html5ks.imachine = new (function () {
  "use strict";
  return {
    seen_scene: function (scene) {
      return !!html5ks.store.seen_scenes[scene];
    },
    scene_register: function (scene) {
      html5ks.store.seen_scenes[scene] = true;
    },
    start: function () {
      return this.run("imachine");
    },
    run: function (label) {
      var deferred = when.defer(),
          ilabel = typeof label === "string" ? html5ks.data.imachine[label] : label,
          i = 0,
          runInst = function () {
            var inst = ilabel[i++];
            switch (typeof inst) {
              case "undefined":
                deferred.resolve();
                break;
              case "object":
                var cmd = inst[0];
                var args = inst.slice(1);
                switch (inst[0]) {
                  case "jump_out":
                    var newlabel = args[0];
                    if (newlabel === "restart") {
                      html5ks.menu.mainMenu();
                    } else if (!html5ks.data.imachine[newlabel]) {
                      throw new Error("label does not exist");
                    } else {
                      this.run(newlabel);
                    }
                    break;
                  case "iscene":
                    this.scene_register(inst[1]);
                  case "act_op":
                    switch (inst[1]) {
                      case "op_vid1":
                        html5ks.api.movie_cutscene("op_1").then(runInst, deferred.reject);
                        break;
                      default:
                        html5ks.api[cmd].apply(html5ks.api, args).then(function () { runInst(); }, deferred.reject);
                    }
                    break;
                  case "imenu":
                    html5ks.api.iscene(args[0]).then(function (choice) {
                      this._return = choice;
                      runInst();
                    }.bind(this), console.error);
                    break;
                  case "if":
                    var cpy = inst.slice(0),
                        type = '',
                        next = null;
                    el: while (type = cpy.shift()) {
                      switch (type) {
                        case "if":
                        case "elif":
                          var cond = cpy.shift();
                          next = cpy.shift();
                          switch (cond[0]) {
                            case "_return":
                              if (this._return == cond[1]) {
                                break el;
                              }
                              break;
                            case "seen_scene":
                              if (this.seen_scene(cond[1])) {
                                break el;
                              }
                              break;
                            case "attraction_sc":
                            case "attraction_hanako":
                            case "attraction_kenji":
                              if (html5ks.store.attraction[cond[0]] > cond[1]) {
                                break el;
                              }
                              break;
                            default:
                              throw new Error("unhandled if statement");
                          }
                          break;
                        case "else":
                          next = cpy.shift();
                          break el;
                      }
                    }
                    return html5ks.imachine.run(next).then(runInst, console.error);
                  case "path_end":
                    // TODO: disp vid + add to persistent
                    deferred.resolve();
                    break;
                  default:
                    console.error("unknown imachine inst");
                    console.log(inst);
                }
            }
          }.bind(this);
      runInst();
      return deferred.promise;
    }
  };
})();