// Web Worker that renders the maraca shake by executing the MATLAB
// implementation in ../matlab through numbl. The stages run as separate
// executeCode calls so intermediates can be cached and cheap parameter
// changes skip the expensive ones:
//   solve tier   -> maraca_basis + maraca_impacts (cached on solve-tier params)
//   radiate tier -> maraca_radiate (cached on the listener and direct_gain)
//   output tier  -> maraca_output (always cheap, always re-run)
// Tensors cross the boundary as numbl RuntimeValues (column-major Float64).

import { executeCode, type RuntimeValue, type RuntimeTensor } from 'numbl';
import { hashMFiles, type MFile } from '../mfiles';
import { SOLVE_KEYS, RADIATE_KEYS, type MaracaParams } from '../params';

export interface RenderRequest {
  type: 'render';
  id: number;
  params: MaracaParams;
  quality: 'preview' | 'full';
  mfiles: MFile[];
}

export interface RenderResponse {
  type: 'result';
  id: number;
  quality: 'preview' | 'full';
  y: Float32Array;               // final signal, [-1, 1]
  sampleRate: number;
  impactT: Float32Array;         // impact times, s
  impactV: Float32Array;         // impact speeds, m/s
  impactPos: Float32Array;       // 3 x I unit positions on the shell
  rateT: Float32Array;           // expected-rate envelope, s
  rateHz: Float32Array;          // expected impacts per second
  modeF: Float32Array;           // mode frequencies, Hz
  modeL: Float32Array;           // spherical-harmonic degree of each mode
  modeZeta: Float32Array;        // damping ratio of each mode
  modeSigma: Float32Array;       // radiation efficiency of each mode
  diag: {
    modesKept: number;
    breathingHz: number;
    breathingDryHz: number;
    impactCount: number;
    meanV: number;
    maxV: number;
    meanTauUs: number;
    durationS: number;
    peakPa: number;
    peakSplDb: number;
    directPeakPa: number;
    listenerDistM: number;
    warnings: string[];
    solveMs: number;             // 0 when the cached solve was reused
    radiateMs: number;           // 0 when the cached radiation was reused
    solveCached: boolean;
    radiateCached: boolean;
    oversample: number;
  };
}

export interface ProgressMessage {
  type: 'progress';
  id: number;
  stage: 'solve' | 'radiate' | 'output';
  frac: number;
}

// Raised by a fault in the .m code (the user can edit it), so it is reported
// rather than left to stall the request.
export interface ErrorMessage {
  type: 'error';
  id: number;
  message: string;
  file?: string;
  line?: number;
}

// Impacts drawn for the raster plot. The full process runs to thousands, and
// plotting every one of them is neither visible nor worth the transfer.
const MAX_PLOT_IMPACTS = 4000;

interface SolveEntry {
  timp: RuntimeValue;
  jimp: RuntimeValue;
  tauimp: RuntimeValue;
  fimp: RuntimeValue;
  ximp: RuntimeValue;
  fsHi: number;
  impactT: Float32Array;
  impactV: Float32Array;
  impactPos: Float32Array;
  rateT: Float32Array;
  rateHz: Float32Array;
  modeF: Float32Array;
  modeL: Float32Array;
  modeZeta: Float32Array;
  modeSigma: Float32Array;
  breathingHz: number;
  breathingDryHz: number;
  impactCount: number;
  meanV: number;
  maxV: number;
  meanTauUs: number;
  durationS: number;
}

interface RadiateEntry {
  p: RuntimeValue;
  directPeakPa: number;
  listenerDistM: number;
  listenerInside: boolean;
}

// Small LRU caches so preview- and full-quality intermediates coexist. A
// radiate-tier change right after a full render then reuses the full solve,
// and the "preview" is silently upgraded to full quality.
const solveCache = new Map<string, SolveEntry>();
const radiateCache = new Map<string, RadiateEntry>();
const SOLVE_CACHE_MAX = 2;
const RADIATE_CACHE_MAX = 3;

function lruGet<T>(cache: Map<string, T>, key: string): T | undefined {
  const v = cache.get(key);
  if (v !== undefined) {
    cache.delete(key);
    cache.set(key, v);
  }
  return v;
}

function lruSet<T>(cache: Map<string, T>, key: string, value: T, max: number): void {
  cache.delete(key);
  cache.set(key, value);
  while (cache.size > max) {
    const oldest = cache.keys().next().value as string;
    cache.delete(oldest);
  }
}

function keyFor(params: MaracaParams, keys: readonly (keyof MaracaParams)[]): string {
  return keys.map((k) => String(params[k])).join('|');
}

// MATLAB source lines assigning every parameter onto a struct P.
function pLiteral(params: MaracaParams): string {
  const lines: string[] = [];
  for (const [k, v] of Object.entries(params)) {
    if (typeof v === 'number') lines.push(`P.${k} = ${v};`);
    else if (typeof v === 'boolean') lines.push(`P.${k} = ${v ? 1 : 0};`);
  }
  return lines.join('\n');
}

function runStage(mfiles: MFile[], source: string, inputs?: Record<string, RuntimeValue>) {
  return executeCode(
    source,
    { initialVariableValues: inputs, displayResults: false },
    mfiles,
    'stage.m',
  );
}

function asTensor(v: RuntimeValue): RuntimeTensor {
  const t = v as RuntimeTensor;
  if (!t || t.kind !== 'tensor') throw new Error('expected tensor result from numbl stage');
  return t;
}

function asScalar(v: RuntimeValue): number {
  if (typeof v === 'number') return v;
  const t = v as RuntimeTensor;
  if (t && t.kind === 'tensor' && t.data.length === 1) return t.data[0];
  if (typeof v === 'boolean') return v ? 1 : 0;
  throw new Error('expected scalar result from numbl stage');
}

function toF32(v: RuntimeValue): Float32Array {
  const t = asTensor(v);
  const out = new Float32Array(t.data.length);
  for (let i = 0; i < t.data.length; i++) out[i] = t.data[i];
  return out;
}

const SKIP_WARNING = /skipping (\S+\.m) \(syntax error at line (\d+)\)/;

self.onmessage = (ev: MessageEvent<RenderRequest>) => {
  const msg = ev.data;
  if (msg.type !== 'render') return;

  // numbl reports a file it could not parse through console.warn and then
  // skips it, so the failure surfaces at the call site as "Undefined
  // function". Capture the warning to report the actual syntax error instead.
  const warnings: string[] = [];
  const origWarn = console.warn;
  console.warn = (...args: unknown[]) => {
    warnings.push(args.map(String).join(' '));
  };

  try {
    render(msg);
  } catch (err) {
    // Most likely a fault in the (user-editable) .m code. Report it so the
    // request completes and the message reaches the code panel.
    const e = err as { message?: string; file?: string; line?: number };
    let m: ErrorMessage = {
      type: 'error',
      id: msg.id,
      message: e?.message ? String(e.message) : String(err),
      file: typeof e?.file === 'string' ? e.file : undefined,
      line: typeof e?.line === 'number' ? e.line : undefined,
    };
    for (const w of warnings) {
      const hit = SKIP_WARNING.exec(w);
      if (hit) {
        m = { type: 'error', id: msg.id, message: 'syntax error', file: hit[1], line: Number(hit[2]) };
        break;
      }
    }
    (self as unknown as Worker).postMessage(m);
  } finally {
    console.warn = origWarn;
  }
};

function render(msg: RenderRequest): void {
  const { id, params, mfiles } = msg;
  let quality = msg.quality;

  // The .m sources are part of the cache identity: editing the code must
  // invalidate everything computed from the previous version.
  const codeKey = hashMFiles(mfiles);
  const solveParamsKey = codeKey + '|' + keyFor(params, SOLVE_KEYS);
  const fullSolveKey = solveParamsKey + `|os=${params.oversample}`;
  if (quality === 'preview' && solveCache.has(fullSolveKey)) {
    quality = 'full'; // full-rate impact process already cached
  }

  const oversample = quality === 'preview' ? Math.min(1, params.oversample) : params.oversample;
  const fsHi = params.sample_rate * oversample;

  const post = (m: ProgressMessage) => (self as unknown as Worker).postMessage(m);

  // ---- solve stage: mode basis and the stochastic impact process ----
  const solveKey = solveParamsKey + `|os=${oversample}`;
  let solveMs = 0;
  let solveCached = true;
  let solveEntry = lruGet(solveCache, solveKey);
  if (!solveEntry) {
    solveCached = false;
    post({ type: 'progress', id, stage: 'solve', frac: 0.15 });
    const t0 = performance.now();
    const r = runStage(mfiles, `
${pLiteral(params)}
basis = maraca_basis(P);
[timp, jimp, tauimp, fimp, ximp, ginfo] = maraca_impacts(P);
modeF = basis.f;
modeL = basis.l;
modeZeta = basis.zeta;
modeSigma = basis.sigma;
breathingHz = basis.breathingHz;
breathingDryHz = basis.breathingDryHz;
impactCount = ginfo.count;
meanV = ginfo.meanV;
maxV = ginfo.maxV;
meanTauUs = ginfo.meanTauUs;
durationS = ginfo.durationS;
rateT = ginfo.rateT;
rateHz = ginfo.rateHz;
vimp = ginfo.vimp;
`);
    solveMs = performance.now() - t0;

    const impactCount = asScalar(r.variableValues.impactCount);
    const allT = toF32(r.variableValues.timp);
    const allV = toF32(r.variableValues.vimp);
    const allX = toF32(r.variableValues.ximp);
    // thin uniformly for the raster plot, keeping the time ordering
    const stride = Math.max(1, Math.ceil(impactCount / MAX_PLOT_IMPACTS));
    const nPlot = Math.ceil(impactCount / stride);
    const impactT = new Float32Array(nPlot);
    const impactV = new Float32Array(nPlot);
    const impactPos = new Float32Array(nPlot * 3);
    for (let i = 0, j = 0; j < nPlot; i += stride, j++) {
      impactT[j] = allT[i];
      impactV[j] = allV[i];
      impactPos[j * 3] = allX[i * 3];
      impactPos[j * 3 + 1] = allX[i * 3 + 1];
      impactPos[j * 3 + 2] = allX[i * 3 + 2];
    }

    solveEntry = {
      timp: r.variableValues.timp,
      jimp: r.variableValues.jimp,
      tauimp: r.variableValues.tauimp,
      fimp: r.variableValues.fimp,
      ximp: r.variableValues.ximp,
      fsHi,
      impactT,
      impactV,
      impactPos,
      rateT: toF32(r.variableValues.rateT),
      rateHz: toF32(r.variableValues.rateHz),
      modeF: toF32(r.variableValues.modeF),
      modeL: toF32(r.variableValues.modeL),
      modeZeta: toF32(r.variableValues.modeZeta),
      modeSigma: toF32(r.variableValues.modeSigma),
      breathingHz: asScalar(r.variableValues.breathingHz),
      breathingDryHz: asScalar(r.variableValues.breathingDryHz),
      impactCount,
      meanV: asScalar(r.variableValues.meanV),
      maxV: asScalar(r.variableValues.maxV),
      meanTauUs: asScalar(r.variableValues.meanTauUs),
      durationS: asScalar(r.variableValues.durationS),
    };
    lruSet(solveCache, solveKey, solveEntry, SOLVE_CACHE_MAX);
  }

  // ---- radiate stage ----
  const radiateKey = solveKey + '||' + keyFor(params, RADIATE_KEYS);
  let radiateMs = 0;
  let radiateCached = true;
  let radEntry = lruGet(radiateCache, radiateKey);
  if (!radEntry) {
    radiateCached = false;
    post({ type: 'progress', id, stage: 'radiate', frac: 0.55 });
    const t0 = performance.now();
    const r = runStage(mfiles, `
${pLiteral(params)}
basis = maraca_basis(P);
[p, radinfo] = maraca_radiate(P, basis, timp, jimp, tauimp, fimp, ximp, ${solveEntry.fsHi});
directPeakPa = radinfo.directPeakPa;
listenerDistM = radinfo.listenerDistM;
listenerInside = radinfo.listenerInside;
`, {
      timp: solveEntry.timp,
      jimp: solveEntry.jimp,
      tauimp: solveEntry.tauimp,
      fimp: solveEntry.fimp,
      ximp: solveEntry.ximp,
    });
    radiateMs = performance.now() - t0;
    radEntry = {
      p: r.variableValues.p,
      directPeakPa: asScalar(r.variableValues.directPeakPa),
      listenerDistM: asScalar(r.variableValues.listenerDistM),
      listenerInside: asScalar(r.variableValues.listenerInside) !== 0,
    };
    lruSet(radiateCache, radiateKey, radEntry, RADIATE_CACHE_MAX);
  }

  // ---- output stage ----
  post({ type: 'progress', id, stage: 'output', frac: 0.9 });
  const rOut = runStage(mfiles, `
${pLiteral(params)}
[y, peakPa] = maraca_output(P, p, ${oversample});
`, { p: radEntry.p });

  const y32 = toF32(rOut.variableValues.y);
  const peakPa = asScalar(rOut.variableValues.peakPa);

  const warnings: string[] = [];
  if (radEntry.listenerInside) {
    warnings.push(
      'the listener is at or inside the shell surface; the multipole field is evaluated at the nearest valid radius instead',
    );
  }
  if (!params.normalize) {
    let peak = 0;
    for (let i = 0; i < y32.length; i++) peak = Math.max(peak, Math.abs(y32[i]));
    if (peak > 1.0) {
      warnings.push(
        `clipping: peak is ${peakPa.toFixed(2)} Pa but full_scale_pa is ${params.full_scale_pa.toFixed(2)}`,
      );
    }
  }
  const topMode = solveEntry.modeF[solveEntry.modeF.length - 1];
  if (topMode < 0.4 * params.max_mode_hz) {
    warnings.push(
      `the highest retained mode is only ${topMode.toFixed(0)} Hz; raise max degree l to keep the shell from sounding truncated`,
    );
  }

  const resp: RenderResponse = {
    type: 'result',
    id,
    quality,
    y: y32,
    sampleRate: params.sample_rate,
    impactT: solveEntry.impactT.slice(),
    impactV: solveEntry.impactV.slice(),
    impactPos: solveEntry.impactPos.slice(),
    rateT: solveEntry.rateT.slice(),
    rateHz: solveEntry.rateHz.slice(),
    modeF: solveEntry.modeF.slice(),
    modeL: solveEntry.modeL.slice(),
    modeZeta: solveEntry.modeZeta.slice(),
    modeSigma: solveEntry.modeSigma.slice(),
    diag: {
      modesKept: solveEntry.modeF.length,
      breathingHz: solveEntry.breathingHz,
      breathingDryHz: solveEntry.breathingDryHz,
      impactCount: solveEntry.impactCount,
      meanV: solveEntry.meanV,
      maxV: solveEntry.maxV,
      meanTauUs: solveEntry.meanTauUs,
      durationS: solveEntry.durationS,
      peakPa,
      peakSplDb: 20 * Math.log10(peakPa / 20e-6 + 1e-30),
      directPeakPa: radEntry.directPeakPa,
      listenerDistM: radEntry.listenerDistM,
      warnings,
      solveMs,
      radiateMs,
      solveCached,
      radiateCached,
      oversample,
    },
  };
  (self as unknown as Worker).postMessage(resp, [
    resp.y.buffer,
    resp.impactT.buffer,
    resp.impactV.buffer,
    resp.impactPos.buffer,
    resp.rateT.buffer,
    resp.rateHz.buffer,
    resp.modeF.buffer,
    resp.modeL.buffer,
    resp.modeZeta.buffer,
    resp.modeSigma.buffer,
  ]);
}