From d0893f4012636d61904df7dcb30f0abd86c99867 Mon Sep 17 00:00:00 2001
From: Harsha Teja Kanna <h7kanna@users.noreply.github.com>
Date: Mon, 23 Sep 2024 04:21:30 -0400
Subject: [PATCH] Fix serde of table align

Closes GH-142.
---
 src/mdast.rs   | 88 ++++++++++++++++++++++++++++++++++++++++++++++----
 tests/serde.rs | 12 ++++---
 2 files changed, 90 insertions(+), 10 deletions(-)

diff --git a/src/mdast.rs b/src/mdast.rs
index f0ad92ae..d207cd3c 100644
--- a/src/mdast.rs
+++ b/src/mdast.rs
@@ -33,11 +33,6 @@ pub enum ReferenceKind {
 ///
 /// Used to align the contents of table cells within a table.
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-#[cfg_attr(
-    feature = "serde",
-    derive(serde::Serialize, serde::Deserialize),
-    serde(rename_all = "lowercase")
-)]
 pub enum AlignKind {
     /// Left alignment.
     ///
@@ -78,10 +73,91 @@ pub enum AlignKind {
     /// > | | --- |
     ///       ^^^
     /// ```
-    // To do: this should serialize in serde as `null`.
     None,
 }
 
+/// Implement serde according to <https://github.com/syntax-tree/mdast?tab=readme-ov-file#aligntype>
+#[cfg(feature = "serde")]
+impl serde::ser::Serialize for AlignKind {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::ser::Serializer,
+    {
+        match self {
+            AlignKind::Left => serializer.serialize_unit_variant("AlignKind", 0, "left"),
+            AlignKind::Right => serializer.serialize_unit_variant("AlignKind", 1, "right"),
+            AlignKind::Center => serializer.serialize_unit_variant("AlignKind", 2, "center"),
+            AlignKind::None => serializer.serialize_none(),
+        }
+    }
+}
+
+#[cfg(feature = "serde")]
+struct AlignKindVisitor;
+
+#[cfg(feature = "serde")]
+impl<'de> serde::de::Visitor<'de> for AlignKindVisitor {
+    type Value = AlignKind;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str("'left', 'right', 'center' or null")
+    }
+
+    fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+    where
+        E: serde::de::Error,
+    {
+        match v {
+            "left" => Ok(AlignKind::Left),
+            "right" => Ok(AlignKind::Right),
+            "center" => Ok(AlignKind::Center),
+            &_ => Err(serde::de::Error::invalid_type(
+                serde::de::Unexpected::Str(v),
+                &self,
+            )),
+        }
+    }
+
+    fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
+    where
+        E: serde::de::Error,
+    {
+        match v {
+            b"left" => Ok(AlignKind::Left),
+            b"right" => Ok(AlignKind::Right),
+            b"center" => Ok(AlignKind::Center),
+            &_ => Err(serde::de::Error::invalid_type(
+                serde::de::Unexpected::Bytes(v),
+                &self,
+            )),
+        }
+    }
+
+    fn visit_none<E>(self) -> Result<Self::Value, E>
+    where
+        E: serde::de::Error,
+    {
+        Ok(AlignKind::None)
+    }
+
+    fn visit_unit<E>(self) -> Result<Self::Value, E>
+    where
+        E: serde::de::Error,
+    {
+        Ok(AlignKind::None)
+    }
+}
+
+#[cfg(feature = "serde")]
+impl<'de> serde::de::Deserialize<'de> for AlignKind {
+    fn deserialize<D>(deserializer: D) -> Result<AlignKind, D::Error>
+    where
+        D: serde::de::Deserializer<'de>,
+    {
+        deserializer.deserialize_any(AlignKindVisitor)
+    }
+}
+
 /// Nodes.
 #[derive(Clone, Eq, PartialEq)]
 #[cfg_attr(
diff --git a/tests/serde.rs b/tests/serde.rs
index e10e6926..2edc9acc 100644
--- a/tests/serde.rs
+++ b/tests/serde.rs
@@ -606,26 +606,30 @@ fn serde_heading() -> Result<(), Error> {
 fn serde_table() -> Result<(), Error> {
     // To do: `"none"` should serialize in serde as `null`.
     assert_serde(
-        "| a | b |\n| - | -: |\n| 1 | 2 |",
+        "| a | b | c | d |\n| - | :- | -: | :-: |\n| 1 | 2 | 3 | 4 |",
         r#"{
   "type": "root",
   "children": [
     {
       "type": "table",
-      "align": ["none", "right"],
+      "align": [null, "left", "right", "center"],
       "children": [
         {
           "type": "tableRow",
           "children": [
             {"type": "tableCell", "children": [{"type": "text", "value": "a"}]},
-            {"type": "tableCell", "children": [{"type": "text", "value": "b"}]}
+            {"type": "tableCell", "children": [{"type": "text", "value": "b"}]},
+            {"type": "tableCell", "children": [{"type": "text", "value": "c"}]},
+            {"type": "tableCell", "children": [{"type": "text", "value": "d"}]}
           ]
         },
         {
           "type": "tableRow",
           "children": [
             {"type": "tableCell","children": [{"type": "text", "value": "1"}]},
-            {"type": "tableCell","children": [{"type": "text", "value": "2"}]}
+            {"type": "tableCell","children": [{"type": "text", "value": "2"}]},
+            {"type": "tableCell","children": [{"type": "text", "value": "3"}]},
+            {"type": "tableCell","children": [{"type": "text", "value": "4"}]}
           ]
         }
       ]