Adds ability to change search provider

App/Web Search/SearchProvider.swift

@@ -0,0 +1,42 @@
+//
+//  SearchProvider.swift
+//  App
+//
+//  Created by James Magahern on 3/9/21.
+//
+
+import Foundation
+
+class SearchProvider
+{
+    static let google = SearchProvider(resolver: { query in
+        // gbv=1: no JS
+        URL(string: "https://google.com/search?q=\(query.sanitized())&gbv=1")!
+    })
+    
+    static let duckduckgo = SearchProvider(resolver: { query in
+        // html version is the one without JS
+        URL(string: "https://html.duckduckgo.com/html/?q=\(query.sanitized())")!
+    })
+    
+    static let searxnor = SearchProvider(resolver: { query in
+        URL(string: "http://searx.nor/search?q=\(query.sanitized())&categories=general")!
+    })
+    
+    func searchURLWithQuery(_ query: String) -> URL {
+        return resolver(query)
+    }
+    
+    internal let resolver: (String) -> URL
+    internal init(resolver: @escaping (String) -> URL) {
+        self.resolver = resolver
+    }
+}
+
+fileprivate extension String {
+    func sanitized() -> String {
+        self
+            .replacingOccurrences(of: " ", with: "+")
+            .addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
+    }
+}