// Web Worker that renders the pizzicato bass 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   -> bass_notes + bass_basis (one coupled eigensolve per
//                   fingering; the expensive stage, cached on the strings,
//                   the body, and the gesture's pitches)
//   radiate tier -> bass_radiate (pluck projection + closed-form synthesis +
//                   radiation; cached on the pluck, the tempo, the listener,
//                   and the synthesis rate)
//   output tier  -> bass_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, midiHz, type BassParams } from '../params';

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

export interface RenderResponse {
  type: 'result';
  id: number;
  quality: 'preview' | 'full';
  y: Float32Array;               // final signal, [-1, 1]
  sampleRate: number;
  noteT: Float32Array;           // note onsets, s
  noteMidi: Float32Array;        // pitches
  noteStr: Float32Array;         // string index, 1 = G2 .. 4 = E1
  noteStop: Float32Array;        // semitones above the open string
  noteForce: Float32Array;       // pluck forces, N
  mode1F: Float32Array;          // coupled modes of the first fingering, Hz
  mode1Zeta: Float32Array;       // their damping ratios
  mode1BodyFrac: Float32Array;   // their body-energy fraction (0 string .. 1 body)
  bodyF: Float32Array;           // the body mode table, Hz
  bodyZeta: Float32Array;
  bodyA: Float32Array;           // mass-normalized bridge amplitudes, 1/sqrt(kg)
  bodyMono: Float32Array;        // 1 = monopole (A0), 0 = dipole
  diag: {
    noteCount: number;
    fingerings: number;
    modesTotal: number;
    modesNote1: number;
    fundHz: number;
    fundT60: number;
    meanForce: number;
    durationS: number;
    peakPa: number;
    peakSplDb: number;
    listenerDistM: number;
    warnings: string[];
    solveMs: number;             // 0 when the cached eigensolves were 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;
}

// Basis fields that cross from the solve stage into the radiate stage as
// numbl RuntimeValues, plus their Float32 copies for the plots.
interface SolveEntry {
  vars: Record<string, RuntimeValue>;
  noteT: Float32Array;
  noteMidi: Float32Array;
  noteStr: Float32Array;
  noteStop: Float32Array;
  noteForce: Float32Array;
  mode1F: Float32Array;
  mode1Zeta: Float32Array;
  mode1BodyFrac: Float32Array;
  bodyF: Float32Array;
  bodyZeta: Float32Array;
  bodyA: Float32Array;
  bodyMono: Float32Array;
  fingerings: number;
  modesTotal: number;
  meanForce: number;
  durationS: number;
}

interface RadiateEntry {
  p: RuntimeValue;
  fundHz: number;
  fundT60: number;
  listenerDistM: number;
  listenerInside: boolean;
  fsHi: number;
  oversample: number;
}

// Small LRU caches. The solve cache does not depend on the oversample rate,
// so a preview render right after a full one reuses the same eigensolves.
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: BassParams, keys: readonly (keyof BassParams)[]): string {
  return keys.map((k) => String(params[k])).join('|');
}

// MATLAB source lines assigning every parameter onto a struct P.
function pLiteral(params: BassParams): 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;
}

// The basis fields handed from the solve stage into the radiate stage, in the
// order the reassembly script expects.
const BASIS_FIELDS = [
  'fIdx', 'off', 'nModes', 'pmOff', 'ns', 'Lv', 'mu', 'T', 'f0', 'str', 'stop',
  'f', 'zeta', 'Vm', 'Dd', 'Fcoef', 'ybAmp', 'bodyFrac', 'PMflat',
  'bodyF', 'bodyZeta', 'bodyA', 'bodyS', 'bodyMono',
];

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 solveKey = codeKey + '|' + keyFor(params, SOLVE_KEYS);

  const fullOversample = params.oversample;
  const radiateParamsKey = solveKey + '||' + keyFor(params, RADIATE_KEYS);
  if (quality === 'preview' && radiateCache.has(radiateParamsKey + `|os=${fullOversample}`)) {
    quality = 'full'; // full-rate radiation 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: the gesture and the coupled eigensolves ----
  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)}
[tOn, midi, str, stop, force, ninfo] = bass_notes(P);
basis = bass_basis(P, str, stop);
${BASIS_FIELDS.map((f) => `b_${f} = basis.${f};`).join('\n')}
n1 = basis.nModes(1);
mode1F = basis.f(1:n1);
mode1Zeta = basis.zeta(1:n1);
mode1BodyFrac = basis.bodyFrac(1:n1);
fingerings = basis.nf;
modesTotal = basis.n;
meanForce = ninfo.meanForce;
durationS = ninfo.durationS;
`);
    solveMs = performance.now() - t0;

    const vars: Record<string, RuntimeValue> = {};
    for (const f of BASIS_FIELDS) vars[`b_${f}`] = r.variableValues[`b_${f}`];
    solveEntry = {
      vars,
      noteT: toF32(r.variableValues.tOn),
      noteMidi: toF32(r.variableValues.midi),
      noteStr: toF32(r.variableValues.str),
      noteStop: toF32(r.variableValues.stop),
      noteForce: toF32(r.variableValues.force),
      mode1F: toF32(r.variableValues.mode1F),
      mode1Zeta: toF32(r.variableValues.mode1Zeta),
      mode1BodyFrac: toF32(r.variableValues.mode1BodyFrac),
      bodyF: toF32(r.variableValues.b_bodyF),
      bodyZeta: toF32(r.variableValues.b_bodyZeta),
      bodyA: toF32(r.variableValues.b_bodyA),
      bodyMono: toF32(r.variableValues.b_bodyMono),
      fingerings: asScalar(r.variableValues.fingerings),
      modesTotal: asScalar(r.variableValues.modesTotal),
      meanForce: asScalar(r.variableValues.meanForce),
      durationS: asScalar(r.variableValues.durationS),
    };
    lruSet(solveCache, solveKey, solveEntry, SOLVE_CACHE_MAX);
  }

  // ---- radiate stage: pluck projection + closed-form synthesis ----
  const radiateKey = radiateParamsKey + `|os=${oversample}`;
  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)}
${BASIS_FIELDS.map((f) => `basis.${f} = b_${f};`).join('\n')}
basis.nf = length(basis.off);
basis.n = length(basis.f);
[tOn, midi, str, stop, force, ninfo] = bass_notes(P);
[p, radinfo] = bass_radiate(P, basis, tOn, str, stop, force, ${fsHi});
fundHz = radinfo.fundHz;
fundT60 = radinfo.fundT60;
listenerDistM = radinfo.listenerDistM;
listenerInside = radinfo.listenerInside;
`, solveEntry.vars);
    radiateMs = performance.now() - t0;
    radEntry = {
      p: r.variableValues.p,
      fundHz: asScalar(r.variableValues.fundHz),
      fundT60: asScalar(r.variableValues.fundT60),
      listenerDistM: asScalar(r.variableValues.listenerDistM),
      listenerInside: asScalar(r.variableValues.listenerInside) !== 0,
      fsHi,
      oversample,
    };
    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] = bass_output(P, p, ${radEntry.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 within 35 cm of the bridge, inside or against the body; the field there is not free',
    );
  }
  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)}`,
      );
    }
  }
  // wolf warning: the fundamental pulled well away from equal temperament
  const target = midiHz(solveEntry.noteMidi[0]) * params.tuning_trim;
  const cents = 1200 * Math.log2(radEntry.fundHz / target);
  if (Math.abs(cents) > 35) {
    warnings.push(
      `the first note sounds ${Math.abs(cents).toFixed(0)} cents ${cents > 0 ? 'sharp' : 'flat'}: its fundamental is being pulled by a body resonance (wolf territory)`,
    );
  }

  const resp: RenderResponse = {
    type: 'result',
    id,
    quality,
    y: y32,
    sampleRate: params.sample_rate,
    noteT: solveEntry.noteT.slice(),
    noteMidi: solveEntry.noteMidi.slice(),
    noteStr: solveEntry.noteStr.slice(),
    noteStop: solveEntry.noteStop.slice(),
    noteForce: solveEntry.noteForce.slice(),
    mode1F: solveEntry.mode1F.slice(),
    mode1Zeta: solveEntry.mode1Zeta.slice(),
    mode1BodyFrac: solveEntry.mode1BodyFrac.slice(),
    bodyF: solveEntry.bodyF.slice(),
    bodyZeta: solveEntry.bodyZeta.slice(),
    bodyA: solveEntry.bodyA.slice(),
    bodyMono: solveEntry.bodyMono.slice(),
    diag: {
      noteCount: solveEntry.noteT.length,
      fingerings: solveEntry.fingerings,
      modesTotal: solveEntry.modesTotal,
      modesNote1: solveEntry.mode1F.length,
      fundHz: radEntry.fundHz,
      fundT60: radEntry.fundT60,
      meanForce: solveEntry.meanForce,
      durationS: solveEntry.durationS,
      peakPa,
      peakSplDb: 20 * Math.log10(peakPa / 20e-6 + 1e-30),
      listenerDistM: radEntry.listenerDistM,
      warnings,
      solveMs,
      radiateMs,
      solveCached,
      radiateCached,
      oversample: radEntry.oversample,
    },
  };
  (self as unknown as Worker).postMessage(resp, [
    resp.y.buffer,
    resp.noteT.buffer,
    resp.noteMidi.buffer,
    resp.noteStr.buffer,
    resp.noteStop.buffer,
    resp.noteForce.buffer,
    resp.mode1F.buffer,
    resp.mode1Zeta.buffer,
    resp.mode1BodyFrac.buffer,
    resp.bodyF.buffer,
    resp.bodyZeta.buffer,
    resp.bodyA.buffer,
    resp.bodyMono.buffer,
  ]);
}