// devMode.js
// Minimal, single-file dev mode with scriptable console API

/**
 * Initialize dev mode: exposes a scriptable API for stepping through state history.
 * @param {object} opts
 * @param {function} opts.getState - returns current app state
 * @param {function} opts.setState - sets app state
 * @param {function} opts.render - triggers app re-render
 */
export function initDevMode({ getState, setState, render }) {
  let history = [];
  let pointer = -1;
  let firstLoad = true;

  function pushState(state) {
    if (pointer < history.length - 1) history = history.slice(0, pointer + 1);
    history.push(clone(state));
    pointer = history.length - 1;
    logInstructions();
  }
  function goTo(idx) {
    if (idx < 0 || idx >= history.length) return;
    pointer = idx;
    setState(clone(history[pointer]));
    render();
    logInstructions();
  }
  function next() {
    if (pointer < history.length - 1) goTo(pointer + 1);
  }
  function prev() {
    if (pointer > 0) goTo(pointer - 1);
  }
  function get() {
    return history[pointer];
  }
  function clone(obj) {
    return JSON.parse(JSON.stringify(obj));
  }
  function table(obj) {
    console.table(dev.history);
  }
  function logInstructions() {
    if (firstLoad) {
      console.log('[DevMode] State history debugger');
      console.log('Usage:');
      console.log('- dev.next()   // step forward');
      console.log('- dev.prev()   // step backward');
      console.log('- dev.goTo(n)  // jump to state n (1-based)');
      console.log('- dev.get()    // get current state');
      console.log('- dev.table()  // display history as a table');
      console.log('- dev.history  // array of all states');
      console.log('- dev.pointer  // current pointer (0-based)');
      firstLoad = false;
    }
  }

  // Expose API globally for console use
  window.dev = {
    next,
    prev,
    goTo,
    get,
    table,
    get pointer() { return pointer; },
    get history() { return history.slice(); },
  };

  // Initial state
  pushState(getState());

  return { pushState };
}