Iris/gradle/modded-version-sources.gradle

import groovy.json.JsonSlurper

List<String> sourceOverlays = (List<String>) irisModTarget.overlays
List<File> adapterSourceRoots = [projectDir, file('../modded-common'), file('../client-common')]

tasks.named('compileTestJava', JavaCompile).configure {
    options.release.set((int) irisModTarget.java)
}
tasks.withType(Test).configureEach {
    javaLauncher.set(javaToolchains.launcherFor {
        languageVersion = JavaLanguageVersion.of((int) irisModTarget.java)
    })
}

Closure<List<File>> overlayDirectories = { File adapter, String kind ->
    sourceOverlays.collect { String overlay -> new File(adapter, "src/versions/${overlay}/${kind}") }
}
Closure<Integer> overlayOrigin = { List<File> overlays, String path ->
    for (int index = overlays.size() - 1; index >= 0; index--) {
        if (new File(overlays.get(index), path).isFile()) {
            return index
        }
    }
    return -1
}

['java', 'resources'].each { String kind ->
    if (!adapterSourceRoots.any { File adapter -> overlayDirectories(adapter, kind).any { File directory -> directory.isDirectory() } }) {
        return
    }
    TaskProvider<Sync> prepareSources = tasks.register("prepareVersion${kind.capitalize()}", Sync) {
        adapterSourceRoots.each { File adapter ->
            List<File> overlays = overlayDirectories(adapter, kind)
            from(new File(adapter, "src/main/${kind}")) {
                exclude { FileTreeElement entry -> overlayOrigin(overlays, entry.path) >= 0 }
            }
            overlays.eachWithIndex { File overlay, int index ->
                from(overlay) {
                    exclude { FileTreeElement entry -> !entry.directory && overlayOrigin(overlays, entry.path) != index }
                }
            }
        }
        includeEmptyDirs = false
        into(layout.buildDirectory.dir("generated/sources/iris/${kind}"))
    }
    Set<File> replacedRoots = adapterSourceRoots.collect { File adapter ->
        new File(adapter, "src/main/${kind}").canonicalFile
    }.toSet()
    List<Object> retainedRoots = sourceSets.main."${kind}".srcDirs.findAll { File source ->
        !replacedRoots.contains(source.canonicalFile)
    }.toList()
    sourceSets.main."${kind}".setSrcDirs(retainedRoots + [prepareSources])
    tasks.named('verifyLoggingPolicy').configure { dependsOn(prepareSources) }
    tasks.named('verifyNativeBoundary').configure { dependsOn(prepareSources) }
}

List<File> testRulesFiles = sourceOverlays.collect { String overlay ->
    file("../modded-common/src/versions/${overlay}/test/source-replacements.json")
}
boolean testOverlays = testRulesFiles.any { File rules -> rules.isFile() } || adapterSourceRoots.any { File adapter ->
    overlayDirectories(adapter, 'test/java').any { File directory -> directory.isDirectory() }
}
if (testOverlays) {
    List<Map<String, Object>> testRules = testRulesFiles.collect { File rules ->
        rules.isFile() ? (Map<String, Object>) new JsonSlurper().parse(rules) : [:]
    }
    TaskProvider<Sync> prepareTests = tasks.register('prepareVersionTests', Sync) {
        testRulesFiles.findAll { File rules -> rules.isFile() }.each { File rules -> inputs.file(rules) }
        adapterSourceRoots.each { File adapter ->
            List<File> overlays = overlayDirectories(adapter, 'test/java')
            from(new File(adapter, 'src/test/java')) {
                exclude { FileTreeElement entry -> overlayOrigin(overlays, entry.path) >= 0 }
            }
            overlays.eachWithIndex { File overlay, int index ->
                from(overlay) {
                    exclude { FileTreeElement entry -> !entry.directory && overlayOrigin(overlays, entry.path) != index }
                }
            }
        }
        includeEmptyDirs = false
        into(layout.buildDirectory.dir('generated/sources/iris/test'))
        doLast {
            project.fileTree(destinationDir).matching { include('**/*.java') }.each { File source ->
                String path = destinationDir.toPath().relativize(source.toPath()).toString().replace(File.separator, '/')
                int origin = adapterSourceRoots.collect { File adapter ->
                    overlayOrigin(overlayDirectories(adapter, 'test/java'), path)
                }.max()
                String content = source.getText('UTF-8')
                String rewritten = content
                for (int index = origin + 1; index < testRules.size(); index++) {
                    Map<String, Object> replacements = testRules.get(index)
                    List<Map<String, String>> rules = (List<Map<String, String>>) (replacements.get('global') ?: [])
                    Map<String, List<Map<String, String>>> fileRules = (Map<String, List<Map<String, String>>>) (replacements.get('files') ?: [:])
                    for (Map<String, String> rule : rules + (fileRules.get(path) ?: [])) {
                        rewritten = rewritten.replaceAll(rule.pattern, rule.replacement)
                    }
                }
                if (content != rewritten) {
                    source.setText(rewritten, 'UTF-8')
                }
            }
        }
    }
    sourceSets.test.java.setSrcDirs([prepareTests])
}