/**
 * Layers and groups of vector art in the editor (#190): the two lists of the inspector, the buttons
 * that group, and what a press in the tab does to a shape that stands in a group or on a hidden layer.
 */
import { CanvasTextMetrics, type FederatedPointerEvent } from 'pixi.js';
import { beforeAll, beforeEach, describe, expect, it } from 'vitest';
import { buildAsset } from '../../src/core/commands/assetCommands';
import {
  AddVectorLayerCommand,
  GroupVectorShapesCommand,
  SetVectorLayerHiddenCommand,
} from '../../src/core/commands/vectorArtCommands';
import type { VectorArtAsset, VectorItem, VectorShape } from '../../src/core/model/Asset';
import { createEmptyProject } from '../../src/core/model/Project';
import type { Vec2 } from '../../src/core/model/Properties';
import { allShapes } from '../../src/core/model/vectorTree';
import type { InspectorHost } from '../../src/editor/inspector/host';
import {
  buildShapeListSection,
  buildShapeSection,
  currentLayerList,
  currentShapeList,
  moveShapesToLayer,
  pickShapeRow,
  shapeListSignature,
  shapeSignature,
} from '../../src/editor/inspector/shapeSection';
import { EditorState, shapeSelection } from '../../src/editor/state';
import { activeLayerOf, pickVectorLayer } from '../../src/editor/vectorart/activeLayer';
import { groupShapes, ungroupShapes } from '../../src/editor/vectorart/grouping';
import { VectorArtCanvas } from '../../src/editor/vectorart/VectorArtCanvas';
import { Button, Label, VStack, type Widget } from '../../src/ui';
import { resetRenderLoop } from '../../src/ui/render';
import { PaintCache } from '../../src/viewport/vectorArtPicture';

beforeAll(() => {
  CanvasTextMetrics.measureText = (() => ({ width: 10, height: 10, lines: [], lineWidths: [] })) as never;
  PaintCache.prototype.gradient = (() => null) as never;
});
beforeEach(() => resetRenderLoop());

/** A square of 20 pixels with its corner at `x`, `y`. */
function square(id: string, x: number, y = 0): VectorShape {
  return {
    id,
    name: id.toUpperCase(),
    fill: 0x336699,
    opacity: 1,
    rings: [
      {
        closed: true,
        points: [
          { x, y },
          { x: x + 20, y },
          { x: x + 20, y: y + 20 },
          { x, y: y + 20 },
        ],
      },
    ],
  };
}

function text(items: readonly VectorItem[]): string {
  return items.map((item) => ('items' in item ? `${item.id}[${text(item.items)}]` : item.id)).join(' ');
}

/** A drawing with the squares a, b and c side by side on its one layer. */
function rig() {
  const state = new EditorState();
  state.loadProject(createEmptyProject('p', 'P'), 1);
  const asset = buildAsset('vectorart', 'Drawing') as VectorArtAsset;
  asset.layers[0]!.items.push(square('a', 0), square('b', 40), square('c', 80));
  state.project.assets.push(asset);
  const host: InspectorHost = {
    state,
    body: new VStack(),
    fields: new Map(),
    nameField: null,
    project: () => state.project,
    liveVariables: () => null,
  };
  /** The rows of the current selection, built anew as the inspector does after a change. */
  const build = (): void => {
    host.body.removeChildren();
    host.fields.clear();
    const s = state.selection;
    if (s?.kind === 'shape') buildShapeSection(host, asset.id, s.shapeId, s.shapeIds);
    else buildShapeListSection(host, asset);
  };
  const widgets = <T extends Widget>(type: new (...args: never[]) => T): T[] => {
    const found: T[] = [];
    const walk = (widget: Widget): void => {
      if (widget instanceof type) found.push(widget);
      for (const child of widget.children) walk(child as Widget);
    };
    walk(host.body);
    return found;
  };
  const button = (label: string) => widgets(Button).find((b) => b.text === label)!;
  const texts = () => widgets(Label).map((label) => label.text);
  const group = (...ids: string[]): string => {
    const command = new GroupVectorShapesCommand(asset.id, ids);
    state.execute(command);
    return command.groupId;
  };
  const addLayer = (): string => {
    const command = new AddVectorLayerCommand(asset.id);
    state.execute(command);
    return command.layerId;
  };
  const tree = () => asset.layers.map((layer) => text(layer.items));
  return { state, asset, host, build, button, texts, group, addLayer, tree };
}

describe('the lists of the inspector', () => {
  it('lists the layers top first and marks the one worked on', () => {
    const r = rig();
    const base = r.asset.layers[0]!.id;
    const upper = r.addLayer();
    r.build();
    expect(currentLayerList()!.shownIds).toEqual([upper, base]);
    // Nothing was picked yet, so the topmost layer is the one worked on – and it is empty.
    expect(activeLayerOf(r.state, r.asset)?.id).toBe(upper);
    expect(currentShapeList()).toBeNull();
    expect(r.texts()).toContain('Nothing on this layer yet – the Pen draws onto it.');
    pickVectorLayer(r.state, r.asset.id, base);
    r.build();
    expect(currentShapeList()!.shownIds).toEqual(['c', 'b', 'a']);
  });

  it('follows the selected shape onto its layer, and remembers it once the shape is let go', () => {
    const r = rig();
    const base = r.asset.layers[0]!.id;
    r.addLayer();
    r.state.select(shapeSelection(r.asset.id, ['b']));
    expect(activeLayerOf(r.state, r.asset)?.id).toBe(base);
    r.state.select({ kind: 'asset', assetId: r.asset.id });
    expect(activeLayerOf(r.state, r.asset)?.id).toBe(base);
  });

  it('lets go of the shapes of another layer when a layer is picked', () => {
    const r = rig();
    const upper = r.addLayer();
    r.state.select(shapeSelection(r.asset.id, ['b']));
    pickVectorLayer(r.state, r.asset.id, upper);
    expect(r.state.selection).toEqual({ kind: 'asset', assetId: r.asset.id });
    expect(activeLayerOf(r.state, r.asset)?.id).toBe(upper);
  });

  it('rebuilds the rows for another layer, a group and a hidden layer', () => {
    const r = rig();
    const base = r.asset.layers[0]!.id;
    pickVectorLayer(r.state, r.asset.id, base);
    const flat = shapeListSignature(r.asset);
    r.group('a', 'b');
    const grouped = shapeListSignature(r.asset);
    expect(grouped).not.toBe(flat);
    r.state.execute(new SetVectorLayerHiddenCommand(r.asset.id, base, true));
    const hidden = shapeListSignature(r.asset);
    expect(hidden).not.toBe(grouped);
    const upper = r.addLayer();
    pickVectorLayer(r.state, r.asset.id, base);
    const onBase = shapeListSignature(r.asset);
    pickVectorLayer(r.state, r.asset.id, upper);
    expect(shapeListSignature(r.asset)).not.toBe(onBase);
    expect(shapeSignature(r.state.project, r.asset.id, 'a', ['a'])).toContain(`@${base}[`);
  });

  it('shows a group over its shapes and selects all of them from its row', () => {
    const r = rig();
    const g = r.group('a', 'b');
    r.state.select(shapeSelection(r.asset.id, ['a']));
    r.build();
    expect(currentShapeList()!.shownIds).toEqual(['c', g, 'b', 'a']);
    pickShapeRow(r.state, r.asset.id, g, false);
    expect(r.state.selectedShapeIds).toEqual(['a', 'b']);
  });

  it('adds a group to the selection with Ctrl and takes it out again as a whole', () => {
    const r = rig();
    const g = r.group('a', 'b');
    r.state.select(shapeSelection(r.asset.id, ['c']));
    pickShapeRow(r.state, r.asset.id, g, true);
    expect(r.state.selectedShapeIds).toEqual(['c', 'a', 'b']);
    pickShapeRow(r.state, r.asset.id, g, true);
    expect(r.state.selectedShapeIds).toEqual(['c']);
    pickShapeRow(r.state, r.asset.id, 'c', true);
    expect(r.state.selection).toEqual({ kind: 'asset', assetId: r.asset.id });
  });

  it('puts a shape added from the inspector onto the layer worked on', () => {
    const r = rig();
    const base = r.asset.layers[0]!.id;
    r.addLayer();
    pickVectorLayer(r.state, r.asset.id, base);
    r.build();
    r.button('Add shape').onClick!();
    expect(r.asset.layers[0]!.items).toHaveLength(4);
    expect(r.asset.layers[1]!.items).toHaveLength(0);
  });
});

describe('grouping from the inspector', () => {
  it('groups the selection, which then reads as the group, and ungroups it again', () => {
    const r = rig();
    r.state.select(shapeSelection(r.asset.id, ['a', 'c']));
    r.build();
    expect(r.button('Group').enabled).toBe(true);
    expect(r.button('Ungroup').enabled).toBe(false);
    r.button('Group').onClick!();
    const made = r.asset.layers[0]!.items[1]!;
    expect(r.tree()).toEqual([`b ${made.id}[a c]`]);
    expect(r.state.selectedShapeIds).toEqual(['a', 'c']);
    r.build();
    expect(r.button('Ungroup').enabled).toBe(true);
    r.button('Ungroup').onClick!();
    expect(r.tree()).toEqual(['b a c']);
    r.state.undo();
    r.state.undo();
    expect(r.tree()).toEqual(['a b c']);
  });

  it('ungroups the group the primary shape stands in when no group is picked as a whole', () => {
    const r = rig();
    r.group('a', 'b');
    r.state.select(shapeSelection(r.asset.id, ['a']));
    r.build();
    expect(r.button('Ungroup').enabled).toBe(true);
    r.button('Ungroup').onClick!();
    expect(r.tree()).toEqual(['a b c']);
  });

  it('moves a whole picked group with the order buttons, and a lone shape inside its group', () => {
    const r = rig();
    const g = r.group('a', 'b');
    r.state.select(shapeSelection(r.asset.id, ['a', 'b']));
    r.build();
    r.button('To front').onClick!();
    expect(r.tree()).toEqual([`c ${g}[a b]`]);
    r.state.select(shapeSelection(r.asset.id, ['a']));
    r.build();
    expect(r.button('Backward').enabled).toBe(false);
    r.button('Forward').onClick!();
    expect(r.tree()).toEqual([`c ${g}[b a]`]);
  });

  it('switches Group off across two layers', () => {
    const r = rig();
    const upper = r.addLayer();
    moveShapesToLayer(r.state, r.asset.id, ['c'], upper);
    r.state.select(shapeSelection(r.asset.id, ['a', 'c']));
    r.build();
    expect(r.button('Group').enabled).toBe(false);
  });

  it('offers the Layer row from two layers on and moves a picked group as a whole', () => {
    const r = rig();
    const g = r.group('a', 'b');
    r.state.select(shapeSelection(r.asset.id, ['a', 'b']));
    r.build();
    expect(r.host.fields.has('shapeLayer')).toBe(false);
    const upper = r.addLayer();
    r.build();
    expect(r.host.fields.has('shapeLayer')).toBe(true);
    moveShapesToLayer(r.state, r.asset.id, ['a', 'b'], upper);
    expect(r.tree()).toEqual(['c', `${g}[a b]`]);
    // The selection went along, so the layer worked on is now the upper one.
    expect(activeLayerOf(r.state, r.asset)?.id).toBe(upper);
    // Already there: no second step, so one undo takes the move back.
    moveShapesToLayer(r.state, r.asset.id, ['a', 'b'], upper);
    r.state.undo();
    expect(r.tree()).toEqual([`${g}[a b] c`, '']);
  });
});

/** Presses run on one clock, far enough apart that no two join into a double-click. */
let clock = 0;

function pressAt(global: Vec2, held: 'ctrl' | 'shift' | null = null) {
  clock += 1000;
  return {
    timeStamp: clock,
    button: 0,
    global,
    altKey: false,
    ctrlKey: held === 'ctrl',
    metaKey: false,
    shiftKey: held === 'shift',
    stopPropagation: () => undefined,
  } as unknown as FederatedPointerEvent;
}

interface Pressable {
  shiftPresses(asset: VectorArtAsset, local: Vec2): boolean;
  press(asset: VectorArtAsset, e: FederatedPointerEvent, local: Vec2): void;
  move(local: Vec2): void;
  release(): void;
}

function tab() {
  const r = rig();
  const canvas = new VectorArtCanvas(r.state);
  canvas.show(r.asset.id);
  canvas.resize(400, 400);
  canvas.redraw();
  const target = canvas as unknown as Pressable;
  const at = (x: number, y: number) => canvas.imageToScreen(x, y);
  // A Shift press only reaches the tab where it is not a pan, which the tab says itself.
  const click = (point: Vec2, held: 'ctrl' | 'shift' | null = null) => {
    if (held === 'shift' && !target.shiftPresses(r.asset, point)) return;
    target.press(r.asset, pressAt(point, held), point);
    target.release();
  };
  const drag = (from: Vec2, to: Vec2) => {
    target.press(r.asset, pressAt(from), from);
    target.move(to);
    target.release();
  };
  const corner = (id: string) => allShapes(r.asset).find((s) => s.id === id)!.rings[0]!.points[0];
  return { ...r, canvas, at, click, drag, corner };
}

describe('the tab', () => {
  it('selects the whole group on a press on one of its shapes, the pressed one first', () => {
    const t = tab();
    t.group('a', 'b');
    t.click(t.at(50, 10));
    expect(t.state.selection).toMatchObject({ shapeId: 'b', shapeIds: ['a', 'b'] });
    t.click(t.at(90, 10));
    expect(t.state.selection).toMatchObject({ shapeId: 'c', shapeIds: ['c'] });
  });

  it('selects the outermost group of a shape that stands two groups deep', () => {
    const t = tab();
    const inner = t.group('a');
    t.group(inner, 'b');
    t.click(t.at(10, 10));
    expect(t.state.selection).toMatchObject({ shapeId: 'a', shapeIds: ['a', 'b'] });
  });

  it('moves a group by dragging one of its shapes, as one undo step', () => {
    const t = tab();
    t.group('a', 'b');
    t.drag(t.at(10, 10), t.at(15, 40));
    expect(t.corner('a')).toMatchObject({ x: 5, y: 30 });
    expect(t.corner('b')).toMatchObject({ x: 45, y: 30 });
    expect(t.corner('c')).toMatchObject({ x: 80, y: 0 });
    t.state.undo();
    expect(t.corner('a')).toMatchObject({ x: 0, y: 0 });
    expect(t.corner('b')).toMatchObject({ x: 40, y: 0 });
  });

  it('carries every selected shape when one of them is dragged, grouped or not', () => {
    const t = tab();
    t.state.select(shapeSelection(t.asset.id, ['a', 'c']));
    t.drag(t.at(90, 10), t.at(90, 30));
    expect(t.state.selection).toMatchObject({ shapeId: 'c', shapeIds: ['a', 'c'] });
    expect(t.corner('a')).toMatchObject({ x: 0, y: 20 });
    expect(t.corner('c')).toMatchObject({ x: 80, y: 20 });
    expect(t.corner('b')).toMatchObject({ x: 40, y: 0 });
  });

  it.each(['ctrl', 'shift'] as const)(
    'adds a shape to the selection with %s held and takes it out again',
    (held) => {
      const t = tab();
      t.click(t.at(10, 10));
      t.click(t.at(90, 10), held);
      expect(t.state.selectedShapeIds).toEqual(['a', 'c']);
      t.click(t.at(50, 10), held);
      expect(t.state.selectedShapeIds).toEqual(['a', 'c', 'b']);
      t.click(t.at(90, 10), held);
      expect(t.state.selectedShapeIds).toEqual(['a', 'b']);
      // Nothing was moved or changed on the way.
      expect(t.corner('c')).toMatchObject({ x: 80, y: 0 });
    },
  );

  it('leaves a Shift press to the pan beside the shapes and with another tool', () => {
    const t = tab();
    const target = t.canvas as unknown as Pressable;
    expect(target.shiftPresses(t.asset, t.at(10, 10))).toBe(true);
    expect(target.shiftPresses(t.asset, t.at(10, 60))).toBe(false);
    t.canvas.setTool('pen');
    expect(target.shiftPresses(t.asset, t.at(10, 10))).toBe(false);
  });

  it('leaves the selection as it is on a click that moves nothing', () => {
    const t = tab();
    t.group('a', 'b');
    t.click(t.at(10, 10));
    t.click(t.at(50, 10));
    expect(t.state.selection).toMatchObject({ shapeId: 'b', shapeIds: ['a', 'b'] });
    expect(t.corner('a')).toMatchObject({ x: 0, y: 0 });
    // No step was made: the last one is still the grouping.
    t.state.undo();
    expect(t.tree()).toEqual(['a b c']);
  });

  it('groups and ungroups the selection, and does nothing while only the drawing is selected', () => {
    const t = tab();
    t.state.select(shapeSelection(t.asset.id, ['a', 'b']));
    expect(groupShapes(t.state, t.asset.id)).toBe(true);
    expect(t.tree()[0]).toMatch(/^\S+\[a b\] c$/);
    expect(ungroupShapes(t.state, t.asset.id)).toBe(true);
    expect(t.tree()).toEqual(['a b c']);
    expect(ungroupShapes(t.state, t.asset.id)).toBe(false);
    t.state.select({ kind: 'asset', assetId: t.asset.id });
    expect(groupShapes(t.state, t.asset.id)).toBe(false);
  });

  it('does not let a shape on a hidden layer be pressed', () => {
    const t = tab();
    const base = t.asset.layers[0]!.id;
    t.state.execute(new SetVectorLayerHiddenCommand(t.asset.id, base, true));
    t.click(t.at(10, 10));
    expect(t.state.selection).toEqual({ kind: 'asset', assetId: t.asset.id });
  });

  it('draws with the pen onto the layer worked on, and nothing onto a hidden one', () => {
    const t = tab();
    const base = t.asset.layers[0]!.id;
    const upper = t.addLayer();
    pickVectorLayer(t.state, t.asset.id, base);
    t.canvas.setTool('pen');
    t.click(t.at(150, 150));
    expect(t.asset.layers[0]!.items).toHaveLength(4);
    expect(t.asset.layers[1]!.items).toHaveLength(0);
    t.canvas.onKeyDown({ key: 'Escape' } as KeyboardEvent);
    t.state.execute(new SetVectorLayerHiddenCommand(t.asset.id, upper, true));
    pickVectorLayer(t.state, t.asset.id, upper);
    t.click(t.at(170, 170));
    expect(allShapes(t.asset)).toHaveLength(4);
  });
});