From e9ecdf582e6babb484ab247cd18f30dde0e13692 Mon Sep 17 00:00:00 2001
From: Dillon Kearns <dillon@incrementalelm.com>
Date: Wed, 14 Sep 2022 15:53:27 -0700
Subject: [PATCH] Fix casing in route matching.

---
 codegen/Generate.elm                | 42 +++++++++++++++++++++++++++--
 codegen/elm.json                    |  1 +
 src/Pages/Internal/RoutePattern.elm | 22 ++++++++++++---
 3 files changed, 60 insertions(+), 5 deletions(-)

diff --git a/codegen/Generate.elm b/codegen/Generate.elm
index ea198348..7f34977a 100644
--- a/codegen/Generate.elm
+++ b/codegen/Generate.elm
@@ -20,6 +20,7 @@ import Gen.String
 import Gen.Tuple
 import Pages.Internal.RoutePattern as RoutePattern exposing (RoutePattern)
 import Pretty
+import Regex exposing (Regex)
 
 
 type alias Flags =
@@ -314,7 +315,7 @@ routeToPath routes =
                                                 (\param ->
                                                     case param of
                                                         RoutePattern.StaticParam name ->
-                                                            [ Elm.string name ]
+                                                            [ Elm.string (toKebab name) ]
                                                                 |> Elm.list
 
                                                         RoutePattern.DynamicParam name ->
@@ -342,7 +343,7 @@ routeToPath routes =
                                                     (\param ->
                                                         case param of
                                                             RoutePattern.StaticParam name ->
-                                                                [ Elm.string name ]
+                                                                [ Elm.string (toKebab name) ]
                                                                     |> Elm.list
 
                                                             RoutePattern.DynamicParam name ->
@@ -402,6 +403,43 @@ expose declaration =
             }
 
 
+{-| Decapitalize the first letter of a string.
+decapitalize "This is a phrase" == "this is a phrase"
+decapitalize "Hello, World" == "hello, World"
+-}
+decapitalize : String -> String
+decapitalize word =
+    -- Source: https://github.com/elm-community/string-extra/blob/4.0.1/src/String/Extra.elm
+    changeCase Char.toLower word
+
+
+{-| Change the case of the first letter of a string to either uppercase or
+lowercase, depending of the value of `wantedCase`. This is an internal
+function for use in `toSentenceCase` and `decapitalize`.
+-}
+changeCase : (Char -> Char) -> String -> String
+changeCase mutator word =
+    -- Source: https://github.com/elm-community/string-extra/blob/4.0.1/src/String/Extra.elm
+    String.uncons word
+        |> Maybe.map (\( head, tail ) -> String.cons (mutator head) tail)
+        |> Maybe.withDefault ""
+
+
+toKebab : String -> String
+toKebab string =
+    string
+        |> decapitalize
+        |> String.trim
+        |> Regex.replace (regexFromString "([A-Z])") (.match >> String.append "-")
+        |> Regex.replace (regexFromString "[_-\\s]+") (always "-")
+        |> String.toLower
+
+
+regexFromString : String -> Regex
+regexFromString =
+    Regex.fromString >> Maybe.withDefault Regex.never
+
+
 port onSuccessSend : List File -> Cmd msg
 
 
diff --git a/codegen/elm.json b/codegen/elm.json
index 9126cbde..e560557c 100644
--- a/codegen/elm.json
+++ b/codegen/elm.json
@@ -11,6 +11,7 @@
             "elm/core": "1.0.5",
             "elm/html": "1.0.0",
             "elm/json": "1.1.3",
+            "elm/regex": "1.0.0",
             "mdgriffith/elm-codegen": "2.0.0",
             "the-sett/elm-pretty-printer": "3.0.0",
             "the-sett/elm-syntax-dsl": "6.0.2"
diff --git a/src/Pages/Internal/RoutePattern.elm b/src/Pages/Internal/RoutePattern.elm
index 0df84010..e591739e 100644
--- a/src/Pages/Internal/RoutePattern.elm
+++ b/src/Pages/Internal/RoutePattern.elm
@@ -13,6 +13,7 @@ import Elm
 import Elm.Annotation exposing (Annotation)
 import Elm.CodeGen
 import Html exposing (Html)
+import Regex exposing (Regex)
 
 
 {-| -}
@@ -145,7 +146,7 @@ routeToBranch route =
                                     (\segment ->
                                         case segment of
                                             StaticSegment name ->
-                                                Elm.CodeGen.stringPattern (decapitalize name)
+                                                Elm.CodeGen.stringPattern (toKebab name)
 
                                             DynamicSegment name ->
                                                 Elm.CodeGen.varPattern (decapitalize name)
@@ -175,7 +176,7 @@ routeToBranch route =
                                                     (\segment ->
                                                         case segment of
                                                             StaticSegment name ->
-                                                                Elm.CodeGen.stringPattern (decapitalize name)
+                                                                Elm.CodeGen.stringPattern (toKebab name)
 
                                                             DynamicSegment name ->
                                                                 Elm.CodeGen.varPattern (decapitalize name)
@@ -196,7 +197,7 @@ routeToBranch route =
                                     (\segment ->
                                         case segment of
                                             StaticSegment name ->
-                                                Elm.CodeGen.stringPattern (decapitalize name)
+                                                Elm.CodeGen.stringPattern (toKebab name)
 
                                             DynamicSegment name ->
                                                 Elm.CodeGen.varPattern (decapitalize name)
@@ -573,3 +574,18 @@ unconsPattern list =
                 )
                 listFirst
                 listRest
+
+
+toKebab : String -> String
+toKebab string =
+    string
+        |> decapitalize
+        |> String.trim
+        |> Regex.replace (regexFromString "([A-Z])") (.match >> String.append "-")
+        |> Regex.replace (regexFromString "[_-\\s]+") (always "-")
+        |> String.toLower
+
+
+regexFromString : String -> Regex
+regexFromString =
+    Regex.fromString >> Maybe.withDefault Regex.never