/**
 * SelectionEngine Tests – Selection modes, filters, box selection, hover, listeners
 */
import { describe, it, expect, beforeEach } from 'vitest';
import { SelectionEngine } from '../src/canvas/SelectionEngine';
import { RenderEngine } from '../src/canvas/RenderEngine';
import { SpatialIndex } from '../src/canvas/SpatialIndex';
import { LayerManager } from '../src/canvas/LayerManager';
import { ZoomPanController } from '../src/canvas/ZoomPanController';
import type { CADElement, CADLayer } from '../src/types/cad.types';

function createMockCanvas(w = 800, h = 600): HTMLCanvasElement {
  const canvas = document.createElement('canvas');
  canvas.width = w;
  canvas.height = h;
  const ctx = canvas.getContext('2d');
  if (ctx) {
    ctx.fillRect = (() => {}) as any;
    ctx.strokeRect = (() => {}) as any;
    ctx.beginPath = (() => {}) as any;
    ctx.moveTo = (() => {}) as any;
    ctx.lineTo = (() => {}) as any;
    ctx.stroke = (() => {}) as any;
    ctx.fill = (() => {}) as any;
    ctx.save = (() => {}) as any;
    ctx.restore = (() => {}) as any;
    ctx.scale = (() => {}) as any;
    ctx.arc = (() => {}) as any;
    ctx.setLineDash = (() => {}) as any;
    ctx.clearRect = (() => {}) as any;
    ctx.translate = (() => {}) as any;
    ctx.rotate = (() => {}) as any;
    ctx.clip = (() => {}) as any;
    ctx.fillText = (() => {}) as any;
    ctx.quadraticCurveTo = (() => {}) as any;
    ctx.closePath = (() => {}) as any;
  }
  return canvas;
}

function makeLayer(id: string, overrides: Partial<CADLayer> = {}): CADLayer {
  return {
    id,
    name: id,
    visible: true,
    locked: false,
    color: '#ffffff',
    lineType: 'solid',
    transparency: 0,
    sortOrder: 0,
    parentId: null,
    ...overrides,
  };
}

function makeLine(id: string, x1: number, y1: number, x2: number, y2: number, layerId = 'layer-1'): CADElement {
  return {
    id,
    type: 'line',
    layerId,
    x: (x1 + x2) / 2,
    y: (y1 + y2) / 2,
    width: Math.abs(x2 - x1),
    height: Math.abs(y2 - y1),
    properties: { x1, y1, x2, y2 },
  };
}

function makeRect(id: string, cx: number, cy: number, w: number, h: number, layerId = 'layer-1'): CADElement {
  return {
    id,
    type: 'rect',
    layerId,
    x: cx,
    y: cy,
    width: w,
    height: h,
    properties: {},
  };
}

function setup(): {
  canvas: HTMLCanvasElement;
  zpc: ZoomPanController;
  spatialIndex: SpatialIndex;
  layerManager: LayerManager;
  renderEngine: RenderEngine;
  selectionEngine: SelectionEngine;
} {
  const canvas = createMockCanvas(800, 600);
  const zpc = new ZoomPanController(canvas);
  const spatialIndex = new SpatialIndex();
  const layerManager = new LayerManager();
  layerManager.addLayer(makeLayer('layer-1'));
  const renderEngine = new RenderEngine(canvas, zpc, spatialIndex, layerManager);
  const selectionEngine = new SelectionEngine(renderEngine, spatialIndex, layerManager);
  return { canvas, zpc, spatialIndex, layerManager, renderEngine, selectionEngine };
}

describe('SelectionEngine', () => {
  let s: ReturnType<typeof setup>;

  beforeEach(() => {
    s = setup();
  });

  describe('initial state', () => {
    it('should have empty selection', () => {
      expect(s.selectionEngine.getSelectedIds().size).toBe(0);
    });

    it('should have default options (single mode, all filter)', () => {
      const opts = s.selectionEngine.getOptions();
      expect(opts.mode).toBe('single');
      expect(opts.filter).toBe('all');
      expect(opts.additive).toBe(false);
      expect(opts.subtractive).toBe(false);
    });

    it('should have null hover', () => {
      expect(s.selectionEngine.getHoverId()).toBeNull();
    });
  });

  describe('setOptions', () => {
    it('should update options partially', () => {
      s.selectionEngine.setOptions({ filter: 'lines' });
      expect(s.selectionEngine.getOptions().filter).toBe('lines');
    });
  });

  describe('clickSelect – hit', () => {
    it('should select an element when clicking on it', () => {
      const line = makeLine('l1', 50, 50, 150, 50);
      s.spatialIndex.insert(line);
      const result = s.selectionEngine.clickSelect(100, 50, [line]);
      expect(result).not.toBeNull();
      expect(result!.id).toBe('l1');
      expect(s.selectionEngine.getSelectedIds().has('l1')).toBe(true);
    });

    it('should select a rect element when clicking within it', () => {
      const rect = makeRect('r1', 100, 100, 80, 60);
      s.spatialIndex.insert(rect);
      const result = s.selectionEngine.clickSelect(100, 100, [rect]);
      expect(result).not.toBeNull();
      expect(result!.id).toBe('r1');
    });
  });

  describe('clickSelect – miss', () => {
    it('should return null when clicking empty space', () => {
      const line = makeLine('l1', 50, 50, 150, 50);
      s.spatialIndex.insert(line);
      const result = s.selectionEngine.clickSelect(400, 400, [line]);
      expect(result).toBeNull();
      expect(s.selectionEngine.getSelectedIds().size).toBe(0);
    });

    it('should clear selection when clicking empty space in non-additive mode', () => {
      const line = makeLine('l1', 50, 50, 150, 50);
      s.spatialIndex.insert(line);
      s.selectionEngine.clickSelect(100, 50, [line]);
      expect(s.selectionEngine.getSelectedIds().size).toBe(1);
      s.selectionEngine.clickSelect(400, 400, [line]);
      expect(s.selectionEngine.getSelectedIds().size).toBe(0);
    });
  });

  describe('clickSelect – additive mode', () => {
    it('should add to selection in additive mode', () => {
      const l1 = makeLine('l1', 50, 50, 150, 50);
      const l2 = makeLine('l2', 50, 100, 150, 100);
      s.spatialIndex.insert(l1);
      s.spatialIndex.insert(l2);
      s.selectionEngine.setOptions({ additive: true });
      s.selectionEngine.clickSelect(100, 50, [l1, l2]);
      s.selectionEngine.clickSelect(100, 100, [l1, l2]);
      expect(s.selectionEngine.getSelectedIds().size).toBe(2);
    });

    it('should not clear on miss in additive mode', () => {
      const l1 = makeLine('l1', 50, 50, 150, 50);
      s.spatialIndex.insert(l1);
      s.selectionEngine.setOptions({ additive: true });
      s.selectionEngine.clickSelect(100, 50, [l1]);
      s.selectionEngine.clickSelect(400, 400, [l1]);
      expect(s.selectionEngine.getSelectedIds().size).toBe(1);
    });
  });

  describe('clickSelect – subtractive mode', () => {
    it('should remove from selection in subtractive mode', () => {
      const l1 = makeLine('l1', 50, 50, 150, 50);
      s.spatialIndex.insert(l1);
      // First select normally
      s.selectionEngine.clickSelect(100, 50, [l1]);
      expect(s.selectionEngine.getSelectedIds().has('l1')).toBe(true);
      // Now subtract
      s.selectionEngine.setOptions({ subtractive: true });
      s.selectionEngine.clickSelect(100, 50, [l1]);
      expect(s.selectionEngine.getSelectedIds().has('l1')).toBe(false);
    });
  });

  describe('clickSelect – filter modes', () => {
    it('should not select when filter does not match', () => {
      const rect = makeRect('r1', 100, 100, 80, 60);
      s.spatialIndex.insert(rect);
      s.selectionEngine.setOptions({ filter: 'lines' });
      const result = s.selectionEngine.clickSelect(100, 100, [rect]);
      expect(result).toBeNull();
    });

    it('should select when filter matches lines', () => {
      const line = makeLine('l1', 50, 50, 150, 50);
      s.spatialIndex.insert(line);
      s.selectionEngine.setOptions({ filter: 'lines' });
      const result = s.selectionEngine.clickSelect(100, 50, [line]);
      expect(result).not.toBeNull();
      expect(result!.id).toBe('l1');
    });

    it('should select rects with rects filter', () => {
      const rect = makeRect('r1', 100, 100, 80, 60);
      s.spatialIndex.insert(rect);
      s.selectionEngine.setOptions({ filter: 'rects' });
      const result = s.selectionEngine.clickSelect(100, 100, [rect]);
      expect(result).not.toBeNull();
    });
  });

  describe('box selection', () => {
    it('should select elements within box (window mode)', () => {
      const r1 = makeRect('r1', 100, 100, 40, 40);
      const r2 = makeRect('r2', 300, 300, 40, 40);
      s.spatialIndex.insert(r1);
      s.spatialIndex.insert(r2);
      // Window: left-to-right, fully enclosed
      s.selectionEngine.startBoxSelect(50, 50);
      s.selectionEngine.updateBoxSelect(200, 200, [r1, r2]);
      const selected = s.selectionEngine.finishBoxSelect([r1, r2]);
      // r1 bbox: 80,80 to 120,120 — fully within 50,50 to 200,200
      expect(selected.length).toBe(1);
      expect(selected[0].id).toBe('r1');
    });

    it('should select elements intersecting box (crossing mode)', () => {
      const r1 = makeRect('r1', 100, 100, 40, 40);
      s.spatialIndex.insert(r1);
      // Crossing: right-to-left (start.x > end.x)
      s.selectionEngine.startBoxSelect(200, 200);
      s.selectionEngine.updateBoxSelect(90, 90, [r1]);
      const selected = s.selectionEngine.finishBoxSelect([r1]);
      expect(selected.length).toBe(1);
    });

    it('should clear box start/end after finish', () => {
      s.selectionEngine.startBoxSelect(50, 50);
      s.selectionEngine.updateBoxSelect(100, 100, []);
      s.selectionEngine.finishBoxSelect([]);
      expect(s.selectionEngine.isBoxSelecting()).toBe(false);
    });

    it('should return empty when no box started', () => {
      const result = s.selectionEngine.finishBoxSelect([]);
      expect(result).toEqual([]);
    });

    it('cancelBoxSelect should stop box selection', () => {
      s.selectionEngine.startBoxSelect(50, 50);
      s.selectionEngine.cancelBoxSelect();
      expect(s.selectionEngine.isBoxSelecting()).toBe(false);
    });
  });

  describe('clearSelection', () => {
    it('should clear all selected ids', () => {
      const l1 = makeLine('l1', 50, 50, 150, 50);
      s.spatialIndex.insert(l1);
      s.selectionEngine.clickSelect(100, 50, [l1]);
      s.selectionEngine.clearSelection();
      expect(s.selectionEngine.getSelectedIds().size).toBe(0);
    });
  });

  describe('hover', () => {
    it('should set and get hover id', () => {
      s.selectionEngine.setHover('el-1');
      expect(s.selectionEngine.getHoverId()).toBe('el-1');
    });

    it('should clear hover with null', () => {
      s.selectionEngine.setHover('el-1');
      s.selectionEngine.setHover(null);
      expect(s.selectionEngine.getHoverId()).toBeNull();
    });
  });

  describe('selectByIds', () => {
    it('should select by ids', () => {
      s.selectionEngine.selectByIds(['a', 'b', 'c']);
      expect(s.selectionEngine.getSelectedIds().size).toBe(3);
    });

    it('should add to selection when additive=true', () => {
      s.selectionEngine.selectByIds(['a']);
      s.selectionEngine.selectByIds(['b'], true);
      expect(s.selectionEngine.getSelectedIds().size).toBe(2);
    });
  });

  describe('selectAll', () => {
    it('should select all visible elements matching filter', () => {
      const l1 = makeLine('l1', 50, 50, 150, 50);
      const l2 = makeLine('l2', 50, 100, 150, 100);
      s.spatialIndex.insert(l1);
      s.spatialIndex.insert(l2);
      s.selectionEngine.selectAll([l1, l2]);
      expect(s.selectionEngine.getSelectedIds().size).toBe(2);
    });
  });

  describe('invertSelection', () => {
    it('should invert current selection', () => {
      const l1 = makeLine('l1', 50, 50, 150, 50);
      const l2 = makeLine('l2', 50, 100, 150, 100);
      s.spatialIndex.insert(l1);
      s.spatialIndex.insert(l2);
      s.selectionEngine.selectByIds(['l1']);
      s.selectionEngine.invertSelection([l1, l2]);
      const ids = s.selectionEngine.getSelectedIds();
      expect(ids.has('l1')).toBe(false);
      expect(ids.has('l2')).toBe(true);
    });
  });

  describe('quickSelect', () => {
    it('should select by type', () => {
      const l1 = makeLine('l1', 50, 50, 150, 50);
      const r1 = makeRect('r1', 100, 100, 80, 60);
      const result = s.selectionEngine.quickSelect([l1, r1], { type: 'line' });
      expect(result.length).toBe(1);
      expect(result[0].id).toBe('l1');
    });

    it('should select by layerId', () => {
      const l1 = makeLine('l1', 50, 50, 150, 50, 'layer-1');
      const l2 = makeLine('l2', 50, 100, 150, 100, 'layer-2');
      const result = s.selectionEngine.quickSelect([l1, l2], { layerId: 'layer-1' });
      expect(result.length).toBe(1);
      expect(result[0].id).toBe('l1');
    });
  });

  describe('listeners', () => {
    it('should call listener on selection change', () => {
      let called = false;
      let received: CADElement[] = [];
      s.selectionEngine.addListener((els) => {
        called = true;
        received = els;
      });
      const l1 = makeLine('l1', 50, 50, 150, 50);
      s.spatialIndex.insert(l1);
      s.selectionEngine.clickSelect(100, 50, [l1]);
      expect(called).toBe(true);
      expect(received.length).toBe(1);
      expect(received[0].id).toBe('l1');
    });

    it('should remove listener', () => {
      let called = false;
      const fn = (els: CADElement[]) => { called = true; };
      s.selectionEngine.addListener(fn);
      s.selectionEngine.removeListener(fn);
      const l1 = makeLine('l1', 50, 50, 150, 50);
      s.spatialIndex.insert(l1);
      s.selectionEngine.clickSelect(100, 50, [l1]);
      expect(called).toBe(false);
    });
  });

  describe('getSelectedElements', () => {
    it('should filter allElements by selected ids', () => {
      const l1 = makeLine('l1', 50, 50, 150, 50);
      const l2 = makeLine('l2', 50, 100, 150, 100);
      s.selectionEngine.selectByIds(['l1']);
      const result = s.selectionEngine.getSelectedElements([l1, l2]);
      expect(result.length).toBe(1);
      expect(result[0].id).toBe('l1');
    });
  });
});