/**
 * Get/Set variables: the two nodes whose declared ports are variables of the behavior around them,
 * rather than names of their own. What that costs is the wiring – a port has to follow the variable
 * it names when that is renamed or swapped, and take its edges along.
 */
import { describe, expect, it } from 'vitest';
import { AddPortCommand, SetVariablePortCommand } from '../../src/core/commands/portCommands';
import {
  AddStructFieldCommand,
  AddVariableCommand,
  RemoveVariableCommand,
  RenameVariableCommand,
} from '../../src/core/commands/variableCommands';
import {
  GET_VARIABLES,
  type GraphNode,
  GraphInterpreter,
  resolveDef,
  SET_VARIABLES,
} from '../../src/core/graph';
import type { BehaviorAsset } from '../../src/core/model/Asset';
import { behaviorLookup } from '../../src/core/model/behaviorPrograms';
import { fakeContext, graphEditor, makeBehavior, makeProject, roundTrip } from '../helpers';

/** `px` and `py` are set in one node and read back in another, their sum landing in `sum`. */
function bothWays() {
  const fixture = makeProject();
  const behavior = makeBehavior(fixture, 'B', ['px', 'py', 'sum']);
  const edit = graphEditor(fixture, behavior);
  const start = edit.addNode('OnStart');
  const set = edit.addNode(SET_VARIABLES, { px: 7, py: 9 });
  const get = edit.addNode(GET_VARIABLES);
  const add = edit.addNode('Add');
  const store = edit.addNode('SetVariable', { variable: 'sum' });
  for (const node of [set, get])
    for (const key of ['px', 'py'])
      fixture.stack.execute(new AddPortCommand(behavior.id, node.id, { key, kind: 'number' }));
  edit.wire([
    [start, 'exec', set, 'exec'],
    [set, 'exec', store, 'exec'],
    [get, 'px', add, 'a'],
    [get, 'py', add, 'b'],
    [add, 'result', store, 'value'],
  ]);
  return { fixture, behavior, set, get, edit };
}

function run(
  behavior: BehaviorAsset,
  fixture: ReturnType<typeof makeProject>,
  variables: Record<string, number> = { px: 0, py: 0, sum: 0 },
) {
  const interpreter = new GraphInterpreter(behavior.graph, behaviorLookup(fixture.project));
  const ctx = fakeContext({ variables });
  interpreter.fire('OnStart', ctx);
  return ctx.variables;
}

const portKeys = (behavior: BehaviorAsset, node: GraphNode, side: 'inputs' | 'outputs') =>
  resolveDef(node, behavior.graph, () => null)![side].map((p) => `${p.key}:${p.type}`);

describe('a node that reads or writes several variables at once', () => {
  it('writes each variable it names and reads each one back', () => {
    const { fixture, behavior } = bothWays();
    expect(run(behavior, fixture)).toEqual({ px: 7, py: 9, sum: 16 });
  });

  it('takes the port type from the variable, so a number output stays a number', () => {
    const { fixture, behavior, get, set } = bothWays();
    fixture.stack.execute(new AddVariableCommand(behavior.id, 'alive', 'boolean'));
    fixture.stack.execute(new AddPortCommand(behavior.id, get.id, { key: 'alive', kind: 'boolean' }));
    expect(portKeys(behavior, get, 'outputs')).toEqual(['px:number', 'py:number', 'alive:boolean']);
    // The exec port is the node's own; only the variables come from the declaration.
    expect(portKeys(behavior, set, 'inputs')).toEqual(['exec:exec', 'px:number', 'py:number']);
  });

  it('follows a renamed variable, edge and all', () => {
    const { fixture, behavior, get } = bothWays();
    fixture.stack.execute(new RenameVariableCommand(behavior.id, 'px', 'column'));
    expect((get.ports ?? []).map((p) => p.key)).toEqual(['column', 'py']);
    expect(behavior.graph.edges.some((e) => e.from.node === get.id && e.from.port === 'column')).toBe(true);
    expect(run(behavior, fixture, { column: 0, py: 0, sum: 0 })).toEqual({ column: 7, py: 9, sum: 16 });

    fixture.stack.undo();
    expect((get.ports ?? []).map((p) => p.key)).toEqual(['px', 'py']);
    expect(run(behavior, fixture)).toEqual({ px: 7, py: 9, sum: 16 });
  });

  it('keeps the edge when a port is pointed at another variable', () => {
    const { fixture, behavior, get } = bothWays();
    fixture.stack.execute(new AddVariableCommand(behavior.id, 'alive', 'boolean'));
    fixture.stack.execute(
      new SetVariablePortCommand(behavior.id, get.id, 'px', { key: 'alive', kind: 'boolean' }),
    );
    expect(portKeys(behavior, get, 'outputs')).toEqual(['alive:boolean', 'py:number']);
    expect(behavior.graph.edges.some((e) => e.from.node === get.id && e.from.port === 'alive')).toBe(true);

    fixture.stack.undo();
    expect(portKeys(behavior, get, 'outputs')).toEqual(['px:number', 'py:number']);
    expect(behavior.graph.edges.some((e) => e.from.node === get.id && e.from.port === 'px')).toBe(true);
  });

  it('keeps a port whose variable was removed, so undoing the removal restores the graph', () => {
    const { fixture, behavior, get } = bothWays();
    fixture.stack.execute(new RemoveVariableCommand(behavior.id, 'px'));
    // Left standing rather than dropped: taking the port would have to take its edge too, and
    // undo could not put either back. The inspector marks it as naming no variable.
    expect((get.ports ?? []).map((p) => p.key)).toEqual(['px', 'py']);

    fixture.stack.undo();
    expect(behavior.variables.map((v) => v.key)).toEqual(['px', 'py', 'sum']);
    expect(run(behavior, fixture)).toEqual({ px: 7, py: 9, sum: 16 });
  });

  /**
   * The rule that decides how far a `Get variables` may reach: a data node answers once per pulse
   * and that answer is kept, so a single node cannot straddle a write of one of its variables – the
   * later reader would be served the value from before it. A second node is the way across.
   */
  it('answers once per pulse, so a reader past a write needs a node of its own', () => {
    const fixture = makeProject();
    const behavior = makeBehavior(fixture, 'B', ['px', 'py', 'sum', 'fresh']);
    const edit = graphEditor(fixture, behavior);
    const start = edit.addNode('OnStart');
    const early = edit.addNode(GET_VARIABLES);
    const late = edit.addNode(GET_VARIABLES);
    const write = edit.addNode(SET_VARIABLES, { px: 7 });
    const before = edit.addNode('SetVariable', { variable: 'sum' });
    const after = edit.addNode('SetVariable', { variable: 'py' });
    const again = edit.addNode('SetVariable', { variable: 'fresh' });
    for (const node of [early, late, write])
      fixture.stack.execute(new AddPortCommand(behavior.id, node.id, { key: 'px', kind: 'number' }));
    edit.wire([
      [start, 'exec', before, 'exec'],
      [before, 'exec', write, 'exec'],
      [write, 'exec', after, 'exec'],
      [after, 'exec', again, 'exec'],
      [early, 'px', before, 'value'],
      [early, 'px', after, 'value'],
      [late, 'px', again, 'value'],
    ]);
    // `py` is the point: the same node read past the write still answers 1, while `late` sees 7.
    expect(run(behavior, fixture, { px: 1, py: 0, sum: 0, fresh: 0 })).toEqual({
      px: 7,
      py: 1,
      sum: 1,
      fresh: 7,
    });
  });

  it('survives a save and load, which is what makes the pick more than a session', () => {
    const { fixture, behavior } = bothWays();
    const loaded = roundTrip(fixture.project);
    const asset = loaded.assets.find((a) => a.id === behavior.id) as BehaviorAsset;
    const set = asset.graph.nodes.find((n) => n.type === SET_VARIABLES)!;
    expect((set.ports ?? []).map((p) => `${p.key}:${p.kind}`)).toEqual(['px:number', 'py:number']);
    expect(run(asset, { project: loaded, stack: fixture.stack })).toEqual({ px: 7, py: 9, sum: 16 });
  });

  /**
   * A struct port writes the way the singular node does: the bundle it is handed is merged in, so a
   * `Pack` of one field leaves the rest standing. Tetris leans on this – each strand of `Next move`
   * packs only the field it changes and lets the plural node keep the other three.
   */
  it('merges a partial bundle into a struct variable instead of replacing it', () => {
    const fixture = makeProject();
    const behavior = makeBehavior(fixture, 'B');
    fixture.stack.execute(new AddVariableCommand(behavior.id, 'piece', 'struct'));
    for (const key of ['shape', 'rot'])
      fixture.stack.execute(new AddStructFieldCommand(behavior.id, 'piece', { key, kind: 'number' }));
    const edit = graphEditor(fixture, behavior);
    const start = edit.addNode('OnStart');
    const set = edit.addNode(SET_VARIABLES);
    const pack = edit.addNode('PackStruct', { rot: 2 });
    fixture.stack.execute(new AddPortCommand(behavior.id, set.id, { key: 'piece', kind: 'struct' }));
    fixture.stack.execute(new AddPortCommand(behavior.id, pack.id, { key: 'rot', kind: 'number' }));
    edit.wire([
      [start, 'exec', set, 'exec'],
      [pack, 'value', set, 'piece'],
    ]);

    const ctx = fakeContext({ variables: { piece: { shape: 3, rot: 0 } } });
    new GraphInterpreter(behavior.graph, behaviorLookup(fixture.project)).fire('OnStart', ctx);
    expect(ctx.variables.piece).toEqual({ shape: 3, rot: 2 });
  });

  /**
   * The other half of how far a plural node may reach: it collects every input before it writes any
   * of them, so an input fed from a variable the same node writes sees the value from before.
   */
  it('reads every input before it writes any, so a plural set cannot feed itself', () => {
    const fixture = makeProject();
    const behavior = makeBehavior(fixture, 'B', ['px', 'py']);
    const edit = graphEditor(fixture, behavior);
    const start = edit.addNode('OnStart');
    const read = edit.addNode('GetVariable', { variable: 'px' });
    const set = edit.addNode(SET_VARIABLES, { px: 7 });
    for (const key of ['px', 'py'])
      fixture.stack.execute(new AddPortCommand(behavior.id, set.id, { key, kind: 'number' }));
    edit.wire([
      [start, 'exec', set, 'exec'],
      [read, 'value', set, 'py'],
    ]);
    expect(run(behavior, fixture, { px: 1, py: 0 })).toEqual({ px: 7, py: 1 });
  });
});