Allow showing by author

src/main/kotlin/com/alecstrong/conway/main.kt

@@ -14,17 +14,20 @@ fun main(vararg args: String) {
   ConwayCli().main(args.toList())
 }
 
-internal class ConwayCli: CliktCommand(name = "conway") {
-  val folder by option("-D",
+internal class ConwayCli : CliktCommand(name = "conway") {
+  val folder by option("--folders",
       help = "Input directories <directory1>,<directory2>").split(",")
+  val author by option("--author", help = "alias to search by")
   val since: String? by option("--since")
 
-  private val inFolderCommits = mutableMapOf<String, Int>()
-  private val allCommits = mutableMapOf<String, Int>()
-
   private fun InputStream.forCommits(body: (email: String, changed: Int, file: String) -> Unit) {
     InputStreamReader(this).useLines { sequence ->
       val iterator = sequence.iterator()
+
+      if (!iterator.hasNext()) {
+        echo("There were no commits for the given arguments", err = true)
+        return
+      }
       iterator.next() // Skip initial newline
 
       while (iterator.hasNext()) {
@@ -48,13 +51,19 @@ internal class ConwayCli: CliktCommand(name = "conway") {
     }
   }
 
-  override fun run() {
-    val since = if (since == null) "" else "--since=\"$since\""
+  private fun contributionsByFolders(folders: List<String>) {
+    val inFolderCommits = mutableMapOf<String, Int>()
+    val allCommits = mutableMapOf<String, Int>()
+
+    val args = mutableListOf("git", "log", "--numstat")
+    if (since != null) {
+      args.add("--since=\"$since\"")
+    }
+    args.add("--no-merges")
+    args.add("--pretty=%n%ae")
 
-    Runtime.getRuntime().exec(
-        arrayOf("git", "log", "--numstat", since, "--no-merges",
-            "--pretty=%n%ae")).inputStream.forCommits { email, changed, file ->
-      if (folder!!.any { file.startsWith(it) }) {
+    Runtime.getRuntime().exec(args.toTypedArray()).inputStream.forCommits { email, changed, file ->
+      if (folders.any { file.startsWith(it) }) {
         inFolderCommits[email] = inFolderCommits.getOrDefault(email, 0) + changed
       }
       allCommits[email] = allCommits.getOrDefault(email, 0) + changed
@@ -95,6 +104,54 @@ internal class ConwayCli: CliktCommand(name = "conway") {
         }
   }
 
+  private fun contributionsByAuthor(author: String) {
+    val folderCommits = mutableMapOf<String, Long>()
+
+    val folders = folder ?: listOf("") //default to root
+
+    val args = mutableListOf("git", "log", "--numstat", "--author", author)
+    if (since != null) {
+      args.add("--since=\"$since\"")
+    }
+    args.add("--no-merges")
+    args.add("--pretty=%n%ae")
+
+    echo("Finding folders with 1% or greater contributions for $author")
+
+    Runtime.getRuntime().exec(args.toTypedArray()).inputStream.forCommits { _, changed, file ->
+      val folder = folders.firstOrNull { file.startsWith(it) } ?: return@forCommits
+      val nextLevelDirectory = file.substringAfter(folder).trim('/').substringBefore('/')
+
+      folderCommits[nextLevelDirectory] = folderCommits.getOrDefault(nextLevelDirectory, 0) + changed
+    }
+
+    val totalChanges = folderCommits.values.sum()
+
+    folderCommits.mapNotNull { (folder, changes) ->
+      val percentageInFolder = changes
+          .toBigDecimal()
+          .multiply(BigDecimal.valueOf(100))
+          .divide(totalChanges.toBigDecimal(), 2, RoundingMode.HALF_UP)
+
+      return@mapNotNull if (percentageInFolder >= BigDecimal.valueOf(1)) {
+        folder to percentageInFolder
+      } else {
+        null
+      }
+    }.sortedByDescending { it.second }
+        .forEach { (folder, changes) ->
+          echo("$author writes ${changes.toPlainString()}% of their code in $folder")
+        }
+  }
+
+  override fun run() {
+    if (author != null) {
+      contributionsByAuthor(author!!)
+    } else if (folder != null) {
+      contributionsByFolders(folder!!)
+    }
+  }
+
   private data class Contribution(
     val author: String,
     val percentageInFolder: BigDecimal,