feat: Change log DSL

src/functionalTest/kotlin/git/semver/plugin/gradle/GitSemverPluginFunctionalTest.kt

@@ -119,33 +119,11 @@ class GitSemverPluginFunctionalTest {
                   createReleaseCommit = true
 //                  changeLogFormat = ChangeLogFormat.scopeChangeLog
                   changeLogFormat {
-                        appendLine("# My changelog").appendLine()
-
-                        withBreakingChanges {
-                            appendLine("## Breaking changes")
-                            format {
-                                "- ${'$'}{fullHeader()}"
-                            }
-                            appendLine()
-                        }
-                        withType("fix") {
-                            appendLine("## Bug Fixes")
-                            format {
-                                "- ${'$'}{scope()}${'$'}{header()}"
-                            }
-                            appendLine()
-                        }
-                        withType("feat") {
-                            appendLine("## Features")
-                            format {
-                                "- ${'$'}{scope()}${'$'}{header()}"
-                            }
-                            appendLine()
-                        }
+                        appendLine("# Test changelog").appendLine()
                         withType("test") {
                             appendLine("## Test")
-                            format {
-                                "- ${'$'}{scope()}${'$'}{header()}"
+                            formatChanges {
+                                appendLine("- ${'$'}{scope()}${'$'}{header()}")
                             }
                             appendLine()
                         }

src/main/kotlin/git/semver/plugin/changelog/ChangeLogBuilder.kt

@@ -0,0 +1,127 @@
+package git.semver.plugin.changelog
+
+import java.util.*
+
+open class ChangeLogBuilder(
+    val groupKey: String? = null,
+    private val commitInfos: List<ChangeLogFormat.CommitInfo>,
+    private val context: ChangeLogFormat.Context
+) : DocumentBuilder() {
+
+    fun formatChanges(block: ChangeLogTextFormatter.() -> Unit) {
+        for (commitInfo in commitInfos()) {
+            val formatter = ChangeLogTextFormatter(commitInfo)
+            formatter.block()
+            appendLine(formatter.build())
+            context.flagCommit(commitInfo)
+        }
+    }
+
+    fun skip() {
+        for (commitInfo in commitInfos()) {
+            context.flagCommit(commitInfo)
+        }
+    }
+
+    //<editor-fold desc="filter">
+    fun withBreakingChanges(block: ChangeLogBuilder.() -> Unit) {
+        with({ it.isBreaking }, "!", block)
+    }
+
+    fun withScope(vararg scopes: String, block: ChangeLogBuilder.() -> Unit) {
+        for (scope in scopes) {
+            with({ it.scope == scope }, scope, block)
+        }
+    }
+
+    fun withType(vararg types: String, block: ChangeLogBuilder.() -> Unit) {
+        for (type in types) {
+            with({ it.type == type }, type, block)
+        }
+    }
+
+    fun otherwise(block: ChangeLogBuilder.() -> Unit) {
+        with({ true }, block)
+    }
+
+    fun with(filter: (ChangeLogFormat.CommitInfo) -> Boolean, block: ChangeLogBuilder.() -> Unit) =
+        with(filter, null, block)
+
+    fun with(
+        filter: (ChangeLogFormat.CommitInfo) -> Boolean,
+        key: String?,
+        block: ChangeLogBuilder.() -> Unit
+    ) {
+        val filteredCommits = commitInfos().filter(filter)
+        if (filteredCommits.isNotEmpty()) {
+            val builder = ChangeLogBuilder(key, filteredCommits, context)
+            builder.block()
+            append(builder.build())
+        }
+    }
+    //</editor-fold>
+
+    //<editor-fold desc="grouping">
+    fun groupByScope(block: ChangeLogBuilder.() -> Unit) {
+        groupBySorted({ it.scope }, block)
+    }
+
+    fun groupByType(block: ChangeLogBuilder.() -> Unit) {
+        groupBySorted({ it.type }, block)
+    }
+
+    fun groupBy(keySelector: (ChangeLogFormat.CommitInfo) -> String?, block: ChangeLogBuilder.() -> Unit) {
+        processGroups(commitInfos().mapNotNull { keyMapper(keySelector, it) }
+            .groupBy({ it.first }, { it.second }), block)
+    }
+
+    fun groupBySorted(
+        keySelector: (ChangeLogFormat.CommitInfo) -> String?,
+        block: ChangeLogBuilder.() -> Unit
+    ) {
+        processGroups(commitInfos().mapNotNull { keyMapper(keySelector, it) }
+            .groupByTo(TreeMap(), { it.first }, { it.second }), block)
+    }
+
+    private fun keyMapper(
+        keySelector: (ChangeLogFormat.CommitInfo) -> String?,
+        it: ChangeLogFormat.CommitInfo
+    ): Pair<String, ChangeLogFormat.CommitInfo>? {
+        return (keySelector(it) ?: return null) to it
+    }
+
+    private fun processGroups(
+        groupedByScope: Map<String, List<ChangeLogFormat.CommitInfo>>,
+        block: ChangeLogBuilder.() -> Unit
+    ) {
+        for ((key, scopeCommits) in groupedByScope.filterKeys { it.isNotEmpty() }) {
+            val builder = ChangeLogBuilder(key, scopeCommits, context)
+            block(builder)
+            append(builder.build())
+        }
+    }
+    //</editor-fold>
+
+    private fun commitInfos() = commitInfos.filter { !context.isCommitFlagged(it) }
+}
+
+class ChangeLogTextFormatter(
+    private val commitInfo: ChangeLogFormat.CommitInfo
+) : DocumentBuilder() {
+    fun header() = (commitInfo.message ?: commitInfo.text).lineSequence().first()
+
+    fun body() = commitInfo.text.lineSequence()
+        .drop(1)
+        .dropWhile { it.isEmpty() }
+        .takeWhile { it.isNotEmpty() }
+
+    fun fullHeader() = commitInfo.text.lineSequence().first()
+
+    fun scope(format: String = "%s: ") = commitInfo.scope?.let { format.format(it) }.orEmpty()
+    fun type(format: String = "%s: ") = commitInfo.type?.let { format.format(it) }.orEmpty()
+
+    fun hash(format: String = "%s", len: Int = 40) =
+        commits().joinToString(" ", "", " ") { format.format(it.sha.take(len)) }
+
+    fun commits() = commitInfo.commits
+}