import assert from "node:assert/strict";
import fs from "node:fs";
import factory from "../../web/app/src/vendor/blender/web_engine.js";

const root = new URL("../../", import.meta.url);
const golden = JSON.parse(fs.readFileSync(new URL("tests/golden/M9-12/weight-paint.json", root), "utf8"));
const fixture = fs.readFileSync(new URL(`tests/files/web/${golden.fixture}`, root));
const wasmBinary = fs.readFileSync(new URL("web/app/src/vendor/blender/web_engine.wasm", root));

function call(engine, handle, name, payload) {
  const bytes = new TextEncoder().encode(JSON.stringify(payload));
  const pointer = engine._malloc(bytes.byteLength);
  try {
    engine.HEAPU8.set(bytes, pointer);
    assert.equal(engine._web_engine_apply_command(handle, pointer, bytes.byteLength), 0,
      `${name}: ${engine.UTF8ToString(engine._web_engine_last_error_message())}`);
  }
  finally {
    engine._free(pointer);
  }
}

function open(engine, handle, bytes) {
  const pointer = engine._malloc(bytes.byteLength);
  try {
    engine.HEAPU8.set(bytes, pointer);
    assert.equal(engine._web_engine_open_blend(handle, pointer, bytes.byteLength), 0,
      engine.UTF8ToString(engine._web_engine_last_error_message()));
  }
  finally {
    engine._free(pointer);
  }
}

function snapshot(engine, handle) {
  const dataOut = engine._malloc(4);
  const lengthOut = engine._malloc(4);
  try {
    assert.equal(engine._web_engine_get_scene_snapshot(handle, dataOut, lengthOut), 0);
    const pointer = engine.HEAPU32[dataOut >>> 2];
    const length = engine.HEAPU32[lengthOut >>> 2];
    return JSON.parse(new TextDecoder().decode(engine.HEAPU8.slice(pointer, pointer + length)));
  }
  finally {
    engine._free(dataOut);
    engine._free(lengthOut);
  }
}

function save(engine, handle) {
  const dataOut = engine._malloc(4);
  const lengthOut = engine._malloc(4);
  try {
    assert.equal(engine._web_engine_save_blend(handle, dataOut, lengthOut), 0);
    const pointer = engine.HEAPU32[dataOut >>> 2];
    const length = engine.HEAPU32[lengthOut >>> 2];
    const bytes = engine.HEAPU8.slice(pointer, pointer + length);
    engine._web_engine_free_buffer(pointer);
    return bytes;
  }
  finally {
    engine._free(dataOut);
    engine._free(lengthOut);
  }
}

function weightsByVertex(snapshotValue) {
  const mesh = snapshotValue.meshes.find((item) => item.id === `mesh:${golden.mesh}`);
  assert.ok(mesh?.skinWeights, "weight golden mesh has no skinWeights");
  return golden.steps[0].vertices.map((expectedVertex) => {
    const result = {};
    for (const [groupIndex, groupName] of mesh.skinWeights.boneNames.entries()) {
      const offset = expectedVertex.index * 4;
      const slot = mesh.skinWeights.indices.slice(offset, offset + 4).findIndex((value) => value === groupIndex);
      result[groupName] = slot < 0 ? 0 : mesh.skinWeights.weights[offset + slot];
    }
    return result;
  });
}

function compareStep(actualSnapshot, expected, label) {
  const actual = weightsByVertex(actualSnapshot);
  assert.deepEqual(actual.map((weights) => Object.keys(weights).sort()), expected.vertices.map(() => expected.groups.slice().sort()), `${label} group schema`);
  expected.vertices.forEach((vertex, index) => {
    for (const group of expected.groups) {
      const error = Math.abs((actual[index][group] ?? 0) - (vertex.weights[group] ?? 0));
      assert.ok(error <= golden.tolerance, `${label} vertex=${vertex.index} group=${group} error=${error}`);
    }
  });
}

const engine = await factory({ wasmBinary: wasmBinary.slice() });
const handle = engine._web_engine_create();
assert.ok(handle > 0);
try {
  open(engine, handle, fixture);
  call(engine, handle, "initial", { type: "setVertexWeights", objectId: `object:${golden.object}`, vertexGroup: "WebPaintGroup", indices: [0, 1], values: [0.75, 0.25] });
  compareStep(snapshot(engine, handle), golden.steps[0], "initial");
  call(engine, handle, "normalize", { type: "setVertexWeights", objectId: `object:${golden.object}`, vertexGroup: "WebPaintGroup", indices: [2], values: [0.5], normalize: true });
  compareStep(snapshot(engine, handle), golden.steps[1], "normalize");
  call(engine, handle, "limit-normalize", { type: "setVertexWeights", objectId: `object:${golden.object}`, vertexGroup: "WebPaintGroup", indices: [3], values: [0.4], limit: 2, normalize: true });
  compareStep(snapshot(engine, handle), golden.steps[2], "limit-normalize");
  call(engine, handle, "mirror", { type: "setVertexWeights", objectId: `object:${golden.object}`, vertexGroup: "WebPaintGroup", indices: [0], values: [0.9], mirror: true, mirrorAxis: 0, mirrorTolerance: 1e-4 });
  compareStep(snapshot(engine, handle), golden.steps[3], "mirror");
  const saved = save(engine, handle);
  const reopened = engine._web_engine_create();
  try {
    open(engine, reopened, saved);
    compareStep(snapshot(engine, reopened), golden.steps[3], "save-reopen");
  }
  finally {
    engine._web_engine_destroy(reopened);
  }
}
finally {
  engine._web_engine_destroy(handle);
}

process.stdout.write(`weight-paint-golden-ok fixture=${golden.fixture} steps=${golden.steps.map((step) => step.name).join(",")} normalize=passed limit=passed mirror=passed save-reopen=passed\n`);