chore: doc_src: build method detection util

build.gradle

@@ -531,6 +531,12 @@ tasks.register('webManual', Sync) {
     }
 }
 
+providers.exec {
+    ignoreExitValue = true
+    commandLine ["doc_src/detect_build_method"]
+}
+def docMethod = exe.result.get() == 0 ? exe.standardOutput.asText.get().trim() : ''
+
 ext.manualIndexXmls = fileTree(dir: 'doc_src', include: '**/OmegaTUsersManual_xinclude full.xml')
 manualIndexXmls.each { xml ->
     def lang = xml.parentFile.name
@@ -539,10 +545,7 @@ manualIndexXmls.each { xml ->
         inputs.files fileTree(dir: "doc_src/${lang}", includes: ['**/*.xml', 'images/*.png'],
                 excludes: ['xhtml5/*', 'index.xml'])
         outputs.files layout.buildDirectory.file("docs/pdfs/OmegaT_documentation_${lang}.PDF")
-        onlyIf {
-            conditions([exePresent('docker') || exePresent('nerdctl'), 'Docker or nerdctl is not installed'],
-                    [!project.hasProperty('forceSkipDocumentBuild'), 'Specified forceSkipDocumentBuild property'])
-        }
+        onlyIf {project.hasProperty('publish') || !project.hasProperty('forceSkipDocumentBuild')}
         workingDir = 'doc_src'
         commandLine './docgen', "-Dlanguage=${lang}", "-Dtarget=../build/docs/pdfs", 'pdf'
         doLast {

doc_src/build.xml

@@ -27,6 +27,66 @@
 
     <include file="../../doc_src_paths.xml"/>
 
+    <!-- Check DocBook XSL Stylesheets -->
+    <property name="libxml2.version" value="2.12.4" />
+    <target name="check-docbook-stylesheets">
+        <condition property="docbook.stylesheets.available">
+            <and>
+                <available file="${dbk}/docbook.xsl" />
+                <available file="${dbk}/fo/docbook.xsl" />
+                <greater
+                    arg1="1.79.2"
+                    arg2="1.79.2" />
+            </and>
+        </condition>
+        <fail message="DocBook XSL Stylesheets not found or incorrect version. Please install v1.79.2 or above."
+              unless="docbook.stylesheets.available" />
+    </target>
+
+    <!-- Check DocBook XML -->
+    <target name="check-docbook-xml">
+        <condition property="docbook.xml.available">
+            <available file="../../docbook-utf8.xsl" />
+        </condition>
+        <fail message="DocBook XML 4.5 not found at ${docbook.xml.dir}. Please ensure it is installed."
+              unless="docbook.xml.available" />
+    </target>
+
+    <!-- Check libxml2 -->
+    <target name="check-libxml2">
+        <exec executable="xml2-config" outputproperty="libxml2.detected.version">
+            <arg value="--version" />
+        </exec>
+        <condition property="libxml2.version.correct">
+            <greater arg1="${libxml2.detected.version}" arg2="${libxml2.version}" />
+        </condition>
+        <fail message="libxml2 version ${libxml2.version} or higher is required. Detected: ${libxml2.detected.version}"
+              unless="libxml2.version.correct" />
+    </target>
+
+    <!-- Check Saxon -->
+    <target name="check-saxon">
+        <condition property="saxon.available">
+            <available file="${saxon}" />
+        </condition>
+        <fail message="Saxon 6-5-5 not found in ${saxon}. Please ensure it is installed."
+              unless="saxon.available" />
+    </target>
+
+    <!-- Check XMLmind Web Help Compiler -->
+    <target name="check-whc">
+        <condition property="whc.available">
+            <available file="${whc}" />
+        </condition>
+        <fail message="XMLmind Web Help Compiler 3.5_1 not found at ${whc}. Please ensure it is installed."
+              unless="whc.available" />
+    </target>
+
+    <!-- Composite check for all dependencies -->
+    <target name="check-dependencies" depends="check-docbook-stylesheets, check-docbook-xml, check-libxml2, check-saxon, check-whc">
+        <echo message="All dependencies are satisfied." />
+    </target>
+
     <target name="include">
         <exec executable="xmllint"
               dir="." >

doc_src/detect_build_method

@@ -0,0 +1,21 @@
+#!/usr/bin/bash
+
+## RESULT
+METHOD="container"
+
+## Detect container runtime and cli
+CMD="$(type -p docker)" && $CMD info >/dev/null 2>&1 || CMD="$(type -p nerdctl)"
+if [ "$CMD" == "" ]; then
+  METHOD="ant"
+else
+  $CMD info > /dev/null 2>&1 || METHOD="ant"
+fi
+
+## Detect ant, and dependencies
+if [ "$METHOD" == "ant" ]; then
+  CMD="$(type -p ant)"
+  if [ "$CMD" != "" ]; then
+    $CMD check-dependencies >> /dev/null 2>&1 || METHOD=""
+  fi
+fi
+echo $METHOD