// lib/editor/canvas/sticky_note_overlay.dart
//
// Page-anchored paper sticky: sized/positioned by the parent in page space,
// shares the editor brush/color/tool, locks inner pan/zoom so writing feels
// like drawing on the sticky surface itself.

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:uuid/uuid.dart';

import '../../models/ink_stroke.dart';
import '../../models/scratch_link.dart';
import '../../storage/badnote_sidecar.dart';
import '../engine/brush.dart';
import '../input/pen_config.dart' show kDefaultEraserRadius;
import '../notebook/ink_stroke_adapter.dart';
import '../persistence/sidecar_repository.dart';
import 'editor_tool.dart';
import 'pen_canvas.dart';
import 'pen_stroke.dart';

/// Default world size for a fresh sticky scratchpad (absolute px).
const Size kStickyWorldSize = Size(1200, 900);

/// Floating sticky-note card glued to a PDF page (parent supplies pixel size).
class StickyNoteOverlay extends StatefulWidget {
  const StickyNoteOverlay({
    super.key,
    required this.link,
    required this.repo,
    required this.onClose,
    required this.onDelete,
    required this.onDragPx,
    required this.onResizePx,
    this.brush = BrushKind.ballpoint,
    this.color = const Color(0xFF1A1A1A),
    this.tool = EditorToolKind.brush,
    this.strokeWidth = 0.008,
    this.allowFingerDrawing = false,
  });

  final ScratchLink link;
  final SidecarRepository repo;
  final VoidCallback onClose;
  final VoidCallback onDelete;

  /// Header drag delta in viewer/page pixels.
  final void Function(double dx, double dy) onDragPx;

  /// Corner resize delta in viewer/page pixels.
  final void Function(double dx, double dy) onResizePx;

  final BrushKind brush;
  final Color color;
  final EditorToolKind tool;
  final double strokeWidth;
  final bool allowFingerDrawing;

  @override
  State<StickyNoteOverlay> createState() => _StickyNoteOverlayState();
}

class _StickyNoteOverlayState extends State<StickyNoteOverlay> {
  static const _uuid = Uuid();

  final TransformationController _transform = TransformationController();
  List<InkStroke> _strokes = [];
  Size _world = kStickyWorldSize;
  Timer? _saveTimer;
  bool _dirty = false;

  @override
  void initState() {
    super.initState();
    final pad = widget.repo.scratchpadFor(widget.link.id);
    if (pad != null) {
      _world = Size(pad.canvasWidth, pad.canvasHeight);
      _strokes = pad.strokes.where((s) => isFreehandTool(s.tool)).toList();
    }
  }

  @override
  void dispose() {
    _saveTimer?.cancel();
    if (_dirty) {
      _persist(flush: true);
    }
    _transform.dispose();
    super.dispose();
  }

  void _scheduleSave() {
    _dirty = true;
    _saveTimer?.cancel();
    _saveTimer = Timer(const Duration(milliseconds: 600), () => _persist());
  }

  Future<void> _persist({bool flush = false}) async {
    if (!_dirty && !flush) return;
    widget.repo.scheduleScratchpadSave(
      widget.link.id,
      SidecarScratchpad(
        canvasWidth: _world.width,
        canvasHeight: _world.height,
        strokes: List<InkStroke>.of(_strokes),
      ),
    );
    _dirty = false;
    if (flush) await widget.repo.flush();
  }

  void _onStrokeComplete(PenStroke pen) {
    setState(() {
      _strokes = [
        ..._strokes,
        inkStrokeFromPen(pen, _world, id: _uuid.v4(), createdAt: DateTime.now()),
      ];
    });
    _scheduleSave();
  }

  void _onErase(int index, List<PenStroke> replacements) {
    if (index < 0 || index >= _strokes.length) return;
    setState(() {
      final next = List<InkStroke>.of(_strokes)..removeAt(index);
      for (final r in replacements) {
        next.insert(
          index,
          inkStrokeFromPen(r, _world, id: _uuid.v4(), createdAt: DateTime.now()),
        );
      }
      _strokes = next;
    });
    _scheduleSave();
  }

  Future<void> _close() async {
    _saveTimer?.cancel();
    await _persist(flush: true);
    widget.onClose();
  }

  CanvasTool get _canvasTool {
    switch (widget.tool) {
      case EditorToolKind.eraser:
        return CanvasTool.eraser;
      case EditorToolKind.select:
        return CanvasTool.select;
      case EditorToolKind.highlighter:
        return CanvasTool.highlighter;
      case EditorToolKind.brush:
      case EditorToolKind.shape:
      case EditorToolKind.text:
        return CanvasTool.pen;
    }
  }

  BrushKind get _canvasBrush =>
      widget.tool == EditorToolKind.highlighter
          ? BrushKind.highlighter
          : widget.brush;

  @override
  Widget build(BuildContext context) {
    final cs = Theme.of(context).colorScheme;
    return Material(
      elevation: 8,
      borderRadius: BorderRadius.circular(4),
      color: const Color(0xFFFFF8E1),
      clipBehavior: Clip.antiAlias,
      child: Stack(
        children: [
          Column(
            children: [
              _StickyHeader(
                onDragDelta: widget.onDragPx,
                onClose: _close,
                onDelete: () async {
                  await _persist(flush: true);
                  widget.onDelete();
                },
                cs: cs,
              ),
              Expanded(
                child: PenCanvas(
                  pageSize: _world,
                  strokes: penStrokesFromInk(_strokes, _world),
                  transformationController: _transform,
                  tool: _canvasTool,
                  brush: _canvasBrush,
                  color: widget.color,
                  strokeWidth: widget.strokeWidth,
                  eraserRadius: kDefaultEraserRadius,
                  allowFingerDrawing: widget.allowFingerDrawing,
                  scaleEnabled: false,
                  panEnabled: false,
                  minScale: 1.0,
                  maxScale: 1.0,
                  onStrokeComplete: _onStrokeComplete,
                  onEraseStroke: _onErase,
                  pageWidget: const ColoredBox(color: Color(0xFFFFFDE7)),
                ),
              ),
            ],
          ),
          Positioned(
            right: 0,
            bottom: 0,
            child: GestureDetector(
              onPanUpdate: (d) => widget.onResizePx(d.delta.dx, d.delta.dy),
              child: MouseRegion(
                cursor: SystemMouseCursors.resizeUpLeftDownRight,
                child: SizedBox(
                  width: 28,
                  height: 28,
                  child: Icon(
                    Icons.south_east,
                    size: 16,
                    color: cs.onSurface.withValues(alpha: 0.45),
                  ),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

class _StickyHeader extends StatelessWidget {
  const _StickyHeader({
    required this.onDragDelta,
    required this.onClose,
    required this.onDelete,
    required this.cs,
  });

  final void Function(double dx, double dy) onDragDelta;
  final VoidCallback onClose;
  final VoidCallback onDelete;
  final ColorScheme cs;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      behavior: HitTestBehavior.opaque,
      onPanUpdate: (d) => onDragDelta(d.delta.dx, d.delta.dy),
      child: Container(
        height: 36,
        padding: const EdgeInsets.symmetric(horizontal: 4),
        decoration: const BoxDecoration(
          color: Color(0xFFFFE082),
          borderRadius: BorderRadius.vertical(top: Radius.circular(4)),
        ),
        child: Row(
          children: [
            const Icon(Icons.drag_indicator, size: 18),
            const SizedBox(width: 4),
            const Expanded(
              child: Text(
                '便利贴',
                style: TextStyle(fontSize: 13, fontWeight: FontWeight.w600),
              ),
            ),
            Text(
              '拖标题定位 · 角缩放',
              style: TextStyle(
                fontSize: 10,
                color: cs.onSurface.withValues(alpha: 0.5),
              ),
            ),
            IconButton(
              tooltip: '删除',
              icon: const Icon(Icons.delete_outline, size: 18),
              visualDensity: VisualDensity.compact,
              onPressed: onDelete,
            ),
            IconButton(
              tooltip: '收起',
              icon: const Icon(Icons.close, size: 18),
              visualDensity: VisualDensity.compact,
              onPressed: onClose,
            ),
          ],
        ),
      ),
    );
  }
}