From e76903cb47d66b23408fdd860d8921facc7a6617 Mon Sep 17 00:00:00 2001
From: ConnorSkees <39542938+ConnorSkees@users.noreply.github.com>
Date: Sun, 7 Jun 2020 14:23:15 -0400
Subject: [PATCH] initial implementation of selector-replace

---
 src/builtin/selector.rs    | 23 +++++++++++++++++++++-
 src/selector/extend/mod.rs | 12 ++++--------
 tests/selector-replace.rs  | 40 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+), 9 deletions(-)
 create mode 100644 tests/selector-replace.rs

diff --git a/src/builtin/selector.rs b/src/builtin/selector.rs
index 88f327b..a437dbd 100644
--- a/src/builtin/selector.rs
+++ b/src/builtin/selector.rs
@@ -177,7 +177,28 @@ fn selector_replace(
     super_selector: &Selector,
 ) -> SassResult<Value> {
     args.max_args(3)?;
-    todo!("built-in fn selector-replace")
+    let selector = arg!(args, scope, super_selector, 0, "selector").to_selector(
+        args.span(),
+        scope,
+        super_selector,
+        "selector",
+        false,
+    )?;
+    let target = arg!(args, scope, super_selector, 1, "original").to_selector(
+        args.span(),
+        scope,
+        super_selector,
+        "original",
+        false,
+    )?;
+    let source = arg!(args, scope, super_selector, 2, "replacement").to_selector(
+        args.span(),
+        scope,
+        super_selector,
+        "replacement",
+        false,
+    )?;
+    Ok(Extender::replace(selector.0, source.0, target.0).to_sass_list())
 }
 
 fn selector_unify(
diff --git a/src/selector/extend/mod.rs b/src/selector/extend/mod.rs
index 4fe65d4..70f7e90 100644
--- a/src/selector/extend/mod.rs
+++ b/src/selector/extend/mod.rs
@@ -189,9 +189,8 @@ impl Extender {
                     if i != 0 {
                         extended = list.components[0..i].to_vec();
                     }
-
-                    extended.extend(result.into_iter());
                 }
+                extended.extend(result.into_iter());
             } else {
                 if !extended.is_empty() {
                     extended.push(complex);
@@ -275,8 +274,6 @@ impl Extender {
             return None;
         }
 
-        // dbg!(&extended_not_expanded);
-
         let mut first = true;
 
         let mut originals: Vec<ComplexSelector> = Vec::new();
@@ -359,7 +356,7 @@ impl Extender {
 
         // If `self.mode` isn't `ExtendMode::Normal` and we didn't use all the targets in
         // `extensions`, extension fails for `compound`.
-        if targets_used.len() != extensions.len() {
+        if targets_used.len() > 0 && targets_used.len() != extensions.len() {
             return None;
         }
 
@@ -443,7 +440,7 @@ impl Extender {
                             to_unify.push_back(state.extender.components.clone());
                         }
                     }
-                    if originals.is_empty() {
+                    if !originals.is_empty() {
                         to_unify.push_front(vec![ComplexSelectorComponent::Compound(
                             CompoundSelector {
                                 components: originals,
@@ -473,8 +470,6 @@ impl Extender {
             })
             .collect();
 
-        dbg!(&unified_paths);
-
         Some(
             unified_paths
                 .into_iter()
@@ -631,6 +626,7 @@ impl Extender {
                 }
             })
             .collect();
+
         // Older browsers support `:not`, but only with a single complex selector.
         // In order to support those browsers, we break up the contents of a `:not`
         // unless it originally contained a selector list.
diff --git a/tests/selector-replace.rs b/tests/selector-replace.rs
new file mode 100644
index 0000000..853f2bd
--- /dev/null
+++ b/tests/selector-replace.rs
@@ -0,0 +1,40 @@
+#![cfg(test)]
+
+#[macro_use]
+mod macros;
+
+test!(
+    simple,
+    "a {\n  color: selector-replace(\"c\", \"c\", \"d\");\n}\n",
+    "a {\n  color: d;\n}\n"
+);
+test!(
+    compound,
+    "a {\n  color: selector-replace(\"c.d\", \"c\", \"e\");\n}\n",
+    "a {\n  color: e.d;\n}\n"
+);
+test!(
+    complex,
+    "a {\n  color: selector-replace(\"c d\", \"d\", \"e f\");\n}\n",
+    "a {\n  color: c e f, e c f;\n}\n"
+);
+test!(
+    psuedo_matches,
+    "a {\n  color: selector-replace(\":matches(c)\", \"c\", \"d\");\n}\n",
+    "a {\n  color: :matches(d);\n}\n"
+);
+test!(
+    psuedo_not,
+    "a {\n  color: selector-replace(\":not(c)\", \"c\", \"d\");\n}\n",
+    "a {\n  color: :not(d);\n}\n"
+);
+test!(
+    no_op,
+    "a {\n  color: selector-replace(\"c\", \"d\", \"e\");\n}\n",
+    "a {\n  color: c;\n}\n"
+);
+test!(
+    partial_no_op,
+    "a {\n  color: selector-replace(\"c, d\", \"d\", \"e\");\n}\n",
+    "a {\n  color: c, e;\n}\n"
+);