1 files changed, 98 insertions, 0 deletions
diff --git a/Digitigrade/Router.php b/Digitigrade/Router.php
new file mode 100644
index 0000000..fb984d5
--- /dev/null
+++ b/Digitigrade/Router.php
@@ -0,0 +1,98 @@
+<?php
+namespace Digitigrade;
+
+use Digitigrade\HttpResponseStatus\InternalServerError;
+use Digitigrade\HttpResponseStatus\NoHandlerFound;
+
+class Router extends Singleton {
+
+    private readonly string $requestPath;
+    private array $routes;
+
+    protected function __construct() {
+        $this->requestPath = $_GET['requestPath'] ?? $_SERVER['PATH_INFO'] ?? explode('?', $_SERVER['REQUEST_URI'], 2)[0] ?? '/';
+        $this->routes = [];
+    }
+
+    /**
+     * Processes and sends a response to the current request
+     * @return void
+     */
+    public function processRequest() {
+        try {
+            $this->processRequestInner();
+        } catch (HttpResponseStatus $e) {
+            http_response_code($e->httpCode());
+            echo '<h1>' . $e->httpReason() . '</h1><pre>' . $e->getMessage() . '</pre>';
+        }
+    }
+
+    private function processRequestInner() {
+        $context = null;
+        try {
+            $route = $this->matchPath($this->requestPath);
+            if ($route == null) {
+                throw new NoHandlerFound($this->requestPath);
+            }
+            $context = 'handler for /' . implode('/', $route[0]);
+            $route[1]($route[2]); // call handler with args
+        } catch (\Exception $e) {
+            if (is_a($e, HttpResponseStatus::class)) {
+                throw $e;
+            }
+            throw new InternalServerError($e, $context);
+        } catch (\Error $e) {
+            throw new InternalServerError($e, $context);
+        }
+    }
+
+    public function mount(string $pathSpec, callable $handler) {
+        $this->routes[] = [$this->explodePathPieces($pathSpec), $handler];
+    }
+
+    private function explodePathPieces(string $pathSpec): array {
+        $pieces = explode('/', $pathSpec);
+        if ($pieces[0] == '')
+            array_shift($pieces);
+        return $pieces;
+    }
+
+    private function matchPath(string $requestPath): ?array {
+        // find matching candidates
+        $pieces = $this->explodePathPieces($requestPath);
+        $candidates = [];
+        foreach ($this->routes as $route) {
+            $routePieces = $route[0];
+            if (count($routePieces) != count($pieces))
+                continue;
+            $args = [];
+            $matches = true;
+            for ($i = 0; $i < count($pieces); $i++) {
+                if (str_starts_with($routePieces[$i], ':')) { // this is a parameter
+                    $args[substr($routePieces[$i], 1)] = $pieces[$i];
+                } elseif ($routePieces[$i] != $pieces[$i]) {
+                    $matches = false;
+                    break;
+                }
+            }
+            if ($matches) {
+                $candidates[] = [$route[0], $route[1], $args];
+            }
+        }
+
+        // select the best matching one (has the longest path, for now)
+        $bestScore = 0;
+        $bestItem = null;
+        foreach ($candidates as $c) {
+            $score = count($c[0]) - count(array_filter($c[0], function ($item) {
+                return str_starts_with($item, ':');
+            })) * 0.1;
+            if ($score > $bestScore) {
+                $bestItem = $c;
+                $bestScore = $score;
+            }
+        }
+        return $bestItem;
+    }
+
+}