/**
 * A link is picked on its line (#289): a click near the curve means that link, Ctrl adds another,
 * a rubber band takes every line it crosses, and Delete removes what is picked in one undo step.
 * A hidden link has no line, so it is never among the paths these rules are asked about.
 */
import { beforeEach, describe, expect, it } from 'vitest';
import { CreateAssetCommand } from '../../src/core/commands/assetCommands';
import { AddNodeCommand, ConnectCommand, NameTransitionCommand } from '../../src/core/commands/graphCommands';
import { type Graph, STATE, STATE_IN, STATE_NAME_PARAM, STATE_OUT } from '../../src/core/graph';
import { createEmptyProject, findGraphAsset } from '../../src/core/model/Project';
import { hideLinks, removeGraphSelection, removeSelection } from '../../src/editor/actions';
import {
  distanceToPath,
  edgeAt,
  type EdgePath,
  edgesInBand,
  pathMiddle,
} from '../../src/editor/graph/edgeHit';
import { selfLoop } from '../../src/editor/graph/transitions';
import { describeEdge, edgeSignature } from '../../src/editor/inspector/edgeSection';
import { edgeSelection, EditorState, graphSelection } from '../../src/editor/state';

const curve = (edgeId: string, y1: number, y2: number): EdgePath => ({
  edgeId,
  kind: 'curve',
  start: { x: 0, y: y1 },
  end: { x: 200, y: y2 },
});

describe('which link a point means', () => {
  it('takes the link whose curve runs within the tolerance, and none further off', () => {
    const paths = [curve('a', 0, 100)];
    const on = pathMiddle(paths[0]!);
    expect(on).toEqual({ x: 100, y: 50 });
    expect(edgeAt(paths, { x: on.x + 4, y: on.y }, 6)).toBe('a');
    expect(edgeAt(paths, { x: on.x + 40, y: on.y }, 6)).toBeNull();
    // The straight line between the ports is not the curve: its quarter point is well off it.
    expect(distanceToPath(paths[0]!, { x: 50, y: 25 })).toBeGreaterThan(6);
  });

  it('takes the one drawn last where two cross', () => {
    const paths = [curve('under', 0, 100), curve('over', 100, 0)];
    expect(edgeAt(paths, { x: 100, y: 50 }, 6)).toBe('over');
    expect(edgeAt([...paths].reverse(), { x: 100, y: 50 }, 6)).toBe('under');
  });

  it('follows a straight transition and a loop back into its own state', () => {
    const line: EdgePath = { edgeId: 'line', kind: 'line', start: { x: 0, y: 0 }, end: { x: 100, y: 100 } };
    const loop: EdgePath = {
      edgeId: 'loop',
      kind: 'loop',
      loop: selfLoop({ x: 300, y: 300, w: 100, h: 40 }),
    };
    expect(edgeAt([line, loop], { x: 52, y: 48 }, 6)).toBe('line');
    expect(edgeAt([line, loop], { x: 80, y: 20 }, 6)).toBeNull();
    expect(edgeAt([line, loop], pathMiddle(loop), 6)).toBe('loop');
    // Inside the loop is not on it.
    expect(edgeAt([line, loop], { x: 350, y: 285 }, 6)).toBeNull();
  });

  it('means the transition when its name plate is pressed, before any line under it', () => {
    const paths = [curve('line', 0, 0)];
    const plates = [{ edgeId: 'named', x: 80, y: -8, w: 40, h: 16 }];
    expect(edgeAt(paths, { x: 100, y: 0 }, 6, plates)).toBe('named');
    expect(edgeAt(paths, { x: 20, y: 0 }, 6, plates)).toBe('line');
  });

  it('gives a band every link it crosses, not only those with an end inside', () => {
    const paths = [curve('a', 0, 100), curve('far', 400, 400)];
    expect(edgesInBand(paths, { x1: 90, y1: 20, x2: 110, y2: 80 })).toEqual(['a']);
    // Drawn the other way round it is the same rectangle.
    expect(edgesInBand(paths, { x1: 110, y1: 80, x2: 90, y2: 20 })).toEqual(['a']);
    expect(edgesInBand(paths, { x1: 90, y1: 150, x2: 110, y2: 200 })).toEqual([]);
    expect(edgesInBand(paths, { x1: -10, y1: -10, x2: 300, y2: 500 })).toEqual(['a', 'far']);
  });
});

function fixture() {
  const state = new EditorState();
  state.loadProject(createEmptyProject('p', 'P'), 1);
  const create = new CreateAssetCommand('behavior', 'B');
  expect(state.execute(create)).toBe(true);
  const behaviorId = create.asset.id;
  const graphOf = (): Graph => findGraphAsset(state.project, behaviorId)!.graph;
  const addNode = (type: string): string => {
    const command = new AddNodeCommand(behaviorId, type, 0, 0);
    expect(state.execute(command)).toBe(true);
    return command.node.id;
  };
  const connect = (from: string, to: string, port: string): string => {
    const command = new ConnectCommand(behaviorId, { node: from, port: 'value' }, { node: to, port });
    expect(state.execute(command)).toBe(true);
    return command.edge.id;
  };
  const [one, two, add] = [addNode('Number'), addNode('Number'), addNode('Add')];
  const [first, second] = [connect(one, add, 'a'), connect(two, add, 'b')];
  const edgeIds = () => graphOf().edges.map((e) => e.id);
  return { state, behaviorId, graphOf, one, two, add, first, second, edgeIds };
}

describe('a selection of links', () => {
  let f: ReturnType<typeof fixture>;
  beforeEach(() => {
    f = fixture();
  });

  it('is its own kind, and keeps the graph of its asset on screen', () => {
    f.state.select(edgeSelection(f.behaviorId, [f.first]));
    expect(f.state.selection).toEqual({
      kind: 'edge',
      assetId: f.behaviorId,
      edgeId: f.first,
      edgeIds: [f.first],
    });
    expect(f.state.selectedEdgeIds).toEqual([f.first]);
    expect(f.state.selectedBehaviorId).toBe(f.behaviorId);
  });

  it('adds and takes a link with the toggle, and falls back to the asset when emptied', () => {
    f.state.select(edgeSelection(f.behaviorId, [f.first]));
    f.state.toggleEdge(f.behaviorId, f.second);
    expect(f.state.selection).toMatchObject({ kind: 'edge', edgeId: f.second, edgeIds: [f.first, f.second] });
    f.state.toggleEdge(f.behaviorId, f.second);
    f.state.toggleEdge(f.behaviorId, f.first);
    expect(f.state.selection).toEqual({ kind: 'asset', assetId: f.behaviorId });
  });

  it('rides along with nodes: the node stays what the inspector shows, either toggle keeps the rest', () => {
    f.state.select(graphSelection(f.behaviorId, [f.one], [], [f.first]));
    expect(f.state.selection).toMatchObject({ kind: 'node', nodeId: f.one, edgeIds: [f.first] });
    f.state.toggleEdge(f.behaviorId, f.second);
    expect(f.state.selection).toMatchObject({ kind: 'node', nodeId: f.one, edgeIds: [f.first, f.second] });
    f.state.toggleNode(f.behaviorId, f.two);
    expect(f.state.selectedNodeIds).toEqual([f.one, f.two]);
    expect(f.state.selectedEdgeIds).toEqual([f.first, f.second]);
    // The last node toggled away leaves the links, as a selection of their own.
    f.state.toggleNode(f.behaviorId, f.one);
    f.state.toggleNode(f.behaviorId, f.two);
    expect(f.state.selection).toMatchObject({ kind: 'edge', edgeIds: [f.first, f.second] });
  });

  it('deletes exactly the picked link on Delete, and one undo brings it back', () => {
    f.state.select(edgeSelection(f.behaviorId, [f.first]));
    expect(removeSelection(f.state)).toBe(true);
    expect(f.edgeIds()).toEqual([f.second]);
    // The link is gone, so the selection falls back to the graph it was in.
    expect(f.state.selection).toEqual({ kind: 'asset', assetId: f.behaviorId });
    f.state.undo();
    expect(f.edgeIds()).toEqual([f.first, f.second]);
  });

  it('deletes several links, and a node with them, as one undo step', () => {
    f.state.select(graphSelection(f.behaviorId, [f.one], [], [f.first, f.second]));
    expect(removeSelection(f.state)).toBe(true);
    expect(f.edgeIds()).toEqual([]);
    expect(f.graphOf().nodes.map((n) => n.id)).toEqual([f.two, f.add]);
    f.state.undo();
    expect(f.edgeIds()).toEqual([f.first, f.second]);
    expect(f.graphOf().nodes.map((n) => n.id)).toEqual([f.one, f.two, f.add]);
    f.state.redo();
    expect(f.edgeIds()).toEqual([]);
  });

  it('has nothing to delete when the link is already gone', () => {
    expect(removeGraphSelection(f.state, f.behaviorId, [], [], ['gone'])).toBe(false);
    expect(f.edgeIds()).toEqual([f.first, f.second]);
  });

  it('lets go of a link that is hidden, since it has no line left to be picked on', () => {
    f.state.select(graphSelection(f.behaviorId, [f.one], [], [f.first]));
    expect(hideLinks(f.state, f.behaviorId, [f.first])).toBe(true);
    expect(f.graphOf().edges[0]!.folded).toBe(true);
    expect(f.state.selection).toMatchObject({ kind: 'node', nodeId: f.one, edgeIds: [] });
  });

  it('drops a link from the selection when an undo takes it away', () => {
    f.state.select(edgeSelection(f.behaviorId, [f.first, f.second]));
    f.state.undo();
    expect(f.state.selection).toMatchObject({ kind: 'edge', edgeIds: [f.first] });
  });

  it('describes a link by the names drawn at its two ends', () => {
    expect(describeEdge(f.state.project, f.behaviorId, f.second)).toEqual({
      transition: false,
      from: 'Number',
      output: 'value',
      to: 'Add',
      input: 'b',
      type: 'number',
      name: '',
    });
    expect(describeEdge(f.state.project, f.behaviorId, 'gone')).toBeNull();
    expect(edgeSignature(f.state.project, f.behaviorId, f.first, [f.first, f.second])).toBe('many:2');
    expect(edgeSignature(f.state.project, f.behaviorId, f.first, [f.first])).not.toBe(
      edgeSignature(f.state.project, f.behaviorId, f.second, [f.second]),
    );
  });
});

describe('a picked transition', () => {
  function machine() {
    const state = new EditorState();
    state.loadProject(createEmptyProject('p', 'P'), 1);
    const create = new CreateAssetCommand('statemachine', 'Guard');
    expect(state.execute(create)).toBe(true);
    const id = create.asset.id;
    const [patrol, chase] = ['Patrol', 'Chase'].map((name) => {
      const add = new AddNodeCommand(id, STATE, 0, 0, { [STATE_NAME_PARAM]: name });
      expect(state.execute(add)).toBe(true);
      return add.node.id;
    }) as [string, string];
    const connect = new ConnectCommand(
      id,
      { node: patrol, port: STATE_OUT },
      { node: chase, port: STATE_IN },
    );
    expect(state.execute(connect)).toBe(true);
    return { state, id, edge: connect.edge.id };
  }

  it('is described by its two states and its name, and goes as a transition', () => {
    const m = machine();
    expect(m.state.execute(new NameTransitionCommand(m.id, m.edge, 'alarm'))).toBe(true);
    expect(describeEdge(m.state.project, m.id, m.edge)).toMatchObject({
      transition: true,
      from: 'Patrol',
      to: 'Chase',
      name: 'alarm',
    });
    m.state.select(edgeSelection(m.id, [m.edge]));
    expect(m.state.selectedStateMachineId).toBe(m.id);
    expect(removeSelection(m.state)).toBe(true);
    expect(findGraphAsset(m.state.project, m.id)!.graph.edges).toEqual([]);
  });
});