import { DenseNetwork } from './network.js';

/** Gated action residuals. Ordinary movement uses the frozen base. */
export class MovementNetwork {
  constructor(manifest, base, adapter, jumpAdapter=null) {
    if (!['superhq-motion-gated-v1','superhq-motion-branched-v1'].includes(manifest.format) || manifest.input_width !== 48 ||
        manifest.output_width !== 143 || manifest.gate_indices?.join(',') !== '34,35,36,37' ||
        base.layers[0].inputs !== 34 || adapter.layers[0].inputs !== 48 ||
        base.layers.at(-1).outputs !== 143 || adapter.layers.at(-1).outputs !== 143) {
      throw new Error('Invalid movement action network contract.');
    }
    this.base = base;
    this.adapter = adapter;
    this.branched=manifest.format==='superhq-motion-branched-v1';this.jumpAdapter=jumpAdapter;
    if(this.branched&&(!jumpAdapter||jumpAdapter.layers[0].inputs!==48||jumpAdapter.layers.at(-1).outputs!==143))throw Error('Missing jump residual.');
    this.output = new Float32Array(143);
  }

  forward(input) {
    if (!(input instanceof Float32Array) || input.length !== 48 || !input.every(Number.isFinite)) {
      throw new Error('Expected 48 finite action features.');
    }
    const gate = Math.max(0, Math.min(1, input[34] + input[35] + input[36] + input[37]));
    if(this.branched&&(Array.from(input.subarray(34,38)).some(v=>v<0||v>1)||(input[34]>0&&input.subarray(35,38).some(v=>v>0))))throw Error('Stance and jump gates must be exclusive.');
    this.output.set(this.base.forward(input.subarray(0, 34)));
    if (gate > 0) {
      const delta = (this.branched&&input[34]===0?this.jumpAdapter:this.adapter).forward(input);
      for (let i = 0; i < this.output.length; i++) this.output[i] += gate * delta[i];
    }
    if (!this.output.every(Number.isFinite)) throw new Error('Nonfinite movement prediction.');
    return this.output;
  }

  static async load(baseUrl,{fetch:fetcher=globalThis.fetch}={}) {
    const root = new URL(baseUrl, globalThis.location?.href);
    const request = async url => {
      const response = await fetcher(url);
      if (!response.ok) throw new Error(`Movement asset failed (${response.status}).`);
      return response;
    };
    const manifest = await (await request(new URL('movement.json', root))).json();
    if (manifest.base !== 'base/' || manifest.adapter !== 'adapter/') throw new Error('Invalid action asset paths.');
    if(manifest.format==='superhq-motion-branched-v1'&&manifest.jump_adapter!=='jump/')throw Error('Invalid jump asset path.');
    const load = async name => {
      const folder = new URL(name, root);
      const data = await (await request(new URL('network.json', folder))).json();
      if (data.weights !== 'weights.bin') throw new Error('Invalid weight path.');
      const buffer = await (await request(new URL(data.weights, folder))).arrayBuffer();
      const digest = await crypto.subtle.digest('SHA-256', buffer);
      const hash = Array.from(new Uint8Array(digest), b => b.toString(16).padStart(2, '0')).join('');
      if (hash !== data.sha256) throw new Error('Movement weight checksum differs.');
      return new DenseNetwork(data, buffer);
    };
    const [base, adapter,jump] = await Promise.all([load(manifest.base), load(manifest.adapter),manifest.jump_adapter?load(manifest.jump_adapter):null]);
    return new MovementNetwork(manifest, base, adapter,jump);
  }
}