Fix autolink script (#5990)

This PR fixes the autolink script including:
* Specifying the minSdkVersion for Android. Closes #5983.
* Removing the RNN Pod added by the react-native link script.

autolink/postlink/gradleLinker.js

 var { warnn, errorn, logn, infon, debugn } = require('./log');
 var { insertString } = require('./stringUtils');
 var DEFAULT_KOTLIN_VERSION = '1.3.61';
+// This should be the minSdkVersion required for RNN.
+var DEFAULT_MIN_SDK_VERSION = 19
 
 class GradleLinker {
   constructor() {
       var contents = fs.readFileSync(this.gradlePath, 'utf8');
       contents = this._setKotlinVersion(contents);
       contents = this._setKotlinPluginDependency(contents);
+      contents = this._setMinSdkVersion(contents);
       fs.writeFileSync(this.gradlePath, contents);
       infon('Root build.gradle linked successfully!\n');
     } else {
     return contents;
   }
 
+  /**
+   * Check the current minSdkVersion specified and if it's lower than
+   * the required version, set it to the required version otherwise leave as it is.
+   */
+  _setMinSdkVersion(contents) {
+    var minSdkVersion = this._getMinSdkVersion(contents)
+    // If user entered minSdkVersion is lower than the default, set it to default.
+    if (minSdkVersion < DEFAULT_MIN_SDK_VERSION) {
+      debugn(`   Updating minSdkVersion to ${DEFAULT_MIN_SDK_VERSION}`)
+      return contents.replace(/minSdkVersion\s{0,}=\s{0,}\d*/, `minSdkVersion = ${DEFAULT_MIN_SDK_VERSION}`)
+    } 
+
+    debugn(`   Already specified minSdkVersion ${minSdkVersion}`)
+    return contents.replace(/minSdkVersion\s{0,}=\s{0,}\d*/, `minSdkVersion = ${minSdkVersion}`)
+  }
+
   /**
    * @param { string } contents
    */
     return `"${DEFAULT_KOTLIN_VERSION}"`;
   }
 
+  /**
+   * Get the minSdkVersion value.
+   * @param { string } contents
+   */
+  _getMinSdkVersion(contents) {
+    var minSdkVersion = contents.match(/minSdkVersion\s{0,}=\s{0,}(\d*)/)
+
+    if (minSdkVersion && minSdkVersion[1]) {
+      // It'd be something like 16 for a fresh React Native project.
+      return +minSdkVersion[1] 
+    }
+
+    return DEFAULT_MIN_SDK_VERSION
+  }
+
   /**
    * @param {string} contents
    */

autolink/postlink/path.js

 exports.mainApplicationJava = mainApplicationJava;
 exports.rootGradle = mainApplicationJava.replace(/android\/app\/.*\.java/, "android/build.gradle");;
 
-exports.appDelegate = glob.sync("**/AppDelegate.m", ignoreFolders)[0];
+exports.appDelegate = glob.sync("**/AppDelegate.m", ignoreFolders)[0];
+exports.podFile = glob.sync("**/Podfile", ignoreFolders)[0]

autolink/postlink/podfileLinker.js

+// @ts-check
+var path = require('./path');
+var fs = require("fs");
+var {logn, debugn, infon} = require("./log");
+
+class PodfileLinker {
+  constructor() {
+    this.podfilePath = path.podFile;
+  }
+
+  link() {
+    if (this.podfilePath) {
+      logn("Updating Podfile...")
+      var podfileContent = fs.readFileSync(this.podfilePath, "utf8");
+
+      podfileContent = this._removeRNNPodLink(podfileContent);
+
+      fs.writeFileSync(this.podfilePath, podfileContent);
+      infon("Podfile updated successfully!\n")
+    }
+  }
+
+  /**
+   * Removes the RNN pod added by react-native link script. 
+   */
+  _removeRNNPodLink(contents) {
+    const rnnPodLink  = contents.match(/\s+.*pod 'ReactNativeNavigation'.+react-native-navigation'/)
+
+    if (!rnnPodLink) {
+      debugn("   RNN Pod has not been added to Podfile")
+      return contents
+    }
+
+    debugn("   Removing RNN Pod from Podfile")
+    return contents.replace(rnnPodLink, "")    
+  }
+}
+
+module.exports = PodfileLinker

autolink/postlink/postLinkIOS.js

 // @ts-check
 var AppDelegateLinker = require("./appDelegateLinker");
+var PodfileLinker = require('./podfileLinker');
 
 module.exports = () => {
   console.log("Running iOS postlink script\n");
   new AppDelegateLinker().link();
+  new PodfileLinker().link();
 }