Rework profile.js to use shellInitScriptChooser()

lib/setup/profile.js

@@ -8,6 +8,9 @@ var util = require('util');
 var chalk = require('chalk');
 var isNoEntry = require('../util/codes').isNoEntry;
 
+var bashProfileFileName = '.bash_profile';
+var bashrcFileName = '.bashrc';
+
 /**
  * Generate the string to be included in the shell init script.
  *
@@ -66,7 +69,104 @@ var appendScript = function(name, options) {
 };
 
 /**
- * Update `~/.bash_profile` and `.zshrc` shell profile files.
+ * Chooses the correct shell init script to insert avn initialization string to,
+ * based on the following criteria:
+ * 1. Append to the one that's present, if the other doesn't exist,
+ * 2. If both exist, append to the one that is sourced by the other, or
+ * 3. If both exist, but neither sources the other,
+ *    append to .bashrc if platform is 'linux',
+ *    or append to .bash_profile if platform is 'darwin' (i.e. macOS)
+ *
+ * @private
+ * @function setup.profile.~shellInitScriptChooser
+ * @return {Promise}
+ */
+var shellInitScriptChooser = function() {
+  var bashrcFile = path.join(process.env.HOME, bashrcFileName);
+  var bashProfileFile = path.join(process.env.HOME, bashProfileFileName);
+  var bashProfileNotExist;
+  var bashrcNotExist;
+
+  // Notice: will change fs.stat to fs.access in the future
+  // Reason: NodeJS 0.10 doesn't have fs.access (added in NodeJS 0.11.15)
+
+  // Check if .bash_profile exists
+  return fs.stat(bashProfileFile)
+  .catch(function(err) {
+    bashProfileNotExist = err;
+  })
+
+  // Check if .bashrc exists
+  .then(function() {
+    return fs.stat(bashrcFile)
+    .catch(function(err) {
+      bashrcNotExist = err;
+    });
+  })
+
+  .then(function() {
+    if (!bashProfileNotExist && !bashrcNotExist) {
+      return fs.readFile(bashProfileFile, 'utf8')
+      .then(function(data) {
+        // RegExp to detect "~/.bashrc",
+        // "$HOME/.bashrc", or "/home/user/.bashrc"
+        var bashrcRe = new RegExp(' ?source +(\\\\\\n)? *(~\/.bashrc|' +
+          '\"?\\$HOME\/.bashrc\"?|[\'\"]?\/home\/\\w+\/.bashrc[\'\"]?)');
+
+        if (bashrcRe.test(data)) {
+          return bashrcFileName;
+        }
+        return;
+      })
+
+      .then(function(appendFile) {
+        if (appendFile) {
+          return appendFile;
+        }
+
+        return fs.readFile(bashrcFile, 'utf8')
+        .then(function(data) {
+          // RegExp to detect "~/.bash_profile",
+          // "$HOME/.bash_profile", or "/home/user/.bash_profile"
+          var bashProfileRe = new RegExp(' ?source +(\\\\\\n)? *' +
+            '(~\/.bash_profile|\"?\\$HOME\/.bash_profile\"?|' +
+            '[\'\"]?\/home\/\\w+\/.bash_profile[\'\"]?)');
+
+          if (bashProfileRe.test(data)) {
+            return bashProfileFileName;
+          }
+          return;
+        });
+      })
+
+      .then(function(appendFile) {
+        if (appendFile) {
+          return appendFile;
+        }
+
+        // Neither .bashrc nor .bash_profile sources the other
+        var platformsToInitScript = {
+          linux:  bashrcFileName,
+          darwin: bashProfileFileName,
+        };
+
+        return platformsToInitScript[process.platform] || bashProfileFileName;
+      });
+    }
+
+    else if (!bashProfileNotExist || !bashrcNotExist) { // XOR file existence
+      return (bashProfileNotExist && bashrcFileName) ||
+             (bashrcNotExist && bashProfileFileName);
+    }
+
+    else {  // Default if neither exists
+      return bashProfileFileName;
+    }
+  });
+};
+
+/**
+ * Update `~/.bash_profile` and `.zshrc`, or `.bashrc` shell profile files.
  *
  * Adds the necessary commands to load `avn.sh` when a new shell is launched.
  *
@@ -77,33 +177,53 @@ var appendScript = function(name, options) {
 module.exports.update = function() {
   var handled = false;
   var changed = false;
+  var appendFile;
 
-  var promise = Promise.map(['.bash_profile', '.zshrc'], function(name) {
-    return appendScript(name);
-  })
-  .each(function(result) {
-    if (result) {
-      handled = true;
-      changed = changed || (result === 'change');
+  var promise = shellInitScriptChooser()
+  .then(function(initScript) {
+    appendFile = initScript;
+
+    if (appendFile === bashProfileFileName) {
+      return Promise.map([bashProfileFileName, '.zshrc'], function(name) {
+        return appendScript(name);
+      })
+      .each(function(result) {
+        if (result) {
+          handled = true;
+          changed = changed || (result === 'change');
+        }
+      });
     }
-  });
 
-  promise = promise.then(function() {
+    else if (appendFile === bashrcFileName) {
+      return appendScript(bashrcFileName)
+      .then(function(result) {
+        if (result) {
+          handled = true;
+          changed = changed || (result === 'change');
+        }
+      });
+    }
+  })
+
+  .then(function() {
     if (!handled) {
-      return appendScript('.bash_profile', { force: true });
+      return appendScript(appendFile, { force: true });
     }
   })
   .then(function(result) {
     if (result) {
       handled = true;
       changed = changed || (result === 'change');
     }
-  });
+  })
 
-  return promise.then(function() {
+  .then(function() {
     if (changed) {
       console.log('%s: %s', chalk.bold.magenta('avn'),
         chalk.bold.cyan('restart your terminal to start using avn'));
     }
   });
+
+  return promise;
 };