// sei.js
// Signal Ecology Integration (SEI)
// Deterministic ecological index for Meaning Units (MU)

const fs = require('fs');
const path = require('path');

const SEI_PATH = path.join(__dirname, 'sei.json');

// Ensure SEI index exists
function ensureSEI() {
  if (!fs.existsSync(SEI_PATH)) {
    fs.writeFileSync(SEI_PATH, JSON.stringify({
      seiVersion: "v0.1",
      species: []
    }, null, 2));
  }
}

// Register MU as a species in the ecology
function registerSpecies(mu) {
  ensureSEI();

  const sei = JSON.parse(fs.readFileSync(SEI_PATH, 'utf8'));

  // Species entry (deterministic, no semantics)
  const speciesEntry = {
    id: mu.id,
    length: mu.payload.length,
    type: mu.payload.type,
    compiledAt: mu.compiledAt,
    ecologicalClass: "meaning-unit",   // substrate-level class
    driftPotential: 0,                 // DSLO v0: no drift allowed
    stability: "deterministic"
  };

  sei.species.push(speciesEntry);

  fs.writeFileSync(SEI_PATH, JSON.stringify(sei, null, 2));

  return sei;
}

module.exports = { registerSpecies };