feat(qr-scanner): add QRScanner plugin

closes #715

src/@ionic-native/plugins/qr-scanner/index.ts

@@ -0,0 +1,228 @@
+import { Plugin, IonicNativePlugin, Cordova } from '@ionic-native/core';
+import { Injectable } from '@angular/core';
+import { Observable } from 'rxjs/Observable';
+
+export interface QRScannerStatus {
+  /**
+   * On iOS and Android 6.0+, camera access is granted at runtime by the user (by clicking "Allow" at the dialog).
+   * The authorized property is a boolean value which is true only when the user has allowed camera access to your app (AVAuthorizationStatus.Authorized).
+   * On platforms with permissions granted at install (Android pre-6.0, Windows Phone) this property is always true.
+   */
+  authorized: boolean;
+  /**
+   * A boolean value which is true if the user permanently denied camera access to the app (AVAuthorizationStatus.Denied).
+   * Once denied, camera access can only be gained by requesting the user change their decision (consider offering a link to the setting via openSettings()).
+   */
+  denied: boolean;
+  /**
+   * A boolean value which is true if the user is unable to grant permissions due to parental controls, organization security configuration profiles, or similar reasons.
+   */
+  restricted: boolean;
+  /**
+   * A boolean value which is true if QRScanner is prepared to capture video and render it to the view.
+   */
+  prepared: boolean;
+  /**
+   * A boolean value which is true when the preview layer is visible (and on all platforms but browser, the native webview background is transparent).
+   */
+  showing: boolean;
+  /**
+   * A boolean value which is true if QRScanner is actively scanning for a QR code.
+   */
+  scanning: boolean;
+  /**
+   * A boolean value which is true if QRScanner is displaying a live preview from the device's camera. Set to false when the preview is paused.
+   */
+  previewing: boolean;
+  /**
+   * A boolean value which is true if the light is enabled.
+   */
+  lightEnabled: boolean;
+  /**
+   * A boolean value which is true only if the users' operating system is able to QRScanner.openSettings().
+   */
+  canOpenSettings: boolean;
+  /**
+   * A boolean value which is true only if the users' device can enable a light in the direction of the currentCamera.
+   */
+  canEnableLight: boolean;
+  /**
+   * A boolean value which is true only if the current device "should" have a front camera.
+   * The camera may still not be capturable, which would emit error code 3, 4, or 5 when the switch is attempted.
+   * (On the browser platform, this value is false until the prepare method is called.)
+   */
+  canChangeCamera: boolean;
+  /**
+   * A number representing the index of the currentCamera. 0 is the back camera, 1 is the front.
+   */
+  currentCamera: number;
+}
+
+/**
+ * @name QR Scanner
+ * @description
+ *
+ * @usage
+ * ```typescript
+ * import { QRScanner, QRScannerStatus } from '@ionic-native/qr-scanner';
+ *
+ *
+ * constructor(private qrScanner: QRScanner) { }
+ *
+ * ...
+ *
+ * // Optionally request the permission early
+ * this.qrScanner.prepare()
+ *   .then((status: QRScannerStatus) => {
+ *      if (status.authorized) {
+ *        // camera permission was granted
+ *
+ *
+ *        // start scanning
+ *        let scanSub = this.qrScanner.scan().subscribe((text: string) => {
+ *          console.log('Scanned something', text);
+ *
+ *          this.qrScanner.hide(); // hide camera preview
+ *          scanSub.unsubscribe(); // stop scanning
+ *        });
+ *
+ *        // show camera preview
+ *        this.qrScanner.show();
+ *
+ *        // wait for user to scan something, then the observable callback will be called
+ *
+ *      } else if (status.denied) {
+ *        // camera permission was permanently denied
+ *        // you must use QRScanner.openSettings() method to guide the user to the settings page
+ *        // then they can grant the permission from there
+ *      } else {
+ *        // permission was denied, but not permanently. You can ask for permission again at a later time.
+ *      }
+ *   })
+ *   .catch((e: any) => console.log('Error is', e));
+ *
+ *
+ * ```
+ * @interfaces
+ * QRScannerStatus
+ */
+@Plugin({
+  pluginName: 'QRScanner',
+  plugin: 'cordova-plugin-qrscanner',
+  pluginRef: 'QRScanner',
+  repo: 'https://github.com/bitpay/cordova-plugin-qrscanner',
+  platforms: ['Android', 'Browser', 'iOS', 'Windows']
+})
+@Injectable()
+export class QRScanner extends IonicNativePlugin {
+
+  /**
+   * Request permission to use QR scanner.
+   * @return {Promise<QRScannerStatus>}
+   */
+  @Cordova({
+    callbackStyle: 'node'
+  })
+  prepare(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Call this method to enable scanning. You must then call the `show` method to make the camera preview visible.
+   * @return {Observable<string>} returns an Observable that emits the scanned text. Unsubscribe from the observable to stop scanning.
+   */
+  @Cordova({
+    callbackStyle: 'node',
+    observable: true,
+    clearFunction: 'cancelScan'
+  })
+  scan(): Observable<string> { return; }
+
+  /**
+   * Configures the native webview to have a transparent background, then sets the background of the <body> and <html> DOM elements to transparent, allowing the webview to re-render with the transparent background.
+   * @returns {Promise<QRScannerStatus>}
+   */
+  @Cordova()
+  show(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Configures the native webview to be opaque with a white background, covering the video preview.
+   * @returns {Promise<QRScannerStatus>}
+   */
+  @Cordova()
+  hide(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Enable the device's light (for scanning in low-light environments).
+   * @returns {Promise<QRScannerStatus>}
+   */
+  @Cordova({
+    callbackStyle: 'node'
+  })
+  enableLight(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Disable the device's light.
+   * @return {Promise<QRScannerStatus>}
+   */
+  @Cordova({
+    callbackStyle: 'node'
+  })
+  disableLight(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Use front camera
+   * @return {Promise<QRScannerStatus>}
+   */
+  @Cordova({
+    callbackStyle: 'node'
+  })
+  useFrontCamera(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Use back camera
+   * @return {Promise<QRScannerStatus>}
+   */
+  @Cordova({
+    callbackStyle: 'node'
+  })
+  useBackCamera(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Set camera to be used.
+   * @param camera {number} Provide `0` for back camera, and `1` for front camera.
+   * @return {Promise<QRScannerStatus>}
+   */
+  @Cordova({
+    callbackStyle: 'node'
+  })
+  useCamera(camera: number): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Pauses the video preview on the current frame and pauses scanning.
+   * @return {Promise<QRScannerStatus>}
+   */
+  @Cordova()
+  pausePreview(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Resumse the video preview and resumes scanning.
+   * @return {Promise<QRScannerStatus>}
+   */
+  @Cordova()
+  resumePreview(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Returns permission status
+   * @return {Promise<QRScannerStatus>}
+   */
+  @Cordova()
+  getStatus(): Promise<QRScannerStatus> { return; }
+
+  /**
+   * Opens settings to edit app permissions.
+   */
+  @Cordova({
+    sync: true
+  })
+  openSettings(): void {}
+
+}