From c02d7a5fd8eaaf183c7a4afee6d2503deb146812 Mon Sep 17 00:00:00 2001
From: qkzk <qu3nt1n@gmail.com>
Date: Wed, 21 Dec 2022 00:30:00 +0100
Subject: fix wrong navigation order. Rename everything to selectable content

---
 src/selectable_content.rs | 66 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 src/selectable_content.rs

(limited to 'src/selectable_content.rs')

diff --git a/src/selectable_content.rs b/src/selectable_content.rs
new file mode 100644
index 0000000..4669e70
--- /dev/null
+++ b/src/selectable_content.rs
@@ -0,0 +1,66 @@
+/// Make a content selectable content for a struct.
+/// This trait allows to navigate through a vector of element `content_type`.
+/// It implements: `is_empty`, `len`, `next`, `prev`, `selected`.
+/// `selected` returns an optional reference to the value.
+pub trait SelectableContent<T> {
+    fn is_empty(&self) -> bool;
+    fn len(&self) -> usize;
+    fn next(&mut self);
+    fn prev(&mut self);
+    fn selected(&self) -> Option<&T>;
+}
+
+/// Implement the `SelectableContent` for struct `$struc` with content type `$content_type`.
+/// This trait allows to navigate through a vector of element `content_type`.
+/// It implements: `is_empty`, `len`, `next`, `prev`, `selected`.
+/// `selected` returns an optional reference to the value.
+#[macro_export]
+macro_rules! impl_selectable_content {
+    ($content_type:ident, $struct:ident) => {
+        use $crate::selectable_content::SelectableContent;
+
+        /// Implement a selectable content for this struct.
+        /// This trait allows to navigate through a vector of element `content_type`.
+        /// It implements: `is_empty`, `len`, `next`, `prev`, `selected`.
+        /// `selected` returns an optional reference to the value.
+        impl SelectableContent<$content_type> for $struct {
+            /// True if the content is empty.
+            fn is_empty(&self) -> bool {
+                self.content.is_empty()
+            }
+
+            /// The size of the content.
+            fn len(&self) -> usize {
+                self.content.len()
+            }
+
+            /// Select the prev item.
+            fn prev(&mut self) {
+                if self.is_empty() {
+                    self.index = 0
+                } else if self.index > 0 {
+                    self.index -= 1;
+                } else {
+                    self.index = self.len() - 1
+                }
+            }
+
+            /// Select the next item.
+            fn next(&mut self) {
+                if self.is_empty() {
+                    self.index = 0;
+                } else {
+                    self.index = (self.index + 1) % self.len()
+                }
+            }
+
+            /// Returns a reference to the selected content.
+            fn selected(&self) -> Option<&$content_type> {
+                match self.is_empty() {
+                    true => None,
+                    false => Some(&self.content[self.index]),
+                }
+            }
+        }
+    };
+}
-- 
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