Allow for parsing of migration names

spec/Way/Generators/MigrationNameParserSpec.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace spec\Way\Generators;
+
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+
+class MigrationNameParserSpec extends ObjectBehavior
+{
+    function it_is_initializable()
+    {
+        $this->shouldHaveType('Way\Generators\MigrationNameParser');
+    }
+
+    function it_parses_a_basic_migration_name()
+    {
+        $this->parse('create_orders_table')->shouldBe([
+            'action' => 'create',
+            'tableName' => 'orders'
+        ]);
+    }
+
+    function it_parses_a_complex_migration_name()
+    {
+        $this->parse('add_first_name_and_last_name_to_recent_orders_table')->shouldBe([
+            'action' => 'add',
+            'tableName' => 'recent_orders'
+        ]);
+    }
+
+    function it_requires_a_valid_crud_action_name()
+    {
+        $this->shouldThrow('Way\Generators\InvalidActionType')->duringParse('foo_orders_table');
+    }
+
+}

src/Way/Generators/InvalidActionType.php

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+<?php namespace Way\Generators;
+
+class InvalidActionType extends \Exception {}

src/Way/Generators/MigrationNameParser.php

@@ -0,0 +1,78 @@
+<?php namespace Way\Generators;
+
+class MigrationNameParser {
+
+    /**
+     * Recognized CRUD types
+     *
+     * @var array
+     */
+    public static $acceptableTypes = [
+        'create', 'add', 'update', 'delete', 'destroy'
+    ];
+
+    /**
+     * Parse a migration name, like:
+     * create_orders_table
+     * add_last_name_to_recent_orders_table
+     *
+     * @param $migrationName
+     * @throws InvalidActionType
+     * @return array
+     */
+    public function parse($migrationName)
+    {
+        // Split the migration name into pieces
+        // create_orders_table => ['create', 'orders', 'table']
+        $pieces = explode('_', $migrationName);
+
+        // We'll start by fetching the CRUD action type
+        $action = array_shift($pieces);
+
+        // This action type must be something we understand
+        if ( ! in_array($action, self::$acceptableTypes))
+        {
+            throw new InvalidActionType;
+        }
+
+        // Next, we can remove any "table" string at
+        // the end of the migration name, like:
+        // create_orders_table
+        if (end($pieces) == 'table') array_pop($pieces);
+
+        // Now, we need to figure out the table name
+        $tableName = $this->getTableName($pieces);
+
+        return compact('action', 'tableName');
+    }
+
+    /**
+     * Determine what the table name should be
+     *
+     * @param array $pieces
+     * @return string
+     */
+    protected function getTableName(array $pieces)
+    {
+        $tableName = [];
+
+        // This is deceptively complex, because
+        // there are a number of ways to write
+        // these migration names. We'll work backwards
+        // to figure out the name.
+        foreach(array_reverse($pieces) as $piece)
+        {
+            // Once we get to a connecting word (if any), this
+            // will signal the end of our search. So, for
+            // add_name_to_archived_lessons, "archived_lessons"
+            // would be the table name
+            if (in_array($piece, ['to', 'for', 'on'])) break;
+
+            $tableName[] = $piece;
+        }
+
+        // We can't forget to reverse it back again!
+        return implode('_', array_reverse($tableName));
+    }
+
+}