From 5dd940eb52b40c78a2078ed0a02440e84bee0306 Mon Sep 17 00:00:00 2001
From: "Gabriel A. Giovanini" <mail@gabrielgio.me>
Date: Sat, 1 Nov 2025 17:49:20 +0100
Subject: feat: Write css dark/light theme on standalone url

This will allow tho write both themes into the same css file.
Also mend with the css generate by chroma so it can be nested.
---
 pkg/handler/git/handler.go    |  2 ++
 pkg/handler/router.go         |  9 ++++++++
 pkg/handler/static/handler.go | 49 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+)

(limited to 'pkg')

diff --git a/pkg/handler/git/handler.go b/pkg/handler/git/handler.go
index ffa5dfd..d046d19 100644
--- a/pkg/handler/git/handler.go
+++ b/pkg/handler/git/handler.go
@@ -349,6 +349,7 @@ func (g *GitHandler) Blob(w http.ResponseWriter, r *ext.Request) error {
 	formatter := html.New(
 		html.WithLineNumbers(true),
 		html.WithLinkableLineNumbers(true, "L"),
+		html.WithClasses(true),
 	)
 
 	iterator, err := lexer.Tokenise(nil, string(file))
@@ -440,6 +441,7 @@ func (g *GitHandler) Commit(w http.ResponseWriter, r *ext.Request) error {
 	formatter := html.New(
 		html.WithLineNumbers(true),
 		html.WithLinkableLineNumbers(true, "L"),
+		html.WithClasses(true),
 	)
 
 	iterator, err := lexer.Tokenise(nil, diff)
diff --git a/pkg/handler/router.go b/pkg/handler/router.go
index fea8827..bc81350 100644
--- a/pkg/handler/router.go
+++ b/pkg/handler/router.go
@@ -31,6 +31,14 @@ func MountHandler(
 		return nil, err
 	}
 
+	cssStaticHandler, err := static.ServeStaticCSSHandler(
+		configRepo.GetSyntaxHighlight(),
+		configRepo.GetSyntaxHighlightDark(),
+	)
+	if err != nil {
+		return nil, err
+	}
+
 	mux := ext.NewRouter()
 	mux.AddMiddleware(ext.Compress)
 	mux.AddMiddleware(ext.Log)
@@ -45,6 +53,7 @@ func MountHandler(
 	}
 
 	mux.HandleFunc("/static/{file}", staticHandler)
+	mux.HandleFunc("/static/theme", cssStaticHandler)
 	mux.HandleFunc("/{name}/about/{$}", gitHandler.About)
 	mux.HandleFunc("/{name}", gitHandler.Multiplex)
 	mux.HandleFunc("/{name}/{rest...}", gitHandler.Multiplex)
diff --git a/pkg/handler/static/handler.go b/pkg/handler/static/handler.go
index cdb2ae6..779c786 100644
--- a/pkg/handler/static/handler.go
+++ b/pkg/handler/static/handler.go
@@ -1,6 +1,8 @@
 package static
 
 import (
+	"fmt"
+	"io"
 	"io/fs"
 	"mime"
 	"net/http"
@@ -8,6 +10,9 @@ import (
 
 	"git.gabrielgio.me/cerrado/pkg/ext"
 	"git.gabrielgio.me/cerrado/static"
+	"github.com/alecthomas/chroma/v2"
+	"github.com/alecthomas/chroma/v2/formatters/html"
+	"github.com/alecthomas/chroma/v2/styles"
 )
 
 func ServeStaticHandler() (ext.ErrorRequestHandler, error) {
@@ -28,3 +33,47 @@ func ServeStaticHandler() (ext.ErrorRequestHandler, error) {
 		return nil
 	}, nil
 }
+
+func ServeStaticCSSHandler(lightTheme, darkTheme string) (ext.ErrorRequestHandler, error) {
+	var (
+		lightStyle = styles.Get(lightTheme)
+		darkStyle  = styles.Get(darkTheme)
+		formatter  = html.New(
+			html.WithCSSComments(false),
+		)
+	)
+
+	return func(w http.ResponseWriter, r *ext.Request) error {
+		ext.SetMIME(w, "text/css")
+
+		var style *chroma.Style
+		style = darkStyle
+		w.Write([]byte("[data-bs-theme=\"dark\"] {\n"))
+		err := formatter.WriteCSS(&ws{w}, style)
+		if err != nil {
+			return err
+		}
+		w.Write([]byte("}\n"))
+
+		style = lightStyle
+		w.Write([]byte("[data-bs-theme=\"light\"] {\n"))
+		err = formatter.WriteCSS(&ws{w}, style)
+		if err != nil {
+			return err
+		}
+		w.Write([]byte("\n}"))
+
+		return nil
+	}, nil
+}
+
+type ws struct {
+	inner io.Writer
+}
+
+// This is very cursed, and rely on the fact that it writes every css rule at time.
+// it adds & to the begging so it can be nested by the ServeStaticCSSHandler.
+// This will allow the follow bootstrap data-bs-theme.
+func (w *ws) Write(p []byte) (n int, err error) {
+	return fmt.Fprintf(w.inner, "& %s", string(p))
+}
-- 
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