refactor(platform): replace platform checks with capability-based system

- Add PlatformCapabilities interface to define available features
- Remove isWeb(), isCapacitor(), isElectron(), isPyWebView() methods
- Update platform services to implement getCapabilities()
- Refactor DataExportSection to use capability checks instead of platform checks
- Improve platform abstraction and separation of concerns
- Make platform-specific logic more maintainable and extensible

This change decouples components from specific platform implementations,
making the codebase more maintainable and easier to extend with new platforms.

src/components/DataExportSection.vue

@@ -42,17 +42,17 @@
     >
       If no download happened yet, click again here to download now.
     </a>
-    <div class="mt-4" v-if="showPlatformInstructions">
+    <div class="mt-4" v-if="platformCapabilities.needsFileHandlingInstructions">
       <p>
         After the download, you can save the file in your preferred storage
         location.
       </p>
       <ul>
-        <li v-if="platformService.isCapacitor() && isIOS" class="list-disc list-outside ml-4">
+        <li v-if="platformCapabilities.isIOS" class="list-disc list-outside ml-4">
           On iOS: Choose "More..." and select a place in iCloud, or go "Back"
           and save to another location.
         </li>
-        <li v-if="platformService.isCapacitor() && !isIOS" class="list-disc list-outside ml-4">
+        <li v-if="platformCapabilities.isMobile && !platformCapabilities.isIOS" class="list-disc list-outside ml-4">
           On Android: Choose "Open" and then share
           <font-awesome icon="share-nodes" class="fa-fw" />
           to your prefered place.
@@ -68,7 +68,7 @@ import { NotificationIface } from "../constants/app";
 import { db } from "../db/index";
 import { logger } from "../utils/logger";
 import { PlatformServiceFactory } from "../services/PlatformServiceFactory";
-import { PlatformService } from "../services/PlatformService";
+import { PlatformService, PlatformCapabilities } from "../services/PlatformService";
 
 /**
  * @vue-component
@@ -103,17 +103,10 @@ export default class DataExportSection extends Vue {
   private platformService: PlatformService = PlatformServiceFactory.getInstance();
 
   /**
-   * Whether the current platform is iOS
+   * Platform capabilities for the current platform
    */
-  private get isIOS(): boolean {
-    return /iPad|iPhone|iPod/.test(navigator.userAgent);
-  }
-
-  /**
-   * Whether to show platform-specific instructions
-   */
-  private get showPlatformInstructions(): boolean {
-    return this.platformService.isCapacitor();
+  private get platformCapabilities(): PlatformCapabilities {
+    return this.platformService.getCapabilities();
   }
 
   /**
@@ -121,7 +114,7 @@ export default class DataExportSection extends Vue {
    * Revokes object URL when component is unmounted (web platform only)
    */
   beforeUnmount() {
-    if (this.downloadUrl && this.platformService.isWeb()) {
+    if (this.downloadUrl && this.platformCapabilities.hasFileDownload) {
       URL.revokeObjectURL(this.downloadUrl);
     }
   }
@@ -139,7 +132,7 @@ export default class DataExportSection extends Vue {
       const blob = await db.export({ prettyJson: true });
       const fileName = `${db.name}-backup.json`;
 
-      if (this.platformService.isWeb()) {
+      if (this.platformCapabilities.hasFileDownload) {
         // Web platform: Use download link
         this.downloadUrl = URL.createObjectURL(blob);
         const downloadAnchor = this.$refs.downloadLink as HTMLAnchorElement;
@@ -147,13 +140,10 @@ export default class DataExportSection extends Vue {
         downloadAnchor.download = fileName;
         downloadAnchor.click();
         setTimeout(() => URL.revokeObjectURL(this.downloadUrl), 1000);
-      } else if (this.platformService.isCapacitor()) {
-        // Capacitor platform: Write to app directory
+      } else if (this.platformCapabilities.hasFileSystem) {
+        // Native platform: Write to app directory
         const content = await blob.text();
         await this.platformService.writeFile(fileName, content);
-      } else {
-        // Other platforms: Use platform service
-        await this.platformService.writeFile(fileName, await blob.text());
       }
 
       this.$notify(
@@ -161,7 +151,7 @@ export default class DataExportSection extends Vue {
           group: "alert",
           type: "success",
           title: "Export Successful",
-          text: this.platformService.isWeb()
+          text: this.platformCapabilities.hasFileDownload
             ? "See your downloads directory for the backup. It is in the Dexie format."
             : "The backup has been saved to your device.",
         },
@@ -187,7 +177,7 @@ export default class DataExportSection extends Vue {
    */
   public computedStartDownloadLinkClassNames() {
     return {
-      hidden: this.downloadUrl && this.platformService.isWeb(),
+      hidden: this.downloadUrl && this.platformCapabilities.hasFileDownload,
     };
   }
 
@@ -197,7 +187,7 @@ export default class DataExportSection extends Vue {
    */
   public computedDownloadLinkClassNames() {
     return {
-      hidden: !this.downloadUrl || !this.platformService.isWeb(),
+      hidden: !this.downloadUrl || !this.platformCapabilities.hasFileDownload,
     };
   }
 }

src/services/PlatformService.ts

@@ -9,13 +9,38 @@ export interface ImageResult {
   fileName: string;
 }
 
+/**
+ * Platform capabilities interface defining what features are available
+ * on the current platform implementation
+ */
+export interface PlatformCapabilities {
+  /** Whether the platform supports native file system access */
+  hasFileSystem: boolean;
+  /** Whether the platform supports native camera access */
+  hasCamera: boolean;
+  /** Whether the platform is a mobile device */
+  isMobile: boolean;
+  /** Whether the platform is iOS specifically */
+  isIOS: boolean;
+  /** Whether the platform supports native file download */
+  hasFileDownload: boolean;
+  /** Whether the platform requires special file handling instructions */
+  needsFileHandlingInstructions: boolean;
+}
+
 /**
  * Platform-agnostic interface for handling platform-specific operations.
  * Provides a common API for file system operations, camera interactions,
- * platform detection, and deep linking across different platforms
- * (web, mobile, desktop).
+ * and platform detection across different platforms (web, mobile, desktop).
  */
 export interface PlatformService {
+  // Platform capabilities
+  /**
+   * Gets the current platform's capabilities
+   * @returns Object describing what features are available on this platform
+   */
+  getCapabilities(): PlatformCapabilities;
+
   // File system operations
   /**
    * Reads the contents of a file at the specified path.
@@ -59,32 +84,6 @@ export interface PlatformService {
    */
   pickImage(): Promise<ImageResult>;
 
-  // Platform specific features
-  /**
-   * Checks if the current platform is Capacitor (mobile).
-   * @returns true if running on Capacitor
-   */
-  isCapacitor(): boolean;
-
-  /**
-   * Checks if the current platform is Electron (desktop).
-   * @returns true if running on Electron
-   */
-  isElectron(): boolean;
-
-  /**
-   * Checks if the current platform is PyWebView.
-   * @returns true if running on PyWebView
-   */
-  isPyWebView(): boolean;
-
-  /**
-   * Checks if the current platform is web browser.
-   * @returns true if running in a web browser
-   */
-  isWeb(): boolean;
-
-  // Deep linking
   /**
    * Handles deep link URLs for the application.
    * @param url - The deep link URL to handle

src/services/platforms/CapacitorPlatformService.ts

@@ -1,4 +1,4 @@
-import { ImageResult, PlatformService } from "../PlatformService";
+import { ImageResult, PlatformService, PlatformCapabilities } from "../PlatformService";
 import { Filesystem, Directory } from "@capacitor/filesystem";
 import { Camera, CameraResultType, CameraSource } from "@capacitor/camera";
 import { logger } from "../../utils/logger";
@@ -11,6 +11,21 @@ import { logger } from "../../utils/logger";
  * - Platform-specific features
  */
 export class CapacitorPlatformService implements PlatformService {
+  /**
+   * Gets the capabilities of the Capacitor platform
+   * @returns Platform capabilities object
+   */
+  getCapabilities(): PlatformCapabilities {
+    return {
+      hasFileSystem: true,
+      hasCamera: true,
+      isMobile: true,
+      isIOS: /iPad|iPhone|iPod/.test(navigator.userAgent),
+      hasFileDownload: false,
+      needsFileHandlingInstructions: true
+    };
+  }
+
   /**
    * Reads a file from the app's data directory.
    * @param path - Relative path to the file in the app's data directory
@@ -146,38 +161,6 @@ export class CapacitorPlatformService implements PlatformService {
     return new Blob(byteArrays, { type: "image/jpeg" });
   }
 
-  /**
-   * Checks if running on Capacitor platform.
-   * @returns true, as this is the Capacitor implementation
-   */
-  isCapacitor(): boolean {
-    return true;
-  }
-
-  /**
-   * Checks if running on Electron platform.
-   * @returns false, as this is not Electron
-   */
-  isElectron(): boolean {
-    return false;
-  }
-
-  /**
-   * Checks if running on PyWebView platform.
-   * @returns false, as this is not PyWebView
-   */
-  isPyWebView(): boolean {
-    return false;
-  }
-
-  /**
-   * Checks if running on web platform.
-   * @returns false, as this is not web
-   */
-  isWeb(): boolean {
-    return false;
-  }
-
   /**
    * Handles deep link URLs for the application.
    * Note: Capacitor handles deep links automatically.

src/services/platforms/ElectronPlatformService.ts

@@ -1,4 +1,4 @@
-import { ImageResult, PlatformService } from "../PlatformService";
+import { ImageResult, PlatformService, PlatformCapabilities } from "../PlatformService";
 import { logger } from "../../utils/logger";
 
 /**
@@ -14,6 +14,21 @@ import { logger } from "../../utils/logger";
  * - System-level features
  */
 export class ElectronPlatformService implements PlatformService {
+  /**
+   * Gets the capabilities of the Electron platform
+   * @returns Platform capabilities object
+   */
+  getCapabilities(): PlatformCapabilities {
+    return {
+      hasFileSystem: false, // Not implemented yet
+      hasCamera: false, // Not implemented yet
+      isMobile: false,
+      isIOS: false,
+      hasFileDownload: false, // Not implemented yet
+      needsFileHandlingInstructions: false
+    };
+  }
+
   /**
    * Reads a file from the filesystem.
    * @param _path - Path to the file to read
@@ -79,38 +94,6 @@ export class ElectronPlatformService implements PlatformService {
     throw new Error("Not implemented");
   }
 
-  /**
-   * Checks if running on Capacitor platform.
-   * @returns false, as this is not Capacitor
-   */
-  isCapacitor(): boolean {
-    return false;
-  }
-
-  /**
-   * Checks if running on Electron platform.
-   * @returns true, as this is the Electron implementation
-   */
-  isElectron(): boolean {
-    return true;
-  }
-
-  /**
-   * Checks if running on PyWebView platform.
-   * @returns false, as this is not PyWebView
-   */
-  isPyWebView(): boolean {
-    return false;
-  }
-
-  /**
-   * Checks if running on web platform.
-   * @returns false, as this is not web
-   */
-  isWeb(): boolean {
-    return false;
-  }
-
   /**
    * Should handle deep link URLs for the desktop application.
    * @param _url - The deep link URL to handle

src/services/platforms/PyWebViewPlatformService.ts

@@ -1,4 +1,4 @@
-import { ImageResult, PlatformService } from "../PlatformService";
+import { ImageResult, PlatformService, PlatformCapabilities } from "../PlatformService";
 import { logger } from "../../utils/logger";
 
 /**
@@ -15,6 +15,21 @@ import { logger } from "../../utils/logger";
  * - Python-JavaScript bridge functionality
  */
 export class PyWebViewPlatformService implements PlatformService {
+  /**
+   * Gets the capabilities of the PyWebView platform
+   * @returns Platform capabilities object
+   */
+  getCapabilities(): PlatformCapabilities {
+    return {
+      hasFileSystem: false, // Not implemented yet
+      hasCamera: false, // Not implemented yet
+      isMobile: false,
+      isIOS: false,
+      hasFileDownload: false, // Not implemented yet
+      needsFileHandlingInstructions: false
+    };
+  }
+
   /**
    * Reads a file using the Python backend.
    * @param _path - Path to the file to read
@@ -80,38 +95,6 @@ export class PyWebViewPlatformService implements PlatformService {
     throw new Error("Not implemented");
   }
 
-  /**
-   * Checks if running on Capacitor platform.
-   * @returns false, as this is not Capacitor
-   */
-  isCapacitor(): boolean {
-    return false;
-  }
-
-  /**
-   * Checks if running on Electron platform.
-   * @returns false, as this is not Electron
-   */
-  isElectron(): boolean {
-    return false;
-  }
-
-  /**
-   * Checks if running on PyWebView platform.
-   * @returns true, as this is the PyWebView implementation
-   */
-  isPyWebView(): boolean {
-    return true;
-  }
-
-  /**
-   * Checks if running on web platform.
-   * @returns false, as this is not web
-   */
-  isWeb(): boolean {
-    return false;
-  }
-
   /**
    * Should handle deep link URLs through the Python backend.
    * @param _url - The deep link URL to handle

src/services/platforms/WebPlatformService.ts

@@ -1,4 +1,4 @@
-import { ImageResult, PlatformService } from "../PlatformService";
+import { ImageResult, PlatformService, PlatformCapabilities } from "../PlatformService";
 import { logger } from "../../utils/logger";
 
 /**
@@ -15,6 +15,21 @@ import { logger } from "../../utils/logger";
  * due to browser security restrictions. These methods throw appropriate errors.
  */
 export class WebPlatformService implements PlatformService {
+  /**
+   * Gets the capabilities of the web platform
+   * @returns Platform capabilities object
+   */
+  getCapabilities(): PlatformCapabilities {
+    return {
+      hasFileSystem: false,
+      hasCamera: true, // Through file input with capture
+      isMobile: /iPhone|iPad|iPod|Android/i.test(navigator.userAgent),
+      isIOS: /iPad|iPhone|iPod/.test(navigator.userAgent),
+      hasFileDownload: true,
+      needsFileHandlingInstructions: false
+    };
+  }
+
   /**
    * Not supported in web platform.
    * @param _path - Unused path parameter