From 67b332108d7bdabe872c3e2386c8f9365375cccb Mon Sep 17 00:00:00 2001
From: Daniel <845765@qq.com>
Date: Mon, 20 May 2024 11:47:58 +0800
Subject: [PATCH] :art: Use real theme style value replace var in preview mode
 https://github.com/siyuan-note/siyuan/issues/11458

---
 kernel/go.mod          |   2 +
 kernel/go.sum          |   4 ++
 kernel/model/export.go |   5 ++
 kernel/model/theme.go  | 127 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 138 insertions(+)
 create mode 100644 kernel/model/theme.go

diff --git a/kernel/go.mod b/kernel/go.mod
index 505ba7e06..27bcec2d9 100644
--- a/kernel/go.mod
+++ b/kernel/go.mod
@@ -33,6 +33,7 @@ require (
 	github.com/go-ole/go-ole v1.3.0
 	github.com/goccy/go-json v0.10.2
 	github.com/gofrs/flock v0.8.1
+	github.com/gorilla/css v1.0.0
 	github.com/gorilla/websocket v1.5.1
 	github.com/imroc/req/v3 v3.43.5
 	github.com/jinzhu/copier v0.4.0
@@ -60,6 +61,7 @@ require (
 	github.com/spf13/cast v1.6.0
 	github.com/steambap/captcha v1.4.1
 	github.com/studio-b12/gowebdav v0.9.0
+	github.com/vanng822/css v1.0.1
 	github.com/vmihailenco/msgpack/v5 v5.4.1
 	github.com/xrash/smetrics v0.0.0-20240312152122-5f08fbb34913
 	github.com/xuri/excelize/v2 v2.8.1
diff --git a/kernel/go.sum b/kernel/go.sum
index 2c8930aaf..b7659b4ad 100644
--- a/kernel/go.sum
+++ b/kernel/go.sum
@@ -171,6 +171,8 @@ github.com/gopherjs/gopherjs v1.17.2 h1:fQnZVsXk8uxXIStYb0N4bGk7jeyTalG/wsZjQ25d
 github.com/gopherjs/gopherjs v1.17.2/go.mod h1:pRRIvn/QzFLrKfvEz3qUuEhtE/zLCWfreZ6J5gM2i+k=
 github.com/gorilla/context v1.1.2 h1:WRkNAv2uoa03QNIc1A6u4O7DAGMUVoopZhkiXWA2V1o=
 github.com/gorilla/context v1.1.2/go.mod h1:KDPwT9i/MeWHiLl90fuTgrt4/wPcv75vFAZLaOOcbxM=
+github.com/gorilla/css v1.0.0 h1:BQqNyPTi50JCFMTw/b67hByjMVXZRwGha6wxVGkeihY=
+github.com/gorilla/css v1.0.0/go.mod h1:Dn721qIggHpt4+EFCcTLTU/vk5ySda2ReITrtgBl60c=
 github.com/gorilla/securecookie v1.1.2 h1:YCIWL56dvtr73r6715mJs5ZvhtnY73hBvEF8kXD8ePA=
 github.com/gorilla/securecookie v1.1.2/go.mod h1:NfCASbcHqRSY+3a8tlWJwsQap2VX5pwzwo4h3eOamfo=
 github.com/gorilla/sessions v1.2.2 h1:lqzMYz6bOfvn2WriPUjNByzeXIlVzURcPmgMczkmTjY=
@@ -402,6 +404,8 @@ github.com/twitchyliquid64/golang-asm v0.15.1/go.mod h1:a1lVb/DtPvCB8fslRZhAngC2
 github.com/ugorji/go/codec v1.2.12 h1:9LC83zGrHhuUA9l16C9AHXAqEV/2wBQ4nkvumAE65EE=
 github.com/ugorji/go/codec v1.2.12/go.mod h1:UNopzCgEMSXjBc6AOMqYvWC1ktqTAfzJZUZgYf6w6lg=
 github.com/ulikunitz/xz v0.5.6/go.mod h1:2bypXElzHzzJZwzH67Y6wb67pO62Rzfn7BSiF4ABRW8=
+github.com/vanng822/css v1.0.1 h1:10yiXc4e8NI8ldU6mSrWmSWMuyWgPr9DZ63RSlsgDw8=
+github.com/vanng822/css v1.0.1/go.mod h1:tcnB1voG49QhCrwq1W0w5hhGasvOg+VQp9i9H1rCM1w=
 github.com/vmihailenco/msgpack/v5 v5.4.1 h1:cQriyiUvjTwOHg8QZaPihLWeRAAVoCpE00IUPn0Bjt8=
 github.com/vmihailenco/msgpack/v5 v5.4.1/go.mod h1:GaZTsDaehaPpQVyxrf5mtQlH+pc21PIudVV/E3rRQok=
 github.com/vmihailenco/tagparser/v2 v2.0.0 h1:y09buUbR+b5aycVFQs/g70pqKVZNBmxwAhO7/IwNM9g=
diff --git a/kernel/model/export.go b/kernel/model/export.go
index 8a3d4d8c7..b64add327 100644
--- a/kernel/model/export.go
+++ b/kernel/model/export.go
@@ -878,9 +878,14 @@ func ExportHTML(id, savePath string, pdf, image, keepFold, merge bool) (name, do
 	luteEngine.SetFootnotes(true)
 	luteEngine.RenderOptions.ProtyleContenteditable = false
 	luteEngine.SetProtyleMarkNetImg(false)
+
 	// 不进行安全过滤，因为导出时需要保留所有的 HTML 标签
 	// 使用属性 `data-export-html` 导出时 `<style></style>` 标签丢失 https://github.com/siyuan-note/siyuan/issues/6228
 	luteEngine.SetSanitize(false)
+
+	// 使用实际主题样式值替换样式变量 Use real theme style value replace var in preview mode https://github.com/siyuan-note/siyuan/issues/11458
+	fillThemeStyleVar(tree)
+
 	renderer := render.NewProtyleExportRenderer(tree, luteEngine.RenderOptions)
 	dom = gulu.Str.FromBytes(renderer.Render())
 	return
diff --git a/kernel/model/theme.go b/kernel/model/theme.go
new file mode 100644
index 000000000..fdccbdb15
--- /dev/null
+++ b/kernel/model/theme.go
@@ -0,0 +1,127 @@
+// SiYuan - Refactor your thinking
+// Copyright (c) 2020-present, b3log.org
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package model
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/88250/lute/ast"
+	"github.com/88250/lute/parse"
+	"github.com/gorilla/css/scanner"
+	"github.com/siyuan-note/logging"
+	"github.com/siyuan-note/siyuan/kernel/util"
+	"github.com/vanng822/css"
+)
+
+func fillThemeStyleVar(tree *parse.Tree) {
+	themeStyles := getThemeStyleVar(Conf.Appearance.ThemeLight)
+	if 1 > len(themeStyles) {
+		return
+	}
+
+	ast.Walk(tree.Root, func(n *ast.Node, entering bool) ast.WalkStatus {
+		if !entering {
+			return ast.WalkContinue
+		}
+
+		for _, ial := range n.KramdownIAL {
+			if "style" != ial[0] {
+				continue
+			}
+
+			styleSheet := css.Parse(ial[1])
+			buf := bytes.Buffer{}
+			for _, r := range styleSheet.GetCSSRuleList() {
+				styles := getStyleVarName(r.Style.Selector)
+				for style, name := range styles {
+					buf.WriteString(style)
+					buf.WriteString(": ")
+					value := themeStyles[name]
+					if "" == value {
+						// 回退为变量
+						buf.WriteString("var(")
+						buf.WriteString(name)
+						buf.WriteString(")")
+					} else {
+						buf.WriteString(value)
+					}
+					buf.WriteString("; ")
+				}
+			}
+			if 0 < buf.Len() {
+				ial[1] = strings.TrimSpace(buf.String())
+			}
+		}
+		return ast.WalkContinue
+	})
+}
+
+func getStyleVarName(value *css.CSSValue) (ret map[string]string) {
+	ret = map[string]string{}
+
+	var start, end int
+	var style, name string
+	for i, t := range value.Tokens {
+		if scanner.TokenIdent == t.Type && 0 == start {
+			style = strings.TrimSpace(t.Value)
+			continue
+		}
+
+		if scanner.TokenFunction == t.Type && "var(" == t.Value {
+			start = i
+			continue
+		}
+		if scanner.TokenChar == t.Type && ")" == t.Value {
+			end = i
+
+			if 0 < start && 0 < end {
+				for _, tt := range value.Tokens[start+1 : end] {
+					name += tt.Value
+				}
+				name = strings.TrimSpace(name)
+			}
+			start, end = 0, 0
+			ret[style] = name
+			style, name = "", ""
+		}
+	}
+	return
+}
+
+func getThemeStyleVar(theme string) (ret map[string]string) {
+	ret = map[string]string{}
+
+	data, err := os.ReadFile(filepath.Join(util.ThemesPath, theme, "theme.css"))
+	if nil != err {
+		logging.LogErrorf("read theme [%s] css file failed: %s", theme, err)
+		return
+	}
+
+	styleSheet := css.Parse(string(data))
+	for _, rule := range styleSheet.GetCSSRuleList() {
+		for _, style := range rule.Style.Styles {
+			ret[style.Property] = strings.TrimSpace(style.Value.Text())
+			// 如果两个短横线开头 CSS 解析器有问题，--b3-theme-primary: #3575f0; 会被解析为 -b3-theme-primary:- #3575f0
+			// 这里两种解析都放到结果中
+			ret["-"+style.Property] = strings.TrimSpace(strings.TrimPrefix(style.Value.Text(), "-"))
+		}
+	}
+	return
+}