From 6fe0fff9c84586b5412072885995c40595244f2c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Riikka=20Kalliom=C3=A4ki?= <riikka.kalliomaki@gmail.com>
Date: Wed, 17 Apr 2019 20:30:29 +0300
Subject: [PATCH] Add support for optional middle segments

---
 src/RouteParser/Std.php      | 69 ++++++++++++++++++++++++++----------
 test/RouteParser/StdTest.php | 48 ++++++++++++++++++++++---
 2 files changed, 95 insertions(+), 22 deletions(-)

diff --git a/src/RouteParser/Std.php b/src/RouteParser/Std.php
index 4fbdee1..0ac8030 100644
--- a/src/RouteParser/Std.php
+++ b/src/RouteParser/Std.php
@@ -24,29 +24,62 @@ class Std implements RouteParser
 
     public function parse($route)
     {
-        $routeWithoutClosingOptionals = rtrim($route, ']');
-        $numOptionals = strlen($route) - strlen($routeWithoutClosingOptionals);
-
-        // Split on [ while skipping placeholders
-        $segments = preg_split('~' . self::VARIABLE_REGEX . '(*SKIP)(*F) | \[~x', $routeWithoutClosingOptionals);
-        if ($numOptionals !== count($segments) - 1) {
-            // If there are any ] in the middle of the route, throw a more specific error message
-            if (preg_match('~' . self::VARIABLE_REGEX . '(*SKIP)(*F) | \]~x', $routeWithoutClosingOptionals)) {
-                throw new BadRouteException('Optional segments can only occur at the end of a route');
-            }
-            throw new BadRouteException("Number of opening '[' and closing ']' does not match");
+        if (strcspn($route, '[]') === strlen($route)) {
+            return [$this->parsePlaceholders($route)];
         }
 
-        $currentRoute = '';
-        $routeDatas = [];
-        foreach ($segments as $n => $segment) {
-            if ($segment === '' && $n !== 0) {
-                throw new BadRouteException('Empty optional part');
+        $routeDatas = $this->consume($route);
+
+        return array_map([$this, 'parsePlaceholders'], $routeDatas);
+    }
+
+    private function consume(& $route, $recursion = false)
+    {
+        $routeDatas = [''];
+
+        do {
+            $segments = preg_split(
+                '~' . self::VARIABLE_REGEX . '(*SKIP)(*F) | ( \[ | ] )~x',
+                $route,
+                2
+            );
+
+            foreach ($routeDatas as $key => $data) {
+                $routeDatas[$key] = $data . $segments[0];
             }
 
-            $currentRoute .= $segment;
-            $routeDatas[] = $this->parsePlaceholders($currentRoute);
+            if (isset($segments[1])) {
+                $delimiter = $route[strlen($segments[0])];
+                $route = $segments[1];
+
+                if ($delimiter === ']') {
+                    if (!$recursion) {
+                        throw new BadRouteException("Number of opening '[' and closing ']' does not match");
+                    }
+
+                    if (in_array('', $routeDatas, true)) {
+                        throw new BadRouteException('Empty optional part');
+                    }
+
+                    return $routeDatas;
+                }
+
+                $forks = $this->consume($route, true);
+
+                foreach ($routeDatas as $data) {
+                    foreach ($forks as $fork) {
+                        $routeDatas[] = $data . $fork;
+                    }
+                }
+            } else {
+                $route = '';
+            }
+        } while (isset($segments[1]));
+
+        if ($recursion) {
+            throw new BadRouteException("Number of opening '[' and closing ']' does not match");
         }
+
         return $routeDatas;
     }
 
diff --git a/test/RouteParser/StdTest.php b/test/RouteParser/StdTest.php
index e13e4de..646c9ff 100644
--- a/test/RouteParser/StdTest.php
+++ b/test/RouteParser/StdTest.php
@@ -115,6 +115,46 @@ public function provideTestParse()
                     ['/', ['_foo', '.*']]
                 ]
             ],
+            [
+                '/test[/opt]/required',
+                [
+                    ['/test/required'],
+                    ['/test/opt/required'],
+                ]
+            ],
+            [
+                '/test[/opt[/sub1][/sub2]]/required[/end]',
+                [
+                    ['/test/required'],
+                    ['/test/opt/required'],
+                    ['/test/opt/sub1/required'],
+                    ['/test/opt/sub2/required'],
+                    ['/test/opt/sub1/sub2/required'],
+                    ['/test/required/end'],
+                    ['/test/opt/required/end'],
+                    ['/test/opt/sub1/required/end'],
+                    ['/test/opt/sub2/required/end'],
+                    ['/test/opt/sub1/sub2/required/end'],
+                ]
+            ],
+            [
+                '/test[/[opt[/]]]',
+                [
+                    ['/test'],
+                    ['/test/'],
+                    ['/test/opt'],
+                    ['/test/opt/'],
+                ]
+            ],
+            [
+                '/test[/opt][/]',
+                [
+                    ['/test'],
+                    ['/test/opt'],
+                    ['/test/'],
+                    ['/test/opt/'],
+                ]
+            ]
         ];
     }
 
@@ -133,6 +173,10 @@ public function provideTestParseError()
                 '/testopt]',
                 "Number of opening '[' and closing ']' does not match"
             ],
+            [
+                '/test]opt',
+                "Number of opening '[' and closing ']' does not match"
+            ],
             [
                 '/test[]',
                 'Empty optional part'
@@ -145,10 +189,6 @@ public function provideTestParseError()
                 '[[test]]',
                 'Empty optional part'
             ],
-            [
-                '/test[/opt]/required',
-                'Optional segments can only occur at the end of a route'
-            ],
         ];
     }
 }