import { parseDFF } from './rw/dff.js';
import { parseTXD } from './rw/txd.js';
import { Viewer } from './viewer.js';

const canvas = document.getElementById('view');
const statusEl = document.getElementById('status');

const viewer = new Viewer(canvas);

// The page shows nothing but the model, so a failure is the only thing worth
// putting on screen. Everything else goes to the console.
function setError(text) {
  statusEl.textContent = text || '';
  statusEl.style.display = text ? 'block' : 'none';
}

async function fetchBuffer(url) {
  const res = await fetch(url);
  if (!res.ok) throw new Error(`${res.status} fetching ${url}`);
  return res.arrayBuffer();
}

async function fetchJSON(url) {
  const res = await fetch(url);
  if (!res.ok) throw new Error(`${res.status} fetching ${url}`);
  return res.json();
}

// A vehicle clump is recognisable by its frame names: every one of them has a
// chassis and a set of wheel dummies.
function looksLikeVehicle(dff) {
  return dff.frames.some((frame) => /^(chassis|wheel_[lr][fmb]_dummy)$/i.test(frame.name));
}

// Paint comes from the url (?c1=3&c2=1, carcols palette indices, the same
// numbers ChangeVehicleColor takes) and falls back to the vehicle's first
// factory combo. An index with no entry is left for the viewer to default.
function resolvePaint(catalogue, id) {
  if (!catalogue) return null;
  const params = new URLSearchParams(location.search);
  const info = catalogue.vehicles && catalogue.vehicles[id];
  const factory = (info && info.colors && info.colors[0]) || [];

  return [0, 1, 2, 3].map((slot) => {
    const given = params.get(`c${slot + 1}`);
    const index = given !== null && given !== '' ? Number(given) : factory[slot];
    return Number.isFinite(index) ? catalogue.palette[index] || null : null;
  });
}

// Parts come from ?u=1010,1008 - component ids, the same numbers
// AddVehicleComponent takes. Fitting a left hand body kit part fits its right
// hand twin too, which is what carmods' link section is for.
async function resolveUpgrades(meta, catalogue) {
  const raw = new URLSearchParams(location.search).get('u');
  if (!raw || !catalogue || !catalogue.upgrades) return [];

  const wanted = [];
  for (const field of raw.split(',')) {
    const id = Number(field.trim());
    if (!Number.isFinite(id)) continue;
    wanted.push(id);
    if (catalogue.links[id] !== undefined) wanted.push(catalogue.links[id]);
  }

  const parts = await Promise.all(
    [...new Set(wanted)]
      .filter((id) => catalogue.upgrades[id])
      .map(async (id) => ({
        id,
        name: catalogue.upgrades[id].name,
        dff: parseDFF(await fetchBuffer(`${meta.base}/${id}.dff`)),
      }))
  );
  return parts;
}

// Paintjobs are numbered from zero, the way ChangeVehiclePaintjob counts them.
// Anything outside the vehicle's range means no paintjob, which is what 3 does
// in game.
async function fetchPaintjob(meta, catalogue, id, index) {
  const info = catalogue && catalogue.vehicles && catalogue.vehicles[id];
  if (!info || !Number.isFinite(index) || index < 0 || index >= info.paintjobs) return null;
  return parseTXD(await fetchBuffer(`${meta.base}/${id}_pj${index}.txd`));
}

function render(name, dffBuffer, txdBuffers, options = {}) {
  const dff = parseDFF(dffBuffer);
  const txds = txdBuffers.filter(Boolean).map((buffer) => parseTXD(buffer));
  const report = viewer.load(dff, txds, options);

  const textureCount = txds.reduce((total, txd) => total + txd.textures.size, 0);
  console.log(
    `${name}: rw ${dff.versionText}, ${report.meshes} mesh(es), ` +
      `${report.vertices} verts, ${report.triangles} tris, ` +
      `${textureCount} textures${options.vehicle ? ', vehicle' : ''}` +
      (options.paintjobs ? `, ${options.paintjobs} paintjob(s)` : '')
  );
  const warnings = [...dff.errors, ...txds.flatMap((txd) => txd.errors)];
  if (report.missingTextures.size) {
    warnings.push('not in txd: ' + [...report.missingTextures].join(', '));
  }
  warnings.forEach((warning) => console.warn(warning));

  setError('');
  return dff;
}

async function loadModel(kind, id) {
  try {
    const res = await fetch(`/api/${kind}/${encodeURIComponent(id)}`);
    const meta = await res.json();
    if (!res.ok) {
      setError(meta.error || `${res.status} loading ${id}`);
      return;
    }

    // The shared dictionary and the carcols catalogue are optional: a missing
    // one costs textures or factory colours, not the render.
    const [dffBuffer, txdBuffer, sharedBuffer, catalogue] = await Promise.all([
      fetchBuffer(meta.dff),
      meta.txd ? fetchBuffer(meta.txd) : null,
      meta.shared ? fetchBuffer(meta.shared).catch(() => null) : null,
      meta.meta ? fetchJSON(meta.meta).catch(() => null) : null,
    ]);

    const vehicle = kind === 'vehicle';
    const info = (vehicle && catalogue && catalogue.vehicles[id]) || null;
    const wanted = new URLSearchParams(location.search).get('pj');
    // The vehicle's own textures win over the shared ones.
    render(id, dffBuffer, [txdBuffer, sharedBuffer], {
      vehicle,
      paint: vehicle ? resolvePaint(catalogue, id) : null,
      upgrades: vehicle ? await resolveUpgrades(meta, catalogue) : null,
      wheelScale: info ? info.wheelScale : 1,
      paintjob:
        vehicle && wanted !== null && wanted !== ''
          ? await fetchPaintjob(meta, catalogue, id, Number(wanted))
          : null,
      paintjobs: info ? info.paintjobs : 0,
    });

    if (vehicle && catalogue) {
      // Repainting needs no reload, so leave the palette and the viewer within
      // reach of the console: setColors(3, 1) is ChangeVehicleColor(v, 3, 1).
      window.setColors = (...ids) =>
        viewer.setPaint(ids.map((index) => catalogue.palette[index] || null));
      window.carcols = catalogue;
      window.viewer = viewer;
      // setPaintjob(0) is ChangeVehiclePaintjob(v, 0); anything out of range
      // takes it back off, the way 3 does in game.
      window.setPaintjob = async (index) =>
        viewer.applyPaintjob(await fetchPaintjob(meta, catalogue, id, index));
      // What ?u= accepts here, as id -> part name. Wheels are listed for every
      // vehicle because any wheel fits anything.
      window.mods = Object.fromEntries(
        ((info && info.mods) || [])
          .concat(catalogue.wheels || [])
          .filter((partId) => catalogue.upgrades && catalogue.upgrades[partId])
          .map((partId) => [partId, catalogue.upgrades[partId].name])
      );
    }
  } catch (err) {
    console.error(err);
    setError(err.message);
  }
}

// Dropped vehicles get the shared dictionary fetched for them, otherwise most
// of the body renders untextured.
async function sharedVehicleTxd() {
  try {
    const meta = await fetchJSON('/api/vehicle/411');
    return meta.shared ? await fetchBuffer(meta.shared) : null;
  } catch {
    return null;
  }
}

function setupDragAndDrop() {
  document.body.addEventListener('dragover', (e) => {
    e.preventDefault();
    document.body.classList.add('dragging');
  });
  document.body.addEventListener('dragleave', () => document.body.classList.remove('dragging'));
  document.body.addEventListener('drop', async (e) => {
    e.preventDefault();
    document.body.classList.remove('dragging');
    const files = [...e.dataTransfer.files];
    const dffFile = files.find((f) => f.name.toLowerCase().endsWith('.dff'));
    const txdFiles = files.filter((f) => f.name.toLowerCase().endsWith('.txd'));
    if (!dffFile) {
      setError('drop a .dff (and its .txd) together');
      return;
    }
    try {
      const name = dffFile.name.replace(/\.dff$/i, '');
      const dffBuffer = await dffFile.arrayBuffer();
      const txdBuffers = await Promise.all(txdFiles.map((f) => f.arrayBuffer()));

      const vehicle = looksLikeVehicle(parseDFF(dffBuffer));
      if (vehicle && txdBuffers.length < 2) txdBuffers.push(await sharedVehicleTxd());

      render(name, dffBuffer, txdBuffers, { vehicle });
    } catch (err) {
      console.error(err);
      setError(err.message);
    }
  });
}

setupDragAndDrop();

const match = location.pathname.match(/^\/samp\/(skin|vehicle)\/(.+)$/);
if (match) loadModel(match[1], decodeURIComponent(match[2]));