Support selecting theme on the footer (#35741)

Fixes: https://github.com/go-gitea/gitea/pull/27576

services/context/context.go

@@ -103,7 +103,7 @@ func GetValidateContext(req *http.Request) (ctx *ValidateContext) {
 }
 
 func NewTemplateContextForWeb(ctx *Context) TemplateContext {
-	tmplCtx := NewTemplateContext(ctx)
+	tmplCtx := NewTemplateContext(ctx, ctx.Req)
 	tmplCtx["Locale"] = ctx.Base.Locale
 	tmplCtx["AvatarUtils"] = templates.NewAvatarUtils(ctx)
 	tmplCtx["RenderUtils"] = templates.NewRenderUtils(ctx)

services/context/context_template.go

@@ -5,13 +5,16 @@ package context
 
 import (
 	"context"
+	"net/http"
 	"time"
+
+	"code.gitea.io/gitea/services/webtheme"
 )
 
 var _ context.Context = TemplateContext(nil)
 
-func NewTemplateContext(ctx context.Context) TemplateContext {
-	return TemplateContext{"_ctx": ctx}
+func NewTemplateContext(ctx context.Context, req *http.Request) TemplateContext {
+	return TemplateContext{"_ctx": ctx, "_req": req}
 }
 
 func (c TemplateContext) parentContext() context.Context {
@@ -33,3 +36,19 @@ func (c TemplateContext) Err() error {
 func (c TemplateContext) Value(key any) any {
 	return c.parentContext().Value(key)
 }
+
+func (c TemplateContext) CurrentWebTheme() *webtheme.ThemeMetaInfo {
+	req := c["_req"].(*http.Request)
+	var themeName string
+	if webCtx := GetWebContext(c); webCtx != nil {
+		if webCtx.Doer != nil {
+			themeName = webCtx.Doer.Theme
+		}
+	}
+	if themeName == "" {
+		if cookieTheme, _ := req.Cookie("gitea_theme"); cookieTheme != nil {
+			themeName = cookieTheme.Value
+		}
+	}
+	return webtheme.GuaranteeGetThemeMetaInfo(themeName)
+}

services/webtheme/webtheme.go

@@ -17,9 +17,9 @@ import (
 )
 
 var (
-	availableThemes             []*ThemeMetaInfo
-	availableThemeInternalNames container.Set[string]
-	themeOnce                   sync.Once
+	availableThemes   []*ThemeMetaInfo
+	availableThemeMap map[string]*ThemeMetaInfo
+	themeOnce         sync.Once
 )
 
 const (
@@ -28,9 +28,25 @@ const (
 )
 
 type ThemeMetaInfo struct {
-	FileName     string
-	InternalName string
-	DisplayName  string
+	FileName       string
+	InternalName   string
+	DisplayName    string
+	ColorblindType string
+	ColorScheme    string
+}
+
+func (info *ThemeMetaInfo) GetDescription() string {
+	if info.ColorblindType == "red-green" {
+		return "Red-green colorblind friendly"
+	}
+	return ""
+}
+
+func (info *ThemeMetaInfo) GetExtraIconName() string {
+	if info.ColorblindType == "red-green" {
+		return "gitea-colorblind-redgreen"
+	}
+	return ""
 }
 
 func parseThemeMetaInfoToMap(cssContent string) map[string]string {
@@ -54,7 +70,7 @@ func parseThemeMetaInfoToMap(cssContent string) map[string]string {
 |('(\\'|[^'])*')
 |([^'";]+)
 )
-\s*;
+\s*;?
 \s*
 )
 `
@@ -102,17 +118,19 @@ func parseThemeMetaInfo(fileName, cssContent string) *ThemeMetaInfo {
 		return themeInfo
 	}
 	themeInfo.DisplayName = m["--theme-display-name"]
+	themeInfo.ColorblindType = m["--theme-colorblind-type"]
+	themeInfo.ColorScheme = m["--theme-color-scheme"]
 	return themeInfo
 }
 
 func initThemes() {
 	availableThemes = nil
 	defer func() {
-		availableThemeInternalNames = container.Set[string]{}
+		availableThemeMap = map[string]*ThemeMetaInfo{}
 		for _, theme := range availableThemes {
-			availableThemeInternalNames.Add(theme.InternalName)
+			availableThemeMap[theme.InternalName] = theme
 		}
-		if !availableThemeInternalNames.Contains(setting.UI.DefaultTheme) {
+		if availableThemeMap[setting.UI.DefaultTheme] == nil {
 			setting.LogStartupProblem(1, log.ERROR, "Default theme %q is not available, please correct the '[ui].DEFAULT_THEME' setting in the config file", setting.UI.DefaultTheme)
 		}
 	}()
@@ -147,6 +165,9 @@ func initThemes() {
 		if availableThemes[i].InternalName == setting.UI.DefaultTheme {
 			return true
 		}
+		if availableThemes[i].ColorblindType != availableThemes[j].ColorblindType {
+			return availableThemes[i].ColorblindType < availableThemes[j].ColorblindType
+		}
 		return availableThemes[i].DisplayName < availableThemes[j].DisplayName
 	})
 	if len(availableThemes) == 0 {
@@ -160,7 +181,21 @@ func GetAvailableThemes() []*ThemeMetaInfo {
 	return availableThemes
 }
 
-func IsThemeAvailable(internalName string) bool {
+func GetThemeMetaInfo(internalName string) *ThemeMetaInfo {
 	themeOnce.Do(initThemes)
-	return availableThemeInternalNames.Contains(internalName)
+	return availableThemeMap[internalName]
+}
+
+// GuaranteeGetThemeMetaInfo guarantees to return a non-nil ThemeMetaInfo,
+// to simplify the caller's logic, especially for templates.
+// There are already enough warnings messages if the default theme is not available.
+func GuaranteeGetThemeMetaInfo(internalName string) *ThemeMetaInfo {
+	info := GetThemeMetaInfo(internalName)
+	if info == nil {
+		info = GetThemeMetaInfo(setting.UI.DefaultTheme)
+	}
+	if info == nil {
+		info = &ThemeMetaInfo{DisplayName: "unavailable", InternalName: "unavailable", FileName: "unavailable"}
+	}
+	return info
 }

services/webtheme/webtheme_test.go

@@ -34,4 +34,10 @@ gitea-theme-meta-info {
 	--k2: real;
 }`)
 	assert.Equal(t, map[string]string{"--k2": "real"}, m)
+
+	// compressed CSS, no trailing semicolon
+	m = parseThemeMetaInfoToMap(`gitea-theme-meta-info{--k1:"v1"}`)
+	assert.Equal(t, map[string]string{"--k1": "v1"}, m)
+	m = parseThemeMetaInfoToMap(`gitea-theme-meta-info{--k1:"v1";--k2:"v2"}`)
+	assert.Equal(t, map[string]string{"--k1": "v1", "--k2": "v2"}, m)
 }