import assert from "node:assert/strict";
import test from "node:test";
import { advanceGraphCamera } from "../apps/platform-web/src/screens/spatial/graph/camera.ts";

const viewport = { width: 800, height: 600 };

function wheel(overrides = {}) {
  return {
    deltaX: 0,
    deltaY: 0,
    deltaMode: 0,
    shiftKey: false,
    zoom: false,
    x: 0,
    y: 0,
    ...overrides,
  };
}

test("pans along both axes in graph-space units at the current scale", () => {
  const next = advanceGraphCamera(
    { center: { x: 3, y: -2 }, scale: 2 },
    wheel({ deltaX: 20, deltaY: -10 }),
    viewport,
  );

  assert.deepEqual(next, { center: { x: 13, y: -7 }, scale: 2 });
});

test("converts line-mode wheel deltas using sixteen pixels per line", () => {
  const next = advanceGraphCamera(
    { center: { x: 0, y: 0 }, scale: 1 },
    wheel({ deltaX: 2, deltaY: 3, deltaMode: 1 }),
    viewport,
  );

  assert.deepEqual(next, { center: { x: 32, y: 48 }, scale: 1 });
});

test("shift-wheel maps a vertical delta to horizontal panning", () => {
  const next = advanceGraphCamera(
    { center: { x: 8, y: 4 }, scale: 2 },
    wheel({ deltaY: 12, shiftKey: true }),
    viewport,
  );

  assert.deepEqual(next, { center: { x: 14, y: 4 }, scale: 2 });
});

test("zoom keeps the graph point beneath the pointer fixed", () => {
  const camera = { center: { x: 40, y: -12 }, scale: 1.25 };
  const input = wheel({ deltaY: -80, zoom: true, x: 180, y: 260 });
  const size = { width: 600, height: 500 };
  const before = {
    x: camera.center.x + (input.x - size.width / 2) / camera.scale,
    y: camera.center.y + (input.y - size.height / 2) / camera.scale,
  };

  const next = advanceGraphCamera(camera, input, size);
  const after = {
    x: next.center.x + (input.x - size.width / 2) / next.scale,
    y: next.center.y + (input.y - size.height / 2) / next.scale,
  };

  assert.ok(Math.abs(after.x - before.x) < 1e-10);
  assert.ok(Math.abs(after.y - before.y) < 1e-10);
});

test("clamps zoom to the configured minimum and viewport maximum", () => {
  const camera = { center: { x: 0, y: 0 }, scale: 1 };
  const size = { width: 800, height: 600 };
  const zoomIn = advanceGraphCamera(
    camera,
    wheel({ deltaY: -10_000, zoom: true, x: 400, y: 300 }),
    size,
  );
  const zoomOut = advanceGraphCamera(
    camera,
    wheel({ deltaY: 10_000, zoom: true, x: 400, y: 300 }),
    size,
  );

  assert.equal(zoomIn.scale, 2.4);
  assert.equal(zoomOut.scale, 0.22);
});