import Utils from './utils';

class SwiperClass {
  constructor(params = {}) {
    const self = this;
    self.params = params;

    // Events
    self.eventsListeners = {};

    if (self.params && self.params.on) {
      Object.keys(self.params.on).forEach((eventName) => {
        self.on(eventName, self.params.on[eventName]);
      });
    }
  }
  on(events, handler, priority) {
    const self = this;
    if (typeof handler !== 'function') return self;
    const method = priority ? 'unshift' : 'push';
    events.split(' ').forEach((event) => {
      if (!self.eventsListeners[event]) self.eventsListeners[event] = [];
      self.eventsListeners[event][method](handler);
    });
    return self;
  }
  once(events, handler, priority) {
    const self = this;
    if (typeof handler !== 'function') return self;
    function onceHandler(...args) {
      handler.apply(self, args);
      self.off(events, onceHandler);
    }
    return self.on(events, onceHandler, priority);
  }
  off(events, handler) {
    const self = this;
    if (!self.eventsListeners) return self;
    events.split(' ').forEach((event) => {
      if (typeof handler === 'undefined') {
        self.eventsListeners[event] = [];
      } else {
        self.eventsListeners[event].forEach((eventHandler, index) => {
          if (eventHandler === handler) {
            self.eventsListeners[event].splice(index, 1);
          }
        });
      }
    });
    return self;
  }
  emit(...args) {
    const self = this;
    if (!self.eventsListeners) return self;
    let events;
    let data;
    let context;
    if (typeof args[0] === 'string' || Array.isArray(args[0])) {
      events = args[0];
      data = args.slice(1, args.length);
      context = self;
    } else {
      events = args[0].events;
      data = args[0].data;
      context = args[0].context || self;
    }
    const eventsArray = Array.isArray(events) ? events : events.split(' ');
    eventsArray.forEach((event) => {
      if (self.eventsListeners && self.eventsListeners[event]) {
        const handlers = [];
        self.eventsListeners[event].forEach((eventHandler) => {
          handlers.push(eventHandler);
        });
        handlers.forEach((eventHandler) => {
          eventHandler.apply(context, data);
        });
      }
    });
    return self;
  }
  useModulesParams(instanceParams) {
    const instance = this;
    if (!instance.modules) return;
    Object.keys(instance.modules).forEach((moduleName) => {
      const module = instance.modules[moduleName];
      // Extend params
      if (module.params) {
        Utils.extend(instanceParams, module.params);
      }
    });
  }
  useModules(modulesParams = {}) {
    const instance = this;
    if (!instance.modules) return;
    Object.keys(instance.modules).forEach((moduleName) => {
      const module = instance.modules[moduleName];
      const moduleParams = modulesParams[moduleName] || {};
      // Extend instance methods and props
      if (module.instance) {
        Object.keys(module.instance).forEach((modulePropName) => {
          const moduleProp = module.instance[modulePropName];
          if (typeof moduleProp === 'function') {
            instance[modulePropName] = moduleProp.bind(instance);
          } else {
            instance[modulePropName] = moduleProp;
          }
        });
      }
      // Add event listeners
      if (module.on && instance.on) {
        Object.keys(module.on).forEach((moduleEventName) => {
          instance.on(moduleEventName, module.on[moduleEventName]);
        });
      }

      // Module create callback
      if (module.create) {
        module.create.bind(instance)(moduleParams);
      }
    });
  }
  static set components(components) {
    const Class = this;
    if (!Class.use) return;
    Class.use(components);
  }
  static installModule(module, ...params) {
    const Class = this;
    if (!Class.prototype.modules) Class.prototype.modules = {};
    const name = module.name || (`${Object.keys(Class.prototype.modules).length}_${Utils.now()}`);
    Class.prototype.modules[name] = module;
    // Prototype
    if (module.proto) {
      Object.keys(module.proto).forEach((key) => {
        Class.prototype[key] = module.proto[key];
      });
    }
    // Class
    if (module.static) {
      Object.keys(module.static).forEach((key) => {
        Class[key] = module.static[key];
      });
    }
    // Callback
    if (module.install) {
      module.install.apply(Class, params);
    }
    return Class;
  }
  static use(module, ...params) {
    const Class = this;
    if (Array.isArray(module)) {
      module.forEach(m => Class.installModule(m));
      return Class;
    }
    return Class.installModule(module, ...params);
  }
}

export default SwiperClass;
