == null) {
      return TextSpan(
        text: localText.substring(before, overlap),
        style: mergedStyle,
      );
    }
    // Capture the issue + analyzer-supplied fixes so hover
    // handlers can publish a self-contained request without
    // round-tripping through the host on every pointer event.
    final fixes = fixesFor(issue);
    final severity = switch (issue.type) {
      IssueType.error => IssueHoverSeverity.error,
      IssueType.warning => IssueHoverSeverity.warning,
      IssueType.info => IssueHoverSeverity.info,
    };
    return TextSpan(
      text: localText.substring(before, overlap),
      style: mergedStyle,
      mouseCursor: SystemMouseCursors.help,
      onEnter: (PointerEnterEvent e) {
        _hideTimer?.cancel();
        _hideTimer = null;
        hoverRequest.value = IssueHoverRequest(
          line: issue.line,
          message: issue.message,
          severity: severity,
          fixes: fixes,
          globalPosition: e.position,
        );
      },
      onExit: (PointerExitEvent _) {
        scheduleHoverDismiss();
      },
    );
  }

  void _flatten(InlineSpan span, TextStyle? inherited, List<_Leaf> out) {
    if (span is! TextSpan) return;
    final merged = inherited == null
        ? span.style
        : (span.style == null ? inherited : inherited.merge(span.style));
    final t = span.text;
    if (t != null && t.isNotEmpty) {
      out.add(_Leaf(t, merged));
    }
    final children = span.children;
    if (children != null) {
      for (final c in children) {
        _flatten(c, merged, out);
      }
    }
  }
}

class _Override {
  final int start;
  final int end;
  final TextStyle style;
  final Issue? issue;
  const _Override(this.start, this.end, this.style, {this.issue});
}

class _Leaf {
  final String text;
  final TextStyle? style;
  const _Leaf(this.text, this.style);
}