var NfcTechDemo = {
  init: function nd_init() {
    dump('NfcTechDemo init');
    var content = document.getElementById('content');
    var errorMsg = document.getElementById('error-message');

    var nfc = window.navigator.mozNfc;
    if (!nfc) {
      errorMsg.textContent = 'NFC API not available.';
      return;
    }

    if (!nfc.enabled) {
      errorMsg.textContent = 'NFC is not enabled.';
      return;
    }

    document.getElementById('isoDep-container').hidden = true;
    document.getElementById('nfcA-container').hidden = true;

    nfc.ontagfound = this.handleTagFound.bind(this);
    nfc.ontaglost = this.handleTagLost.bind(this);
  },

  handleTagFound: function nd_handleTagFound(event) {
    // clear success/error message.
    var errorMsg = document.getElementById('error-message');
    errorMsg.textContent = '';
    var sucMsg = document.getElementById('success-message');
    sucMsg.textContent = '';

    document.getElementById('isoDep-container').hidden = true;
    document.getElementById('nfcA-container').hidden = true;

    var tag = event.tag;
    var tagContainer = document.getElementById('tag-container');
    var techList = tagContainer.querySelector('[data-type="tech-list"]');
    techList.textContent = tag.techList || 'null';

    if (tag.techList.indexOf('ISO-DEP') != -1) {
      this.processIsoDep(tag);
      sucMsg.textContent = 'transceive ISO-DEP succeeds.';
    } else if (tag.techList.indexOf('NFC-A') != -1 && tag.type) {
      this.processNfcA(tag);
      sucMsg.textContent = 'transceive NFCA succeeds.';
    }

    return false;
  },

  handleTagLost: function nd_handleTagLost() {
  },

  processIsoDep: function nd_processIsoDep(tag) {
    var container = document.getElementById('isoDep-container');
    container.hidden = false;
    var isoDep = tag.selectTech('ISO-DEP');
    this.getVersion(isoDep, container).then(
      () => { return this.getKeyInfo(isoDep, container); });
  },

  processNfcA: function nd_processNfcA(tag) {
    document.getElementById('nfcA-container').hidden = false;
    var container;
    var nfcA = tag.selectTech('NFC-A');

    if (tag.type.toLowerCase() === "type2") {
      document.getElementById('type1-container').hidden = true;
      document.getElementById('type2-container').hidden = false;

      container = document.getElementById('type2-container');
      container.querySelector('[data-type="tag-type"]').textContent = tag.type;

      this.write1BlockType2(nfcA, container).
        then(this.read4BlocksType2(nfcA, container));
    } else if (tag.type.toLowerCase() === "type1") {
      document.getElementById('type1-container').hidden = false;
      document.getElementById('type2-container').hidden = true;

      container = document.getElementById('type1-container');
      container.querySelector('[data-type="tag-type"]').textContent = tag.type;

      this.getUIDType1(nfcA, container);
    }

  },

  getVersion: function nd_getVersion(isoDep, container) {
    var ndefHelper = new NDEFHelper();
    return new Promise((resolve, reject) => {
      isoDep.transceive(new Uint8Array([0x90, 0x60, 0x00, 0x00, 0x00])).
        then(response => {
          container.querySelector('[data-type="hw-vendor-id"]').textContent =
            response[0].toString(16);
          container.querySelector('[data-type="hw-type"]').textContent =
            response[1].toString(16) + '.' + response[2].toString(16);
          container.querySelector('[data-type="hw-version"]').textContent =
            response[3].toString(16) + '.' + response[4].toString(16);
          container.querySelector('[data-type="hw-storage"]').textContent =
            1 << (response[5] >> 1);
          container.querySelector('[data-type="hw-protocol"]').textContent =
            response[6].toString(16);
          // Assuming the status code is 0x91, 0xaf,
          // sending 0xaf to get additional info.
          return isoDep.transceive(new Uint8Array([0x90, 0xaf, 0x00, 0x00, 0x00])); }).
        then(response => {
          container.querySelector('[data-type="sw-vendor-id"]').textContent =
            response[0].toString(16);
          container.querySelector('[data-type="sw-type"]').textContent =
            response[1].toString(16) + '.' + response[2].toString(16);
          container.querySelector('[data-type="sw-version"]').textContent =
            response[3].toString(16) + '.' + response[4].toString(16);
          container.querySelector('[data-type="sw-storage"]').textContent =
            1 << (response[5] >> 1);
          container.querySelector('[data-type="sw-protocol"]').textContent =
            response[6].toString(16);
          // Assuming the status code is 0x91, 0xaf,
          // sending 0xaf to get additional info.
          return isoDep.transceive(new Uint8Array([0x90, 0xaf, 0x00, 0x00, 0x00])); }).
        then(response => {
          // Assuming it uses 7 bytes UID, if a random ID is used, it will be of
          // 4 bytes.
          container.querySelector('[data-type="uid"]').textContent =
            ndefHelper.dumpUint8Array(response.subarray(0, 7));
          container.querySelector('[data-type="batch-num"]').textContent =
            ndefHelper.dumpUint8Array(response.subarray(7, 12));
          container.querySelector('[data-type="production-date"]').textContent =
            'Week ' + response[12].toString(16) + '/ 20' + response[13].toString(16);
          resolve();
        });
    });
  },

  getKeyInfo: function nd_getKeyInfo(isoDep, container) {
    return new Promise((resolve, reject) => {
      isoDep.transceive(new Uint8Array([0x90, 0x45, 0x00, 0x00, 0x00])).
        then(response => {
          container.querySelector('[data-type="key-settings"]').textContent =
            response[0].toString(16);
          container.querySelector('[data-type="max-keys"]').textContent =
            response[1].toString(16);
          return isoDep.transceive(new Uint8Array([0x90, 0x64, 0x00, 0x00, 0x01, 0x00, 0x00])); }).
        then(response => {
          container.querySelector('[data-type="key-version"]').textContent =
            response[0].toString(16);
          resolve();
        });
    });
  },

  read4BlocksType2: function nd_read4BlocksType2(nfcA, container) {
    return new Promise((resolve, reject) => {
      var command = new Uint8Array([0x30, 0x05]);
      nfcA.transceive(command).
        then(response => {
          var ndefHelper = new NDEFHelper();
          container.querySelector('[data-type="read"]').textContent =
          ndefHelper.dumpUint8Array(response);
          resolve();
        });
    });
  },

  write1BlockType2: function nd_write1BlockType2(nfcA, container) {
    return new Promise((resolve, reject) => {
      var command = new Uint8Array([0xA2, 0x05, 0x01, 0x02, 0x03, 0x04]);
      nfcA.transceive(command).
        then(response => {
          var ndefHelper = new NDEFHelper();
          container.querySelector('[data-type="write"]').textContent =
          ndefHelper.dumpUint8Array(command.subarray(2,6));
          resolve();
        });
    });
  },

  getUIDType1: function nd_getUIDType1(nfcA, container) {
    return new Promise((resolve, reject) => {
      var command = new Uint8Array([0x78, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]);
      nfcA.transceive(command).
        then(response => {
          container.querySelector('[data-type="hr0"]').textContent =
          response[0].toString(16);
          container.querySelector('[data-type="hr1"]').textContent =
          response[1].toString(16);
          container.querySelector('[data-type="uid0"]').textContent =
          response[2].toString(16);
          container.querySelector('[data-type="uid1"]').textContent =
          response[3].toString(16);
          container.querySelector('[data-type="uid2"]').textContent =
          response[4].toString(16);
          container.querySelector('[data-type="uid3"]').textContent =
          response[5].toString(16);
          resolve();
        });
    });
  },

};
window.addEventListener('load', () => NfcTechDemo.init());